Perhaps you should try some spelling variations:
sach hoc » cach hoc, sach hoi, mach hoc
cuu cong » cua cong, thu cong, cac cong
cong hoc » dong hoc, cong hoa, cong coc
san khoa » toan khoa, hang khoa, da khoa
tu sach » thu sach, su sach, te sach
hoc san » hoc dan, toc san, hoc can
va nhan » van nhan, ca nhan, va phan
nhan va » nhan tai, nhan dan, nhan tao

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 hoc tap, nghien cuu cong hoc san khoa ((hoc xa) or (hoc ma)) hoi va nhan va~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoc tap, nghien cuu cong hoc san khoa ((hoc xa) OR (hoc ma)) hoi va nhan va.
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien cuu cong hoc san khoa ((hoc xa) or (hoc ma)) hoi va nhan va*.