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   2045篇
  免费   212篇
  国内免费   65篇
耳鼻咽喉   7篇
儿科学   72篇
妇产科学   31篇
基础医学   344篇
口腔科学   47篇
临床医学   266篇
内科学   437篇
皮肤病学   41篇
神经病学   234篇
特种医学   270篇
外科学   131篇
综合类   41篇
一般理论   1篇
预防医学   209篇
眼科学   26篇
药学   110篇
中国医学   1篇
肿瘤学   54篇
  2021年   11篇
  2020年   10篇
  2019年   14篇
  2018年   17篇
  2017年   18篇
  2016年   21篇
  2015年   30篇
  2014年   29篇
  2013年   63篇
  2012年   55篇
  2011年   63篇
  2010年   53篇
  2009年   63篇
  2008年   74篇
  2007年   101篇
  2006年   70篇
  2005年   75篇
  2004年   60篇
  2003年   65篇
  2002年   54篇
  2001年   46篇
  2000年   49篇
  1999年   49篇
  1998年   79篇
  1997年   84篇
  1996年   94篇
  1995年   77篇
  1994年   58篇
  1993年   62篇
  1992年   32篇
  1991年   42篇
  1990年   43篇
  1989年   73篇
  1988年   43篇
  1987年   52篇
  1986年   41篇
  1985年   59篇
  1984年   38篇
  1983年   47篇
  1982年   46篇
  1981年   36篇
  1980年   35篇
  1979年   26篇
  1978年   29篇
  1977年   26篇
  1976年   11篇
  1975年   12篇
  1971年   10篇
  1970年   13篇
  1969年   15篇
排序方式: 共有2322条查询结果,搜索用时 9 毫秒
131.
OBJECTIVE: Voxel-based morphometry is a method for detecting group differences in the density or volume of brain matter. The authors reviewed the literature on use of voxel-based morphometry in schizophrenia imaging research to examine the capabilities of this method for clearly identifying specific structural differences in patients with schizophrenia, compared with healthy subjects. The authors looked for consistently reported results of relative deficits in gray and white matter in schizophrenia and evaluated voxel-based morphometry methods in order to propose a future strategy for using voxel-based morphometry in schizophrenia research. METHOD: The authors reviewed all voxel-based morphometry studies of schizophrenia that were published to May 2004 (15 studies). The studies included a total of 390 patients with a diagnosis of schizophrenia and 364 healthy volunteers. RESULTS: Gray and white matter deficits in patients with schizophrenia, relative to healthy comparison subjects, were reported in a total of 50 brain regions. Deficits were reported in two of the 50 regions in more than 50% of the studies and in nine of the 50 regions in one study only. The most consistent findings were of relative deficits in the left superior temporal gyrus and the left medial temporal lobe. Use of a smaller smoothing kernel (4-8 mm) led to detection of a greater number of regions implicated in schizophrenia. CONCLUSIONS: This review implicates the left superior temporal gyrus and the left medial temporal lobe as key regions of structural difference in patients with schizophrenia, compared to healthy subjects. The diversity of regions reported in voxel-based morphometry studies is in part related to the choice of variables in the automated process, such as smoothing kernel size and linear versus affine transformation, as well as to differences in patient groups. Voxel-based morphometry can be used as an exploratory whole-brain approach to identify abnormal brain regions in schizophrenia, which should then be validated by using region-of-interest analyses.  相似文献   
132.
CONTEXT: There have been very few randomized controlled treatment studies of anorexia nervosa. OBJECTIVE: To evaluate factors leading to nonacceptance and noncompletion of treatment for 2 specific therapies and their combination in the treatment of anorexia nervosa. DESIGN: Randomized prospective study. SETTING: Weill-Cornell Medical Center, White Plains, NY; University of Minnesota, Minneapolis; and Stanford University, Stanford, Calif.Patients One hundred twenty-two patients meeting DSM-IV criteria for anorexia nervosa. INTERVENTIONS: Treatment with cognitive-behavioral therapy, fluoxetine hydrochloride, or their combination for 1 year. MAIN OUTCOME MEASURES: Dropout rate and acceptance of treatment (defined as staying in treatment at least 5 weeks). RESULTS: Of the 122 randomized cases, 21 (17%) were withdrawn; the overall dropout rate was 46% (56/122) in the remaining patients. Treatment acceptance occurred in 89 (73%) of the 122 randomized cases. Of the 41 assigned to medication alone, acceptance occurred in 23 (56%). In the other 2 groups, acceptance rate was differentiated by high and low obsessive preoccupation scores (rates of 91% and 60%, respectively). The only predictor of treatment completion was high self-esteem, which was associated with a 51% rate of treatment acceptance. CONCLUSION: Acceptance of treatment and relatively high dropout rates pose a major problem for research in the treatment of anorexia nervosa. Differing characteristics predict dropout rates and acceptance, which need to be carefully studied before comparative treatment trials are conducted.  相似文献   
133.
