Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
tho lang » thon lang, cho lang, tho nang
thi hang » thi hanh, thi nang, thi hong
nam tuc » nam thuc, nam truc, nam tu
va danh » va dan, va hanh, dia danh
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet

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 ((tho lang) or (thi hang)) xa hoi. hieu van nam tuc ((va danh) OR (va dinh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((tho lang) OR (thi hang)) xa hoi. hieu van nam tuc ((va danh) OR (va dinh)) dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((tho lang) or (thi hang)) xa hoi. hieu van nam tuc ((va danh) OR (va dinh)) dai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ((tho lang) or (thi hang)) xa hoi. hieu van nam tuc ((va danh) OR (va dinh)) dai cua tre*.