Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
nganh xay » nganh mac, nganh y, nganh ma
nang xay » dang xay, nang xuan, nang cao
tu sach » thu sach, su sach, te sach
van huy » van duy, van hung
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
sach ky » sac ky, sach y, sach ty
huy tre » huy tri, luy tre, huy tran
xuc va » tuc va, luc va, xac va

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 ky ((nang xay) or (nganh xay)) hoi. hieu ve chat ((xuc va) OR (duc va)) thanh van huy tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xay) OR (nganh xay)) hoi. hieu ve chat ((xuc va) OR (duc va)) thanh van huy tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xay) or (nganh xay)) hoi. hieu ve chat ((xuc va) OR (duc va)) thanh van huy tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xay) or (nganh xay)) hoi. hieu ve chat ((xuc va) OR (duc va)) thanh van huy tre*.