Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
su sach » so sach, vu sach
tinh vi » trinh vi, tinh voi, tinh va
va tinh » may tinh
nam xua » nam cua, nam mua, nam qua
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
xua va » xuat va, vua va, sua va
co hoi » co hoc, co loi
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ((co hoi) or (xa hoi)). ((hieu van) or (hieu va)) nam xua va tinh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((co hoi) OR (xa hoi)). ((hieu van) OR (hieu va)) nam xua va tinh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((co hoi) or (xa hoi)). ((hieu van) or (hieu va)) nam xua va tinh vi cua tre*.