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   4463篇
  免费   194篇
  国内免费   8篇
耳鼻咽喉   20篇
儿科学   340篇
妇产科学   164篇
基础医学   568篇
口腔科学   163篇
临床医学   263篇
内科学   773篇
皮肤病学   71篇
神经病学   249篇
特种医学   112篇
外科学   555篇
综合类   105篇
一般理论   2篇
预防医学   264篇
眼科学   143篇
药学   605篇
中国医学   20篇
肿瘤学   248篇
  2023年   24篇
  2022年   68篇
  2021年   123篇
  2020年   69篇
  2019年   85篇
  2018年   108篇
  2017年   84篇
  2016年   99篇
  2015年   109篇
  2014年   170篇
  2013年   209篇
  2012年   305篇
  2011年   328篇
  2010年   172篇
  2009年   166篇
  2008年   241篇
  2007年   267篇
  2006年   204篇
  2005年   214篇
  2004年   184篇
  2003年   169篇
  2002年   150篇
  2001年   116篇
  2000年   100篇
  1999年   90篇
  1998年   33篇
  1997年   33篇
  1996年   26篇
  1995年   18篇
  1994年   15篇
  1993年   16篇
  1992年   68篇
  1991年   56篇
  1990年   58篇
  1989年   54篇
  1988年   49篇
  1987年   41篇
  1986年   53篇
  1985年   39篇
  1984年   27篇
  1983年   23篇
  1981年   14篇
  1979年   16篇
  1977年   16篇
  1976年   11篇
  1974年   17篇
  1973年   19篇
  1972年   15篇
  1970年   9篇
  1969年   10篇
排序方式: 共有4665条查询结果,搜索用时 15 毫秒
31.
Various 2-adrenoceptor agonists were assessed for their effects on alcohol abstinence syndrome in rats. In the first experimental model, groups of Wistar rats were made alcohol dependent by feeding alcohol together with sweetened milk for 15 days. The volume of fluid intake was measured every 12 h to determine daily ethanol consumption. Abstinence signs following abrupt alcohol withdrawal were observed in control as well as test groups receiving various 2-adrenoceptor agonists. Clonidine, guanfacine and B-HT 920, in equimolar concentration (0.5 M/kg), effectively attenuated the various abstinence signs, which developed after alcohol withdrawal. In the other experimental model, rats were subjected to cold water immersion to induce wet shakes. The inhibitory action of 2-adrenoceptor agonists was assessed in this test model. Clonidine, guanfacine and B-HT 920 markedly suppressed the cold water immersion-induced wet shakes and pretreatment with yohimbine (0.1 and 2.0 M/kg) reversed this inhibitory effect. The present data reveal the possible therapeutic potential of 2-adrenoceptor agonists in alleviating alcohol abstinence syndrome, and suggest that the resultant reduced noradrenergic activity may be responsible for the beneficial action.  相似文献   
32.
Maternal and Child Health Journal - While the city offers economic opportunities for women in many countries, their safety and security remain vulnerable to urban violence, especially in poor...  相似文献   
33.
34.

Since the emergence of the COVID-19 pandemic, there has been an increasing body of research focused on the effects that measures like stay-at-home orders and social distancing are having on other aspects of health, including mental health and sexual health. Currently, there are limited extant data on the effects of the pandemic on sexual and gender minorities. Between April 15, 2020, and May 15, 2020, we invited participants in an ongoing U.S. national cohort study (Together 5000) to complete a cross-sectional online survey about the pandemic, and its effects on mental and sexual health and well-being (n?=?3991). Nearly all (97.7%) were living in an area where they were told they should only leave their homes for essentials. Most (70.1%) reported reducing their number of sex partners as a result of the pandemic. Among the 789 participants prescribed HIV pre-exposure prophylaxis (PrEP), 29.9% said they stopped taking their PrEP entirely, and 14.2% started selectively skipping doses. For those who had been taking PrEP, discontinuing PrEP was associated with having no new sex partners (β?=?0.90, 95% CI 0.40–1.40). Among the 152 HIV-positive participants, 30.9% said they were unable to maintain an HIV-related medical appointment because of the pandemic and 13.8% said they had been unable to retrieve HIV medications. Additionally, 35.3% of participants were experiencing moderate to severe anxiety because of the pandemic and 36.7% reported symptoms of depression. In a multivariable logistic regression, reporting a new sex partner in the prior 30 days was significantly associated with being aged 30 or older (vs. not, AOR?=?1.21), being Black (AOR?=?1.79) or Latinx (AOR?=?1.40, vs. white), and being unsure if they had been in close contact with someone diagnosed with COVID-19 (AOR?=?1.32, vs. no contact). It was unassociated with COVID-19-induced anxiety, depression, or knowing someone hospitalized with COVID-19. The pandemic has caused disruptions in sexual behavior (partner reduction) as well as difficulties navigating PrEP and HIV care continua. Findings will guide more comprehensive public health responses to optimize HIV prevention and treatment in the era of COVID-19.

