Perhaps you should try some spelling variations:
sach trien » sach tien, sach tren, sach thieu
trien khai » trien nha
chan khoa » nhan khoa, chai khoa, chat khoa
khai khoa » thai khoa, chai khoa, khat khoa
toc sach » hoc sach, doc sach, thuoc sach
sach xin » sach kinh, sach tien, sach xa
xin chan » dan chan, ban chan, can chan
khoa hoc » hoa hoc
tu sach » thu sach, su sach, te sach

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 xin chan khoa hoc ) or ( tu sach trien khai khoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( toc sach xin chan khoa hoc ) OR ( tu sach trien khai khoa hoc )).
• Adding a wildcard symbol may retrieve word variants: (( toc sach xin chan khoa hoc ) or ( tu sach trien khai khoa hoc ))*.