Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
tu sach » thu sach, su sach, te sach
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach thu nang cao hoi. hieu va tham thuc va hanh ((dai va) or (mai va)) thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nang cao hoi. hieu va tham thuc va hanh ((dai va) OR (mai va)) thiet.
• Adding a wildcard symbol may retrieve word variants: tu sach thu nang cao hoi. hieu va tham thuc va hanh ((dai va) or (mai va)) thiet*.