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   7857篇
  免费   507篇
  国内免费   24篇
耳鼻咽喉   48篇
儿科学   227篇
妇产科学   107篇
基础医学   1177篇
口腔科学   165篇
临床医学   678篇
内科学   1578篇
皮肤病学   309篇
神经病学   945篇
特种医学   369篇
外科学   686篇
综合类   43篇
一般理论   1篇
预防医学   585篇
眼科学   162篇
药学   584篇
中国医学   14篇
肿瘤学   710篇
  2023年   57篇
  2022年   81篇
  2021年   147篇
  2020年   120篇
  2019年   149篇
  2018年   177篇
  2017年   137篇
  2016年   161篇
  2015年   218篇
  2014年   266篇
  2013年   345篇
  2012年   585篇
  2011年   553篇
  2010年   332篇
  2009年   325篇
  2008年   499篇
  2007年   461篇
  2006年   438篇
  2005年   460篇
  2004年   405篇
  2003年   407篇
  2002年   376篇
  2001年   124篇
  2000年   97篇
  1999年   134篇
  1998年   109篇
  1997年   81篇
  1996年   67篇
  1995年   57篇
  1994年   39篇
  1993年   49篇
  1992年   74篇
  1991年   61篇
  1990年   61篇
  1989年   74篇
  1988年   61篇
  1987年   42篇
  1986年   46篇
  1985年   48篇
  1984年   44篇
  1983年   32篇
  1981年   25篇
  1980年   21篇
  1979年   48篇
  1978年   23篇
  1977年   25篇
  1976年   21篇
  1974年   21篇
  1973年   20篇
  1971年   21篇
排序方式: 共有8388条查询结果,搜索用时 15 毫秒
11.
Post-traumatic ulnar carpal translocation is a rare, severe ligamentous injury to the wrist. Radiologic findings include widening of the radiocarpal joint space at the radial styloid process and ulnar displacement of the carpus. Less than 50% of the lunate articulates with the radius in the neutral position; the lunate is tilted dorsally with palmar subluxation due to a ruptured radioscapholunate (RSL) ligament. This malposition should be called rotatory palmar subluxation of the lunate (RPSL), by analogy to rotatory subluxation of the scaphoid (RSS). In contrast to dorsiflexed intercalated segment instability (DISI), in RPSL the RSL ligament is ruptured and, in the majority of cases, the scapholunate ligament remains intact. A prompt diagnosis should lead to successful treatment.  相似文献   
12.
OBJECTIVE: Apathy is among the most frequent neuropsychiatric symptoms in dementia, particularly Alzheimer disease. The Apathy Evaluation Scale (AES) has been widely employed for assessing apathy in different patient groups. To further facilitate the usage of the AES, an abbreviated version was constructed. METHOD: On basis of a sample of 356 nursing home residents, a cross-validation procedure was carried out to develop a brief version of the AES. According to a thorough clinical examination, 85% of the residents were demented, 8% presented with mild cognitive impairment, whereas 7% did not present any cognitive deficits. After subdividing the patient group into two matched samples, the first subsample was used to identify problematic items due to defined psychometric and content-related criteria. The original 18-item scale was thus reduced to 10 items. Psychometric properties of the shortened version were subsequently reassessed in the second subsample. RESULTS: The short version demonstrated favorable psychometric properties that could be confirmed by cross-validation with the second sample. Correlations with the original full-length version were high (r = 0.97 for both subsamples); the shortened scale yielded no substantial losses regarding internal consistency or construct validity (correlations with the respective subscales of the Neuropsychiatric Inventory). CONCLUSION: The frequency of apathetic symptoms in the nursing home residents included confirms the clinical importance of apathy for understanding dementia. Given this specific patient population, setting, and mode of data collection, the short-version AES seems to be a valuable and time-efficient instrument for assessing apathy.  相似文献   
13.
