Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan
dieu cua » dieu tra
vu sach » vu bach, su sach, vu khach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
van am » van nam, van lam, van dam
de cua » le cua, te cua

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 ty xang xa hoi. hieu van am ((thuc dan) OR (thuc vat)) thanh ((de cua) or (dieu cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ty xang xa hoi. hieu van am ((thuc dan) OR (thuc vat)) thanh ((de cua) OR (dieu cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ty xang xa hoi. hieu van am ((thuc dan) OR (thuc vat)) thanh ((de cua) or (dieu cua)) te".
• Adding a wildcard symbol may retrieve word variants: vu sach ty xang xa hoi. hieu van am ((thuc dan) OR (thuc vat)) thanh ((de cua) or (dieu cua)) te*.