Perhaps you should try some spelling variations:
thien van » thi van
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
nam thuc » nam thuoc, am thuc, nam thu
mai hoi » mai khoi, dai hoi, lai hoi
ca tren » cau tren, cu tren, la tren
sach ky » sach y, sach ty, sach kem
ma hoi » xa hoi, ma hoa, me hoi
sac ky » cac ky, sai ky
vi ca » vit ca, li ca, va ca

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 ky) or (sac ky)) nang ((ma hoi) OR (mai hoi)). thien van nam thuc van hanh vi ca tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang ((ma hoi) OR (mai hoi)). thien van nam thuc van hanh vi ca tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sac ky)) nang ((ma hoi) OR (mai hoi)). thien van nam thuc van hanh vi ca tren".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) nang ((ma hoi) OR (mai hoi)). thien van nam thuc van hanh vi ca tren*.