The provision of telephone advice to members of the general public from staff based in accident and emergency departments is common practice. However, it is largely conducted on an ad hoc basis without the use of formal guidelines or decision support. The evidence base from which to derive guidelines for the telephone assessment and advice of many common conditions is lacking. This study, using the Delphi technique, was undertaken to develop a number of benchmarks for use as objective measures against which the comprehensiveness of telephone assessments could be tested. Consensus views on the essential and desirable items to be considered for each of 10 presenting complaints was achieved. It is argued that establishing consensus views on clinical topics provides an effective means of developing an evidence base where other sources of evidence are lacking.  相似文献   
134.
135.
Among the most serious problems a doctor can have may be those which are the result of a defect of character or a flaw in ethics. Under these circumstances, unacceptable behavior patterns may arise. Examples of unacceptable patterns of behavior include dishonesty, intentionally harming a patient, sexual harassment, and substance abuse. For years, doctors who have these patterns have been handled with kid gloves by those who educate, train, and supervise professionals in the healthcare industry. Counseling, coaching, training, supervising, transfers to less critical disciplines, disciplinary warnings, and offering opportunities to resign have been the typical protocols. Traditionally, outright firing of residents and doctors has been relatively taboo and too radical for the medical profession. Why has this been the case? Reasons may include unwillingness to get involved or to deal with the stress of disciplining a colleague, an unwillingness which often is grounded in fears of retaliation. In a litigious society, fears of slander lawsuits, for example, may be all-too-real. However, the implied paternalism and the practice of protecting doctors' careers by preserving their professional status as practicing doctors have become increasingly problematic. Aside from the fact that it is unethical, allowing problem doctors to continue to practice medicine may have an adverse impact on the well-being of patients and therefore may represent an enormous legal liability for organizations that employ them. In this first of a two-part series, problems that now exist and implementation of a performance management system as a starting point for removing rogues from the system are discussed. A subsequent paper will detail how such a system operates.  相似文献   
136.
Ortegon DP  Dixon PS  Crow KK  Mueller DL  Kerby JD 《The Journal of trauma》2003,55(4):755-60; discussion 760-1
BACKGROUND: We previously demonstrated that HBOC-201 is an efficient resuscitation fluid. However, little is known about its immunomodulatory effects. The goal of this study was to investigate human neutrophil activation after exposure to HBOC-201 and other low-volume resuscitation fluids. METHODS: Whole blood from 10 healthy volunteers was serially diluted with HBOC-201, 7.5% hypertonic saline (HTS), 7.5% hypertonic saline-6% dextran 70 (HSD), Hextend, or PentaLyte. After an incubation period, samples were analyzed for oxidative burst and CD11b expression using flow cytometry. RESULTS: Increases in both CD11b and oxidative burst activity were noted in samples diluted with HBOC-201, Hextend, PentaLyte, and lactated Ringer's solution. Samples maximally diluted with HBOC-201 demonstrated increased CD11b expression when compared with lactated Ringer's solution and Hextend (196.11% vs. 22.68% and 33.97%; p = 0.018 and p = 0.033). CONCLUSION: Although differences were noted only at the highest dilutions, further studies investigating the effects of HBOC-201 are warranted.  相似文献   
137.
138.
139.
140.
Four studies have reported that the mediodorsal nucleus of the thalamus (MD) is smaller and contains fewer neurons in schizophrenia. The MD is a key node in a circuit proposed to be dysfunctional in the disorder. However, one study did not find a MD volume loss in schizophrenia, and all the studies to date are relatively small. Given the importance of establishing unequivocally the presence of MD pathology, we have carried out a study of the volume and number of neurons in the left and right MD in 21 patients with schizophrenia and 27 healthy comparison subjects. We also measured the size of MD neurons, and estimated total thalamic volume. We found no difference in the volume of the MD, the number of MD neurons, or the size of MD neurons in either hemisphere in schizophrenia. Neither was total thalamic volume altered. There are no obvious methodological or clinical factors to explain our failure to replicate the finding of MD involvement in schizophrenia. Hence our negative observations, in the largest sample yet investigated, cast doubt on the robustness and/or the generalisability of MD neuropathology in schizophrenia.  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