Perhaps you should try some spelling variations:
khong thuoc » khang thuoc, hong phuoc, dong thuoc
nghien huu » nghien cuu, nguyen huu, nhiem huu
khoa nhanh » khoan thanh, hoc nhanh, khoa hinh
khong hoc » khung hoc, thong hoc, khong chuc
sach doi » sach hoi, sach moi, sach dao
huu toan » huu tuan, cuu toan, huy toan
van nhan » van phan, van thanh, danh nhan
nhan dan » phan dau, gian dan, nhan tai
tu sach » thu sach, su sach, te sach
doi tap » doi tac, doi dap, doi tai
hoi van » hoi va, hoi dan, hai van

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach doi tap, nghien huu toan khoa nhanh ((khong hoc) or (khong thuoc)) xa hoi van nhan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach doi tap, nghien huu toan khoa nhanh ((khong hoc) OR (khong thuoc)) xa hoi van nhan dan.
• Adding a wildcard symbol may retrieve word variants: tu sach doi tap, nghien huu toan khoa nhanh ((khong hoc) or (khong thuoc)) xa hoi van nhan dan*.