Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
nghien cac » nghiep cach, nghien cuu, nghiep cay
sach hoc » cach hoc, sach hoi, mach hoc
cac cong » cua cong
cong hoc » dong hoc, cong hoa, cong coc
hoc toan » hoc tan, hop toan, hoa toan
khoa hoc » hoa hoc
dan nhan » danh nhan, van nhan, ban nhan
dan chan » dan gian, dan ca, van chat
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: thuoc sach hoc tap, nghien cac cong hoc toan khoa hoc xa hoi ((dan nhan) or (dan chan)) van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach hoc tap, nghien cac cong hoc toan khoa hoc xa hoi ((dan nhan) OR (dan chan)) van.
• Adding a wildcard symbol may retrieve word variants: thuoc sach hoc tap, nghien cac cong hoc toan khoa hoc xa hoi ((dan nhan) or (dan chan)) van*.