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   5129篇
  免费   19篇
  国内免费   10篇
耳鼻咽喉   23篇
儿科学   736篇
妇产科学   208篇
基础医学   547篇
口腔科学   197篇
临床医学   165篇
内科学   1060篇
皮肤病学   207篇
神经病学   302篇
特种医学   86篇
外科学   1151篇
综合类   16篇
预防医学   96篇
眼科学   84篇
药学   156篇
中国医学   2篇
肿瘤学   122篇
  2023年   6篇
  2022年   13篇
  2021年   92篇
  2020年   12篇
  2019年   620篇
  2018年   513篇
  2017年   316篇
  2016年   14篇
  2015年   13篇
  2014年   26篇
  2013年   43篇
  2012年   24篇
  2011年   25篇
  2010年   25篇
  2009年   14篇
  2008年   18篇
  2007年   12篇
  2006年   15篇
  2005年   10篇
  2004年   6篇
  2003年   3篇
  2002年   5篇
  2001年   8篇
  2000年   3篇
  1999年   7篇
  1998年   2篇
  1997年   6篇
  1996年   3篇
  1995年   2篇
  1994年   4篇
  1993年   8篇
  1992年   4篇
  1991年   2篇
  1989年   3篇
  1987年   1篇
  1985年   264篇
  1984年   354篇
  1983年   198篇
  1982年   286篇
  1981年   280篇
  1980年   259篇
  1979年   299篇
  1978年   240篇
  1977年   218篇
  1976年   252篇
  1975年   221篇
  1974年   194篇
  1973年   211篇
  1972年   2篇
  1968年   1篇
排序方式: 共有5158条查询结果,搜索用时 0 毫秒
81.

Background

Surgical site infections (SSIs) are a major cause of morbidity, mortality, and healthcare costs, and patients undergoing simultaneous colorectal/liver resections are at an especially high SSI risk.

Methods

Data were collected on all patients undergoing synchronous colorectal/liver resection from 2011 to 2016 (n = 424). The intervention, implemented in 2013, included 13 multidisciplinary perioperative components. The primary endpoints were superficial/deep and organ space SSIs. Secondary endpoints were hospital length of stay (LOS) and 30-day readmission rate. To control for changes in SSI rates independent of the intervention, interrupted time series analysis was conducted.

Results

Overall, superficial/deep, and organ space SSIs decreased by 60.5% (p < 0.001), 80.6% (p < 0.001), and 47.6% (p = 0.008), respectively. In the pre-intervention cohort (n = 231), there were 79 (34.2%), 31 (13.4%), and 48 (20.8%) total, superficial/deep, and organs space SSIs, respectively. In the post-intervention cohort (n = 193), there were 26 (13.5%), 5 (2.6%), and 21 (10.9%) total, superficial/deep, and organs space SSIs, respectively. Median LOS decreased from 9 to 8 days (p < 0.001). Readmission rates did not change (p = 0.6). Interrupted time series analysis found no significant trends in SSI rate within the pre-intervention (p = 0.35) and post-intervention (p = 0.55) periods.

