Perhaps you should try some spelling variations:
hien cac » thien cac, hieu cac, dien cac
vien cac » vien bach, vien dai, vien da
dinh va » dinh van, dinh ve, tinh va
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
lao va » tao va, cao va, bao va
va cua » va chua, via cua, ca cua

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) or (sach y)) nang xa hoi. hieu ((hien cac) OR (vien cac)) lao va dinh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang xa hoi. hieu ((hien cac) OR (vien cac)) lao va dinh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach y)) nang xa hoi. hieu ((hien cac) OR (vien cac)) lao va dinh va cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) nang xa hoi. hieu ((hien cac) OR (vien cac)) lao va dinh va cua tre*.