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   2355398篇
  免费   171945篇
  国内免费   3333篇
耳鼻咽喉   32082篇
儿科学   76135篇
妇产科学   62880篇
基础医学   348679篇
口腔科学   63654篇
临床医学   212475篇
内科学   458046篇
皮肤病学   51799篇
神经病学   185784篇
特种医学   88134篇
外国民族医学   489篇
外科学   354328篇
综合类   47561篇
现状与发展   12篇
一般理论   855篇
预防医学   183720篇
眼科学   54377篇
药学   175378篇
  11篇
中国医学   4576篇
肿瘤学   129701篇
  2021年   19078篇
  2019年   19678篇
  2018年   27194篇
  2017年   20464篇
  2016年   22844篇
  2015年   25762篇
  2014年   36271篇
  2013年   54237篇
  2012年   75083篇
  2011年   79905篇
  2010年   47302篇
  2009年   44772篇
  2008年   75007篇
  2007年   79901篇
  2006年   80683篇
  2005年   78190篇
  2004年   74739篇
  2003年   72016篇
  2002年   69676篇
  2001年   108779篇
  2000年   111484篇
  1999年   93526篇
  1998年   27054篇
  1997年   23710篇
  1996年   24091篇
  1995年   22768篇
  1994年   20918篇
  1993年   19747篇
  1992年   72020篇
  1991年   70091篇
  1990年   68408篇
  1989年   65672篇
  1988年   60313篇
  1987年   59137篇
  1986年   55232篇
  1985年   53020篇
  1984年   39326篇
  1983年   33404篇
  1982年   19870篇
  1979年   35870篇
  1978年   25655篇
  1977年   21238篇
  1976年   20333篇
  1975年   21816篇
  1974年   26149篇
  1973年   24807篇
  1972年   23205篇
  1971年   22037篇
  1970年   20247篇
  1969年   19316篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This paper gives the historical sketch necessary for an understanding of the current state of American psychiatry. It reviews some of the reasons why the rendering of good hospital care must be reconsidered, and describes some of the main features of the future public institution.  相似文献   
992.
During almost 12 years of development and clinical trials, diclofenac sodium has been shown to be both effective and safe as a new nonsteroidal antiinflammatory drug (NSAID) for the treatment of rheumatic diseases including ankylosing spondylitis (AS). We compared the safety and efficacy of 75, 100, or 125 mg/day of diclofenac with the same doses of indomethacin in a multicenter, randomized, parallel group trial in patients with AS. A single blind placebo washout period of 2 days to 2 weeks preceded the 13-week double blind treatment period. Both diclofenac and indomethacin produced significant (p less than 0.001) improvement from baseline for all 14 efficacy variables analyzed. There were no significant between treatment differences. Differences favored diclofenac in the frequency and the severity of adverse experiences reported and in the frequency of complaints affecting the central nervous system.  相似文献   
993.
Various cases are presented demonstrating the role of computed tomography (CT) in the assessment of serosal and bowel wall pathology. Reference is made to the morphology of the lesions. Illustrative examples of tumors, secondary malignant dissemination, irradiation injury to the gut, and intramural gas associated with ulcerative colitis, are all illustrated.  相似文献   
994.
995.
996.
997.
The spontaneous quantal and nonquantal acetylcholine release was investigated at the temperature range from 10 to 35 degrees C in white mouse semidiaphragm. The quantal release was evaluated by calculation of miniature end-plate potentials frequency, while the nonquantal one--from the H-effect value. The spontaneous quantal release increased exponentially with the temperature growth. The temperature dependence of the nonquantal release showed two relative maxima: at 20 degrees and 35 degrees C. At 10 degrees C the nonquantal release was absent. The value of calculated effective energy of activation of the quantal release was 57.0 kJ/mol in the investigated temperature range. The effective energy of activation for the nonquantal release process in intervals 15-20 degrees C and 25-35 degrees C was 45.5 and 38.2 kJ/mol, relatively. It is suggested that the nonquantal release is rather due to active transport processes than to simple diffusion of acetylcholine molecules.  相似文献   
998.
Application of thiamine (1 X 10(-11)-1 X 10(-3) mol/l) on the membrane of cochlear round window increased the amplitude and decreased the latency of the auditory nerve action potential, waves I and II of brainstem auditory-evoked electrical potentials in response to acoustic clicks of different intensity. The mechanism of thiamine action on auditory-evoked electric potentials is discussed.  相似文献   
999.
1000.
We examined several possible causes for the high incidence of poor sensory acuity in the limbs of 176 patients with moderate to severe peripheral vascular insufficiency. We investigated the relationships of diabetes, alcoholism, and smoking, as well as the severity of peripheral vascular disease, to the integrity of basic sensory modalities such as two-point discrimination and perception of light touch. The presence or absence of diabetes exerted the strongest effect on peripheral sensation. In patients who did not have diabetes, sensation in the limbs was most strongly affected by whether the patient was an alcoholic. Smoking did not have a significant effect on limb sensation. Among nondiabetic, nonalcoholic patients, there was a weak residual effect related to the severity of the peripheral vascular insufficiency. Even among these patients, however, systemic factors predominated in determining the loss of sensation. We also examined the extent to which loss of sensation might be related to the development of ulcers. Among patients who were not diabetic, there was a highly significant relationship between loss of sensation and the presence of limb ulceration. Surprisingly, however, there was no discernable relationship between the presence of ulcers in diabetic patients and the degree of loss of peripheral sensation. This result suggests that a large percentage of ulcers seen in diabetic patients are not of neurogenic origin.  相似文献   
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