Perhaps you should try some spelling variations:
cach khoa » bach khoa, cac khoa, cac khoan
khoa khau » khoa kham, khoa phau, khoa chau
khau tong » khau thong, khau cong, khau thuong
khong he » khong khi, hong ha, khong _
tue cach » tu cach, thuc cach, ve cach
sach tri » sach tren, sach truc, sach bai
sach tai » sach bai, sach tham, sach dao
khoa he » hoa he, khoa hoc, khoa thu
so sach » so sanh, bo sach, co sach
tu sach » thu sach, su sach, te sach
le dac » le dan, le duc
tai le » thi le, tri le, tai he
thong » trong

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( so sach tri tue cach khoa khau tong ) or ( tu sach tai le dac ((khoa he) OR (khong he)) thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach tri tue cach khoa khau tong ) OR ( tu sach tai le dac ((khoa he) OR (khong he)) thong )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( so sach tri tue cach khoa khau tong ) or ( tu sach tai le dac ((khoa he) OR (khong he)) thong ))".
• Adding a wildcard symbol may retrieve word variants: (( so sach tri tue cach khoa khau tong ) or ( tu sach tai le dac ((khoa he) OR (khong he)) thong ))*.