Perhaps you should try some spelling variations:
sach tien » sach tren, sach thieu
sac tinh » dac tinh, cac tinh, sat tinh
tinh cao » tinh chat, tinh cach, tinh giao
cao khoa » lao khoa, bao khoa, cac khoa
khoa hoc » hoa hoc
tinh lao » dinh lam, tinh nam, tinh va
lao kha » lao khoa, bao kha, cao kha
kha hoc » nha hoc, kha hoa, khi hoc
so sach » so sanh, bo sach, co sach
tien da » tien dam, tien dat, tien dua
tu sac » tu sach, tu cac, tu san
te sac » te sach, te cac, te san

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((( tu sac tinh cao khoa hoc ) or ( te sac tinh lao kha hoc ))) or ( so sach tien da khoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( tu sac tinh cao khoa hoc ) OR ( te sac tinh lao kha hoc ))) OR ( so sach tien da khoa hoc )).
• Adding a wildcard symbol may retrieve word variants: (((( tu sac tinh cao khoa hoc ) or ( te sac tinh lao kha hoc ))) or ( so sach tien da khoa hoc ))*.