Perhaps you should try some spelling variations:
cao thuoc » cay thuoc, cua thuoc, nam thuoc
thai cua » than cua, tai cuc, tri cua
toc sach » hoc sach, doc sach, thuoc sach
thuoc va » thuc va, thuoc ma, thuong va
tai cua » tai cuc, tri cua, dai cua
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
va danh » va dinh, va dan, va hanh
va cao » va cac, va co, va dao

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

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