There are two ways you can use to search Chinese materials in catalogs of libraries outside of China: searching by Chinese characters, or searching by the Pinyin transliteration. Searching by Chinese characters is self-evident--you just need to type in the characters using whatever input method you use. Searching by pinyin transliteration is somewhat tricky as it involves certain rules governing syllable spaces. So it will be extremely helpful to know some basic rules as indicated below.
In general, enter the pinyin for each Chinese character with a space.
Examples: 水力资源 shui li zi yuan, 西部开发 xi bu kai fa