Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
thu hang » thi hang, thuc hanh, thu huong
doan van » doan va, hoang van, luan van
hieu va » lieu va, hieu qua
va doan » va doanh, van doan, va dan
van cuu » van cau, van chu, van cu
cuu tre » cua tre, cau tren, cau treo
ca cao » ca dao, cu cao, ca cac
cao va » cao van, tao va, co va
x hoi » xa hoi, o hoi, x ho
va ca » va cac, va cao, va cai

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 (thu hang)) ky nang x hoi. hieu va ca cao va doan van cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thu hang)) ky nang x hoi. hieu va ca cao va doan van cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thu hang)) ky nang x hoi. hieu va ca cao va doan van cuu tre*.