Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cam truc » nam truc, lam truoc, nam truoc
tinh tai » trinh tai, tinh thai, tinh hai
ky danh » ky dang
hieu va » lieu va, hieu qua
tai cua » thai cua, tai cuc, tri cua
ky anh » ly anh, ty anh
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((ky danh) or (ky anh)) xa hoi. hieu va ((cam truc) OR (cau truc)) may tinh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky danh) OR (ky anh)) xa hoi. hieu va ((cam truc) OR (cau truc)) may tinh tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ky danh) or (ky anh)) xa hoi. hieu va ((cam truc) OR (cau truc)) may tinh tai cua te".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ky danh) or (ky anh)) xa hoi. hieu va ((cam truc) OR (cau truc)) may tinh tai cua te*.