Perhaps you should try some spelling variations:
vien cach » vien bach, vien cac, vien canh
hieu vien » hieu hien, hieu viec, thieu nien
cach thuc » anh thuc, cac thu
duy sang » duy van, duy can, duy anh
hanh lai » hanh lam, hanh tai, thanh lap
va hanh » van hanh, va thanh, va danh
cua tre » cuu tre, cua triet, dua tren
tu sach » thu sach, su sach, te sach
thuc va » thuc vat, thuc dan, thuc day
ma hoi » mai hoi, xa hoi, ma hoa
cua te » cua tu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((duy sang) OR (ky nang)) ma hoi. hieu vien cach thuc va hanh lai ((cua tre) OR (cua te))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((duy sang) or (ky nang)) ma hoi. hieu vien cach thuc va hanh lai ((cua tre) OR (cua te))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ((duy sang) or (ky nang)) ma hoi. hieu vien cach thuc va hanh lai ((cua tre) OR (cua te))*.