Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
vanh dai » van dai, vanh tai, lanh dao
tu sach » thu sach, su sach, te sach
ky lang » ky nang, tay lang
ky dang » ky nang, ky danh
ky tang » ky nang, kho tang, ky trong
hieu va » lieu va, hieu qua
va nham » va cham, va tham, va nha
thuc va » thuc vat, thuc dan, thuc day
va vanh » va van, va danh, va hanh
cua tre » cua te, cuu tre, cua triet

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 lang) OR (ky dang))) or (ky tang)) xa hoi. hieu va nham thuc va vanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((((ky lang) OR (ky dang))) OR (ky tang)) xa hoi. hieu va nham thuc va vanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((((ky lang) OR (ky dang))) or (ky tang)) xa hoi. hieu va nham thuc va vanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((((ky lang) OR (ky dang))) or (ky tang)) xa hoi. hieu va nham thuc va vanh dai cua tre*.