Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
san khoa » toan khoa, hang khoa, da khoa
khoa hoc » hoa hoc
phan dan » phan dang, phan dau, nhan dan
cuu mon » cuu mo, cuu mot, cuu cong
mon hoc » toan hoc, dong hoc
hoc san » hoc dan, toc san, hoc can
va phan » van phan, va phat, va phap
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: ((toc sach) or (doc sach)) hoc tap, nghien cuu mon hoc san khoa hoc xa hoi va phan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) hoc tap, nghien cuu mon hoc san khoa hoc xa hoi va phan dan.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) hoc tap, nghien cuu mon hoc san khoa hoc xa hoi va phan dan*.