Perhaps you should try some spelling variations:
nhan thuc » nhan luc, dan thuc, toan thuc
doc sach » toc sach, nuoc sach, bo sach
tren cua » trien cua, tien cua, tren ca
dan tren » dat tren, dau tren, van tren
hoc sach » hoc sinh, hoc cac, hoc anh
thuc ca » thuc cua, thuc can, thuc cao
va nhan » van nhan, ca nhan, va phan
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
ca dan » cac dan, ca dao
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((doc sach) OR (dac sac))) or (hoc sach)) ky nang ma hoi. lieu va nhan thuc ca dan tren cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((doc sach) OR (dac sac))) OR (hoc sach)) ky nang ma hoi. lieu va nhan thuc ca dan tren cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((doc sach) OR (dac sac))) or (hoc sach)) ky nang ma hoi. lieu va nhan thuc ca dan tren cua tre*".