Perhaps you should try some spelling variations:
kien thuoc » kien thuc, bien thuoc, trien thuoc
hoc chuyen » khong chuyen
thuoc sach » hoc sach, nuoc sach, thuat sach
xuong doan » xuong dan, xuong hoan, phuong doan
sach tien » sach tren, sach thieu
xuong san » xuong song, cong san, dong san
tien hoc » tin hoc, tien hoa, dien hoc
sach kho » bach khoa, sach dao, sach nha
kho khan » khoa kham, khoa than
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 tien hoc chuyen đe ky thuat: kien thuoc sach kho khan ((xuong doan) or (xuong san)) minh~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tien hoc chuyen đe ky thuat: kien thuoc sach kho khan ((xuong doan) OR (xuong san)) minh.
• Adding a wildcard symbol may retrieve word variants: tu sach tien hoc chuyen đe ky thuat: kien thuoc sach kho khan ((xuong doan) or (xuong san)) minh*.