Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dang xay » dang van, van xay
ve triet » va trien, su triet
xay hoi » xa hoi, tay hoi, cay phoi
thi van » thi lan, thi hanh, thi nang
nam sua » nam cua, nam suu, nam qua
nam mua » nam cua, nam qua, nam xua
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
sach o » sach lo, sac o, sach y
o dang » xo dang, do dang, so dang
vi ve » va ve, gi ve, ve ve

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach o dang xay hoi. thi van ((nam sua) or (nam mua)) va danh vi ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach o dang xay hoi. thi van ((nam sua) OR (nam mua)) va danh vi ve triet.
• Adding a wildcard symbol may retrieve word variants: thu sach o dang xay hoi. thi van ((nam sua) or (nam mua)) va danh vi ve triet*.