Perhaps you should try some spelling variations:
dang xay » dang van, van xay
bach ky » bac ky
ky dang » ky nang, ky danh
xay hoi » xa hoi, tay hoi, cay phoi
hieu va » lieu va, hieu qua
va tich » va tinh
va dich » van dich
cua tre » cua te, cuu tre, cua triet
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: vu bach ky dang xay hoi. hieu va cau truc ((va tich) OR (va dich)) va ((cua tre) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu bach ky dang xay hoi. hieu va cau truc ((va tich) OR (va dich)) va ((cua tre) OR (cua vat)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu bach ky dang xay hoi. hieu va cau truc ((va tich) OR (va dich)) va ((cua tre) or (cua vat))".
• Adding a wildcard symbol may retrieve word variants: vu bach ky dang xay hoi. hieu va cau truc ((va tich) OR (va dich)) va ((cua tre) or (cua vat))*.