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   2418篇
  免费   197篇
  国内免费   15篇
耳鼻咽喉   16篇
儿科学   75篇
妇产科学   39篇
基础医学   332篇
口腔科学   97篇
临床医学   204篇
内科学   620篇
皮肤病学   62篇
神经病学   261篇
特种医学   73篇
外科学   235篇
综合类   8篇
一般理论   1篇
预防医学   176篇
眼科学   19篇
药学   212篇
中国医学   8篇
肿瘤学   192篇
  2024年   3篇
  2023年   30篇
  2022年   55篇
  2021年   126篇
  2020年   61篇
  2019年   85篇
  2018年   87篇
  2017年   72篇
  2016年   87篇
  2015年   99篇
  2014年   122篇
  2013年   127篇
  2012年   208篇
  2011年   197篇
  2010年   108篇
  2009年   88篇
  2008年   159篇
  2007年   159篇
  2006年   151篇
  2005年   139篇
  2004年   126篇
  2003年   117篇
  2002年   89篇
  2001年   9篇
  2000年   7篇
  1999年   9篇
  1998年   12篇
  1997年   14篇
  1996年   12篇
  1995年   8篇
  1994年   8篇
  1993年   7篇
  1992年   3篇
  1991年   5篇
  1990年   3篇
  1989年   4篇
  1988年   2篇
  1987年   2篇
  1986年   7篇
  1985年   1篇
  1984年   3篇
  1983年   9篇
  1982年   3篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
  1973年   1篇
  1954年   1篇
  1947年   1篇
排序方式: 共有2630条查询结果,搜索用时 15 毫秒
61.
Clinical Rheumatology - The objective of this analysis is to examine whether the severity of systemic sclerosis (SSc)-hand involvement influences patient-reported outcome measure (PROM) completion...  相似文献   
62.
Although glucagon is known to stimulate the cyclic adenosine monophosphate (cAMP)-mediated hepatocyte bile secretion, the precise mechanisms accounting for this choleretic effect are unknown. We recently reported that hepatocytes express the water channel aquaporin-8 (AQP8), which is located primarily in intracellular vesicles, and its relocalization to plasma membranes can be induced with dibutyryl cAMP. In this study, we tested the hypothesis that glucagon induces the trafficking of AQP8 to the hepatocyte plasma membrane and thus increases membrane water permeability. Immunoblotting analysis in subcellular fractions from isolated rat hepatocytes indicated that glucagon caused a significant, dose-dependent increase in the amount of AQP8 in plasma membranes (e.g., 102% with 1 micromol/L glucagon) and a simultaneous decrease in intracellular membranes (e.g., 38% with 1 micromol/L glucagon). Confocal immunofluorescence microscopy in cultured hepatocytes confirmed the glucagon-induced redistribution of AQP8 from intracellular vesicles to plasma membrane. Polarized hepatocyte couplets showed that this redistribution was specifically to the canalicular domain. Glucagon also significantly increased hepatocyte membrane water permeability by about 70%, which was inhibited by the water channel blocker dimethyl sulfoxide (DMSO). The inhibitors of protein kinase A, H-89, and PKI, as well as the microtubule blocker colchicine, prevented the glucagon effect on both AQP8 redistribution to hepatocyte surface and cell membrane water permeability. In conclusion, our data suggest that glucagon induces the protein kinase A and microtubule-dependent translocation of AQP8 water channels to the hepatocyte canalicular plasma membrane, which in turn leads to an increase in membrane water permeability. These findings provide evidence supporting the molecular mechanisms of glucagon-induced hepatocyte bile secretion.  相似文献   
63.
OBJECTIVES: Changes in extracellular matrix glycosaminoglycans (GAGs) of the intestinal mucosa have been associated with inflammatory bowel disease. The aim of the present study was to follow the changes in GAGs metabolism during the progression from non-inflamed to inflamed intestinal colon of patients with Crohn's disease (CD), using direct biochemical analysis and specific immunohistochemistry against chondroitin/dermatan sulfate and heparan sulfate. DESIGN AND METHODS: The content of GAGs from inflamed and non-inflamed colon of eight patients with active CD was estimated by uronic acid per dry weight of tissue and analyzed by agarose gel electrophoresis and ion-exchange chromatography. Intestinal sections were stained using antibodies against dermatan sulfate/chondroitin 4-sulfate (DS/CS), heparan sulfate (HS), and ICAM-1 (CD54), and analyzed by confocal microscopy. RESULTS: There was a reduction in the amount of GAGs in the non-inflamed colon of patients with CD. In the inflamed colon, HS, CS and DS showed increased concentrations compared with the non-inflamed colon. GAGs showed a diffuse distribution in the lamina propria and in the basement membrane of both inflamed and non-inflamed mucosa of patients with CD. CONCLUSION: We observed a marked reduction in GAGs with altered patterns of distribution in the non-inflamed colon of patients with CD. The increase in the synthesis of GAGs observed in the inflamed colon may be a compensatory mechanism for the restoration of the integrity of the intestinal mucosa.  相似文献   
64.
65.
At present, there is a growing trend toward the intentional adulteration of dietary supplements (DS) with synthetic pharmaceuticals, which represents an alarming emerging risk to consumers and a serious problem for regulatory agencies. An amazing array of synthetic drugs and their analogues have been reported as adulterants in DS. Mainly, the presence of analogues represents a serious health risk as their efficacy and toxic effects have not been clinically assessed yet and may result in unpredictable adverse effects. The purpose of this review is to provide an overview, over the period 2009–2019, of the most frequently reported adulterants in DS for the treatment of erectile dysfunction, obesity/overweight, diabetes mellitus, and hypertension and the analytical methods used for their detection.  相似文献   
66.
67.
Binge eating is a distressing, transdiagnostic eating disorder symptom associated with impulsivity, particularly in negative mood states. Neuroimaging studies of bulimia nervosa (BN) report reduced activity in frontostriatal regions implicated in self-regulatory control, and an influential theory posits that binge eating results from self-regulation failures under stress. However, there is no direct evidence that psychological stress impairs self-regulation in binge-eating disorders, or that any such self-regulatory deficits generalize to binge eating in underweight individuals (i.e., anorexia nervosa bingeing/purging subtype; AN-BP). We therefore determined the effect of acute stress on inhibitory control in 85 women (BN, 33 women; AN-BP, 22 women; 30 control participants). Participants underwent repeated functional MRI scanning during performance of the Stop-signal anticipation task, a validated measure of proactive (i.e., anticipation of stopping) and reactive (outright stopping) inhibition. Neural and behavioral responses to induced stress and a control task were evaluated on 2 consecutive days. Women with BN had reduced proactive inhibition, while prefrontal responses were increased in both AN-BP and BN. Reactive inhibition was neurally and behaviorally intact in both diagnostic groups. Both AN-BP and BN groups showed distinct stress-induced changes in inferior and superior frontal activity during both proactive and reactive inhibition. However, task performance was unaffected by stress. These results offer novel evidence of reduced proactive inhibition in BN, yet inhibitory control deficits did not generalize to AN-BP. Our findings identify intriguing alterations of stress responses and inhibitory function associated with binge eating, but they counsel against stress-induced failures of inhibitory control as a comprehensive explanation for loss-of-control eating.SIGNIFICANCE STATEMENT Binge eating is a common psychiatric syndrome that feels uncontrollable to the sufferer. Theoretically, it has been related to reduced self-regulation under stress, but there remains no direct evidence for this link in binge-eating disorders. Here, we examined how experimentally induced stress affected response inhibition in control participants and women with anorexia nervosa and bulimia nervosa. Participants underwent repeated brain scanning under stressful and neutral conditions. Although patient groups had intact action cancellation, the slowing of motor responses was impaired in bulimia nervosa, even when the likelihood of having to stop increased. Stress altered brain responses for both forms of inhibition in both groups, yet performance remained unimpaired. These findings counsel against a simple model of stress-induced disinhibition as an adequate explanation for binge eating.  相似文献   
68.
Background

