Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
cao hoi » cau hoi, co hoi, cao hoc
cam tuc » cam xuc, cam tu, nam thuc
tinh de » tinh da, sinh de, minh de
tinh he » trinh he, hinh he, tinh ha
ca viet » va viet, co viet, hoa viet
va cam » va cham, va cac, va cao
tuc va » thuc va, truc va, tuc xa

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. lieu va cam tuc va ((tinh de) OR (tinh he)) ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky nang cao hoi. lieu va cam tuc va ((tinh de) OR (tinh he)) ca viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu hoach)) ky nang cao hoi. lieu va cam tuc va ((tinh de) OR (tinh he)) ca viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky nang cao hoi. lieu va cam tuc va ((tinh de) OR (tinh he)) ca viet*.