首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3531575篇
  免费   294042篇
  国内免费   14166篇
耳鼻咽喉   47900篇
儿科学   112579篇
妇产科学   92340篇
基础医学   561136篇
口腔科学   93796篇
临床医学   317236篇
内科学   629428篇
皮肤病学   93288篇
神经病学   303827篇
特种医学   137855篇
外国民族医学   490篇
外科学   541119篇
综合类   107624篇
现状与发展   24篇
一般理论   2337篇
预防医学   297066篇
眼科学   80596篇
药学   241597篇
  22篇
中国医学   10471篇
肿瘤学   169052篇
  2021年   55164篇
  2020年   35130篇
  2019年   58149篇
  2018年   71606篇
  2017年   54710篇
  2016年   60480篇
  2015年   74342篇
  2014年   108570篇
  2013年   173660篇
  2012年   98889篇
  2011年   99374篇
  2010年   117839篇
  2009年   122232篇
  2008年   86186篇
  2007年   89808篇
  2006年   100270篇
  2005年   95553篇
  2004年   96983篇
  2003年   87424篇
  2002年   76887篇
  2001年   118111篇
  2000年   111568篇
  1999年   107514篇
  1998年   66639篇
  1997年   64233篇
  1996年   62074篇
  1995年   57522篇
  1994年   51464篇
  1993年   48034篇
  1992年   74191篇
  1991年   69865篇
  1990年   65607篇
  1989年   64402篇
  1988年   59365篇
  1987年   58077篇
  1986年   54614篇
  1985年   54412篇
  1984年   49486篇
  1983年   45057篇
  1982年   42165篇
  1981年   39542篇
  1980年   37232篇
  1979年   40223篇
  1978年   35565篇
  1977年   32275篇
  1976年   29612篇
  1975年   27938篇
  1974年   29005篇
  1973年   28026篇
  1972年   26228篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
CONTEXT: Although the nonmedical use of stimulant drugs such as cocaine and methamphetamine is increasingly common in many rural areas of the United States, little is known about the health beliefs of people who use these drugs. PURPOSE: This research describes illicit stimulant drug users' views on health and health-related concepts that may affect their utilization of health care services. METHODS: A respondent-driven sampling plan was used to recruit 249 not-in-treatment, nonmedical stimulant drug users who were residing in 3 rural counties in west central Ohio. A structured questionnaire administered by trained interviewers was used to collect information on a range of topics, including current drug use, self-reported health status, perceived need for substance abuse treatment, and beliefs about health and health services. FINDINGS: Participants reported using a wide variety of drugs nonmedically, some by injection. Alcohol and marijuana were the most commonly used drugs in the 30 days prior to the interview. Powder cocaine was used by 72.3% of the sample, crack by 68.3%, and methamphetamine by 29.7%. Fair or poor health status was reported by 41.3% of the participants. Only 20.9% of the sample felt they needed drug abuse treatment. Less than one third of the sample reported that they would feel comfortable talking to a physician about their drug use, and 65.1% said they preferred taking care of their problems without getting professional help. CONCLUSIONS: Stimulant drug users in rural Ohio are involved with a range of substances and hold health beliefs that may impede health services utilization.  相似文献   
993.
994.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
995.
996.
科学研究的目标是创造和传播知识。这得通过对系统收集以及报告信息的批判性分析来完成。批判性分析始于一个简单的步骤,即在运用复杂统计学分析方法进行比较之前对所收集的数据进行深入检查。根据所收集的数据类型按照标准化方式进行统计学分析。在为解决研究问题而需采用合理、标准化步骤进行比较时,新知识就产生了,同时要避免错误的结论。在对数据进行仔细检查和分析之后,为了保证结论的正确性,再对数据进行一次批判性评论是非常重要的补充步骤。在科学文献中发表研究成果过程中涉及的同行评价对于传播新知识并保证其质量方面是一个非常重要的步骤。如果没有将研究成果发表供同行参考,这项研究就不算完整。  相似文献   
997.
998.
999.
Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.  相似文献   
1000.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号