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   6742篇
  免费   368篇
  国内免费   28篇
耳鼻咽喉   106篇
儿科学   150篇
妇产科学   117篇
基础医学   1211篇
口腔科学   148篇
临床医学   559篇
内科学   1846篇
皮肤病学   167篇
神经病学   463篇
特种医学   151篇
外科学   755篇
综合类   31篇
预防医学   431篇
眼科学   68篇
药学   466篇
中国医学   28篇
肿瘤学   441篇
  2023年   48篇
  2022年   74篇
  2021年   200篇
  2020年   115篇
  2019年   177篇
  2018年   204篇
  2017年   159篇
  2016年   153篇
  2015年   190篇
  2014年   234篇
  2013年   301篇
  2012年   503篇
  2011年   511篇
  2010年   274篇
  2009年   213篇
  2008年   399篇
  2007年   419篇
  2006年   438篇
  2005年   367篇
  2004年   344篇
  2003年   356篇
  2002年   332篇
  2001年   110篇
  2000年   130篇
  1999年   120篇
  1998年   37篇
  1997年   31篇
  1996年   40篇
  1995年   27篇
  1994年   20篇
  1993年   22篇
  1992年   40篇
  1991年   57篇
  1990年   37篇
  1989年   34篇
  1988年   46篇
  1987年   34篇
  1986年   35篇
  1985年   33篇
  1984年   26篇
  1983年   18篇
  1981年   11篇
  1979年   15篇
  1978年   19篇
  1977年   13篇
  1976年   16篇
  1974年   12篇
  1973年   12篇
  1971年   18篇
  1970年   13篇
排序方式: 共有7138条查询结果,搜索用时 12 毫秒
81.
82.
83.

Objective

The aim of this study was to investigate the overgeneralization of autobiographical memory (AM) in bipolar disorder (BD) and assess its association with multiple cognitive domains.

Method

Twenty-eight clinically stable bipolar I patients and an equal number of age- and gender-matched healthy controls (HC) were included. All participants were examined using the autobiographical memory test (AMT) and the neuropsychological battery including the general intelligence, attention, verbal memory, verbal fluency, visual memory, and executive functions domain. Demographic, clinical, and test variables were compared between BD and HC groups. Correlation analyses of AMT scores with cognitive functions were performed within each group, controlling for demographic and clinical variables.

Results

Total and negative scores of AMT were significantly lower in BD patients compared to HC individuals. AMT scores were significantly correlated with WAIS similarities, WCST perseverative errors, and WCST categories completed in BD, whereas AMT scores were correlated with verbal memory and verbal fluency in HC.

Conclusion

Our findings suggest that overgeneral AM is a characteristic of BD and is related to executive function. Future studies should investigate the benefit of additional treatment focusing on overgeneral AM in BD.  相似文献   
84.
Novelty processing can transform short-term into long-term memory. We propose that this memory-reinforcing effect of novelty could be explained by mechanisms outlined in the "synaptic tagging hypothesis." Initial short-term memory is sustained by a transient plasticity change at activated synapses and sets synaptic tags. These tags are later able to capture and process the plasticity-related proteins (PRPs), which are required to transform a short-term synaptic change into a long-term one. Novelty is involved in inducing the synthesis of PRPs [Moncada D, et al. (2011) Proc Natl Acad Sci USA 108:12937-12936], which are then captured by the tagged synapses, consolidating memory. In contrast to novelty, stress can impair learning, memory, and synaptic plasticity. Here, we address questions as to whether novelty-induced PRPs are able to prevent the loss of memory caused by stress and if the latter would not interact with the tag-setting process. We used water-maze (WM) training as a spatial learning paradigm to test our hypothesis. Stress was induced by a strong foot shock (FS; 5 × 1 mA, 2 s) applied 5 min after WM training. Our data show that FS reduced long-term but not short-term memory in the WM paradigm. This negative effect on memory consolidation was time- and training-dependent. Interestingly, novelty exposure prevented the stress-induced memory loss of the spatial task and increased BDNF and Arc expression. This rescuing effect was blocked by anisomycin, suggesting that WM-tagged synapses were not reset by FS and were thus able to capture the novelty-induced PRPs, re-establishing FS-impaired long-term memory.  相似文献   
85.
86.
The authors report a case of nasal malignant melanoma involving the septum, nasal turbinates and nasopharynx which was approached by lateral rhinotomy combined with an anterior transantral approach with excision of the septum and the lateral wall of the nasal cavity for wide exposure of the tumour. Using this technique complete surgical resection of a large nasal malignant melanoma was achieved with minimal morbidity and good aesthetics.  相似文献   
87.
Emerging evidence indicates that tumors can follow several evolutionary paths over a patient's disease course. With the use of serial genomic analysis of samples collected at different points during the disease course of 28 patients with multiple myeloma, we found that the genomes of standard-risk patients show few changes over time, whereas those of cytogenetically high-risk patients show significantly more changes over time. The results indicate the existence of 3 temporal tumor types, which can either be genetically stable, linearly evolving, or heterogeneous clonal mixtures with shifting predominant clones. A detailed analysis of one high-risk patient sampled at 7 time points over the entire disease course identified 2 competing subclones that alternate in a back and forth manner for dominance with therapy until one clone underwent a dramatic linear evolution. With the use of the Vk*MYC genetically engineered mouse model of myeloma we modeled this competition between subclones for predominance occurring spontaneously and with therapeutic selection.  相似文献   
88.
89.
Although it is assumed that hemodynamic responders to pharmacological therapy after a variceal hemorrhage are adequately protected from rebleeding, there is no evidence that either this response or its protective effect extend beyond the usual 2-year follow-up featured in available studies. We aimed to assess the maintenance of hemodynamic response and its impact on outcomes in a large cohort of hemodynamic responders during a long follow-up. One hundred three patients with cirrhosis admitted with acute variceal bleeding between 2001 and 2010 were prospectively evaluated. The hepatic venous pressure gradient (HVPG) was determined 5 days after the bleeding and repeated 5-7 days after maximal tolerated doses of nadolol and nitrates. Hemodynamic responders (HVPG ≤ 12 mm Hg or ≥ 20% decrease from baseline) were maintained on drugs and followed up with annual HVPG measurements. Forty-eight patients (47%) were hemodynamic responders. The median follow-up was 48 months (range, 2-108 months). Long-term HVPG evaluations could not be performed in eight patients (four deaths, two rebleedings, two follow-ups <1 year). Among the remaining 40 patients, hemodynamic response was maintained in 26 (65%) and lost in 14 (35%). There were no baseline differences between the two subgroups. However, 100% of alcoholic patients who remained abstinent maintained long-term response, compared with 36% of nonabstinent alcoholics and 50% of patients with viral cirrhosis. Patients with loss of hemodynamic response rebled more during follow-up and showed a higher incidence of death or liver transplantation. Conclusions: After variceal bleeding, long-term maintenance of hemodynamic response to drug therapy is mainly restricted to patients with alcoholic cirrhosis who remain abstinent. The loss of this long-term response carries worse clinical outcomes.  相似文献   
90.
Endobronchial metastases (EBM) secondary to extrapulmonary primary tumours are rare. The most common solid malignant tumours associated with EBM are breast, renal and colorectal carcinomas. This case report describes the first documented case of EBM from anal canal carcinoma. This neoplasm constitutes less than 1% of colorectal tumours. The clinical presentation of this entity is variable, being asymptomatic in more than 50% of cases. Generally, EBM are diagnosed in advanced stages and the survival after the diagnosis is poor. It is therefore an exceptional clinical manifestation in which bronchoscopy has an important role in the diagnosis and the treatment.  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