Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
su sach » so sach
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
vu sach » vu bach, vu khach
ma hoi » mai hoi, xa hoi, ma hoa
va cam » va cham, va cac, va cao
y tang » ky tang, 6 tang, 7 tang
vi cua » vai cua, di cua
ve cam » ve cham, ve cac, ve cai

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 (vu sach)) y tang ma hoi. hieu ((ve cam) or (va cam)) thuc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) y tang ma hoi. hieu ((ve cam) OR (va cam)) thuc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) y tang ma hoi. hieu ((ve cam) or (va cam)) thuc van hanh vi cua tre*.