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   911篇
  免费   78篇
  国内免费   13篇
耳鼻咽喉   2篇
儿科学   43篇
妇产科学   31篇
基础医学   137篇
口腔科学   14篇
临床医学   58篇
内科学   140篇
皮肤病学   31篇
神经病学   23篇
特种医学   140篇
外科学   222篇
综合类   21篇
预防医学   52篇
眼科学   7篇
药学   33篇
肿瘤学   48篇
  2022年   5篇
  2021年   14篇
  2020年   10篇
  2019年   5篇
  2018年   15篇
  2017年   8篇
  2016年   14篇
  2015年   23篇
  2014年   22篇
  2013年   22篇
  2012年   36篇
  2011年   30篇
  2010年   42篇
  2009年   44篇
  2008年   33篇
  2007年   45篇
  2006年   34篇
  2005年   37篇
  2004年   39篇
  2003年   23篇
  2002年   40篇
  2001年   31篇
  2000年   19篇
  1999年   17篇
  1998年   32篇
  1997年   40篇
  1996年   31篇
  1995年   25篇
  1994年   22篇
  1993年   7篇
  1992年   15篇
  1991年   8篇
  1990年   16篇
  1989年   15篇
  1988年   15篇
  1987年   22篇
  1986年   14篇
  1985年   15篇
  1984年   12篇
  1983年   10篇
  1982年   8篇
  1981年   10篇
  1980年   15篇
  1979年   7篇
  1978年   8篇
  1977年   10篇
  1976年   12篇
  1975年   10篇
  1974年   5篇
  1971年   4篇
排序方式: 共有1002条查询结果,搜索用时 15 毫秒
31.
32.
33.
OBJECTIVE: To evaluate and compare the effects of lisinopril versus atenolol administration on the diurnal blood pressure profile and the nocturnal blood pressure fall in young mild-to-moderate essential hypertensives.METHODS: Thirty patients were studied. After a 2-week placebo run-in period, they were single-blind randomly assigned to receive 20 mg lisinopril or 100 mg atenolol. Using a SpaceLabs 90207 device, their ambulatory blood pressure was measured before and after 12 weeks of therapy. The readings were analysed using Fourer series with four harmonics. RESULTS: Lisinopril and atenolol administration significantly decreased office and ambulatory blood pressure values compared with the placebo period. The daily blood pressure curves obtained from Fourier analysis showed that the circadian rhythm was not altered by lisinopril and atenolol administration. From the night:day ratio for the nocturnal blood pressure fall, we found that atenolol administration minimized the average night-time blood pressure dip by increasing the number of non-dippers. In contrast, lisinopril administration did not modify the day-night difference, preserving the nocturnal blood pressure fall. CONCLUSION: Lisinopril and atenolol administration as a first-step treatment of young essential hypertensives produced comparable degrees of diurnal control of arterial pressure. The blood pressure fall at night in patients treated with atenolol was slightly less than that found with lisinopril treatment.  相似文献   
34.
Refinements in microsurgical techniques coupled with advances in immunosuppressive and immunomodulatory protocols have enabled broader clinical application of vascularized composite allotransplantation (VCA) with encouraging immunological, functional, and esthetic results. However, skin rejection remains a significant obstacle and a serious complication for VCA recipients. Clinical and histopathological features of rejection in VCA have been described in a number of studies, which led to the development of an international consensus on the classification guidelines of rejection in the context of VCA. Nevertheless, currently available diagnostic modalities still have several limitations and shortcomings that can pose a significant diagnostic challenge, particularly when signs of rejection are found to be equivocal. In this review, we provide a critical analysis of these advances and challenges in diagnosing skin rejection. Specifically, we highlight the gaps in understanding of rejection mechanisms, the shortfalls in correlating cellular, molecular, and clinicopathologic markers with rejection grades, deficiencies in defining chronic rejection, and antibody‐mediated rejection after VCA, as well as providing an outlook on novel concepts, such as the utilization of advanced computational analyses and cross‐disciplinary diagnostic approaches.  相似文献   
35.
OBJECTIVESWe herein report a single-centre experience with the SAPIEN 3 Ultra balloon-expandable transcatheter aortic valve implantation (TAVI) system.METHODSBetween March 2019 and January 2020, a total of 79 consecutive patients received transfemoral TAVI using the SAPIEN 3 Ultra device. Data were retrospectively analysed according to updated Valve Academic Research Consortium-2 definitions. Detailed analysis of multislice computed tomography data was conducted to identify potential predictors for permanent pacemaker (PPM) implantation and residual paravalvular leakage (PVL) post TAVI.Open in a separate windowGraphical AbstractRESULTSDevice success and early safety were 97.5% (77/79) and 94.9% (75/79) with resulting transvalvular peak/mean pressure gradients of 21.1 ± 8.2/10.9 ± 4.4 and PVL >mild in 0/79 patients (0%). Mild PVL was seen in 18.9% (15/79) of cases. Thirty-day mortality was 2.5% (2/79). The Valve Academic Research Consortium-2 adjudicated clinical end points disabling stroke, acute kidney injury and myocardial infarction occurred in 1.3% (1/79), 5.1% (4/79) and 0% (0/79) of patients. Postprocedural PPM implantation was necessary in 7.6% (6/79) of patients. Multislice computed tomography analysis revealed significantly higher calcium amounts of the right coronary cusp in patients in need for postprocedural PPM implantation and a higher eccentricity index in patients with postinterventional mild PVL.CONCLUSIONSFirst experience with this newly designed balloon-expandable-transcatheter heart valve demonstrates adequate 30-day outcomes and haemodynamic results with low mortality, low rates of PPM implantation and no residual PVL >mild. The herein-presented multislice computed tomography values with an elevated risk for PPM implantation and residual mild PVL may help to further improve outcomes with this particular transcatheter heart valve in TAVI procedures.  相似文献   
36.
