Perhaps you should try some spelling variations:
thuc van » thuc dan, thuc va, thuc hanh
hang don » hang ton, dang don, hang do
hang doi » hang di, hang loi, huong doi
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
su viet » so viet
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

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 v nang xa hoi. hieu va cac ((thuc van) OR (thuc vat)) ((hang don) or (hang doi)) su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v nang xa hoi. hieu va cac ((thuc van) OR (thuc vat)) ((hang don) OR (hang doi)) su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v nang xa hoi. hieu va cac ((thuc van) OR (thuc vat)) ((hang don) or (hang doi)) su viet".
• Adding a wildcard symbol may retrieve word variants: su sach v nang xa hoi. hieu va cac ((thuc van) OR (thuc vat)) ((hang don) or (hang doi)) su viet*.