Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua triet
soc van » hoc van, oc van, sac van
tu sach » thu sach, su sach, te sach
hieu vu » hieu ve, hieu su, dieu vu
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua

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