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   454篇
  免费   29篇
  国内免费   3篇
耳鼻咽喉   1篇
儿科学   4篇
妇产科学   15篇
基础医学   38篇
口腔科学   4篇
临床医学   27篇
内科学   57篇
皮肤病学   7篇
神经病学   92篇
特种医学   27篇
外科学   138篇
综合类   1篇
预防医学   29篇
眼科学   20篇
药学   9篇
肿瘤学   17篇
  2023年   4篇
  2022年   6篇
  2021年   10篇
  2020年   7篇
  2019年   16篇
  2018年   15篇
  2017年   2篇
  2016年   12篇
  2015年   14篇
  2014年   13篇
  2013年   27篇
  2012年   27篇
  2011年   23篇
  2010年   8篇
  2009年   12篇
  2008年   17篇
  2007年   14篇
  2006年   25篇
  2005年   30篇
  2004年   13篇
  2003年   11篇
  2002年   15篇
  2001年   6篇
  1999年   12篇
  1998年   6篇
  1997年   9篇
  1996年   2篇
  1995年   5篇
  1994年   4篇
  1992年   6篇
  1991年   8篇
  1990年   4篇
  1989年   3篇
  1988年   6篇
  1987年   5篇
  1986年   10篇
  1985年   19篇
  1984年   10篇
  1983年   6篇
  1981年   4篇
  1980年   2篇
  1979年   13篇
  1978年   5篇
  1977年   3篇
  1976年   5篇
  1975年   4篇
  1974年   2篇
  1972年   1篇
  1971年   1篇
  1967年   1篇
排序方式: 共有486条查询结果,搜索用时 31 毫秒
1.
ObjectiveTo evaluate the significance of sonographic perinephric fluid collection on the emergent management of patients with acute urinary stone obstruction.MethodsWe conducted a prospective study with retrospective analysis. Since January 2016 through July 2017, patients admitted to our tertiary hospital's emergency department (ED) with suspected symptomatic urinary stones underwent ultrasound evaluation. Images were prospectively interpreted by experienced radiologist who analyzed each case for the following imaging features: hydronephrosis, perinephric fluid and urethral stone identification. The presence and measurements of perinephric fluid were re-evaluated by second radiologist who was blinded for the first reader's measurements. Retrospective analysis was conducted to evaluate for an association between perinephric fluid collection and the following outcome variables: need for analgesics, the number of doses of analgesics and the amount of morphine (mg) in the ED, elevation of creatinine levels, hospitalization and need for urological interventions.ResultsThe need for analgesics, the number of doses of analgesics and the amount of morphine were significantly associated with the presence of perinephric fluid (p < 0.05). The odds ratio for the need for analgesics was 3.8 in the presence of any perinephric fluid, and 8.9 in the presence of moderate/severe perinephric fluid. No other patient outcome variables were found to be significantly associated with the presence of perinephric fluid (p > 0.05).ConclusionsThis study shows a correlation between sonographic evidence of perinephric fluid and more severe pain. Therefore, an emergency physician can consider the evidence of perinephric fluid, in acute urethral stone obstruction, a predictor for more severe pain.  相似文献   
2.
It has been observed but never proven that anomalies of the anterior communicating artery complex are associated with anterior communicating artery aneurysms (ACAA). Therefore, in an effort to understand the significance of haemodynamic factors in the genesis, as well as the clinical course of ACAA, we evaluated the correlation between certain angiographic patterns of flow in the anterior circulation and the clinical findings of 51 patients with ACAA compared with 50 matched controls. Four significant associations which have never been validated were identified: 1) a dominant A1 (filling both A2's) was found in 57% of ACAA patients versus 14% of controls (p less than 0.001). 2) Unilateral hypoplasia of the opposite A1 was present in 24% of ACAA patients versus 6% of controls (p = 0.01). 3) Exclusive filling of the ACAA from one A1 occurred in 78%. 4) No statistically significant relationship was found between the anatomic flow patterns studied and the patients clinical presentation including age, sex, or grade. We conclude that anterior communicating artery aneurysms are significantly related in a majority of patients with the presence of a dominant A1, probably as the result of enhanced haemodynamic stress caused by this anatomic abnormality in the circulation. However, this association is not constant, and a dominant pattern of flow did not correlate with the clinical course. This is probably a reflection of the differences between factors initiating aneurysm formation and those influencing its growth, as well as of the relative limitations of angiography when pathophysiological extrapolations are attempted.  相似文献   
3.
