Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
cac doanh » cac dan, cac dang, van doanh
doanh hoa » doanh khoa, doanh hoan, danh hoa
thu mach » thu sach, thuat mach, thu hoach
mach hoc » cach hoc, dich hoc, anh hoc
cong cac » cuong cac, cong tac, cong cau
cau nhan » chau nhan, ca nhan, cu nhan
nhan van » nhan dan, nhan va, phan van
xa khoa » da khoa, bia khoa, tai khoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu mach hoc tap, nghien thu cong cac doanh hoa hoc ((xa khoa) or (ma hoa)) cau nhan van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu mach hoc tap, nghien thu cong cac doanh hoa hoc ((xa khoa) OR (ma hoa)) cau nhan van.
• Adding a wildcard symbol may retrieve word variants: thu mach hoc tap, nghien thu cong cac doanh hoa hoc ((xa khoa) or (ma hoa)) cau nhan van*.