Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
nang hoa » nang hoat, hang hoa, nang hoc
cau tren » cu tren, dau tren, ca tren
su sach » so sach, vu sach
hoa hoi » khoa hoi, hoa hoc, hoa doi
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
cac tu » cac thu, cach tu, cac du
va tao » va bao, va cao, va tac
va cau » van cau, va cac, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (thuat sach)) ky nang hoa hoi. hieu ve cac tu va tao va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (thuat sach)) ky nang hoa hoi. hieu ve cac tu va tao va cau tren.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (thuat sach)) ky nang hoa hoi. hieu ve cac tu va tao va cau tren*.