Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hang tai » hang va, dung tai
tai khoi » tai khoa, mai khoi, tao khoi
sach ky » sac ky, sach y, sach ty
ky hang » ky nang, ly hang, ky dang
hieu ve » hieu van
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
va danh » va dinh, va dan, va hanh
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 hang tai khoi. ((hieu ve) or (hieu va)) cau truc va danh ((de cua) or (dai cua)) vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky hang tai khoi. ((hieu ve) OR (hieu va)) cau truc va danh ((de cua) OR (dai cua)) vat.
• Adding a wildcard symbol may retrieve word variants: toc sach ky hang tai khoi. ((hieu ve) or (hieu va)) cau truc va danh ((de cua) or (dai cua)) vat*.