Summary Different methods have been used in the evaluation and monitoring of the cerebral oxygen supply during neuro-interventional therapies. Attenuation of near-infrared light by the chromophores oxyhemoglobin and deoxyhemoglobin have shown to be useful in the study of the cellular oxygen metabolism and oxygen delivery to the brain. Transcranial cerebral oximetry (TCCO) has the advantage of providing real-time information regarding regional brain oxygen saturation (rSO2) by using wavelengths in the near-infrared range.We present a patient with a carotid cavernous fistula who underwent balloon occulusion and concurrent continuous TCCO monitoring. TCCO was found to be a useful tool providing immediate rSO2 values during the angiographic and interventional procedures. Initial balloon occlusion of a carotid cavernous fistula resulted in partial occlusion of the internal carotid artery lumen causing an immediate decrease in rSO2 which correlated with angiographic findings. Subsequent reocclusion of the fistula produced a slower and smaller degree of decrease in rSO2 with clinical improvement in the patient. Changes in rSO2 were detected before any adverse clinical event was observed. TCCO was reliable, safe, sensitive, and provided a real-time assessment tool for the monitoring of brain oxygen supply in a patient undergoing a neuroendovascular procedure.  相似文献   
4.
5.
Our inability to associate distant regulatory elements with the genes they regulate has largely precluded their examination for sequence alterations contributing to human disease. One major obstacle is the large genomic space surrounding targeted genes in which such elements could potentially reside. In order to delineate gene regulatory boundaries, we used whole-genome human-mouse-chicken (HMC) and human-mouse-frog (HMF) multiple alignments to compile conserved blocks of synteny (CBSs), under the hypothesis that these blocks have been kept intact throughout evolution at least in part by the requirement of regulatory elements to stay linked to the genes they regulate. A total of 2116 and 1942 CBSs >200 kb were assembled for HMC and HMF, respectively, encompassing 1.53 and 0.86 Gb of human sequence. To support the existence of complex long-range regulatory domains within these CBSs, we analyzed the prevalence and distribution of chromosomal aberrations leading to position effects (disruption of a gene's regulatory environment), observing a clear bias not only for mapping onto CBS but also for longer CBS size. Our results provide an extensive data set characterizing the regulatory domains of genes and the conserved regulatory elements within them.  相似文献   
6.
Summary Five aneurysm clips and their respective appliers (Heifetz, Vari-Angle, McFadden, Scoville, and Yaargil) were tested for the production of small metal shards that could provoke a foreign body reaction or increase the risk of a stresscorrosion failure. Pivot and Vari-Angle-McFadden clips produced numerous large shards, the Scoville clip produced a few fine shards, and the Yaargil and Heifetz clips produced none. Metal shard production due to cold metal transfer is attributed to the abrasive mechanical interaction between clips and appliers made from metals with different degrees of hardness.  相似文献   
7.
8.
9.
Recent research suggests that viewing sexually explicit media (SEM), i.e., adult videos, may influence sexual risk taking among men who have sex with men. Despite this evidence, very little is known about the content of gay male SEM on the Internet, including the prevalence of sexual risk behaviors and their relation to video- and performer-characteristics, viewing frequency, and favorability. The current study content analyzed 302 sexually explicit videos featuring male same-sex performers that were posted to five highly trafficked adult-oriented websites. Findings revealed that gay male SEM on the Internet features a variety of conventional and nonconventional sexual behaviors. There was a substantial prevalence of unprotected anal intercourse (UAI) (34 %) and was virtually the same as the prevalence of anal sex with a condom (36 %). The presence of UAI was not associated with video length, amateur production, number of video views, favorability, or website source. However, the presence of other potentially high-risk behaviors (e.g., ejaculation in the mouth, and ejaculation on/in/rubbed into the anus) was associated with longer videos, more views, and group sex videos (three or more performers). The findings of high levels of sexual risk behavior and the fact that there was virtually no difference in the prevalence of anal sex with and without a condom in gay male SEM have important implications for HIV prevention efforts, future research on the role of SEM on sexual risk taking, and public health policy.  相似文献   
10.
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