Perhaps you should try some spelling variations:
nghien cac » nghiep cach, nghien cuu, nghiep cay
doanh khoa » toan khoa
cong toan » cong tan, cong hoan, cong tuan
cac thoi » cac toi, cac hop, cac tro
thoi tap » toi tap, hoc tap, thoi dai
cac cong » cua cong
khoa hoc » hoa hoc
phan tai » pham tai, phan thi, han tai
nhan tai » hang tai, van tai, toan tai
hoc mai » hoc ma, hoc dai, hoc bai
mai hoi » mai khoi, dai hoi, lai hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cac thoi tap, nghien cac cong toan doanh khoa hoc mai hoi va ((phan tai) OR (nhan tai))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac thoi tap, nghien cac cong toan doanh khoa hoc mai hoi va ((phan tai) OR (nhan tai))".
• Adding a wildcard symbol may retrieve word variants: tu cac thoi tap, nghien cac cong toan doanh khoa hoc mai hoi va ((phan tai) OR (nhan tai))*.