Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thanh vi » hanh vi, thanh va, thanh ve
thu sach » tu sach, thuat sach, thuoc sach
su sach » so sach, vu sach
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, truc va, duc va
vi cua » vai cua, di cua

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

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