Perhaps you should try some spelling variations:
thien van » thi van
toc sach » hoc sach, doc sach, thuoc sach
ban hanh » ban hang
hanh di » hanh vi, hanh de, hang di
cau cuc » cau cua, cau luc, cau phuc
hoa hoi » khoa hoi, hoa hoc, hoa doi
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((ky lang) OR (ky dang)) hoa hoi. thien van ((cau cuc) or (cau truc)) ban hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky lang) OR (ky dang)) hoa hoi. thien van ((cau cuc) OR (cau truc)) ban hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ky lang) OR (ky dang)) hoa hoi. thien van ((cau cuc) or (cau truc)) ban hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ky lang) OR (ky dang)) hoa hoi. thien van ((cau cuc) or (cau truc)) ban hanh di cua tre*.