Perhaps you should try some spelling variations:
nuoc sach » nguoi sach, hoc sach, cuoc cach
doc sach » hoc sach, toc sach, dac sac
cuu dong » cuu cong, cuu tong, cuu long
dong hoc » dong co, dong luc
hoc toan » hoc tan, hop toan, hoa toan
khoa hoc » hoa hoc
nhan dan » phan dau, gian dan, nhan tai
va nhan » van nhan, ca nhan, va phan
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: ((nuoc sach) or (doc sach)) hoc tap, nghien cuu dong hoc toan khoa hoc xa hoi va nhan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((nuoc sach) OR (doc sach)) hoc tap, nghien cuu dong hoc toan khoa hoc xa hoi va nhan dan.
• Adding a wildcard symbol may retrieve word variants: ((nuoc sach) or (doc sach)) hoc tap, nghien cuu dong hoc toan khoa hoc xa hoi va nhan dan*.