Perhaps you should try some spelling variations:
sach dao » lanh dao
dan khoa » dang khoa, da khoa, san khoa
khoa hoc » hoa hoc
te sach » toc sach
dao tac » dao tao, dao tuc, dao tay
cuu mon » cuu mo, cuu mot, cuu cong
mon hoc » toan hoc, dong hoc
van van » van ban, tan van, san van
ma hoi » mai hoi, ma hoa, me hoi

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach dao tac, nghien cuu mon hoc dan khoa hoc ((ma hoi) OR (xa hoi)) luan van van~".
• Adding a wildcard symbol may retrieve word variants: te sach dao tac, nghien cuu mon hoc dan khoa hoc ((ma hoi) OR (xa hoi)) luan van van*.