Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
hoa doi » hoa dai, hoc doi, xoa doi
ca tren » cau tren, cu tren, la tren
hoa hoi » khoa hoi, hoa hoc, hoc hoi
ve cac » va cac, vien cac
cac su » cach su, cac sau, cac du
va tao » va bao, va cao, va tac
su va » su van, tu va
va ca » va cac, va cao, va cai

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 ((hoa hoi) or (hoa doi)). hieu ve cac su va tao va ca tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky nang ((hoa hoi) OR (hoa doi)). hieu ve cac su va tao va ca tren.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky nang ((hoa hoi) or (hoa doi)). hieu ve cac su va tao va ca tren*.