Perhaps you should try some spelling variations:
thien van » thi van
hieu van » hieu va, lieu va, hieu ve
tinh voi » trinh voi, tinh doi, binh voi
thuc va » thuc vat, thuc dan, thuc day
voi cua » hoi cua, doi cua, moi cua
tu sach » thu sach, su sach, te sach
truc va » thuc vat, trung va
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) OR (thuc va)) tinh voi 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) OR (thuc va)) tinh voi 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) OR (thuc va)) tinh voi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. ((hieu van) or (thien van)) lam ((truc va) OR (thuc va)) tinh voi cua tre*.