Conclusion

In combined colorectal/liver resection patients, implementation of a multidisciplinary care bundle was associated with a 61% reduction in SSIs, with the greatest impact on superficial/deep SSI, and modest reduction in LOS. The absence of trends within each time period indicated that the intervention was likely responsible for SSI reduction. Future efforts should target further reduction in organ space SSI.  相似文献   
82.
A permanent transvenous coronary sinus pacemaker functioned effectively for 22 months both as an atrial and ventricular pacemaker. Slow atrial flutter resulted in failure of the pacemaker to capture the myocardium and thus incorrectly suggested pacemaker dysfunction. Transtelephonic evaluation of this phenomenon was particularly difficult and could have resulted in unnecessary replacement of the pacing unit  相似文献   
83.
84.
Prion protein and prion-like proteins share a number of characteristics. From the molecular point of view, they are constitutive proteins that aggregate following conformational changes into insoluble particles. These particles escape the cellular clearance machinery and amplify by recruiting the soluble for of their constituting proteins. The resulting protein aggregates are responsible for a number of neurodegenerative diseases such as Creutzfeldt-Jacob, Alzheimer, Parkinson and Huntington diseases. In addition, there are increasing evidences supporting the inter-cellular trafficking of these aggregates, meaning that they are “transmissible” between cells. There are also evidences that brain homogenates from individuals developing Alzheimer and Parkinson diseases propagate the disease in recipient model animals in a manner similar to brain extracts of patients developing Creutzfeldt-Jacob's disease. Thus, the propagation of protein aggregates from cell to cell may be a generic phenomenon that contributes to the evolution of neurodegenerative diseases, which has important consequences on human health issues. Moreover, although the distribution of protein aggregates is characteristic for each disease, new evidences indicate the possibility of overlaps and crosstalk between the different disorders. Despite the increasing evidences that support prion or prion-like propagation of protein aggregates, there are many unanswered questions regarding the mechanisms of toxicity and this is a field of intensive research nowadays.  相似文献   
85.
Expansions of trinucleotide or hexanucleotide repeats lead to several neurodegenerative disorders, including Huntington disease [caused by expanded CAG repeats (CAGr) in the HTT gene], and amyotrophic lateral sclerosis [ALS, possibly caused by expanded GGGGCC repeats (G4C2r) in the C9ORF72 gene], of which the molecular mechanisms remain unclear. Here, we demonstrated that lowering the Drosophila homologue of tau protein (dtau) significantly rescued in vivo neurodegeneration, motor performance impairments, and the shortened life-span in Drosophila expressing expanded CAGr or expanded G4C2r. Expression of human tau (htau4R) restored the disease-related phenotypes that had been mitigated by the loss of dtau, suggesting an evolutionarily-conserved role of tau in neurodegeneration. We further revealed that G4C2r expression increased tau accumulation by inhibiting autophagosome–lysosome fusion, possibly due to lowering the level of BAG3, a regulator of autophagy and tau. Taken together, our results reveal a novel mechanism by which expanded G4C2r causes neurodegeneration via an evolutionarily-conserved mechanism. Our findings provide novel autophagy-related mechanistic insights into C9ORF72-ALS and possible entry points to disease treatment.Electronic supplementary materialThe online version of this article (10.1007/s12264-020-00518-2) contains supplementary material, which is available to authorized users.  相似文献   
86.
87.
Aging is a primary risk factor for fatal neurodegenerative disorders, yet the mechanisms underlying physiological healthy aging and pathological aging, and how these mechanisms can divert one scenario to the other, are not completely understood. In recent years, reports indicate that alterations in nucleocytoplasmic transport may be a hallmark of both healthy and pathological aging. In this review, I summarize recent evidence supporting this information, specifically focusing on the association between the nucleocytoplasmic transport and aging of the brain, indicating both common and case-specific mechanisms and their interplay, and pointing out alterations of these mechanisms as regulatory “switches” for the fate of the aging brain. Importantly, some of these alterations are intervenable druggable targets, paving the way to a future pharmacotherapeutic intervention.  相似文献   
88.
89.
ObjectivesTo evaluate the use of the anterolateral thigh fascia free flap for use in neovascularization of mandibular bone in moderate osteoradionecrosis (ORN). All patients had ORN secondary to prior radiation therapy that was not severe enough to warrant segmental resection and reconstruction.Study designCase series.SettingTertiary medical center.MethodsIRB approval was obtained, and a retrospective chart review performed of all mandibular rescue procedures performed from 2011 to 2014. Patients with a minimum of two years of follow-up were included in the study.ResultsAll surgeries were performed by the senior surgeon (MF). Eight patients underwent the mandibular rescue procedure with resolution of pain and return to oral feeding in all patients, and no evidence of ORN progression on follow-up imaging. A total of 9 ALT free flaps were performed (one patient had 2 surgeries). Gender was distributed evenly (4 female/4 male). The average age was 66 (58-78), average length of hospitalization was 2.8 days (1–7), and average follow-up was 46.5 months (25–63).ConclusionsThe mandibular rescue procedure is a novel technique using the ALT fascia lata free flap to provide coverage and nutrient blood flow to mandible devascularized secondary to radiation therapy. The flap provides the advantages of low morbidity, ease of harvest, two-team approach to ablation and reconstruction, and quick recovery resulting in ‘short-stay’ free flap surgery. Although conclusions must be tempered in this small case series, our early clinical experience shows the ALT fascia lata flap holds promise in halting the destructive progression of ORN that is not yet advanced enough to require a segmental resection and reconstruction.  相似文献   
90.
目的对青少年发病的亨廷顿舞蹈病(Huntington disease)家系进行致病IT15基因早期诊断分析,为家系成员提供遗传咨询, 并为后续的HD发病机制及实验治疗研究提供依据。方法按照知情同意原则抽取家系成员外周血,提取基因组DNA,采用改良的降落PCR方法扩增IT15基因致病区域,DNA测序检测异常等位基因(CAG) n 三核苷酸重复次数。结果在该家系三代25名成员中,共发现8名致病IT15基因携带者,其中,III10、III12、III14、IV3和V2 CAG三核苷酸的拷贝数均为48,IV11和IV12均为(CAG) 67, IV14为(CAG) 63,而对照组35名正常人的CAG三核苷酸的拷贝数为8-25,两者之间没有重叠。结论家系中第四代致病基因携带者IV14与第三代患者III10比较,CAG三核苷酸重复次数增加15次,即本家系IT15基因在传递过程中发生了扩增突变。同时,扩增突变导致该家系出现青少年发病及遗传早现现象。  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