Perhaps you should try some spelling variations:
hau treo » cau treo, cau theo, dau tren
cam thuc » am thuc, nam thuc, cam thu
sach dao » lanh dao
hieu van » hieu va, thien van, lieu va
hai hau » hai chau, dai hau, hai hai
va dinh » van dinh, va kinh, va tinh
va danh » va dan, va hanh, dia danh
sach lo » sach doi, sach hoi, sach moi
nang xa » nang x, lang xa, nang ma
van cam » van nam, van lam, van cau

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 lo) OR (sach dao)) nang xa hoi. hieu van cam thuc ((va danh) or (va dinh)) hai hau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach lo) OR (sach dao)) nang xa hoi. hieu van cam thuc ((va danh) OR (va dinh)) hai hau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach lo) OR (sach dao)) nang xa hoi. hieu van cam thuc ((va danh) or (va dinh)) hai hau treo".
• Adding a wildcard symbol may retrieve word variants: su ((sach lo) OR (sach dao)) nang xa hoi. hieu van cam thuc ((va danh) or (va dinh)) hai hau treo*.