Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
hanh dao » lanh dao, thanh dat, thanh dam
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
mai hoi » mai khoi, dai hoi, lai hoi
va hanh » van hanh, va thanh, va danh
dao cua » dai cua, day cua, dan cua
ve cam » ve cham, ve cac, ve cai
va cam » va cham, va cac, va cao
luc va » duc 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: vu sach ky sang mai hoi. hieu ((ve cam) or (va cam)) luc va hanh dao cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky sang mai hoi. hieu ((ve cam) OR (va cam)) luc va hanh dao cua vat*.