  相似文献   
35.
A one day old neonate with a short colon, associated exomphalos minor; bifid scrotum and ileovesical fistula is reported.  相似文献   
36.
A patient who reported with a slowly growing swelling ovr thee lateral aspect of the left ankle, was investigated and diagnosed to have a giant cell tumour which was confirmed on FNAC. The tumour was managed with excision biopsy and reconstruction. The case is being reported for its rare site of occurrence.  相似文献   
37.
OBJECTIVE: One of the difficulties with lumboperitoneal (LP) shunts has been non-invasively ascertaining shunt function. It has been previously reported that in the presence of a functioning LP shunt the perimesencephalic cisterns become obliterated--the "absent cistern sign". In order to more rigorously test this association we performed a retrospective analysis of LP shunt patients at the Hospital for Sick Children, Toronto. METHODS: The CT scans of all patients undergoing LP shunting over a 17 year period were reviewed. The "absent cistern sign" and ventricular size were compared against the results of either an isotope shunt study or surgical findings performed within 2 days of the CT. RESULTS: There were 38 CT scans (27 patients) performed within 2 days of an isotope shunt study and 15 CT scans (14 patients) performed within 2 days of a surgical intervention. These results give the absent cistern sign a sensitivity of 75% and a specificity of 57% when compared to the shunt isotope findings and a sensitivity of 100% and a specificity of 50% when compared to the surgical findings. Over 30% of the CT scans showed ventriculomegaly in the presence of a functioning shunt and, conversely, nearly 45% of the CT scans had normal or small lateral ventricles in the presence of a malfunctioning shunt. CONCLUSIONS: The "absent cistern sign" appears to reliably rule out a completely blocked shunt, but is less reliable in detecting a normal or partially obstructed shunt. Ventricular size correlates poorly with LP shunt function.  相似文献   
38.
39.
Patterns of healing of scaphoid fractures. The importance of vascularity   总被引:2,自引:0,他引:2  
We studied 45 patients with 46 fractures of the scaphoid who presented sequentially over a period of 21 months. MRI enabled us to relate the pattern of the fracture to the blood supply of the scaphoid. Serial MRI studies of the four main patterns showed that each followed a constant sequence during healing and failure to progress normally predicted nonunion.  相似文献   
40.
It is known that polycythemia decreases the fluidity of the blood and impairs tissue perfusion due to red-cell sludging in the microcirculation. In this study, the effect of polycythemic hyperviscosity (PH) on bowel necrosis was evaluated in an experimental model of intestinal ischemia. Twenty-eight Wistar albino rats (90–170 g) were divided into two groups: group 1 was transfused to create hyperviscosity and then intestinal ischemia was produced (n = 16); in group 2 ischemia was produced without transfusion (n = 12). Intestinal ischemia was produced by clamping the superior mesenteric artery and the collateral arcades of the right colic artery for 30 min. Gross and histopathologic evaluations were performed by either immediate necropsy or relaparotomy 24 h later. Microscopic findings were graded from 0 to 3 according to the degree of ischemic changes. In group 1, 2 animals (12.5%) died before 24 h postoperatively; coagulation necrosis with grade 2 or 3 ischemic changes was observed in 10 animals (62.5%). In group 2 only a few hypertrophied Peyer's patches and capillary dilation were found, and all histopathologic changes were between grades 0 and 1. The difference between the histopathologic gradings of the two groups was significant (P < 0.001). It appears that in addition to reduced splanchnic blood flow, a secondary effect of PH is needed to induce ischemic coagulation necrosis. PH of the newborn must be considered a risk factor for necrotizing enterocolitis, so-called spontaneous intestinal perforations, and even intestinal atresia.Presented at the 1st European Congress of Pediatric Surgery, Graz/Austria, May 4–6, 1995  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