Perhaps you should try some spelling variations:
cong thuoc » cong thuc, dong thuoc, cong thuong
long thuoc » luong thuoc, dong thuoc, khong thuoc
hoc nganh » hoc nhanh
cac thoi » cac toi, cac hop, cac tro
thoi tap » toi tap, hoc tap, thoi dai
cuu toan » cuu hoan, cua toan, huu toan
toan hoc » toan khoa, van hoc, hoa hoc
van nhan » van phan, van thanh, danh nhan
nhan dan » phan dau, gian dan, nhan tai
hoi van » hoi va, hoi dan, hai van
ma hoi » mai hoi, xa hoi, ma hoa

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 cuu toan hoc nganh ((cong thuoc) OR (long thuoc)) ma hoi van nhan dan~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac thoi tap, nghien cuu toan hoc nganh ((cong thuoc) OR (long thuoc)) ma hoi van nhan dan".
• Adding a wildcard symbol may retrieve word variants: tu cac thoi tap, nghien cuu toan hoc nganh ((cong thuoc) OR (long thuoc)) ma hoi van nhan dan*.