Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
nham thuc » nhan thuc, nam thuc, nham thu
thu sach » tu sach, thuoc sach, thu hoach
dinh vai » dinh van, dinh vi, dinh va
van dinh » van minh, van dich, va dinh
tang mai » tang ma, tang tai, lang mai
thuc van » thuc vat, thuc dan, thuc va
hieu ve » hieu va, hieu van
ve nham » ve nha, ve cham
mai hoi » mai khoi, dai hoi, lai hoi
ky tang » ky nang, ky dang, kho tang
cua tu » cua tuc, cua su, cua cu

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) or (thuat sach)) ky tang mai hoi. hieu ve nham thuc van dinh vai ((cua te) OR (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) ky tang mai hoi. hieu ve nham thuc van dinh vai ((cua te) OR (cua tu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thuat sach)) ky tang mai hoi. hieu ve nham thuc van dinh vai ((cua te) OR (cua tu))".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuat sach)) ky tang mai hoi. hieu ve nham thuc van dinh vai ((cua te) OR (cua tu))*.