Perhaps you should try some spelling variations:
sach tien » sach tren, sach thieu
tien thuc » trien thuc, kien thuc, bien thuc
hanh khoa » hang khoa, anh khoa, hanh hoa
hoa khong » khoi khong, hoa cong, he khong
khoa hoa » khoa khoa, khoa hoi, kha hoa
sach dao » lanh dao
dao thuc » dan thuc, dao tuc, do thuc
thuc cac » thuc cach, tuc cac, phuc cac
cac khoa » cac khoan, cac khoi, dac khoa
khoa hoc » hoa hoc
hoc bong » hoc cong, hoc trong, hoc luong
te sach » toc sach

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach tien thuc hanh khoa hoa khong ) or ( te sach dao thuc cac khoa hoc bong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach tien thuc hanh khoa hoa khong ) OR ( te sach dao thuc cac khoa hoc bong )).
• Adding a wildcard symbol may retrieve word variants: (( te sach tien thuc hanh khoa hoa khong ) or ( te sach dao thuc cac khoa hoc bong ))*.