Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
va danh » va dinh, va dan, va hanh
van hac » van hoc, van ha, van hai
hac tuc » thac toc, thai tuc
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
cua tre » cua te, cuu tre, cua triet
va anh » van anh, va hanh, va banh
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((ky lang) or (ky dang)) xa hoi. hieu van hac tuc ((va anh) OR (va danh)) va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky lang) OR (ky dang)) xa hoi. hieu van hac tuc ((va anh) OR (va danh)) va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ky lang) or (ky dang)) xa hoi. hieu van hac tuc ((va anh) OR (va danh)) va cua tre*".