you head over to http://www.sciencedirect.com.
They have hundreds of thousands of articles in thousands of journals
on any field in science including Physical Sciences and Engineering,
Life Sciences, Health Sciences and Social Sciences and Humanities.
The following subjects are included under Physical Sciences and
Engineering
* Chemical Engineering
* Chemistry
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* Engineering
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* Mathematics
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and the following can be found under Life Sciences
* Agricultural and Biological Sciences
* Biochemistry, Genetics and Molecular Biology
* Environmental Science
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* Neuroscience