Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tra nang » thi nang, kha nang, da nang
hanh dai » hanh tai, hanh dao, vanh dai
cac truc » cau truc, cac tru, cac trung
va triet » va thiet, va trien, ve triet
tu lang » cu lang, tu lanh, xu lang
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
tu nang » tru nang, tu nong, tu nano
dai va » mai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((((tu nang) or (tu lang))) or (tra nang)) xa hoi. hieu va cac truc va hanh dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((((tu nang) OR (tu lang))) OR (tra nang)) xa hoi. hieu va cac truc va hanh dai va triet.
• Adding a wildcard symbol may retrieve word variants: toc sach ((((tu nang) or (tu lang))) or (tra nang)) xa hoi. hieu va cac truc va hanh dai va triet*.