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   29476篇
  免费   6442篇
  国内免费   162篇
耳鼻咽喉   745篇
儿科学   774篇
妇产科学   842篇
基础医学   1373篇
口腔科学   3492篇
临床医学   4805篇
内科学   6978篇
皮肤病学   652篇
神经病学   2438篇
特种医学   1224篇
外科学   4637篇
综合类   77篇
现状与发展   12篇
一般理论   4篇
预防医学   3677篇
眼科学   479篇
药学   861篇
中国医学   103篇
肿瘤学   2907篇
  2024年   172篇
  2023年   1169篇
  2022年   578篇
  2021年   972篇
  2020年   1454篇
  2019年   762篇
  2018年   1664篇
  2017年   1502篇
  2016年   1741篇
  2015年   1864篇
  2014年   2396篇
  2013年   2820篇
  2012年   1406篇
  2011年   1517篇
  2010年   1717篇
  2009年   2241篇
  2008年   1260篇
  2007年   1021篇
  2006年   1017篇
  2005年   836篇
  2004年   615篇
  2003年   567篇
  2002年   483篇
  2001年   537篇
  2000年   415篇
  1999年   496篇
  1998年   537篇
  1997年   519篇
  1996年   564篇
  1995年   403篇
  1994年   314篇
  1993年   274篇
  1992年   216篇
  1991年   217篇
  1990年   185篇
  1989年   181篇
  1988年   155篇
  1987年   159篇
  1986年   133篇
  1985年   131篇
  1984年   104篇
  1983年   118篇
  1982年   99篇
  1981年   80篇
  1980年   59篇
  1979年   49篇
  1978年   43篇
  1977年   51篇
  1976年   33篇
  1975年   37篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
31.
32.
MR compatibility of Guglielmi detachable coils   总被引:6,自引:0,他引:6  
  相似文献   
33.
34.
Diffusely adhering Escherichia coli (E. coli) strains (DAEC) represent a potential cause of diarrhoea in infants, and the detection of type three secretion system (TTSS) genes in DAEC would substantiate their pathogenic nature. In this work, four isolates of DAEC, recovered from stools of diarrhoeic children, were analysed by PCR, in order to detect the presence of TTSS genes. Primers targeted to the escC, escJ, escN and escV, some of the most conserved TTSS genes in enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC), were used in order to verify the occurrence of homologous genes in our DAEC isolates. By this approach, we were able to characterise DNA fragments corresponding to putative escJ and escN genes in all DAEC isolates. Furthermore, DNA fragments homologous to the escC and escV genes were also amplified from all isolates. Besides the similarity found among the DAEC esc homologues with EPEC and EHEC esc genes, the nucleotide sequence analysis of the flanking regions of the amplified DNA fragments suggests that the putative DAEC esc genes are organised in the same manner as observed in EPEC and in EHEC strains. The results described here provide strong evidence for the presence of a TTSS in the DAEC strains analysed, implicating a pathogenic nature of these isolates.  相似文献   
35.
A Decade of Change in Obesity Surgery   总被引:4,自引:0,他引:4  
Background: The International (formerly National) Bariatric Surgery Registry began collecting data in January 1986. The aim of this study was to examine changes in the practice of surgical treatment of severe obesity that occurred during the decade of 1986 through 1995, as observed in the IBSR data. Methods: All data submitted to the IBSR during the decade were transferred to the IBM mainframe computer for analysis. Characteristics of operative type populations were compared over time using analysis of variance (ANOVA) for age, body mass index (BMI), operative weight and Chi-square (χ2) test for gender. Results: There has been a steady increase over the decade in mean patient weight. The operations used have changed from predominantly ‘simple’ operations to more frequent use of ‘complex’ operations. Within the categories of ‘simple’ and ‘complex’, an increase in the variety of operations occurred. As a group, patients with ‘simple’ operations have been heavier, more often male and public pay patients than those who have undergone ‘complex’ operations. One year weight loss was greater for Roux-en-Y gastric bypass (RGB) than vertical banded gastroplasty (VBG), but follow-up rates were too low to study the relative merits of the operations used. The reported incidence of operative mortality and serious complications (leak with peritonitis, abscess and pulmonary embolism) remained low. Conclusions: These observations and their implications can be summarized in three statements which relate to action for improved patient care in the beginning of the new century: (1) increasing weight of candidates for surgical treatment during this decade indicates the need for earlier use of operative treatment before irreversible complications of obesity can develop; (2) low risk of obesity surgery, decreasing postoperative hospital stay, and early weight control support the continued and increased use of surgical treatment; (3) continued widespread use of both ‘simple’ and ‘complex’ operations with increased modifications of standard RGB and VBG procedures emphasizes the need for standardized long-term data and analyses regarding both weight control and postoperative side-effects.  相似文献   
36.
Society often expects mothers and fathers to share equally in the perinatal grief process because the child was a common bond between them. Unfortunately, in perinatal grief, this is not always the case. The mother and the father can experience incongruent grieving and use discordant coping mechanisms. It is important to evaluate these differences to facilitate communication between the distraught parents. Improved communication can in turn facilitate the grieving process.  相似文献   
37.
38.
39.
Kathleen Rich MS  RN  CCNS 《Journal of Vascular Nursing》2002,20(4):125-35; quiz 136-7
Transcutaneous oxygen (TcPO(2)) measurements provide a noninvasive, objective determination of the oxygen level at the skin surface. This offers a means of estimating the underlying circulation and tissue oxygenation. The purpose of the pilot study was to measure the TcPO(2) value of the lower extremity of healthy men and women and of patients with peripheral arterial disease (PAD) in 4 different body and leg positions 24 hours after peripheral vascular surgery reconstruction. The specific aim was to determine if lower-extremity TcPO(2) measurements were affected by changes in extremity position in these subject populations. A convenience sample of 4 healthy health care professionals and 4 patients who had peripheral vascular reconstruction surgery 24 hours before the measurements were studied. Subjects were studied in 4 different leg and body positions: supine with legs extended, sitting with legs dependent, a 5 degrees head-up reverse Trendelenburg, and supine with legs elevated 10 in. The Radiometer TCM30 TcPO(2) monitor was used to carry out these measures. Findings revealed a statistically significant difference in TcPO(2) measurements between the 2 groups, with the healthy subjects having a significantly higher TcPO(2) measurement in all extremity positions compared with the revascularized subjects with PAD (P =.02-.05). Significant changes were noted in both the foot temperature (P =.03) and TcPO(2) measurements with extremity positions within the healthy subject group (P =.001). The foot and leg TcPO(2) measurements affect from leg and body position did not reach significance (P =.09) in the subjects with PAD. No change in foot temperature with extremity positioning (P =.42) was noted in the subjects with PAD. This pilot study provides a base in which additional research will be performed with TcPO(2) measurements in both the healthy and revascularized person.  相似文献   
40.
Juvenile Parkinsonism: clinical and metabolic characteristics.   总被引:1,自引:1,他引:0       下载免费PDF全文
Twenty one patients with idiopathic Parkinsonism beginning before the age of 40 years were investigated. The mean duration of the disease was 19 years. There was a good and sustained response to levodopa. Only four patients reached stages IV and V (Hoehn and Yahr). Intolerance to levodopa was observed in the more advanced stages of the disease. In the series the familial incidence of Parkinsonism (2 cases) and essential tremor (3 cases) was very low. Thyroid disorder, diabetes mellitus or macrocytic anaemia was not found in any of the cases.  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