EOLSS Search Help

EOLSS provides the user with an effective and efficient tool to search, navigate and browse through each of the component Encyclopedias, through any combination of the twenty, or through the whole of EOLSS.

Please follow the procedure below:

  • Login
  • Click the Welcome note and you will be led to the Search Page. You have the possibility to search the whole EOLSS or some selected Encyclopedias from the twenty listed there.
  • Once you choose the search domain, the results will be listed under the respective encyclopedias. Go to any chapter and you will also see 'Related chapters' under the contents at the very beginning.

This 'Related Chapters' provides a list of chapters in a popup window so that the reader is given a picture of what is available in the close neighborhood of the chapter on the screen, i.e. a list of chapters presented in a thematic organization. These results are helpful in providing you with a systematic access mechanism to the body of knowledge with reference to the search term inserted at the beginning, and to indicate a program of study in gradually increasing depth and detail).

At the bottom of this list 'see also' leads to chapters in other Encyclopedias in EOLSS that may also be of interest to you.

The Table of Contents of the whole EOLSS is so large that it is not easy to browse and systematically pick chapters of interest.

The chapters are at three distinct levels. The chapter level is indicated by the color of its title.

Level 1 (Theme): A chapter at this level introduces a core subject (or a field of knowledge) to a wide audience including undergraduates and non-expert readers needing to grasp the fundamental concepts. These chapters generally avoid the use of technical jargon or complex mathematics.

Level 2 (Topic): A chapter at this level introduces a branch of the core subject (or a sub-field of knowledge) to be covered by a group of Level 3 chapters. The contributions are useful to senior undergraduate and postgraduate students as advanced study cum reference material.

Level 3 (Article): Most of the contributions in the EOLSS are at this level. These chapters cover different aspects of the sub-field in depth and contain relevant and necessary details of the established knowledge associated with it.

There are a few exceptions; the chapters in a few fields such as Regional Reviews of Sustainable Development (Brazil, China, Europe, etc.) extend to Level 2 only.

Using the Search facility:

The search engine is designed to help the user locate relevant data across the Encyclopedias. This help guide is intended to provide the user with a brief idea about the various options available through the search engine.

EOLSS - Search

The user has three options to direct the search:

  • All of the words
  • Exact phrase
  • One or More of These Words:

All of the words: This option returns  the documents which contain all the words specified by the user in the search field box. To search for documents which contain geology, physiology and geomorphology, the search option must be specified as follows.

EOLSS - Search

Exact phrase:  This option to returns documents containing a specific phrase. For example, to search for documents containing the phrase "optimal control systems", the search options must be specified as follows.

EOLSS - Search

One or More of These Words:  This option will return documents which contain any of the words specified in the search box. To search for documents which contain any of the terms geology, quaternary or geomorphology, the search option must be specified as follows.

EOLSS - Search

Searching using wildcard expressions:  Wildcard expressions may be used with any of the three search options available. A search word can contain the wildcard characters * and ?. A ? in a word matches any single character, and a * matches any number of characters. The wildcard characters can be in any position in a word.
For example:

sul*ur would match both sulfur and sulphur thus picking up both U.S. and U.K. spelling.

comput* would match compute, computer, computation, computerization etc.

paleo* would match paleobotany, paleontology, paleolithic, etc.

Rom? would match Rome and Roma, thus picking up both Italian and English spelling.

To use wildcard search with EOLSS Search, enter the wildcard search term or terms, select the desired search option and click Search. Use of the * wildcard character near the beginning of a word will slow searches and is not recommended.

For example, if the search term is specified as contr* systems and the search type is set to 'Exact phrase', the search engine will supply documents containing occurrences of the phrases control systems, controlled systems, controllable systems, etc.

Search results:

The search can be limited to a single category or multiple categories by clicking on the checkboxes. The option 'All Subject Categories' is selected by default. This option displays ten documents from each Encyclopedia in decreasing order of the number of documents retrieved in each category. At the end of each category a link is provided to retrieve all the documents from that category.

Sample result page for option 'All Subject Categories':

EOLSS - Search

The results page displays the search term along with the search type specified by the user. The table header displays the category name together with the total number of documents retrieved from the category. The documents are sorted by the 'score' of the chapter - the total number of occurrences of the search terms in the document. A truncated summary is displayed after each title.

To limit the search to a particular Encyclopedia or group of Encyclopedias, uncheck the 'All Subject Categories' option and check all the relevant Encyclopedias. The result page will contain the documents that meet the search criteria, organized into categories. The title of each document in the search results page is a hyperlink to the document. The search terms specified by the user are highlighted in the chapter.


  • It is not necessary to use 'and' or '+' to connect the search terms, as the search engine will ignore the connectors.
  • Words such as if, the, etc. are termed 'noise words' and are ignored during searches.
  • Special characters and punctuation marks must be avoided, since they will not be recognized by the search engine.