Perhaps you should try some spelling variations:
nghien cua » nghien cuu, nghiep cua, nghiep vua
dac thanh » dao thanh, duc thanh, bac thanh
toc sach » hoc sach, doc sach, thuoc sach
sach hoc » cach hoc, sach hoi, mach hoc
cong dac » cong tac, cong dan, cong cac
cong doc » chong doc, cong coc, cong dot
van nhan » van phan, van thanh, danh nhan
va nhan » ca nhan, va phan, va nha
doc xa » duoc xa, hoc xa, do xa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach hoc tap, nghien cua cong dac thanh cong doc xa hoi ((va nhan) or (van nhan)) van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach hoc tap, nghien cua cong dac thanh cong doc xa hoi ((va nhan) OR (van nhan)) van.
• Adding a wildcard symbol may retrieve word variants: toc sach hoc tap, nghien cua cong dac thanh cong doc xa hoi ((va nhan) or (van nhan)) van*.