Perhaps you should try some spelling variations:
sach trinh » sach tranh, hanh trinh, sach kinh
trinh thuc » trinh tu, trinh thi
hoat khong » hoa khong, hoac khong, hoat dong
thuoc sach » hoc sach, nuoc sach, thuat sach
thuc sach » thu sach, thuc cach, thuat sach
dao thuoc » cao thuoc, tao thuoc, dang thuoc
sach khoa » bach khoa, sach nha, anh khoa
pho thong » he thong
sach chi » sach che, sach nha, sach bai
chi hoat » che hoat, chi hoa, phi hoat
sach dao » lanh dao
khoa pho » khoa phu, khoa khoa, khoa phau
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: (( tu sach trinh thuc sach chi hoat khong ) or ( tu sach dao thuoc sach khoa pho thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach trinh thuc sach chi hoat khong ) OR ( tu sach dao thuoc sach khoa pho thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach trinh thuc sach chi hoat khong ) or ( tu sach dao thuoc sach khoa pho thong ))*.