Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
thu sach » thuat sach, thuoc sach, thu hoach
hanh vai » hanh vi, hanh va, hanh tai
nang tai » hang tai, tang tai, sang tai
tu sach » su sach, te sach, tu cach
truc va » thuc va, thuc vat, trung va
vai cua » dai cua, hai cua, lai cua
vien da » vien dai, hien dai
tai hai » thi hai, dai hai, tai ha
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, tuc xa, duc va

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) or (thu sach)) ky nang tai hai. hieu vien da ((tuc va) OR (truc va)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang tai hai. hieu vien da ((tuc va) OR (truc va)) hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang tai hai. hieu vien da ((tuc va) OR (truc va)) hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang tai hai. hieu vien da ((tuc va) OR (truc va)) hanh vai cua tre*.