Perhaps you should try some spelling variations:
sach day » sach dao, sach dat, sach dau
day nang » da nang, may nang, dai nang
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
nang va » nang van, hang va, nang ma
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
va hoi » xa hoi, va hoc, va hoa
ve cam » ve cham, ve cac, ve cai
va cam » va cham, va cac, va 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: su sach day nang va hoi. hieu ((ve cam) OR (va cam)) duc van hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach day nang va hoi. hieu ((ve cam) OR (va cam)) duc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach day nang va hoi. hieu ((ve cam) OR (va cam)) duc van hanh vi cua tre*.