Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
hoc sach » hoc sinh, hoc cac, hoc anh
cau tren » cu tren, dau tren, ca tren
ky tang » ky nang, ky dang, kho tang
hieu ha » hieu hoa, hieu va, hieu ca
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan tai, dan vat
ky lang » ky nang, ky dang, tay lang
va dan » ca dan, va dao, va dau
ha am » hoa am, ha nam, ha lam

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((ky lang) OR (ky tang)) xa hoi. hieu ha am thuc va dan vai ((cau triet) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((ky lang) OR (ky tang)) xa hoi. hieu ha am thuc va dan vai ((cau triet) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((ky lang) OR (ky tang)) xa hoi. hieu ha am thuc va dan vai ((cau triet) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((ky lang) OR (ky tang)) xa hoi. hieu ha am thuc va dan vai ((cau triet) or (cau tren))*.