Perhaps you should try some spelling variations:
dong phuong » duong phuong, dung phuong, dong huong
thien hach » thien thanh, hien hanh
phuong dan » phuong danh, phuong doan, huong dan
theo sach » thuoc sach, te sach, theo lich
hanh tran » hanh trang, thanh tran, hanh tram
tran van » luan van
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((theo sach) or (thien hach)) - hanh tran van dong phuong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((theo sach) OR (thien hach)) - hanh tran van dong phuong dan toan cao.
• Adding a wildcard symbol may retrieve word variants: hoc ((theo sach) or (thien hach)) - hanh tran van dong phuong dan toan cao*.