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
cuu tre » cua tre, cau treo
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
va cam » va cham, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((nang x) or (lang xa)) hoi. hieu va cam duc van hanh vi ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang x) OR (lang xa)) hoi. hieu va cam duc van hanh vi ((cuu tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang x) or (lang xa)) hoi. hieu va cam duc van hanh vi ((cuu tre) or (cau tren))*.