Perhaps you should try some spelling variations:
nghien huu » nghien cuu, nguyen huu, nhiem huu
doanh khoa » toan khoa
hoa doanh » toan doanh, hoa dan
sach hoc » cach hoc, mach hoc, sach duoc
sach hoi » sach doi, sach moi, cach thoi
tung hoa » trung hoa, tung ho, ung hoa
khoa hoc » hoa hoc
dan chan » dan gian, dan ca, van chat
chan tai » nhan tai, han tai, chan hai
hoi dan » hoa dan, hoc dan, hoi dap
hoc xa » hoc ma

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat ((sach hoc) or (sach hoi)) tap, nghien huu tung hoa doanh khoa hoc xa hoi dan chan tai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat ((sach hoc) OR (sach hoi)) tap, nghien huu tung hoa doanh khoa hoc xa hoi dan chan tai.
• Adding a wildcard symbol may retrieve word variants: thuat ((sach hoc) or (sach hoi)) tap, nghien huu tung hoa doanh khoa hoc xa hoi dan chan tai*.