Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
toc sach » hoc sach, doc sach, thuoc sach
ly quang » le quang, vu quang
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
thuc va » thuc vat, thuc dan, thuc day
va pham » van pham, va phat, va phap
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
ly vang » ly hang, ly van
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ((ly quang) or (ly vang)) x hoi. hieu va pham thuc va danh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ((ly quang) OR (ly vang)) x hoi. hieu va pham thuc va danh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ((ly quang) or (ly vang)) x hoi. hieu va pham thuc va danh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ((ly quang) or (ly vang)) x hoi. hieu va pham thuc va danh vi cua tre*.