Perhaps you should try some spelling variations:
thanh vinh » thanh binh, thanh tinh, than kinh
tan thanh » tran thanh, tang thanh, toan thanh
toc sach » hoc sach, doc sach, thuoc sach
cau treo » cau tren, cau triet, cau trieu
hieu van » hieu va, thien van, lieu va
cau theo » cau thi, cau tao
van bac » van ban, van bao, van hac
ke va » te va
ky va » ly va, my va, ky la

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 va) OR (ke va)) xa hoi. hieu van bac duc tan thanh vinh ((cau treo) or (cau theo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky va) OR (ke va)) xa hoi. hieu van bac duc tan thanh vinh ((cau treo) OR (cau theo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ky va) OR (ke va)) xa hoi. hieu van bac duc tan thanh vinh ((cau treo) or (cau theo))".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ky va) OR (ke va)) xa hoi. hieu van bac duc tan thanh vinh ((cau treo) or (cau theo))*.