Comparison of Bibliographic Search Engines

Inspired from the responses of my post comparing free bibliographic tools, I planned on posting few more articles about other different research tools. Here I am presenting a comparison of bibliographic search engines. The next article will be on scientific document processing tools. This series of comparisons follow a general pattern in which I start with the usage of such tools, followed by setting up a set of criteria to compare on and then I compare different tools. I believe this is a reasonable choice to present these topics.

Bibliographic search engine is a general purpose research tool that contains all the research citations for one or more broad subject area(s) to which people can refer to reliably for their specific personal research. It is different from “personal bibliographic tool” in the sense that a bibliographic search engine is developed for the commons; it must be reliable for any reference it is providing, it must provide a way to export the data but it does not need to present the reference in any specific ‘visual’ or ‘presentation’ format.

The way I search for scientific articles is pretty simple. Say I have a problem to solve that was assigned by some course teachers or my research supervisor. I mark some keywords and Google for them. If I don’t find any relevant information I use combination of those keywords or use alternative keywords adapted from the search results. Once I start getting some keywords that produce relevant results in Google, I pass it to Google Scholar. Sometimes I go to some other subject specific search engines to search using those keywords.

Expected Features from a Bibliographic Search Engine

A bibliographic search engine must be accessible from each and every operating system available. For this reason all such databases are platform independent, i.e. web based.

Providing a reliable collection of references is not an easy task. Obtaining huge publication information, plugging them into the system, providing the information to the user and maintaining them periodically are all enormous amount of tasks. The data collection process may not be free. Moreover, if a search engine wants to provide soft copy of the reference along with the citation information then the search engine provider has to pay for it. For this reason many of these search engines are not free.

I tried to compile a set of features expected from a bibliographic search engine. I believe the following requirements are complete and sufficient for general purpose research.

• Areas: Number of main stream subject areas covered. For example, medical, engineering, etc.
• Search: Support for searching different data fields. For example searching for title, author, abstract, etc.
• Export: Export formats and automation
  • Format: Different formats supported. For example, BibTex, EndNote, RIS, etc.
  • Automation: Communicating through API calls or other ways from external applications
• Document: A soft copy of the document
• Cost: Cost of obtaining the service.

Comparison

Google is inserted twice in the table. This is not a typo. I think general Google search and Google Scholar search are quite different. In few cases research papers are freely available in public domains that Google Scholar may not recognize. So I consider both as different search tools.

Table 1: Comparison matrix of bibliographic search engines.

Name	Subject Area	Search	Export Format	Export Automation	Electronic Copy	Cost
Google	General	General	None	No	No	Free
Google Scholar	General	Title, Author, Publisher, Date, Area	None	No	No	Free
CiteSeer	General	General	BibTeX	May be	Yes, with exceptions	Free
ScienceDirect	General	Title, Author, Journal Name, Volume, Issue, Page	RIS, ASCII	RefWorks	Yes	Paid
IEEE Xplore	Electrical eng., Computer Sci., Electronics	General, Advanced	RIS, ASCII	May be	Yes	Paid
ACM DL	Only ACM Articles, mainly Computer Sci.	General, Advanced	BibTex, End Note, ACM Ref	May be	Yes	Paid
ACM Guide	Computer Sci.	General, Advanced	BibTex, End Note, ACM Ref	May be	Yes	Paid
CSB	Computer Sci.	General, Advanced	BibTex	No	No	Free
DBLP	Computer Sci.	General	BibTex	No	No	Free
Net Bib	Computer Sci	General	BibTex	No	No	Free
PubMed	Biomedical and LifeScience	General, Advanced	Unkn.	May be	Yes	Free
Ingenta Connect	General	General	BibTex, End Note	May be	Yes	Partially Free#
Engineering Village*	Engineering	Unkn.	Unkn.	May be	Yes	Paid
ISI Web of Knowledge*	General	Unkn.	Unkn.	Yes	Yes	Paid
arXiv*	Physics, Math, Computer Sci., Biology	General, Advanced	None	No	Yes	Free

• ^* – Submitted by Kjell Magne Fauske
• ^# – Corrected by Leigh Dodds

Like previous article I need your help here to complete this table. I am requesting more information from you.

Mid Size Search Engines

Some new generation web based bibliographic tools have been evolved that can act as search engines for a specific subject area as well as help a single person or a group of people by acting as personal bibliographic tool. The main problems of this kind of mid sized search engines are that they may be poorly maintained and may not be that much reliable. You can find names and comparison of some of these tools in my previous article.

This article is rather a simplified outline on all the bibliographic search engine available. One must however, depending on his/her specific subject area, find out which search engine best suites for him/her. Your comments on more search engines, grammatical/spelling error and writing style are most welcome.