Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
cau phuc » cau truc, chau phu, huu phuc
phuc van » thuc van, phuc va, chuc van
thang di » hang di, thang loi, thanh doi
hieu ke » hieu kem, chieu ke, hieu ky
tang di » hang di, tang du, tang da
cua tre » cua te, cuu tre, cua triet
y nang » ly nang, v nang, may nang
ke cau » ket cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((y nang) OR (ky nang)) xa hoi. hieu ke cau phuc van ((thang di) or (tang di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((y nang) OR (ky nang)) xa hoi. hieu ke cau phuc van ((thang di) OR (tang di)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((y nang) OR (ky nang)) xa hoi. hieu ke cau phuc van ((thang di) or (tang di)) cua tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((y nang) OR (ky nang)) xa hoi. hieu ke cau phuc van ((thang di) or (tang di)) cua tre*.