Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
su sach » so sach, vu sach
han tai » hang tai, nhan tai, van tai
van han » van hanh, van phan, van nhan
xuc van » duc van, luc van, vuc van
va tham » van tham, va cham, va thuat
nang xa » lang xa, nang ma, mang xa
tai va » thai va, mai va, tri 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 xa) or (nang x)) hoi. hieu ((va tham) OR (va thanh)) xuc van han tai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (nang x)) hoi. hieu ((va tham) OR (va thanh)) xuc van han tai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) or (nang x)) hoi. hieu ((va tham) OR (va thanh)) xuc van han tai va thiet".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (nang x)) hoi. hieu ((va tham) OR (va thanh)) xuc van han tai va thiet*.