Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, te sach, tu cach
truc va » thuc vat, trung va
vai cua » dai cua, hai cua, lai cua
thuc va » thuc vat, thuc dan, thuc day
van cau » van dau, van hau, van chat
nang xa » nang x, lang xa, nang ma
su sach » so sach, vu sach
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) OR (su sach)) ky nang xa hoi. hieu van cau ((truc va) or (thuc va)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang xa hoi. hieu van cau ((truc va) OR (thuc va)) hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) ky nang xa hoi. hieu van cau ((truc va) or (thuc va)) hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) ky nang xa hoi. hieu van cau ((truc va) or (thuc va)) hanh vai cua tre*.