Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sang tao » hang tai
tao khoi » tao hoi, thao khoa, lao khoa
sach ky » sac ky, sach y, sach ty
truc va » thuc va, thuc vat, trung va
hieu va » lieu va, hieu qua
vai cua » dai cua, hai cua, lai cua
hieu ve » hieu van
ky sang » ky nang, ky dang, ky tang
va dan » ca dan, va dao, va dau
de cua » le cua, te cua, dieu cua

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 ky sang tao khoi. ((hieu ve) or (hieu va)) cau truc va dan ((de cua) or (vai cua)) vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky sang tao khoi. ((hieu ve) OR (hieu va)) cau truc va dan ((de cua) OR (vai cua)) vat.
• Adding a wildcard symbol may retrieve word variants: toc sach ky sang tao khoi. ((hieu ve) or (hieu va)) cau truc va dan ((de cua) or (vai cua)) vat*.