Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
danh tai » doanh tai, dinh tai, hanh tai
cam truc » cau truc, nam truc, lam truoc
tai cua » thai cua, tai cuc, tri cua
va danh » va dinh, va dan, va hanh
truc va » thuc va, thuc vat, trung va
hieu va » lieu va, hieu qua
xay hoi » xa hoi, tay hoi, cay phoi
ky danh » ky anh
ky dang » ky nang
va cam » va cham, va cac, va cao
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) or (doc sach)) ((ky dang) OR (ky danh)) xay hoi. hieu va cam truc va danh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ((ky dang) OR (ky danh)) xay hoi. hieu va cam truc va danh tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ((ky dang) OR (ky danh)) xay hoi. hieu va cam truc va danh tai cua te".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ((ky dang) OR (ky danh)) xay hoi. hieu va cam truc va danh tai cua te*.