Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
dau thuc » dan thuc, dai thuc, dam thuc
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
va dau » va dao
sach o » sach lo, sac o, sach y
o lang » hoa lang, hoi lang
ve cum » ve cua
te cua » tue cua, de cua
le cua » ly cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach o lang xa hoi. hieu va dau thuc vat hanh ((ve cum) or (((te cua) OR (le cua)))) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach o lang xa hoi. hieu va dau thuc vat hanh ((ve cum) OR (((te cua) OR (le cua)))) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach o lang xa hoi. hieu va dau thuc vat hanh ((ve cum) or (((te cua) OR (le cua)))) te".
• Adding a wildcard symbol may retrieve word variants: tu sach o lang xa hoi. hieu va dau thuc vat hanh ((ve cum) or (((te cua) OR (le cua)))) te*.