Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cham sat » cham mat, cham soc, khao sat
te sach » toc sach
sat van » sat va, hat van, hoat van
va cham » va chat, va tham
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
lang ha » long ha
nang ma » tang ma, sang ma, nang cao
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: te sach ky ((((nang ma) or (nang x))) or (lang ha)) hoi. hieu va cham sat van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((((nang ma) OR (nang x))) OR (lang ha)) hoi. hieu va cham sat van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ky ((((nang ma) or (nang x))) or (lang ha)) hoi. hieu va cham sat van hanh vi cua tre*.