These Library of Congress Subject Headings can be searched directly (MERLIN Subject Search) or added to a keyword search.
Note: Doing a MERLIN Keyword Search on taois* will find items containing the word Taoism, Taoist or Taoists, but not items containing the word Tao. However, a search for tao* will produce hits containing Taos, New Mexico, which you do not want. Try keyword searches like this: (taois* or tao) and heal* to find works on taoist perspectives on health and healing.
Chinese sounds are not quite the same as English sounds, so there is more than one way to write Chinese words in English (or "Romanize") them. The Wade-Giles Romanization system says, "Tao Te Ching," while the Hanyu Pinyin more commonly used today says, "Daodejing," for example.
This table from the Library of Congress shows how different sounds look in different systems. http://www.loc.gov/catdir/pinyin/romcover.html#7
Another table, from the University of California-Irvine showing just Wade-Giles and Pinyin: http://oclccjk.lib.uci.edu/pytowg.htm
This online Chinese Romanization Converter lets you type one English version of a Chinese word, and it will show you what the other common English version of that word is, so you can try searching things under that spelling, too.