Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
nang mai » nang ma, nang tai, lang mai
duc van » duc va, duc tan, duc manh
cau duc » cao duc, cau luc, chu duc
hieu ve » hieu va, hieu van
te sach » toc sach
mai hoi » mai khoi, dai hoi, lai hoi
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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: ((thu sach) or (te sach)) y nang mai hoi. ((hieu ve) or (lieu va)) cau duc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (te sach)) y nang mai hoi. ((hieu ve) OR (lieu va)) cau duc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (te sach)) y nang mai hoi. ((hieu ve) or (lieu va)) cau duc van hanh vi cua tre*.