Perhaps you should try some spelling variations:
dam thuc » am thuc, dan thuc, dai thuc
sach nay » sach hay, sach vay, sach nang
nam thuc » nam thuoc, am thuc, nam thu
sach tay » xach tay, sach hay, sach tai
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
ca tren » cau tren, cu tren, la tren
hieu va » lieu va, hieu qua
tang ma » mang may, tang van
vi ca » vit ca, li ca, va ca

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach tay) OR (sach nay)) tang ma hoa. hieu va ((dam thuc) or (nam thuc)) va danh vi ca tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach tay) OR (sach nay)) tang ma hoa. hieu va ((dam thuc) OR (nam thuc)) va danh vi ca tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach tay) OR (sach nay)) tang ma hoa. hieu va ((dam thuc) or (nam thuc)) va danh vi ca tren".
• Adding a wildcard symbol may retrieve word variants: te ((sach tay) OR (sach nay)) tang ma hoa. hieu va ((dam thuc) or (nam thuc)) va danh vi ca tren*.