Every book in the library has a unique call number that indicates where it is shelved. Just as a house address tells where exactly a house is located on a street, a call number tells us where exactly on the shelves we can expect to find a book. Call numbers at Owen Library and the University Library System are arranged according to the Library of Congress Classification scheme (LCC). LCC is an alphanumeric scheme, i.e., it uses both letters and numbers.

For example:

HA
1625
.O87
1999

LCC numbers are read from top to bottom.

Look for the letters first, on the top line: HA. Read in alphabetical order, A-Z.

Then look at the whole number on the next line: 1625. Read in numeric order, 1-9999.

Then look at the letter(s) after the dot: O. Again, read in alphabetical order.

Then look at the decimal number: 87. Hint: read left to right numerically; nothing comes before something.

Last, you will see the year the book was published: 1999. Earliest date (or no date) comes first, if the rest of the call number is identical.

DON'T FORGET: Read the number before the . (dot) as a whole number. Read the number after the . (dot) as a decimal. So .A52 comes before .A6.

The four books above are in the correct order.

The complete list of classes & subclasses and the subjects they reperesent is available in the Library of Congress Classification outline. 

PittCat is the gateway searching tool for all of the materials owned by the University Library system (ULS), including articles, books, e-books, journals, e-journals, e-audio and e-video, digital images, government documents, microfilm and movies.

PittCat 就像一个网关搜索工具，囊括了匹大图书馆的所有资源，包括纸本书，电子书，期刊，电子期刊，视听资料，数字影像，政府出版物，缩微出版物，电影, 等等。

数据库为用户提供各种可供搜索的在线资源，是搜索文章的最佳选择之一。这是因为，匹大图书馆系统提供的各种数据库涵盖了丰富的，高质量的学术研究信息 (scholarly research information)，而这正是大多数教授所要的。我们的大部分数据库都提供全文的链接，你可以在线浏览全文。如需搜索数据库：

• 如果你知道想使用的数据库的名字，你可以直接在 Databases A-Z 里找到你需要的数据库。
• 如果你不确定你需要使用哪个数据库，你可以按照 Subject 浏览数据库，或者询问图书馆员。你可以选择亲自询问，致电(814) 269-7300咨询，或者通过 Ask-A-Librarian 在线咨询。

This page adapted from a guide authored by Marian Hampton from Hillman Library at University of Pittsburgh.

These databases are excellent starting points for your research because they have something on every subject:

Owen Library's Food & Drink Policy asks that no food be consumed anywhere in the Library and permits beverages that are in covered containers. Please help us ensure that our collections remain in good condition and will be available for future users by complying with this policy and applying the lessons found in the following video:

• 你知道如何使用PittCat吗？
• 你知道如何选择检索的关键词，在检索时有哪些技巧吗？
• 你知道什么是索书号（call number），如何使用索书号吗？
• 你知道如何获取电子/在线期刊、报纸、杂志吗？
• 你知道有哪些常用的数据库吗？

请浏览：

Once you have narrowed down your topic and come up with the research question your paper will explore, identify the main concepts in your query. Use these concepts as your search terms (i.e., keywords).

See examples below:

How does domestic violence affect children?                                

Compose your search:

domestic violence and children

How else might you compose your search?

family violence and children 

Does providing employment opportunitites to ex-prisoners reduce the risk they will re-offend? (= recidivism).

ex-prisoners and employment and recidivism

ex-convicts and  employment and recidivism

Perhaps broaden the search to find more about recidivism in general:

recidivism

recidivism and causes