Protective effects and its mechanisms of total alkaloids from rhizoma Coptis chinensis on Helicobacter pylori LPS induced gastric lesion in rats Effects of Xiangsha Liujunzi decoction on TLR signal pathway in gastric mucosa tissues of rats with Helicobacter pylori-induced chronic atrophic gastritis Cloning,Expression and Purification of Urease B Subunit of Helicobacter pylori Studies on Effects of Xuedan on the Experimental Gastric Ulcer