Perhaps you should try some spelling variations:
nang doc » nang luc
van hang » van khang, van hoang, van thang
so sach » so sanh, bo sach, co sach
hai chu » hai chau, hoi chu, hai chi
va hang » va nang, va lang, va hanh
van hac » van hoc, van ha, van hai
van bac » van ban, van bao, dan bac
doc hai » hoc hai, duc hai, do hai
chu tre » cho tre, chu tri, cuu tre
sach 2 » sach y
2 nang » v nang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach 2 nang doc hai. thien ((van bac) or (van hac)) xuc ((va hang) OR (van hang)) hai chu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach 2 nang doc hai. thien ((van bac) OR (van hac)) xuc ((va hang) OR (van hang)) hai chu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach 2 nang doc hai. thien ((van bac) or (van hac)) xuc ((va hang) OR (van hang)) hai chu tre*".