Perhaps you should try some spelling variations:
kmay nang » ky nang, kha nang, may nong
cam truc » cau truc, nam truc, lam truoc
may nang » may nong, ky nang, cam nang
van hanh » van thanh, ban hanh, van ban
vu sach » vu bach, su sach, vu khach
van anh » van thanh, tuan anh, van minh
qua cam » qua cham, qua cac, qua ca
ca viet » va viet, co viet, hoa viet
vi ca » vit ca, li ca, va ca

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ((may nang) or (kmay nang)) xa hoi. hieu qua cam truc ((van hanh) OR (van anh)) vi ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ((may nang) OR (kmay nang)) xa hoi. hieu qua cam truc ((van hanh) OR (van anh)) vi ca viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ((may nang) or (kmay nang)) xa hoi. hieu qua cam truc ((van hanh) OR (van anh)) vi ca viet*".