Perhaps you should try some spelling variations:
may thoi » gay thoi, may thi, tay thoi
bo sach » co sach, hoc sach
sach ky » sac ky, sach y, sach ty
ky mang » ky nang, ke mang, ky dang
hieu he » hieu ve, hiem he, hieu le
thuc va » thuc dan, thuc day
he nam » ha nam, nghe nam
dan vi » doan vi, don vi, dan va
vi hoa » voi hoa, vi hoc, va hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach ky mang may thoi. hieu he nam ((thuc va) or (thuc vat)) dan vi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach ky mang may thoi. hieu he nam ((thuc va) OR (thuc vat)) dan vi hoa viet.
• Adding a wildcard symbol may retrieve word variants: bo sach ky mang may thoi. hieu he nam ((thuc va) or (thuc vat)) dan vi hoa viet*.