Perhaps you should try some spelling variations:
chu tren » cu tren, cau tren, chu trang
danh hai » dang hai, lanh hai, manh hai
cam thuc » nam thuc, cam thu, can thuc
hieu van » hieu va, thien van, lieu va
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
sach ly » sach y, sach lo, sach hay
va danh » va dinh, va dan, va hanh
hai chu » hai chau, hoi chu, hai chi
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 ly) or (sach ty)) nang ma hoi. hieu van ((cam thuc) or (am thuc)) va danh hai chu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ly) OR (sach ty)) nang ma hoi. hieu van ((cam thuc) OR (am thuc)) va danh hai chu tren.
• Adding a wildcard symbol may retrieve word variants: su ((sach ly) or (sach ty)) nang ma hoi. hieu van ((cam thuc) or (am thuc)) va danh hai chu tren*.