Perhaps you should try some spelling variations:
nghiep cach » nghiep sach, nghiep cay, nghiep bac
nghien cac » nghien cuu, nghiep cay, nghiep bac
hoan thanh » hoang thanh, ban thanh, van thanh
thanh phan » thanh san, thanh toan, thanh hai
cong hoan » cong hoa, dong hoa, cong san
dan thanh » dang thanh, danh thanh, ban thanh
sach doi » sach hoi, sach moi, sach dao
tu sach » thu sach, su sach, te sach
doi tap » doi tac, doi dap, doi tai
pho hoc » phoi hoc, cho hoc, pho ho
hoi dan » hoa dan, hoc dan, hoi dap
hoc xa » hoc ma

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 doi tap, ((nghien cac) or (nghiep cach)) cong hoan thanh pho hoc xa hoi dan thanh phan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach doi tap, ((nghien cac) OR (nghiep cach)) cong hoan thanh pho hoc xa hoi dan thanh phan.
• Adding a wildcard symbol may retrieve word variants: tu sach doi tap, ((nghien cac) or (nghiep cach)) cong hoan thanh pho hoc xa hoi dan thanh phan*.