Perhaps you should try some spelling variations:
toan dinh » tran dinh, toan kinh, toan doanh
doan dinh » doan hinh, doan tinh, doan minh
cac khien » cac chien, cac phien, cach thien
khien hoc » nhiet hoc, dien hoc
sach xin » sach kinh, sach tien, sach xa
dac khoa » da khoa, dai khoa, dau khoa
khoa hoc » hoa hoc
su sach » so sach, vu sach
xin dac » gian dac, xin duoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( thuat ((toan dinh) or (doan dinh)) cac khien hoc ) or ( su sach xin dac khoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thuat ((toan dinh) OR (doan dinh)) cac khien hoc ) OR ( su sach xin dac khoa hoc )).
• Adding a wildcard symbol may retrieve word variants: (( thuat ((toan dinh) or (doan dinh)) cac khien hoc ) or ( su sach xin dac khoa hoc ))*.