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   1262篇
  免费   84篇
  国内免费   135篇
耳鼻咽喉   4篇
儿科学   13篇
妇产科学   86篇
基础医学   140篇
口腔科学   6篇
临床医学   271篇
内科学   230篇
皮肤病学   12篇
神经病学   108篇
特种医学   30篇
外科学   169篇
综合类   66篇
一般理论   1篇
预防医学   55篇
眼科学   8篇
药学   150篇
中国医学   24篇
肿瘤学   108篇
  2024年   1篇
  2023年   8篇
  2022年   16篇
  2021年   23篇
  2020年   18篇
  2019年   24篇
  2018年   53篇
  2017年   31篇
  2016年   23篇
  2015年   41篇
  2014年   50篇
  2013年   76篇
  2012年   105篇
  2011年   88篇
  2010年   49篇
  2009年   62篇
  2008年   84篇
  2007年   146篇
  2006年   76篇
  2005年   94篇
  2004年   39篇
  2003年   37篇
  2002年   32篇
  2001年   41篇
  2000年   44篇
  1999年   24篇
  1998年   19篇
  1997年   21篇
  1996年   17篇
  1995年   10篇
  1994年   4篇
  1993年   13篇
  1992年   29篇
  1991年   11篇
  1990年   13篇
  1989年   12篇
  1988年   11篇
  1987年   8篇
  1986年   4篇
  1985年   4篇
  1984年   3篇
  1983年   8篇
  1982年   1篇
  1981年   1篇
  1978年   3篇
  1977年   1篇
  1976年   2篇
  1974年   1篇
排序方式: 共有1481条查询结果,搜索用时 31 毫秒
21.
BackgroundWe previously showed the efficacy of bi-anodal transcranial direct current stimulation (tDCS) over the prefrontal cortex (PFC) regions with extracephalic reference placement in improving negative symptoms in schizophrenia. In this ancillary investigation, the effects of this intervention on insight levels, other clinical outcomes, and cardio-respiratory and autonomic functions were examined and the potential of biomarkers for treatment response was explored.MethodsSchizophrenia patients were randomly allocated to receive 10 sessions of bi-anodal tDCS over the PFC regions with extracephalic reference placement (2 mA, 20 minutes, twice daily for 5 weeks) or sham stimulation. We examined, in 60 patients at baseline, immediately after stimulation and at follow-up visits, the insight levels, other clinical outcomes, blood pressure, respiratory rate, heart rate, and heart rate variability.ResultsInsight levels as assessed by the abbreviated version of the Scale to Assess Unawareness in Mental Disorder in schizophrenia awareness of the disease, positive and negative symptoms dimensions, and beliefs about medication compliance as assessed by Medication Adherence Rating Scale were significantly enhanced by active stimulation relative to sham. No effects were observed on cognitive insight, other clinical outcomes, or cardio-respiratory and autonomic functions. Heart rate variability indices as biomarkers were not associated with the clinical response to the intervention.ConclusionsOur results provide evidence for bi-anodal tDCS over the PFC regions with extracephalic reference placement in heightening the levels of insight into the disease and symptoms, as well as beliefs about medication compliance in schizophrenia, without impacting other clinical outcomes and cardio-respiratory/autonomic functions.  相似文献   
22.
Rounded atelectasis is an increasingly recognized but under‐diagnosed and sometimes misdiagnosed pulmonary entity. This pictorial essay will present a broad range of examples of rounded atelectasis across different imaging modalities with inclusion of typical and atypical presentations. These examples will highlight imaging features that allow confident diagnosis and those that warrant further management, such as imaging surveillance, alternate imaging or invasive procedures for histological evaluation.  相似文献   
23.
24.
25.
This study investigated the clinical implications of SETDB1 (also known as KMT1E) in human colon adenocarcinoma. Expression levels of SETDB1 proteins were analyzed by immunohistochemistry staining, and tissue microarrays were used to examine expression profiles in human patients. Our results revealed that SETDB1 protein expression was significantly higher in tumor tissue than in normal tissue for the breast, colon, liver, and lung (p < 0.05). Moreover, an analysis with SurvExpress software suggested that elevated expression of SETDB1 mRNA was significantly associated with the overall survival of colon adenocarcinoma patients (p < 0.05); and additional analysis involving 90 paired samples of colon adenocarcinoma tissue and normal tissue revealed that SETDB1 protein expression was 82% higher in cancerous cells (p < 0.001). High SETDB1 expression was also found to be significantly correlated with histological grade (p = 0.005), TNM stage (p = 0.003), T‐class/primary tumor (p = 0.001), and N‐class/regional lymph nodes (p = 0.017); and Kaplan–Meier survival curves indicated that SETDB1 protein expression was significantly associated with poor survival. Finally, univariate analysis demonstrated that SETDB1 protein expression was related to TNM stage (p = 0.004) and SETDB1 score (p = 0.001), whereas multivariate analysis showed that the influence of SETDB1 on overall colon adenocarcinoma survival was independent from other risk factors. Taken together, our results suggest that the SETDB1 protein could serve as a clinical prognostic indicator for colon adenocarcinoma.  相似文献   
26.

