Perhaps you should try some spelling variations:
nghien cac » nghiep cach, nghien cuu, nghiep cay
cach thoi » cac thoi, cach thuc, cach noi
thoi tap » toi tap, hoc tap, thoi dai
cac cong » cua cong
co cach » co cac, co sach, ca cach
cong co » dong co, cong cu, cong so
co toan » co ton, so toan, cong toan
hoc hoc » hoc hoa, hoc hoi, duoc hoc
toc hoc » toan hoc, duoc hoc
va phap » va phat, ban phap
phap tu » phan tu, pham tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: co cach thoi tap, nghien cac cong co toan ((hoc hoc) or (toc hoc)) xa hoi va phap tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co cach thoi tap, nghien cac cong co toan ((hoc hoc) OR (toc hoc)) xa hoi va phap tu.
• Adding a wildcard symbol may retrieve word variants: co cach thoi tap, nghien cac cong co toan ((hoc hoc) or (toc hoc)) xa hoi va phap tu*.