Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
te sach » toc sach
thuc va » thuc vat, thuc dan, thuc day
sach ky » sac ky, sach y, sach ty
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
tuc va » truc va, tuc xa, duc va
vi cua » vai cua, di cua
o hai » co hai, so hai, o lai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang ((xa hoi) or (o hai)). hieu van cam ((tuc va) OR (thuc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((xa hoi) OR (o hai)). hieu van cam ((tuc va) OR (thuc va)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ((xa hoi) or (o hai)). hieu van cam ((tuc va) OR (thuc va)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ((xa hoi) or (o hai)). hieu van cam ((tuc va) OR (thuc va)) hanh vi cua tre*.