Erenumab is a monoclonal antibody blocking the calcitonin gene–related peptide receptor, which has been approved for the preventive treatment of chronic migraine (CM). The aim of this study was to explore the safety and effectiveness of erenumab in patients suffering from CM and medication overuse headache (MOH) in a real-life setting, up to 1 year.

Methods

Data regarding 81 patients treated with erenumab were retrospectively analyzed. Every 3 months, the following variables were collected: the mean number of headache days per month (headache index (HI)), the average number of painkillers taken per month (analgesic consumption (AC)), the mean number of days with painkiller consumption (number of days on medication (NDM)), the headache intensity (numeric rating scale (NRS) score), the 6-item Headache Impact Test (HIT-6), and the Self-Reported Instrument to Assess Work-Related Difficulties in Patients With Migraine (HEADWORK) scores.

Results

The HI, AC, and NDM and the NRS, HIT-6, and HEADWORK scores were significantly lower at every time point from the 3rd month onward compared to baseline (all P < 0.0001). No significant differences were found between patients who underwent painkiller detoxification before starting erenumab and those who did not (all P > 0.05). No significant differences were found between patients taking erenumab in combination with other preventive treatments and the ones taking it alone (all P ≥ 0.05). Five patients dropped out because of adverse events, which resolved after stopping erenumab.

Conclusion

Erenumab was safe and effective for CM complicated with MOH. Painkiller withdrawal and the association with other preventive treatment(s) seem useless.

  相似文献   
69.
In this study, the larvicidal activity of an enriched fraction of the major lipophilic phenolic compounds from Hypericum carinatum Griseb. (Clusiaceae) was investigated against larvae of Aedes aegypti (Diptera: Culicidae), the main vector of dengue virus in Brazil. The larval mortality rate ranged 37.33 to 72.00 % at concentrations of 66–200 μg/mL. The effect demonstrated to be dose-dependent. The lethal concentration 50 % and confidence interval were 100 and 88–111 μg/mL, respectively. The results could be attributed to the presence of cariphenone A and cariphenone B in concentrations of 1.24?±?0.04 and 0.56?±?0.01 %, respectively, determined by high-performance liquid chromatography. Besides, the results reinforce the potential of genus Hypericum as source of alternative insecticides.  相似文献   
70.
Clinical Oral Investigations - The aim of the present study was to investigate whether peri-implant clinical parameters (modified plaque index (mPI), bleeding and/or suppuration on probing (B/SOP))...  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