Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, te sach, tu cach
qua van » quan van, qua ban, qua san
nam qua » nam quan, nam cua, nam mua
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
su sach » so sach, vu sach
va nam » van nam, ha nam, va nay
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: ((tu sach) or (su sach)) ky ((nang x) or (nang ma)) hoi. hieu va nam qua van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky ((nang x) OR (nang ma)) hoi. hieu va nam qua van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky ((nang x) or (nang ma)) hoi. hieu va nam qua van hanh vi cua tre*.