Perhaps you should try some spelling variations:
dang xay » dang van, van xay
trung va » truong va, trang va, trung ha
su sach » so sach, vu sach
sang ma » tang ma, nang ma, sang tao
hieu va » lieu va, hieu qua
va dinh » van dinh, va kinh, va tinh
dinh ve » dinh ket, dinh van
va tai » va tac, va tap
ve va » ve van, te va, ke va
thiet » thieu

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 y ((((nang x) or (dang xay))) or (sang ma)) hoi. hieu va tai trung va dinh ve va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((((nang x) OR (dang xay))) OR (sang ma)) hoi. hieu va tai trung va dinh ve va thiet.
• Adding a wildcard symbol may retrieve word variants: su sach y ((((nang x) or (dang xay))) or (sang ma)) hoi. hieu va tai trung va dinh ve va thiet*.