What is a Patent?
  A patent for an invention is the grant of a property right to the inventor, issued by the Patent Office (e.g. SIPO, USPTO). Generally, the term of a new Patent of Invention (Standard Patent in Hong Kong) is 20 years from the date on which the application for the patent was filed in the China, Hong Kong or United States.
  The right conferred by the patent grant is, in the language of the statute and of the grant itself, “the right to exclude others from making, using, offering for sale, or selling” the invention in the China, Hong Kong or United States or “importing” the invention into the China, Hong Kong or United States. What is granted is not the right to make, use, offer for sale, sell or import, but the right to exclude others from making, using, offering for sale, selling or importing the invention. Once a patent is issued, the patentee must enforce the patent without aid of the Patent Office.
  What can be Patented?
  The patent law specifies the general field of subject matter that can be patented and the conditions under which a patent may be obtained.
  In the language of the statute, any person who “invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent,” subject to the conditions and requirements of the law. The word “process” is defined by law as a process, act or method, and primarily includes industrial or technical processes. The term “machine” used in the statute needs no explanation. The term “manufacture” refers to articles that are made, and includes all manufactured articles. The term “composition of matter” relates to chemical compositions and may include mixtures of ingredients as well as new chemical compounds. These classes of subject matter taken together include practically everything that is made by man and the processes for making the products.
  PATENT SEARCH LINKS (Patent Offices):

AUSTRALIA: http://www.ipaustralia.gov.au/
CANADA: http://opic.gc.ca/
CHINA: http://www.cpo.cn.net
GERMANY: http://www.deutsches-patentamt.de
FRANCE: http://www.inpi.fr
UNITED KINGDOM: http://www.patent.gov.uk
ITALY: http://www.european-patent-office.org/it/
JAPAN: http://www.jpo-miti.go.jp
U.S.A: http://www.uspto.gov/
WIPO: http://www.wipo.int; http://www.ompi.int