Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
hanh di » hanh vi, hanh de, hang di
nang ma » tang ma, sang ma, nang cao
di cua » dai cua, doi cua, de cua
ve nam » he nam, le nam, te nam
va nam » van nam, ha nam, va nay
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach y) or (sac ky)) nang ma hoi. hieu ((ve nam) OR (va nam)) thuc van hanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach y) OR (sac ky)) nang ma hoi. hieu ((ve nam) OR (va nam)) thuc van hanh di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach y) or (sac ky)) nang ma hoi. hieu ((ve nam) OR (va nam)) thuc van hanh di cua te".
• Adding a wildcard symbol may retrieve word variants: su ((sach y) or (sac ky)) nang ma hoi. hieu ((ve nam) OR (va nam)) thuc van hanh di cua te*.