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   1671篇
  免费   106篇
  国内免费   1篇
耳鼻咽喉   21篇
儿科学   52篇
妇产科学   44篇
基础医学   217篇
口腔科学   9篇
临床医学   226篇
内科学   331篇
皮肤病学   17篇
神经病学   129篇
特种医学   33篇
外科学   160篇
综合类   23篇
一般理论   1篇
预防医学   263篇
眼科学   21篇
药学   100篇
中国医学   2篇
肿瘤学   129篇
  2024年   13篇
  2023年   18篇
  2022年   20篇
  2021年   56篇
  2020年   45篇
  2019年   60篇
  2018年   62篇
  2017年   51篇
  2016年   48篇
  2015年   50篇
  2014年   57篇
  2013年   86篇
  2012年   128篇
  2011年   98篇
  2010年   77篇
  2009年   58篇
  2008年   112篇
  2007年   125篇
  2006年   112篇
  2005年   86篇
  2004年   83篇
  2003年   104篇
  2002年   76篇
  2001年   11篇
  2000年   13篇
  1999年   16篇
  1998年   11篇
  1997年   10篇
  1996年   12篇
  1995年   10篇
  1994年   6篇
  1993年   8篇
  1992年   4篇
  1991年   6篇
  1990年   3篇
  1989年   4篇
  1988年   7篇
  1986年   4篇
  1985年   2篇
  1984年   2篇
  1982年   2篇
  1981年   4篇
  1980年   2篇
  1979年   3篇
  1977年   2篇
  1975年   1篇
  1974年   3篇
  1971年   1篇
  1968年   1篇
  1936年   1篇
排序方式: 共有1778条查询结果,搜索用时 15 毫秒
81.
Background  Osteoarthritis at the thumb carpometacarpal joint can have a profound impact on quality of life. Here, we evaluate radiographic outcomes in patients who have had open complete trapeziectomy, ligament reconstruction with tendon interposition, and acellular dermal matrix (GraftJacket) interposition—Group A, and compare them with those without GraftJacket interposition—Group B. Materials and Methods  Thirty patients who had undergone operative treatment for thumb basal joint arthritis by a single surgeon from 2009 to 2016 were identified, and charts were retrospectively reviewed for demographic data, surgical and radiographic outcomes, and complications. Results  There was no significant difference in pre- and postoperative radial abduction or pre- and postoperative palmar abduction. The difference in intraoperative joint space was significant ( p = 0.006), but the difference in postoperative joint space was not ( p = 0.310). The average amount of metacarpal settling was 6.9 versus 3.7 mm ( p = 0.035) (Groups A and B, respectively). Three patients in Group A developed an inflammatory reaction to the GraftJacket, and one required reoperation for allograft removal. Conclusion  This study suggests that thumb basal joint arthroplasty with GraftJacket interposition does not lead to more favorable radiographic outcomes at long-term follow-up. The increased costs associated with GraftJacket use may not be justified in light of these outcomes.  相似文献   
82.
83.
84.

Purpose

The purpose of this study was to identify the frequency and possible cause of diffuse intrathoracic uptake on post-therapy I-131 scans in thyroid cancer patients.

Methods

We retrospectively reviewed 781 post-therapy scans of 755 thyroid cancer patients who underwent total thyroidectomy and radioactive iodine therapy between January and December 2010. Diffuse intrathoracic uptake on post-therapy scans was examined, and clinical patient characteristics including sex, age, regimen for thyroid-stimulating hormone (TSH) stimulation (thyroid hormone withdrawal or recombinant human TSH injection), TSH, thyroglobulin (Tg) and anti-thyroglobulin antibody (anti-Tg Ab) levels, therapeutic dose of radioactive iodine therapy and prior history of radioactive iodine therapy were recorded.Scan findings were correlated with chest CT, chest radiographs, laboratory tests and/or clinical status. Diffuse intrathoracic uptake without evidence of pathologic condition was categorized as indeterminate. The association between clinical characteristics and intrathoracic uptake were analyzed for negative intrathoracic uptake and indeterminate uptake groups.

Results

Diffuse intrathoracic uptake on post-therapy scans was demonstrated in 39 out of 755 (5.2 %) patients, among which 3 were confirmed as lung metastasis. The 14 patients that showed high Tg or anti-Tg Ab levels were considered to be at risk of having undetected micrometastasis on other imaging modalities. The remaining 22 were indeterminate (2.9 %).Upon comparison of negative intrathoracic uptake and indeterminate uptake groups, TSH stimulation by thyroid hormone withdrawal was shown to be significantly correlated with diffuse intrathoracic uptake (p < 0.05).

