Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
vu sach » vu bach, su sach, vu khach
hanh va » hang va, hanh vi
co viet » so viet, o viet, hoc viet
y dang » ky dang, 2 dang, _ dang
va nam » van nam, ha nam, va nay
me hoi » le hoi
ve nam » he nam, le nam, te nam
va co » vo co

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 y dang ((me hoi) or (ma hoa)). hieu ((ve nam) or (va nam)) thuc van hanh va co viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach y dang ((me hoi) OR (ma hoa)). hieu ((ve nam) OR (va nam)) thuc van hanh va co viet.
• Adding a wildcard symbol may retrieve word variants: vu sach y dang ((me hoi) or (ma hoa)). hieu ((ve nam) or (va nam)) thuc van hanh va co viet*.