Perhaps you should try some spelling variations:
cach thoi » cac thoi, cach thuc, cach noi
hoc doanh » hoa doanh, hoc danh, hoc dan
doanh hoa » doanh khoa, doanh hoan, danh hoa
thoi tap » toi tap, hoc tap, thoi dai
cuu long » cuu cong, cuu tong, cuu nang
long hoc » dong hoc, long soc, long thuoc
nhan dan » phan dau, nhan tai
gian dan » gian lang
su cach » su sach, tu cach, su cac
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: su cach thoi tap, nghien cuu long hoc doanh hoa hoc mai hoi va ((nhan dan) or (gian dan))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su cach thoi tap, nghien cuu long hoc doanh hoa hoc mai hoi va ((nhan dan) OR (gian dan)).
• Adding a wildcard symbol may retrieve word variants: su cach thoi tap, nghien cuu long hoc doanh hoa hoc mai hoi va ((nhan dan) or (gian dan))*.