Perhaps you should try some spelling variations:
thien van » thi van
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu
x hoi » o hoi, x ho, 5 hoi

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 ((x hoi) OR (xa hoi)). ((hieu ve) or (thien van)) nam thuc va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((x hoi) OR (xa hoi)). ((hieu ve) OR (thien van)) nam thuc va hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((x hoi) OR (xa hoi)). ((hieu ve) or (thien van)) nam thuc va hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((x hoi) OR (xa hoi)). ((hieu ve) or (thien van)) nam thuc va hanh vi cuu tre*.