网站 cnx.org 是在线的

Content-length 12410 Location https://openstax.org Server AmazonS3 Date Sat, 18 Oct 2025 07:26:40 GMT X-cache RefreshHit from cloudfront Via 1.1 c0d1c71355dba844bcbee0b54705b9fc.cloudfront.net (CloudFront) X-amz-cf-pop CDG50-P4 X-amz-cf-id vWPERSU0q6Qe2hQdTVcOlpFa1jmnPM9EorT_ZkrdD7urfSatmqpDWA== Age 153 Content-type text/html Last-modified Mon, 06 Oct 2025 16:00:06 GMT X-amz-version-id WwUL0LAJKuOX9S8hMYqeR_peQjoSwSH5 Cache-control public,max-age=60 Etag "3ccb178614842061287ebc963b70929f"

Viewport width=device-width,initial-scale=1,maximum-scale=5 Description OpenStax offers free college textbooks for all types of students, making education accessible & affordable for everyone. Browse our list of available subjects! Og:url https://openstax.org/ Og:type article Og:title OpenStax | Free Textbooks Online with No Catch Og:description OpenStax offers free college textbooks for all types of students, making education accessible & affordable for everyone. Browse our list of available subjects! Og:image https://images.openstax.org/apps/image-cdn/v1/assets.openstax.org/f=webp,w=640,h=480/oscms-prodcms/media/images/240919_OpenStax_Students_Martin_272.original.webp Og:image:alt OpenStax: OpenStax | Free Textbooks Online with No Catch Twitter:card summary_large_image Twitter:site @OpenStax Twitter:title OpenStax | Free Textbooks Online with No Catch Twitter:description OpenStax offers free college textbooks for all types of students, making education accessible & affordable for everyone. Browse our list of available subjects! Twitter:image https://images.openstax.org/apps/image-cdn/v1/assets.openstax.org/f=webp,w=640,h=480/oscms-prodcms/media/images/240919_OpenStax_Students_Martin_272.original.webp Twitter:image:alt OpenStax Mobile-web-app-capable yes Theme-color #fff Application-name @openstax/os-webview Apple-mobile-web-app-capable yes Apple-mobile-web-app-status-bar-style black-translucent Apple-mobile-web-app-title @openstax/os-webview Msapplication-TileColor #fff Msapplication-TileImage Msapplication-config /dist/assets/browserconfig.xml

Ranks provider OpenRank PageRank 5.71 Domain Ranking #6,821