Perhaps you should try some spelling variations:
sanh nganh » anh ngan, dang nganh, sach ngan
nganh cong » nhanh chong, thanh cong
cong khi » cong thai, khong khi, co khi
nha khoa » nhi khoa, da khoa, bia khoa
nhan hoa » nhan khoa, phan hoa, thanh hoa
so sanh » do sanh
su sach » so sach, vu sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( so sanh nganh cong khi đong luc ) or ( su sach ((nha khoa) or (nhan hoa)) khi đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sanh nganh cong khi đong luc ) OR ( su sach ((nha khoa) OR (nhan hoa)) khi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (( so sanh nganh cong khi đong luc ) or ( su sach ((nha khoa) or (nhan hoa)) khi đong luc ))*.