Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
theo sach » thuoc sach, te sach, theo lich
hieu cach » hieu cac, chieu sach, hieu ca
trang cua » tranh cua, trung cua, thang cua
tang cua » mang cua, hang cua, tang luan
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((theo sach) or (hieu cach)) - hanh ((trang cua) or (tang cua)) thong cong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((theo sach) OR (hieu cach)) - hanh ((trang cua) OR (tang cua)) thong cong dan toan cao.
• Adding a wildcard symbol may retrieve word variants: hoc ((theo sach) or (hieu cach)) - hanh ((trang cua) or (tang cua)) thong cong dan toan cao*.