Perhaps you should try some spelling variations:
hanh vinh » thanh vinh, khanh vinh, hanh tinh
doc sach » hoc sach, nuoc sach, dac sac
vinh cuu » dinh cuu, sinh cua, dinh cu
toc sach » hoc sach, thuoc sach, nuoc sach
tan hanh » tan thanh, tang hanh, toan hanh
hieu van » hieu va, thien van, lieu va
bac dan » bach dan, cac dan, ban dan
bac dac » bac dai, ban dac, cac dac
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
cuu tre » cua tre, cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc sach) OR (toc sach)) ky dang xa hoi. hieu van ((bac dac) or (bac dan)) tan hanh vinh cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc sach) OR (toc sach)) ky dang xa hoi. hieu van ((bac dac) OR (bac dan)) tan hanh vinh cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc sach) OR (toc sach)) ky dang xa hoi. hieu van ((bac dac) or (bac dan)) tan hanh vinh cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((doc sach) OR (toc sach)) ky dang xa hoi. hieu van ((bac dac) or (bac dan)) tan hanh vinh cuu tre*.