Perhaps you should try some spelling variations:
sach tien » sach tren, sach thieu
tien chai » tieng thai, tien khi, trien chi
chai khoa » thai khoa, chi khoa, pham khoa
khien cho » khien hoc, hiem cho, khien cua
khoa hoc » hoa hoc
dien cho » dien khoa, trien cho, dien hoa
tu sach » thu sach, su sach, te sach
tu mach » tu cach, tu manh, tu hach

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 tien chai khoa hoc ) or ( tu mach ((khien cho) or (dien cho)) khoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tien chai khoa hoc ) OR ( tu mach ((khien cho) OR (dien cho)) khoa hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tien chai khoa hoc ) or ( tu mach ((khien cho) or (dien cho)) khoa hoc ))*.