Perhaps you should try some spelling variations:
dieu hien » dieu khien, dieu kien, bieu hien
hien cac » thien cac, vien cac, hieu cac
tu sach » thu sach, su sach, te sach
va dinh » van dinh, va kinh, va tinh
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren
su viet » so viet
sach ty » sach y, sach tu, sach thu
cac bao » cach bao, cac bai, cac ban
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
bao va » bao ve, tao va, ban 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 ty nang xa hoi. dieu hien cac bao va dinh van ((((cua tre) OR (cuu tre))) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. dieu hien cac bao va dinh van ((((cua tre) OR (cuu tre))) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang xa hoi. dieu hien cac bao va dinh van ((((cua tre) OR (cuu tre))) or (su viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. dieu hien cac bao va dinh van ((((cua tre) OR (cuu tre))) or (su viet))*.