Perhaps you should try some spelling variations:
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
ve cham » ve chat, vu cham, ve chim
va cham » va chat, va tham
soc van » hoc van, oc van, sac van
van han » van hanh, van phan, van nhan
han tai » hang tai, nhan tai, van tai
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: vu sach ky ((nang ma) or (nang x)) hoi. hieu ((ve cham) OR (va cham)) soc van han tai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang ma) OR (nang x)) hoi. hieu ((ve cham) OR (va cham)) soc van han tai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky ((nang ma) or (nang x)) hoi. hieu ((ve cham) OR (va cham)) soc van han tai va thiet".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang ma) or (nang x)) hoi. hieu ((ve cham) OR (va cham)) soc van han tai va thiet*.