Biology- General

bioRxiv  Preprints in biology; fast access to new discoveries before peer-reviewed publication.
 

PubMed Central (PMC) Free biomedical/life sciences articles, widely used in health & life science education.
 

PubChem  Chemical data from NIH, including structures, safety info, and biological activities.
 

PLOS Journals Peer-reviewed, fully open access science journals with high-quality biology articles.
 

arXiv (q-bio)  Preprints in quantitative biology, good for interdisciplinary modeling.
 

BMC Journals  Open access biology and medical research.