Perhaps you should try some spelling variations:
xuc tuan » duc thuan, quoc tuan, xuan tuan
dinh thi » dinh tri
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cac xuc » cam xuc, cac nuoc, chat xuc
anh thi » anh tho, dang thi, anh thuc
cuc tre » duc tre, cua tre, cuu tre
co hai » co dai, co hoi, o hai
ve cac » va cac, vien cac
o hoc » co hoc, mo hoc, so hoc

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 nang ((o hoc) or (co hai)). hieu ve cac xuc tuan ((anh thi) OR (dinh thi)) cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hoc) OR (co hai)). hieu ve cac xuc tuan ((anh thi) OR (dinh thi)) cuc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((o hoc) or (co hai)). hieu ve cac xuc tuan ((anh thi) OR (dinh thi)) cuc tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hoc) or (co hai)). hieu ve cac xuc tuan ((anh thi) OR (dinh thi)) cuc tre*.