Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
hieu van » hieu va, thien van, lieu va
manh hai » lanh hai, minh hai, thanh hai
thuc dan » thuc hanh, hoc dan, thuc vat
nang xa » nang x, lang xa, nang ma
van cam » van nam, van lam, van cau
sach ky » sach y, sach ty, sach kem
thuc va » thuc vat, thuc day
hai cau » hai chau, hai chu, hai hau
sac ky » cac ky, sai ky

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