Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
van pham » san pham, van phan, van phat
sach kem » hanh kem
dua tren » dung tren
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
hieu van » hieu va, thien van, lieu va
nang xa » nang x, lang xa, nang ma
cuu tre » cua tre, cau tren, cau treo

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 kem) or (sach y)) nang xa hoi. hieu van pham thuc day hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach kem) OR (sach y)) nang xa hoi. hieu van pham thuc day hanh vi ((dua tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu ((sach kem) or (sach y)) nang xa hoi. hieu van pham thuc day hanh vi ((dua tren) or (cuu tre))*.