Perhaps you should try some spelling variations:
nuoc duc » ngoc duc, nuoc cuc, duoc duoc
su sach » vu sach
hieu va » lieu va, hieu qua
tinh de » tinh da, sinh de, tinh he
va tinh » may tinh
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
so sach » so sanh, bo sach, co sach
de cua » le cua, te cua, dieu 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) or (so sach)) ky nang xa hoi. ((hieu ve) OR (hieu va)) nuoc duc va tinh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ky nang xa hoi. ((hieu ve) OR (hieu va)) nuoc duc va tinh de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ky nang xa hoi. ((hieu ve) OR (hieu va)) nuoc duc va tinh de cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky nang xa hoi. ((hieu ve) OR (hieu va)) nuoc duc va tinh de cua tre*.