Perhaps you should try some spelling variations:
van thiet » va thiet, dan thiet, can thiet
dao tang » dao trang, cao tang, dam tang
hanh dao » lanh dao, thanh dat, thanh dam
sach dao » lanh dao
dao van » do van, dang van
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
te sach » toc sach
va cham » va chat, va tham
ve cham » ve chat, vu cham, ve chim
tang ma » mang may, tang van
ma hoi » mai hoi, xa hoi, ma hoa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach dao tang ma hoi. hieu ((ve cham) or (va cham)) thuc va hanh dao van thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach dao tang ma hoi. hieu ((ve cham) OR (va cham)) thuc va hanh dao van thiet.
• Adding a wildcard symbol may retrieve word variants: te sach dao tang ma hoi. hieu ((ve cham) or (va cham)) thuc va hanh dao van thiet*.