Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thanh di » thanh doi, thanh de, thanh do
cau tren » cu tren, dau tren, ca tren
sach ty » sach y, sach tu, sach thu
xuc va » tuc va, luc va, xac va
di cau » da cau, diem cau
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((cac ky) or (sach ty)) nang x hoi. hieu van nam ((xuc va) OR (duc va)) thanh di cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((cac ky) OR (sach ty)) nang x hoi. hieu van nam ((xuc va) OR (duc va)) thanh di cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((cac ky) or (sach ty)) nang x hoi. hieu van nam ((xuc va) OR (duc va)) thanh di cau tren".
• Adding a wildcard symbol may retrieve word variants: su ((cac ky) or (sach ty)) nang x hoi. hieu van nam ((xuc va) OR (duc va)) thanh di cau tren*.