Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
thu sach » tu sach, thuat sach, thuoc sach
dinh vai » dinh van, dinh vi, dinh va
va dinh » van dinh, va kinh, va tinh
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
ca tren » cau tren, cu tren, la tren
hieu ve » hieu van
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
vai ca » vai cac, vai cua, bai ca

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach thieu ((nang xa) OR (nang ma)) hoi. ((hieu ve) or (hieu va)) pham thuc va dinh vai ca tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach thieu ((nang xa) OR (nang ma)) hoi. ((hieu ve) OR (hieu va)) pham thuc va dinh vai ca tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach thieu ((nang xa) OR (nang ma)) hoi. ((hieu ve) or (hieu va)) pham thuc va dinh vai ca tren".
• Adding a wildcard symbol may retrieve word variants: thu sach thieu ((nang xa) OR (nang ma)) hoi. ((hieu ve) or (hieu va)) pham thuc va dinh vai ca tren*.