Perhaps you should try some spelling variations:
thien van » thi van
lam truc » lam truoc, nam truc, lam thuoc
hieu van » hieu va, lieu va, hieu ve
truc va » thuc va, thuc vat, trung va
tinh va » tich va, trinh van, trinh vat
tinh vi » trinh vi, tinh voi, dinh vi
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet

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