Perhaps you should try some spelling variations:
lam thuoc » nam thuoc, am thuc, cay thuoc
cau treo » cau theo, cau tren, cau triet
manh hai » lanh hai, minh hai, thanh hai
lam thuc » am thuc, nam thuc, dam thuc
sach hay » sach han, sach ha, sach nay
hieu van » hieu va, thien van, lieu va
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
va manh » van manh, va danh, va hanh
hai cau » hai chau, hai chu, hai hau
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: su ((sach hay) or (sach ty)) nang ma hoi. hieu van ((lam thuc) OR (lam thuoc)) va manh hai cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach hay) OR (sach ty)) nang ma hoi. hieu van ((lam thuc) OR (lam thuoc)) va manh hai cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach hay) or (sach ty)) nang ma hoi. hieu van ((lam thuc) OR (lam thuoc)) va manh hai cau treo".
• Adding a wildcard symbol may retrieve word variants: su ((sach hay) or (sach ty)) nang ma hoi. hieu van ((lam thuc) OR (lam thuoc)) va manh hai cau treo*.