Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
doan van » doan va, hoang van, luan van
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
van cua » vang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach thu nang xa hoi. hieu vu cham ((tuc va) or (duc va)) doan van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nang xa hoi. hieu vu cham ((tuc va) OR (duc va)) doan van cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach thu nang xa hoi. hieu vu cham ((tuc va) or (duc va)) doan van cua tre*.