BACKGROUND: Systemic vascular resistance (SVR) is an integral therapeutic component of patients with heart failure and shock. We hypothesized that the ratio of the peak mitral regurgitant velocity (MRV) (m/s) to left ventricular outflow time-velocity integral (TVI(LVOT)) (cm) by Doppler would provide a noninvasive correlate of SVR. METHODS: SVR was correlated to MRV/TVI(LVOT) in 33 patients undergoing right heart catheterization. Receiver operating characteristic curves were generated to determine the best-balanced sensitivity and specificity to identify SVR > 14 Wood units (WU) and <10 WU. RESULTS: MRV/TVI(LVOT) correlated well with SVR (r = 0.842, 95% confidence interval 0.7-0.92, P <.001, Y = 0.459 + 49.397*X). By receiver operating characteristics, MRV/TVI(LVOT) > 0.27 had a 70% sensitivity and a 77% specificity to identify SVR > 14 WU. MRV/TVI(LVOT) < 0.2 had a 92% sensitivity and a 88% specificity to identify SVR < 10 WU. CONCLUSION: Doppler echocardiography provides a reliable noninvasive assessment of SVR.  相似文献   
14.
15.
Crry (complement receptor 1–related protein/gene y) is a key cellular complement regulator in rodents. It is also present in Fx1A, the renal tubular preparation used to immunize rats to induce active Heymann nephritis (HN), a model of membranous nephropathy. We hypothesized that rats immunized with anti-Fx1A develop autoantibodies (auto-Abs) to Crry as well as to the megalin-containing HN antigenic complex, and that anti-Crry Abs promote the development of injury in HN by neutralizing the complement regulatory activity of Crry. Rats immunized with Fx1A lacking Crry remained free of proteinuria and glomerular deposits of C3 during a 10-wk follow-up despite typical granular immunoglobulin (Ig)G deposits in glomeruli. Anti-Fx1A auto-Abs were present in their sera at levels that were not different from sera pooled from proteinuric rats with HN induced with nephritogenic Fx1A. Passive administration of sheep anti-Crry Abs to rats immunized with Crry-deficient Fx1A led to proteinuria and glomerular C3 deposition, which were not seen in such rats injected with preimmune IgG, nor in rats with collagen-induced arthritis injected with anti-Crry IgG. To directly examine the role of Crry in HN, rats were immunized with Crry-deficient Fx1A reconstituted with rCrry. This led to typical HN, with 8 out of 15 rats developing proteinuria within 14 wk. Moreover, the extent of glomerular C3 deposition correlated with proteinuria, and anti-Crry Abs were present in glomerular eluates. Thus, Crry is a key nephritogenic immunogen in Fx1A. Formation of neutralizing auto-Abs to Crry impairs its function, leading to unrestricted complement activation by Abs reactive with the HN antigenic complex on the epithelial cell surface.  相似文献   
16.
17.
18.
In a retrospective study, the bilirubin plasma concentrations of every patient admitted to the Psychiatric Hospital were collected. Patients suffering from liver disease, substance abuse, overt hemolysis, or increased liver enzymes were excluded. Schizophrenics showed a significantly higher incidence of hyperbilirubinemia than patients suffering from other psychiatric disorders. This phenomenon seems to be independent of drug usage and therefore points to a relationship between hyperbilirubinemia and schizophrenic psychosis. Hypothetic explanations, such as a possible genetic disposition for Gilbert Syndrome, an increased vulnerability of red-cell membranes, and the role of estrogens in schizophrenic patients, are discussed.  相似文献   
19.
3,4,5,6-Tetrahydro-1H-2,6-methano-2-benzazocin-5-one and its Reduction Products 3,4,5,6-Tetrahydro-1H-2,6-methano-2-benzazocin-5-one 2 has been prepared by oxidation of N-benzyl-4-piperidone 1 with cerium(IV) sulfate. 2 was reduced by sodium borohydride or lithium aluminum hydride in various solvents. The stereoselectivity of these reductions is high. The configurations of the epimeric alcohols were determined by 1H-NMR spectroscopy.  相似文献   
20.
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