Perhaps you should try some spelling variations:
tu sach » thu sach, te sach, tu cach
va hanh » van hanh, va thanh, va danh
cau luc » cau truc, cau phuc
hieu va » lieu va, hieu qua
hieu ve » hieu van
cuu tre » cua tre, cau tren, cau treo
nang xa » nang x, lang xa, nang ma
su sach » so sach, vu sach
y nang » ky nang, ly nang, v nang
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) OR (su sach)) y nang xa hoi. ((hieu ve) or (hieu va)) cau luc va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) y nang xa hoi. ((hieu ve) OR (hieu va)) cau luc va hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) y nang xa hoi. ((hieu ve) or (hieu va)) cau luc va hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) y nang xa hoi. ((hieu ve) or (hieu va)) cau luc va hanh vi cuu tre*.