Perhaps you should try some spelling variations:
thanh dat » thanh san, thanh hai, thanh van
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
lang ha » long ha
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
soc gia » hoc gia, so gia, quoc gia
toc gia » toc giay, tac gia, quoc gia
so sach » so sanh, bo sach, co sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty ((nang xa) or (lang ha)) hoi. hieu van cham ((soc gia) OR (toc gia)) thanh dat cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((nang xa) OR (lang ha)) hoi. hieu van cham ((soc gia) OR (toc gia)) thanh dat cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty ((nang xa) or (lang ha)) hoi. hieu van cham ((soc gia) OR (toc gia)) thanh dat cau tren".
• Adding a wildcard symbol may retrieve word variants: so sach ty ((nang xa) or (lang ha)) hoi. hieu van cham ((soc gia) OR (toc gia)) thanh dat cau tren*.