Perhaps you should try some spelling variations:
dau truc » cau truc, dai truc, doan truc
tu sach » thu sach, su sach, tu cach
te sach » toc sach
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
cu tren » tu tren, dua tren
vi cu » vi su, vi xu, vi du

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 (te sach)) ky nang xa hoi. ((hieu va) or (lieu va)) dau truc va hanh vi cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky nang xa hoi. ((hieu va) OR (lieu va)) dau truc va hanh vi cu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (te sach)) ky nang xa hoi. ((hieu va) or (lieu va)) dau truc va hanh vi cu tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (te sach)) ky nang xa hoi. ((hieu va) or (lieu va)) dau truc va hanh vi cu tren*.