Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hanh tai, anh thai
hinh thai » sinh thai, tinh thai, dinh thi
nang cai » nang cao, nang cap, nang can
nang tai » hang tai, tang tai, sang tai
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
van lam » van nam
lam luc » lao luc, lam duoc
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va

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