Perhaps you should try some spelling variations:
tang mai » tang ma, tang tai, lang mai
va hanh » van hanh, va thanh, va danh
cau duc » cao duc, cau luc, chu duc
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
tu sach » thu sach, su sach, tu cach
te sach » toc sach
cua tre » cua te, cuu tre, cua triet
v tang » 6 tang, 7 tang, 5 tang
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: ((tu sach) or (te sach)) v tang mai hoi. ((hieu ve) or (lieu va)) cau duc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) v tang mai hoi. ((hieu ve) OR (lieu va)) cau duc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) v tang mai hoi. ((hieu ve) or (lieu va)) cau duc va hanh vi cua tre*.