国家哲学社会科学文献中心
美国化学会
可按段落或句子搜索文献
PubMed® comprises more than 33 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full text content from PubMed Central and publisher web sites.
图像检索
More than 200 mio. scientfic documents from more than 8000 content providers. BASE is one of the world's most voluminous search engines for academic web resources.
OA期刊文献检索系统
Δ