Perhaps you should try some spelling variations:
sach trien » sach tien, sach tren, sach thieu
trien khai » trien nha
khai khoa » thai khoa, chai khoa, khat khoa
han chau » ha chau, hat chau, ham chau
hai chau » lai chau, ha chau, hat chau
te sach » toc sach
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 ((han chau) OR (hai chau)) hoa hoc ) or ( tu sach trien khai khoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach ((han chau) OR (hai chau)) hoa hoc ) OR ( tu sach trien khai khoa hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach ((han chau) OR (hai chau)) hoa hoc ) or ( tu sach trien khai khoa hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( te sach ((han chau) OR (hai chau)) hoa hoc ) or ( tu sach trien khai khoa hoc ))*.