Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
qua van » quan van, qua ban, qua san
nam qua » nam quan, nam cua, nam mua
hieu va » hieu qua
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
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 y ((nang xa) or (nang ma)) hoi. ((hieu va) OR (lieu va)) nam qua van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (nang ma)) hoi. ((hieu va) OR (lieu va)) nam qua van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) or (nang ma)) hoi. ((hieu va) OR (lieu va)) nam qua van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (nang ma)) hoi. ((hieu va) OR (lieu va)) nam qua van hanh vi cua tre*.