Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dong tac » cong tac, dong tai, dong bac
cuu cong » cua cong, thu cong, cac cong
cong hoc » dong hoc, cong hoa, cong coc
phan dau » phan tu, hang dau
dan hoa » danh hoa, dan hoat, dan khoa
va phan » van phan, va phat, va phap
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((doi tac) OR (dong tac)), nghien cuu cong hoc dan hoa hoc ma hoi va phan dau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((doi tac) OR (dong tac)), nghien cuu cong hoc dan hoa hoc ma hoi va phan dau".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((doi tac) OR (dong tac)), nghien cuu cong hoc dan hoa hoc ma hoi va phan dau*.