网站简介：Ask questions and browse existing answers from experts in various categories.
网站简介：Provides answers from finance and accounting professionals for a fee. Users can submit their question, and then accept or reject the price/deadline offer provided by an expert. Does not provide content to non-paying users.
网站简介：Oregon's Live Information Service, email or chat live with a reference librarian.
网站简介：Provides free homework help from experts to Indiana students.
网站简介：Naturalists answer questions about nature and wildlife.
网站简介：Aims to give you easy answers to everyday questions. We define words, acronyms, and ideas. We have a computer-related and open-source slant.
网站简介：Online Homework Help and Online Tutoring
网站简介：Weblog-style site that will answer questions about blogs, websites, and other things related to the internet and technology.
网站简介：Ask a question and check out the archives for the many questions asked at this site.
网站简介：Volunteer librarians and graduate students answer inquiries or provide starting places for research at the ipl2 reference center.
网站简介：Experts at the U of Hawaii answer questions about volcanoes and igneous rocks, earthquakes and seismology, natural disasters, geochemistry, the environment, pollution, hydrology and water quality, minerals, gems and crystals, geophysics, sediments and sedimentary rocks, and just plain ol' geology.
网站简介：Allows users to pay for experts, technical assistance, web searching and document delivery.
网站简介：Ask earth scientists at USGS questions about volcanoes, earthquakes, mountains, rocks, maps, ground water, lakes, or rivers through email.
网站简介：Email form for asking reference questions of Kansas City Public librarians.
网站简介：Official site.
网站简介：User-generated questions and answers, also with discussions and expert user profiles.
网站简介：Online form to submit questions to the librarians at the Kentucky Virtual Library.
网站简介：Monthly magazine of science. Website includes articles from past issues.
网站简介：Email or chat with a FIU Reference Librarian.
网站简介：Guidelines and contact information to request help from a New York State reference librarian, via telephone or email.
网站简介：Ask a Librarian email reference service for the faculty, staff and students of Auburn University.y.
网站简介：Ask questions and get help with your science fair project.
网站简介：The Free Library of Philadelphia answers reference questions via an email form and live chat.
网站简介：Ask-a-scientist service designed for K-12 teachers and their students - operated by the Argonne Nat'l. Laboratory, Div. of Educational Programs.
网站简介：Chat reference service with real-time online assistance by Houston Public Library staff as well as librarians nationwide.