Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
ve triet » va trien, su triet
thuc dan » thuc hanh, hoc dan, thuc vat
thuc van » thuc vat, thuc va, thuc hanh
hieu ve » hieu va, hieu van
sach tu » sach thu, cach tu, sach ty
sang ma » tang ma, nang ma, sang tao
tuan ki » tuan kiet, tuan khai, tuan kien
tu sang » thu sang, tu san, tu lang
su viet » so viet
ve cam » ve cham, ve cac, va cam
ma hoi » mai hoi, xa hoi, ma hoa

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 tu sang ma hoi. hieu ve cam ((thuc van) or (thuc dan)) tuan ki ((ve triet) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach tu sang ma hoi. hieu ve cam ((thuc van) OR (thuc dan)) tuan ki ((ve triet) OR (su viet)).
• Adding a wildcard symbol may retrieve word variants: thu sach tu sang ma hoi. hieu ve cam ((thuc van) or (thuc dan)) tuan ki ((ve triet) or (su viet))*.