Perhaps you should try some spelling variations:
mang mai » mang may, lang mai, mang lai
thuc dan » thuc hanh, hoc dan, thuc vat
thuc ban » thuoc ban, thu ban, thuc van
vu sach » vu bach, su sach, vu khach
mai hoi » mai khoi, dai hoi, lai hoi
vi hoa » voi hoa, vi hoc, va hoa
va cam » va cham, va cac, va cao
y mang » cay mang
ve cam » ve cham, ve cac, ve cai

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 mang mai hoi. hieu ((ve cam) or (va cam)) ((thuc ban) OR (thuc dan)) hanh vi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach y mang mai hoi. hieu ((ve cam) OR (va cam)) ((thuc ban) OR (thuc dan)) hanh vi hoa viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach y mang mai hoi. hieu ((ve cam) or (va cam)) ((thuc ban) OR (thuc dan)) hanh vi hoa viet".
• Adding a wildcard symbol may retrieve word variants: vu sach y mang mai hoi. hieu ((ve cam) or (va cam)) ((thuc ban) OR (thuc dan)) hanh vi hoa viet*.