Perhaps you should try some spelling variations:
trien khai » trien nha
sach trien » sach tien, sach tren, sach thieu
khai khoa » thai khoa, chai khoa, khat khoa
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
tai khoa » da khoa, noi khoa
khoa hoc » hoa hoc
lin tai » lin thai, li tai, tin tai

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( ((toc sach) OR (hoc sach)) lin tai khoa hoc ) or ( te sach trien khai khoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((toc sach) OR (hoc sach)) lin tai khoa hoc ) OR ( te sach trien khai khoa hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((toc sach) OR (hoc sach)) lin tai khoa hoc ) or ( te sach trien khai khoa hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( ((toc sach) OR (hoc sach)) lin tai khoa hoc ) or ( te sach trien khai khoa hoc ))*.