Perhaps you should try some spelling variations:
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
hanh vinh » thanh vinh, khanh vinh, anh vinh
doc sac » doc sach, dac sac, hoc sach
bac dan » bach dan, cac dan, ban dan
cuu tre » cua tre, cau tren, cau treo
bac dac » bac dai, ban dac, cac dac
hieu va » lieu va, hieu qua
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sac ky dang xa hoi. hieu va ((bac dac) or (bac dan)) tan ((hanh vinh) or (hanh tinh)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sac ky dang xa hoi. hieu va ((bac dac) OR (bac dan)) tan ((hanh vinh) OR (hanh tinh)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: doc sac ky dang xa hoi. hieu va ((bac dac) or (bac dan)) tan ((hanh vinh) or (hanh tinh)) cuu tre*.