Monoclonal antibodies reactive with human IgE were used to investigate the presence of surface IgE in situ on mononuclear cells infiltrating into the skin lesion of atopic dermatitis (A.D.) by application of the immunoperoxidase technique to tissue sections for light and electron microscopic examination. A substantial proportion of infiltrating macrophages but not of lymphocytes were found to bear IgE on their cell surfaces. These observations raise the possibility that IgE may contribute to the skin inflammation associated with A.D. via non-mast-cell-mediated immune mechanisms. We hypothesize that allergens introduced into the skin lesion of A.D. are potentially capable of interacting not only with IgE-bearing mast cells but also with IgE-bearing macrophages and dendritic cells to cause the release of inflammatory mediators.  相似文献   
37.
Despite a continuously growing knowledge of the impact of factors on kidney graft function, such as donor age, body mass index, and cold ischemia time, few data are available regarding anastomosis time (AT) and its impact on long‐term results. We investigated whether surgical AT correlates with patient and graft survival after kidney transplantation performing a retrospective analysis of 1245 consecutive deceased donor kidney transplantations between 01/2000 and 12/2010 at Innsbruck Medical University. Kaplan–Meier and log‐rank analyses were carried out for 1‐ and 5‐year patient and graft survival. AT was defined as time from anastomosis start until reperfusion. Median AT was 30 min. Five‐year survival of allografts with an AT >30 min was 76.6% compared with 80.6% in the group with AT <30 min (P = 0.027). Patient survival in the group with higher AT similarly was inferior with 85.7% after 5 years compared with 89.6% (P < 0.0001) [Correction added on February 18, 2015, after first online publication: the percentage value for patient survival was previously incorrect and have now been changed to 89.6%]. Cox regression analysis revealed AT as an independent significant factor for patient survival (HR 1.021 per minute; 95% CI 1.006–1.037; P = 0.006). As longer AT closely correlates with inferior long‐term patient survival, it has to be considered as a major risk factor for inferior long‐term results after deceased donor kidney transplantation.  相似文献   
38.
Improved nerve regeneration and functional outcomes would greatly enhance the utility of vascularized composite allotransplantation (VCA) such as hand and upper extremity transplantation. However, research aimed at achieving this goal has been limited by the lack of a functional VCA animal model. We have developed a novel rat midhumeral forelimb transplant model that allows for the characterization of upper extremity functional recovery following transplantation. At the final end point of 12 weeks, we found that animals with forelimb transplantation including median, ulnar and radial nerve coaptation demonstrated significantly improved grip strength and forelimb function as compared to forelimb transplantation without nerve approximation (grip strength: 1.71N ± 0.57 vs. no appreciable recovery; IBB scale: 2.6 ± 0.7? vs. 0.8 ± 0.40; p = 0.0005), and similar recovery to nerve transection‐and‐repair only (grip strength: 1.71N ± 0.57 vs. 2.03 ± 0.42.6; IBB scale: 2.6 ± 0.7 vs. 2.8 ± 0.8; p = ns). Moreover, all forelimb transplant animals with nerve coaptation displayed robust axonal regeneration with myelination and reduced flexor muscle atrophy when compared to forelimb transplant animals without nerve coaptation. In conclusion, this is the first VCA small‐animal model that allows for reliable and reproducible measurement of behavioral functional recovery in addition to histologic evaluation of nerve regeneration and graft reinnervation.  相似文献   
39.
The detection and quantitation of apoptotic cells is becoming increasingly important in the investigation of the role of apoptosis in cellular proliferation and differentiation. The pathogenesis of hematologic disorders such as aplastic anemia and the development of neoplasia are believed to involve dysregulation of apoptosis. To quantitate accurately the proportion of apoptosis cells within different cell types of a heterogeneous cell population such as blood or bone marrow, a method is required that combines the analysis of large numbers of cells with concurrent immunophenotyping of cell surface antigens. In this study, we have evaluated such a method using the fluorescent DNA binding agent, 7-amino actinomycin D (7AAD), to stain three diverse human cell lines, induced to undergo apoptosis by three different stimuli. Flow cytometric analysis defines three populations on the basis of 7AAD fluorescence and forward light scatter. We have shown by cell sorting and subsequent morphological assessment and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling that the populations defined by 7AAD represent live, apoptotic, and late-apoptotic/dead cells. This method is quick, simple, reproducible, and cheap and will be a valuable tool in the investigation of the role of apoptosis in normal physiology and in disease states.  相似文献   
40.
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