Perhaps you should try some spelling variations:
trien chai » trien khai, trien chi, trien nha
sach trien » sach tien, sach tren, sach thieu
chai khoa » thai khoa, chi khoa, pham khoa
chau hoa » cau hoa, chat hoa, chat khoa
te sach » toc sach
sach ha » sach nha, sach han, sach xa
ha chau » hat chau, a chau, lai chau
tu sach » thu sach, su sach, tu cach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach ha chau hoa hoc ) or ( tu sach trien chai khoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach ha chau hoa hoc ) OR ( tu sach trien chai khoa hoc )).
• Adding a wildcard symbol may retrieve word variants: (( te sach ha chau hoa hoc ) or ( tu sach trien chai khoa hoc ))*.