Perhaps you should try some spelling variations:
van chat » cao chat
kinh vai » kinh hai, kinh va, kinh van
tu sach » thu sach, su sach, te sach
cao hoi » cau hoi, co hoi, cao hoc
van cau » van dau, van hau, toan cau
va kinh » va tinh, qua kinh
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (thu hoach)) ky nang cao hoi. hieu ((van cau) OR (van chat)) duc va kinh vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky nang cao hoi. hieu ((van cau) OR (van chat)) duc va kinh vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu hoach)) ky nang cao hoi. hieu ((van cau) OR (van chat)) duc va kinh vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky nang cao hoi. hieu ((van cau) OR (van chat)) duc va kinh vai cuu tre*.