Perhaps you should try some spelling variations:
thuc van » thuc vat, thuc dan, thuc va
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
cau thuc » cau truc, cuu thuc, can thuc
tu sach » thu sach, su sach, te sach
cua tre » cuu tre, cua triet, dua tren
van cau » van dau, van hau, van chat
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (thu hoach)) ky lang xa hoi. hieu van cau thuc van hanh vai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky lang xa hoi. hieu van cau thuc van hanh vai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu hoach)) ky lang xa hoi. hieu van cau thuc van hanh vai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky lang xa hoi. hieu van cau thuc van hanh vai ((cua tre) OR (cua te))*.