二蓿

是一个提供数百万PNG图片素材的站点，帮助设计师们找到最想要的设计素材。Pngtree provides free download of png, png images, backgrounds and vector. Millions of high quality free png images, PSD, AI and EPS Files are available.

提供国内若干免费学术期刊的开放存取。

目前已提供613种专业期刊、20万篇论文全文供读者免费阅览。

集期刊浏览、期刊检索两种功能为一体的开放式的期刊集成揭示与检索系统。

收录台大各学术研究单位出版之中外学术期刊论文篇目与全文。

参考CiteScore系统、泉方学术、GoPubMed等整合开发平台。

查询检索功能、电子全文链接及期刊国内馆藏查询功能。外文期刊文章基本检索

是一个旨在为用户提供OA资源检索和全文链接服务的公共服务平台。

收录的OA期刊数量非常多，属于目前最好的的OA期刊目录网站。DOAJ is a community-curated online directory that indexes and provides access to high quality, open access, peer-reviewed journals.

Open Access Library (www.oalib.com) is an academic search engine and publisher. You can download research papers for free and submit your paper to it. It is a shared academic database.

数字图书馆。搜索书籍。免费下载书籍 | BookSC. Download books for free. Find books

这里有63000+ 的无版权真实照片，网站鼓励众多摄影者们坚持每天拍摄。365 Project is a photography challenge. Take one photo a day to discover and express yourself and improve your daily life.