Perhaps you should try some spelling variations:
canh manh » lanh manh, canh tranh, van manh
trong bai » trong ban, thong bai, trong hai
chi sach » chinh sach, chieu sach, co sach
cua dung » cua dang, cua dong, qua dung
bai toan » bai tap
toan cau » toan cao, toan ban, toan tap
doi chi » doi khi

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi chi sach - ((canh manh) OR (cach mang)) cua dung trong bai toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi chi sach - ((canh manh) OR (cach mang)) cua dung trong bai toan cau".
• Adding a wildcard symbol may retrieve word variants: doi chi sach - ((canh manh) OR (cach mang)) cua dung trong bai toan cau*.