Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
toc sach » hoc sach, doc sach, thuoc sach
va trien » va truyen, va thiet, va tuyen
lang xa » lang ha, dang xay, lang van
hieu ve » hieu van
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan tai, dan vat
y lang » o lang, _ lang, tay lang
va dan » ca dan, va dao, va dau
vai va » mai va, dai va, hai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y lang xa hoi. ((hieu ve) or (hieu va)) pham thuc va dan vai va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y lang xa hoi. ((hieu ve) OR (hieu va)) pham thuc va dan vai va trien.
• Adding a wildcard symbol may retrieve word variants: toc sach y lang xa hoi. ((hieu ve) or (hieu va)) pham thuc va dan vai va trien*.