Perhaps you should try some spelling variations:
sach hoc » cach hoc, sach hoi, mach hoc
cuu long » cuu cong, cuu tong, cuu nang
long hoc » dong hoc, long soc, long thuoc
nhan dan » phan dau, nhan tai
gian dan » gian lang
vu sach » vu bach, su sach, vu khach
dan hoa » danh hoa, dan hoat, dan khoa
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: vu sach hoc tap, nghien cuu long hoc dan hoa hoc xa hoi va ((nhan dan) or (gian dan))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach hoc tap, nghien cuu long hoc dan hoa hoc xa hoi va ((nhan dan) OR (gian dan)).
• Adding a wildcard symbol may retrieve word variants: vu sach hoc tap, nghien cuu long hoc dan hoa hoc xa hoi va ((nhan dan) or (gian dan))*.