Conclusion

The frequency of diffuse intrathoracic uptake on post-therapy scans was 5.2 % and could be seen in thyroid cancer patients with underlying lung metastasis as well as those without definite pathologic condition. In the latter, there was a higher frequency for diffusely increased intrathoracic uptake in those who underwent thyroid hormone withdrawal rather than recombinant human TSH injection.  相似文献   
85.
Objective: While local bias in visual processing in children with autism spectrum disorders (ASD) has been reported to result in difficulties in recognizing faces and facially expressed emotions, but superior ability in disembedding figures, associations between these abilities within a group of children with and without ASD have not been explored. Methods: Possible associations in performance on the Visual Perception Skills Figure–Ground test, a face recognition test and an emotion recognition test were investigated within 25 8–12-years-old children with high-functioning autism/Asperger syndrome, and in comparison to 33 typically developing children. Results: Analyses indicated a weak positive correlation between accuracy in Figure–Ground recognition and emotion recognition. No other correlation estimates were significant. Conclusion: These findings challenge both the enhanced perceptual function hypothesis and the weak central coherence hypothesis, and accentuate the importance of further scrutinizing the existance and nature of local visual bias in ASD.  相似文献   
86.
Although several lines of evidence indicate that glutamate is a neurotransmitter in primary afferent terminals, controversies exist on the proportion and types of such terminals that release glutamate. In the present study quantitative analysis of immunogold labelling was used to assess the presence of glutamate-like immunoreactivity in primary afferent terminals in laminae I – V of the rat spinal cord dorsal horn. Anterograde transport of choleragenoid – horseradish peroxidase from a spinal ganglion and tetramethyl benzidine histochemistry were used to identify primary afferent terminals in laminae I and III – V. Presumed C-fibre terminals in lamina II were identified on morphological criteria (dense sinusoid axon terminals). Primary afferent terminals in all dorsal horn laminae displayed significantly higher levels of glutamate-like immunoreactivity than pleomorphic vesicle-containing profiles in laminae III – IV and large neuronal cell bodies in laminae III – V. The density of gold particles over primary afferent terminals also significantly exceeded the average density of gold particles over laminae II and III – IV. The highest densities of gold particles were present over dense sinusoid axon terminals in lamina II. These findings suggest that glutamate, alone or in combination with other neuroactive compounds, is involved in the transfer of all sensory modalities from primary afferent fibres to dorsal horn neurons.  相似文献   
87.
A functional decline of brain regions underlying memory processing represents a hallmark of cognitive aging. Although a rich literature documents age‐related differences in several memory domains, the effect of aging on networks that underlie multiple memory processes has been relatively unexplored. Here we used functional magnetic resonance imaging during working memory and incidental episodic encoding memory to investigate patterns of age‐related differences in activity and functional covariance patterns common across multiple memory domains. Relative to younger subjects, older subjects showed increased activation in left dorso‐lateral prefrontal cortex along with decreased deactivation in the posterior cingulate. Older subjects showed greater functional covariance during both memory tasks in a set of regions that included a positive prefronto‐parietal‐occipital network as well as a negative network that spanned the default mode regions. These findings suggest that the memory process‐invariant recruitment of brain regions within prefronto‐parietal‐occipital network increases with aging. Our results are in line with the dedifferentiation hypothesis of neurocognitive aging, thereby suggesting a decreased specialization of the brain networks supporting different memory networks.  相似文献   
88.
We assess the number of patients who we have on the Database of a Community Mental Health Team in the UK who have Bipolar Disorder and Borderline Personality Disorder. We report how many of these have been seen as having both disorders. Hence we discuss the issue as to whether Borderline Personality disorder is to be placed within the bipolar spectrum. We note the difficulties regarding the use of phenomenology alone to decide this problem, and we note the similarities in genetics, neuroimaging observations and neurobiological mechanisms among the following conditions; Bipolar Disorder, Unipolar Depression, Post-traumatic Stress Disorder, and Borderline Personality Disorder. Ethiologies such as Trauma, Abuse, Childhood adversity and exposure to War appear to influence all these conditions via epigenetic mechanisms. Hence we argue that for a spectrum to be proposed, conditions in the spectrum need to be underpinned by similar or common Neuroimaging and neurobiological mechanisms.On this basis, it may be reasonable to include Borderline Personality Disorder within a broadly described bipolar spectrum. New details of the common Neurobiological mechanisms continue to emerge.  相似文献   
89.
90.
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