Perhaps you should try some spelling variations:
phap duy » phap day, pham duy, phan duy
tu sach » thu sach, su sach, te sach
danh va » doanh va, hanh va, dan va
va phap » va phat, ban phap
hieu va » lieu va, hieu qua
ty hang » ly hang, ty xang, thi hang
cuu tre » cua tre, cau tren, cau treo
duy va » duy vat, duy van, day va
anh va » hanh va

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 nang) or (ty hang)) xa hoi. hieu va phap duy va ((danh va) or (anh va)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky nang) OR (ty hang)) xa hoi. hieu va phap duy va ((danh va) OR (anh va)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky nang) or (ty hang)) xa hoi. hieu va phap duy va ((danh va) or (anh va)) cuu tre*.