Perhaps you should try some spelling variations:
thien van » thi van
cau tren » cu tren, dau tren, ca tren
cau treo » cau theo, cau triet, cau trieu
danh hai » dang hai, lanh hai, manh hai
cam thuc » am thuc, nam thuc, cam thu
hieu van » hieu va, lieu va, hieu ve
sach ly » sach y, sach lo, sach ty
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
hang xa » hoang xa, hang va, hang ca
ly hang » ly quang
su sach » so sach, vu sach

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