Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
doanh van » doan van, doanh va, doanh ban
viec cac » vien cac, viec cua, viec lam
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
van cuu » van cau, van chu, van cu
cuu tre » cua tre, cau tren, cau treo

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 ma) OR (sang ma)) hoi. hieu viec cac ((vo van) or (le van)) doanh van cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang ma) OR (sang ma)) hoi. hieu viec cac ((vo van) OR (le van)) doanh van cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang ma) OR (sang ma)) hoi. hieu viec cac ((vo van) or (le van)) doanh van cuu tre*".