Perhaps you should try some spelling variations:
nghien cua » nghien cuu, nghiep cua, nghiep vua
doanh khoa » toan khoa
hoc doanh » hoa doanh, hoc danh, hoc dan
thoi dai » hoc dai, hoi dap, hoi dan
cong hoc » dong hoc, cong hoa, cong coc
khoa hoc » hoa hoc
hoa va » hoa van, hoa xa, hoa vo
va von » vay von, van von, va van

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (tu cac)) thoi dai, nghien cua cong hoc doanh khoa hoc ma hoa va von tai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (tu cac)) thoi dai, nghien cua cong hoc doanh khoa hoc ma hoa va von tai.
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (tu cac)) thoi dai, nghien cua cong hoc doanh khoa hoc ma hoa va von tai*.