Perhaps you should try some spelling variations:
van thiet » va thiet, dan thiet, can thiet
thai van » thi van, thanh van, thai vung
han thai » han tai, ban thai, van thai
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
va cham » va chat, va tham
luc va » tuc va, loc va

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 xa) or (lang xa)) hoi. hieu va cham ((duc va) or (luc va)) han thai van thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (lang xa)) hoi. hieu va cham ((duc va) OR (luc va)) han thai van thiet.
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (lang xa)) hoi. hieu va cham ((duc va) or (luc va)) han thai van thiet*.