Background:

Low-dose dextromethorphan (DM) might have anti-inflammatory and neurotrophic effects mechanistically remote from an NMDA receptor. In a randomized, double-blind, controlled 12 week study, we investigated whether add-on dextromethorphan reduced cytokine levels and benefitted opioid-dependent patients undergoing methadone maintenance therapy (MMT).

Methods:

Patients were randomly assigned to a group: DM60 (60mg/day dextromethorphan; n = 65), DM120 (120mg/day dextromethorphan; n = 65), or placebo (n = 66). Primary outcomes were the methadone dose required, plasma morphine level, and retention in treatment. Plasma tumor necrosis factor (TNF)-α, C-reactive protein, interleukin (IL)-6, IL-8, transforming growth factor–β1, and brain-derived neurotrophic factor (BDNF) levels were examined during weeks 0, 1, 4, 8, and 12. Multiple linear regressions with generalized estimating equation methods were used to examine the therapeutic effect.

Results:

After 12 weeks, the DM60 group had significantly longer treatment retention and lower plasma morphine levels than did the placebo group. Plasma TNF-α was significantly decreased in the DM60 group compared to the placebo group. However, changes in plasma cytokine levels, BDNF levels, and the methadone dose required in the three groups were not significantly different.

Conclusions:

We provide evidence—decreased concomitant heroin use—of low-dose add-on DM’s efficacy for treating opioid-dependent patients undergoing MMT.  相似文献   
27.

Background

While post-hepatectomy liver failure (PHLF) accurately predicts short-term mortality, its role in prognosticating long-term overall survival (OS) remains unclear.

Methods

Patients who underwent hepatectomy for colorectal liver metastases (CRLM) after portal vein embolization during 1999–2015 were evaluated retrospectively. PHLF was defined per International Study Group of Liver Surgery (ISGLS) criteria and as PeakBil >7 mg/dl. Survival was analyzed using log-rank statistic and Cox regression; patient mortality within 90 days was excluded.

Results

Of 175 patients, 68 (39%) had PHLF according to ISGLS criteria, including 40 (23%) with ISGLS grade B/C, and 14 (8%) had PeakBil >7 mg/dl. Patients with PeakBil >7 mg/dl had significantly worse OS than patients without PHLF (median OS, 16 vs 58 months, p = 0.001). Patients with ISGLS defined PHLF (p = 0.251) and patients with ISGLS grade B/C PHLF (p = 0.220) did not have worse OS than patients without PHLF.

Conclusion

Peak bilirubin >7 mg/dl impacts on long-term survival after hepatectomy for CRLM and is a better predictor of long-term survival than ISGLS-defined PHLF.  相似文献   
28.
29.
Alzheimer''s disease is a devastating neurodegenerative disease with a dramatically increasing prevalence and no disease-modifying treatment. Inflammatory lifestyle factors increase the risk of developing Alzheimer''s disease. Zinc deficiency is the most prevalent malnutrition in the world and may be a risk factor for Alzheimer''s disease potentially through enhanced inflammation, although evidence for this is limited. Here we provide epidemiological evidence suggesting that zinc supplementation was associated with reduced risk and slower cognitive decline, in people with Alzheimer''s disease and mild cognitive impairment. Using the APP/PS1 mouse model of Alzheimer''s disease fed a control (35 mg/kg zinc) or diet deficient in zinc (3 mg/kg zinc), we determined that zinc deficiency accelerated Alzheimer''s-like memory deficits without modifying amyloid β plaque burden in the brains of male mice. The NLRP3-inflammasome complex is one of the most important regulators of inflammation, and we show here that zinc deficiency in immune cells, including microglia, potentiated NLRP3 responses to inflammatory stimuli in vitro, including amyloid oligomers, while zinc supplementation inhibited NLRP3 activation. APP/PS1 mice deficient in NLRP3 were protected against the accelerated cognitive decline with zinc deficiency. Collectively, this research suggests that zinc status is linked to inflammatory reactivity and may be modified in people to reduce the risk and slow the progression of Alzheimer''s disease.SIGNIFICANCE STATEMENT Alzheimer''s disease is a common condition mostly affecting the elderly. Zinc deficiency is also a global problem, especially in the elderly and also in people with Alzheimer''s disease. Zinc deficiency contributes to many clinical disorders, including immune dysfunction. Inflammation is known to contribute to the risk and progression of Alzheimer''s disease; thus, we hypothesized that zinc status would affect Alzheimer''s disease progression. Here we show that zinc supplementation reduced the prevalence and symptomatic decline in people with Alzheimer''s disease. In an animal model of Alzheimer''s disease, zinc deficiency worsened cognitive decline because of an enhancement in NLRP3-driven inflammation. Overall, our data suggest that zinc status affects Alzheimer''s disease progression, and that zinc supplementation could slow the rate of cognitive decline.  相似文献   
30.
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