Skip to Main Content

How to search: ScienceDirect Expert Searching

This guide will show you how to search in the different Unisa Library resources to find relevant information for your research needs

Request a Literature Search

Need sources for your literature review? Struggling to find sources for your assignment, research proposal or thesis?

The Library can assist with a literature search, which is a systematic and comprehensive search for published, academic material on your specific subject/topic. How do you request one? Simply go to Request a literature search .

If you are experiencing problems accessing the form, please use this link


ScienceDirect is a multidisciplinary database which

hosts authoritative, full-text scientific, technical and health publications.

It contains over 2,500 journals and more than 33,000 books

—over 13 million peer-reviewed publications (and growing).



Combining searches

When Search History is turned on, your searches  and their results are recorded in your search history, which appears below the  search form. You can combine up to five searches from your search  history at one time using the Boolean operators AND and OR.

Combining searches creates a new search which is then added to your search  history. There can be a maximum of 3,000 characters in a combined search.

To combine searches from your search history        

    1. In Search History, select the check boxes associated  with the searches you want to combine.
    2. Select the appropriate Combine with link  to run the combined search:
Combine  with AND                      Retrieves only  the documents that meet the criteria of all the selected searches.
Combine  with OR                      Retrieves documents  which meet the criteria of at least one of the selected searches.

 Example   If you have selected the following searches in search history:

(Chromosome clon!) [All Sources(Agricultural and Biological Sciences)]

(Gene splic!)[All Sources(Medicine and Dentistry)]

•Selecting Combine with AND  retrieves documents that include both "gene" with a form of the word "splice" and "chromosome" with a form of the word "clone" that were subject-classified as either Agricultural and Biological Sciences or Medicine and Dentistry, eliminating any documents that contain only one of the phrases.

•Selecting Combine with OR retrieves documents that include either "gene" with a form of the word "splice" or "chromosome" with a form of the word "clone" that were subject-classified as either Agricultural and Biological Sciences or Medicine and Dentistry

Using the Expert Search function in ScienceDirect

Expert search

With the Expert search forms, you can create more complex, sophisticated searches to search all sources, journals,   books or Reference Works. Expert search is available by first selecting the Advanced search link next to the quick search option and then selecting Expert search.  

Use Expert search to:

Connectors and proximity operators - Expert search


You can use connectors and proximity operators to specify the words you want to include or exclude  from your search results and to search for more than one word in a single  search. If you use more than one connector or operator in your search, ScienceDirect® interprets the search according to the order of precedence.

To search for a specific phrase, enclose the terms in double quotes ("  ") or, for an exact match, brackets ({}). See Searching  for Phrases for more information.

AND When AND is used, all of the terms in  your searchmust appear in the returned documents, even if the terms  are far apart from each other. 
Example   lesion AND pancreatic would only return documents  that contained both the terms lesion and pancreatic.

AND is the default connector. When you enter 2 or more search terms,  AND is automatically inserted between any spaces or hyphens in the terms.

Example   If you searched for heart attack or heart-attack  both would be searched as heart AND attack.

Use OR when at least one of your search terms must appear  in returned documents. You can use OR to search for synonyms, alternate  spellings, or abbreviations.

Example   kidney OR renal would return documents that  contained either of the terms kidney or renal.

Use AND NOT to exclude specific terms from returned documents.

Example   ganglia OR tumor AND NOT malignant would find  documents that contained the terms ganglia or tumor, but not the term  malignant.

Use W/n to specify  how far apart terms may appear in documents. W  represents "within", and n represents  the maximum number of words between the terms.

Note W/n does  not specify the word order. Either word may appear first.
Example   pain W/15 morphine would find documents that  had the terms "pain" and "morphine" within 15 words  of each other.

Use the following guidelines when choosing a number for n:

  • To find terms in the same phrase, use W/3, W/4, or  W/5.
  • To find terms in the same sentence, use W/15.
  • To find terms in the same paragraph, use W/50.

Use PRE/n to find documents in which the  first term precedes the second term within a specified number (n) of words.

Example   behavioural PRE/3 disturbances would find documents  in which behavioural precedes disturbances by three or fewer words.


Prioritizing search terms - Expert search

When you use more than one connector or proximity operator in a search, the operators are processed in a specific order. Understanding the "order of precedence" and following connector guidelines can help you create a more targeted search.

Order of Precedence

  1. OR
  2. W/n, PRE/n
  3. AND
  4. AND NOT
Example The search pain W/15 morphine AND ganglia OR tumor OR lesion is processed in the following order:
  1. OR: First, ScienceDirect® processes the OR connector by looking for documents containing "ganglia," "tumor," or "lesion."
  2. W/15: Next, it looks for documents where "pain" is within 15 words of "morphine."
  3. AND: ScienceDirect processes the AND operator last, returning any documents it found in steps 1 and 2 that contain "ganglia," "tumor," or "lesion," and also contain "pain" is within 15 words of "morphine."

Connector Guidelines

The following guidelines also apply to connectors:

  • If you use two or more of the same connector, they are processed from left to right.
  • If you use different numbers for n in the same search, the final number is used for all values of n. (If the numbers are the same, they are processed left to right.)
    Example   Entering coronary W/2 circadian W/5 rhythm, searches for coronary W/5 circadian W/5 rhythm because 5 is the last number used with a connector.
    Note   Your original search appears on the search results page.
  • Use parentheses to change the connector priority. Connectors inside parentheses have priority over, or operate before, connectors used outside parentheses. Terms in parentheses are processed in the same order that they are input.
    Example The search (morphine AND ganglia) OR tumor is processed in the following order:
    1. Articles that contain "morphine" and " ganglia" are found.
    2. Then, within those articles, articles that contain "tumor " are found.
  • Do not mix the W and PRE connectors in the same expression.
    Example bay W/6 ship PRE/0 channel is an invalid search because it uses both the W/n and PRE/n connectors.
  • Do not use the OR connector in the same expression as a W or PRE connector.
    Example bay W/6 ship OR channel is an invalid search.
  • You can use parentheses to include different operators or use OR in the same search.
    Example title-abs-key((b?y W/6 ship*) AND (ship* PRE/0 channel))

    title-abs-key((bay W/6 ship) OR channel)