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   123218篇
  免费   32094篇
  国内免费   1135篇
耳鼻咽喉   2713篇
儿科学   3246篇
妇产科学   2622篇
基础医学   6006篇
口腔科学   5593篇
临床医学   28242篇
内科学   29946篇
皮肤病学   3656篇
神经病学   15276篇
特种医学   4727篇
外国民族医学   3篇
外科学   21800篇
综合类   761篇
现状与发展   40篇
一般理论   66篇
预防医学   15685篇
眼科学   2673篇
药学   2745篇
中国医学   25篇
肿瘤学   10622篇
  2024年   747篇
  2023年   5080篇
  2022年   1214篇
  2021年   3024篇
  2020年   5474篇
  2019年   2319篇
  2018年   7269篇
  2017年   7604篇
  2016年   8219篇
  2015年   8366篇
  2014年   11002篇
  2013年   13106篇
  2012年   5374篇
  2011年   5251篇
  2010年   7694篇
  2009年   9911篇
  2008年   5181篇
  2007年   4237篇
  2006年   5401篇
  2005年   4161篇
  2004年   3302篇
  2003年   2842篇
  2002年   2801篇
  2001年   2107篇
  2000年   1370篇
  1999年   1968篇
  1998年   2435篇
  1997年   2255篇
  1996年   2272篇
  1995年   2010篇
  1994年   1348篇
  1993年   1165篇
  1992年   968篇
  1991年   874篇
  1990年   730篇
  1989年   710篇
  1988年   673篇
  1987年   574篇
  1986年   514篇
  1985年   469篇
  1984年   476篇
  1983年   516篇
  1982年   497篇
  1981年   465篇
  1980年   344篇
  1979年   197篇
  1978年   269篇
  1977年   213篇
  1976年   203篇
  1974年   177篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
941.
Acase of periodic sweating with multifocal dystonia is reported in a 60-year-old woman. At the age of 48 years, she presented with involuntary twisting of the lower face on the right. Six months later she noticed similar movements in the head and right arm. Four years later she began having attacks of generalized sweating over the whole face, anterior region of the trunk and both arms. The attacks occurred hourly each and every day. They lasted for about 10 min and were followed by voluntary urinary voiding. The biochemical and laboratory investigations showed no abnormalities except for the luteinizing hormone and follicle-stimulating hormone values that were below normal. The computerized tomography and magnetic resonance imaging scans revealed a suprasellar cyst. Clonazepam was introduced with partial improvement of the dystonic movements but not of the sweating attacks. The patient refused surgery. Acetazolamide was added and reduced the sweating attacks. We speculate that the periodic sweating may be related to cerebrospinal fluid production and cyst enlargement, hence the ability of acetazoleamide, which reduces cerebrospinal fluid production, to reduce attacks.  相似文献   
942.
Principle-based ethics and nurses' attitudes towards artificial feeding   总被引:1,自引:0,他引:1  
Nurses often institute artificial feeding for patients who would otherwise starve Recently, the courts in the United States have favoured withholding or withdrawing feedings from patients who currently refuse or previously gave some indication they would refuse artificial nutrition and hydration This paper investigates under what circumstances nurses feel justified in withholding artificial nutrition and hydration Structured interviews were conducted with 40 cancer care nurses from two sites, and 40 dementia care nurses from two sites The interviews were based on two vignettes, one involving an alert patient with terminal cancer, the other a patient suffering end-stage Alzheimer's dementia, and were analysed for themes coinciding with principles of deontological ethics Investigators found that autonomy, beneficence and non-maleficence most often guided nurses' decisions to withhold or implement artificial feeding  相似文献   
943.
In 1980 a syndrome was first described in two adult males, consisting of macrocephaly, pigmented macules on the glans and shaft of the penis, and hamartomatous intestinal polyps. Since then, 10 additional cases have been identified. Herein, we present two new cases and review the cutaneous manifestations as well as additional features in patients with the Ruvalcaba-Myhre-Smith syndrome.  相似文献   
944.
945.
We investigated the role of metabolism in muscle fatigue during voluntary exercise in persons with mild multiple sclerosis (MS). Six MS and 8 healthy control subjects performed intermittent, progressive, isometric contractions of the ankle dorsiflexors, during which we measured maximum voluntary force (MVC), inorganic phosphate (Pi), phosphocreatine (PCr), and pH. During exercise. MVC fell sooner in MS, but by the end of exercise the relative decrease in MVC was similar in both groups. In contrast, at the end of exercise Pi/PCr increased to 1.86 ± 0.22 in controls but to only 0.66 ± 0.04 in MS (P < 0.01); likewise, pH was 6.75±0.04 in controls and unchanged (7.06 ± 0.04) in MS (P <0.01). The smaller metabolic change at the same relative exercise intensity suggests a failure of muscle activation that is present even in mild MS. Neurophsyiologic measures of activation indicated some central activation failure and no neuromuscular junction impairment in MS, and suggested that activation failure beyond the muscle membrane(excitation–contraction coupling) may be important in MS. We conclude that metabolic factors do not play a significant role in the development of muscle fatigue during voluntary exercise in mild MS. © 1994 John Wiley & Sons, Inc.  相似文献   
946.
947.
948.
SUMMARY In order to assess the reliability of drug information supplied by day-stay cases, 85 consecutive patients were interviewed. A comparison of the interview answers with the details previously volunteered during the admission procedure showed an increase of 80% in the information given by the patient. While the detailed interviewing technique is time-consuming and may not be infallible, this substantial increase in information highlights problems in the current routine.  相似文献   
949.
950.
Background: The Na sup + channel is voltage gated and characterized by three distinct states: closed, open, and inactivated. To identify the effects of halothane on the cardiac Na sup + current (INa) at various membrane potentials, the effects of 1.2 mm halothane at different holding potentials (VH) on INa were examined in single, enzymatically isolated guinea pig ventricular myocytes.

Methods: The INa was recorded using the whole-cell configuration of the patch-clamp technique. Currents were generated from resting VH s of -110, -80, or -65 mV. State-dependent block was characterized by monitoring frequency dependence, tonic block, and removal of inactivation by veratridine.

Results: Halothane produced significant (P < 0.05) VH -dependent depressions of peak INa (mean +/- SEM): 24.4 +/- 4.1% (VH = -110 mV), 42.1 +/- 3.4% (VH = -80 mV), and 75.2 +/- 1.5% (VH = -65 mV). Recovery from inactivation was significantly increased when cells were held at -80 mV (control, tau = 6.0 +/- 0.3 ms; halothane, tau = 7.1 +/- 0.4 ms), but not at -110 mV. When using a VH of -80 mV, halothane exhibited a use-dependent block, with block of INa increasing from 8.6 +/- 1.4% to 30.7 +/- 3.5% at test pulse rates of 2 and 11 Hz, respectively. Use-dependent inhibition was not apparent at VH of -110 mV. When inactivation of INa was removed by exposure to 100 micro Meter veratridine, no significant difference was observed in the depressant effect of halothane at both VH s: 26.6 +/- 4.5% (VH = -80 mV) and 26.4 +/- 5.6% (VH = -110 mV).  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