Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
dieu cua » dieu tra
anh dieu » hanh dieu, anh sieu, nganh dieu
vien cac » vien bach, vien dai, vien da
van anh » van thanh, tuan anh, van minh
ky dang » ky nang, ky danh
ky tang » ky nang, kho tang, ky trong
tu sach » thu sach, su sach, te sach
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
cac lo » cac lop, cac co, cac bo
lo van » le van, vo van, so van

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu hoach) or (tu sach)) ((ky tang) OR (ky dang)) ma hoi. hieu vien cac lo van anh dieu cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu hoach) OR (tu sach)) ((ky tang) OR (ky dang)) ma hoi. hieu vien cac lo van anh dieu cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu hoach) or (tu sach)) ((ky tang) OR (ky dang)) ma hoi. hieu vien cac lo van anh dieu cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu hoach) or (tu sach)) ((ky tang) OR (ky dang)) ma hoi. hieu vien cac lo van anh dieu cua tre*.