Perhaps you should try some spelling variations:
phan duc » pham duc, phan tu, phan dau
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
va phan » van phan, va phat, va phap
va hanh » van hanh, va thanh, va danh
luu tre » luu tru, cuu tre, luy tre
vi luu » vi lua
x hoi » xa hoi, o hoi, 5 hoi

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang ((x hoi) OR (x ho)). hieu va phan duc va hanh vi luu tre~.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang ((x hoi) or (x ho)). hieu va phan duc va hanh vi luu tre*.