Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh lai » hanh lam, hanh tai, thanh lap
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va thanh, va danh
vu cham » va cham, vu kham, tu cham
sach tu » sach thu, cach tu, sach ty
tu sach » thu sach, su sach, te sach
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
hieu vu » hieu va, hieu ve, hieu su
soc va » hoc va, loc va, doc va

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 tu ((sang ma) or (nang ma)) hoi. hieu vu cham soc va hanh lai ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu ((sang ma) OR (nang ma)) hoi. hieu vu cham soc va hanh lai ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach tu ((sang ma) or (nang ma)) hoi. hieu vu cham soc va hanh lai ((cua tre) or (cau tren))*.