Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
cam luc » cam xuc, cau luc
cuu tre » cua tre, cau tren, cau treo
hieu ve » hieu va
mai hoi » mai khoi, dai hoi, lai hoi
ky tang » ky nang, ky dang, kho tang
ky lang » ky nang, ky dang, tay lang
luc va » duc va, tuc va, loc va
vi cuu » vi luu, vinh cuu

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 ((ky lang) or (ky tang)) mai hoi. ((hieu ve) or (hieu van)) cam luc va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky tang)) mai hoi. ((hieu ve) OR (hieu van)) cam luc va hanh vi cuu tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) or (ky tang)) mai hoi. ((hieu ve) or (hieu van)) cam luc va hanh vi cuu tre*.