Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
su triet » su viet, su tien, ve triet
dang xay » dang van, van xay
ve phan » va phan, ke phan, ve phat
danh ve » dinh ve, hanh ve, anh ve
va danh » va dinh, va dan, va hanh
thuc va » thuc vat, thuc dan, thuc day
su sach » so sach, vu sach
ve pham » vi pham, v pham, ve phat
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
ve su » va su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (thuoc sach)) ky dang xay hoi. hieu ((ve pham) OR (ve phan)) thuc va danh ve su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (thuoc sach)) ky dang xay hoi. hieu ((ve pham) OR (ve phan)) thuc va danh ve su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (thuoc sach)) ky dang xay hoi. hieu ((ve pham) OR (ve phan)) thuc va danh ve su triet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (thuoc sach)) ky dang xay hoi. hieu ((ve pham) OR (ve phan)) thuc va danh ve su triet*.