Perhaps you should try some spelling variations:
khoa sach » hoc sach
gian dang » gian dan, gian lang, gian dong
sach luan » sach luyen, sach han, san luan
trien chi » trien thi, trien khai, trieu thi
luan dieu » luan tieu, lan dieu, luan hieu
pho sach » pham sach, khoe sach, pho trach
dieu cua » dieu tra
pham lan » pham luan, pham van, phan lan
pham can » pham van, pham ca, pham san
tiep cua » tiep can, tap cua, tiep va
gian don » gian dan, giang son, gian dien
cap qua » cac qua, cay qua, tap quan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( pho ((gian dang) OR (gian don)) trien chi ) OR ((( pho ((cap qua) OR (cau qua)) tiep cua ) OR ((( ((pham can) OR (pham lan)) luan dieu cua ) OR ((( pho sach luan dieu tri ) OR ( khoa sach luan dieu tri ))))))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( pho ((gian dang) or (gian don)) trien chi ) or ((( pho ((cap qua) OR (cau qua)) tiep cua ) or ((( ((pham can) or (pham lan)) luan dieu cua ) or ((( pho sach luan dieu tri ) or ( khoa sach luan dieu tri ))))))))~".
• Adding a wildcard symbol may retrieve word variants: (( pho ((gian dang) or (gian don)) trien chi ) or ((( pho ((cap qua) OR (cau qua)) tiep cua ) or ((( ((pham can) or (pham lan)) luan dieu cua ) or ((( pho sach luan dieu tri ) or ( khoa sach luan dieu tri ))))))))*.