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   1769篇
  免费   61篇
  国内免费   2篇
耳鼻咽喉   8篇
儿科学   33篇
妇产科学   96篇
基础医学   164篇
口腔科学   7篇
临床医学   121篇
内科学   493篇
皮肤病学   10篇
神经病学   209篇
特种医学   45篇
外科学   383篇
综合类   2篇
一般理论   1篇
预防医学   83篇
眼科学   5篇
药学   75篇
中国医学   1篇
肿瘤学   96篇
  2023年   10篇
  2022年   17篇
  2021年   46篇
  2020年   16篇
  2019年   42篇
  2018年   54篇
  2017年   37篇
  2016年   33篇
  2015年   29篇
  2014年   66篇
  2013年   88篇
  2012年   151篇
  2011年   138篇
  2010年   67篇
  2009年   70篇
  2008年   107篇
  2007年   126篇
  2006年   120篇
  2005年   100篇
  2004年   89篇
  2003年   74篇
  2002年   69篇
  2001年   28篇
  2000年   26篇
  1999年   27篇
  1998年   15篇
  1997年   11篇
  1996年   10篇
  1995年   7篇
  1994年   7篇
  1993年   8篇
  1992年   18篇
  1991年   17篇
  1990年   18篇
  1989年   17篇
  1988年   11篇
  1987年   12篇
  1986年   6篇
  1985年   6篇
  1984年   6篇
  1983年   5篇
  1982年   4篇
  1981年   5篇
  1980年   3篇
  1979年   5篇
  1978年   2篇
  1974年   2篇
  1970年   1篇
  1968年   1篇
  1966年   2篇
排序方式: 共有1832条查询结果,搜索用时 687 毫秒
41.
Malondialdehyde (MDA), a major lipid peroxidation product, spontaneously binds to, and modifies proteins. In vivo, proteins are physiologically exposed to micromolar MDA concentrations for long periods. In order to mimic this process in vitro, protein modification is often performed by short exposure to millimolar MDA concentrations, also in order to generate antigenic structures for antibody production.  相似文献   
42.
43.
BACKGROUND: Suspension trauma syndrome is a life-threatening event that occurs when a person is “trapped” in a prolonged passive suspension. It is most commonly seen in people who engage in occupational or sport activities that require harness suspension. The aim of this study is to identify the predisposing factors, pathophysiology, and management of suspension trauma. METHODS: A review and analysis of the literature published in English and Spanish from 1972 to 2020 on suspension trauma were performed. Search sources were PubMed, Medline, Cochrane Library, MeSH, UpToDate, and Google Scholar. Articles referring to suspension trauma associated with other injury mechanisms (traumatic impact injuries, drowning, asphyxiation, or bleeding), case reports, and pediatric population were excluded. RESULTS: Forty-one articles were identified. Of these, 29 articles related to mechanism, pathophysiology, and management of individuals who suffered prolonged suspension trauma without associated traumatic injuries were included in the study. We encountered several controversies describing the putative pathophysiology, ranging from blood sequestration in the lower extremities versus accumulation of metabolic waste and hyperkalemia to dorsal hook-type harness as a trigger cause of positional asphyxia; to vascular compression of femoral vessels exerted by the harness causing decreased venous return. Pstients suspended in a full-body harness with dorsal hook showed more hemodynamic alterations in response to the compressive effect on the rib cage, causing a reduction in perfusion by presenting a decrease in pulse pressure. Management strategies varied across studies. CONCLUSIONS: Progress has been made in individualizing the population at risk and in the management of suspension trauma. We recommend the formation of consensus definitions, larger cohort or registry studies to be conducted, and experimental animal models to better understand the mechanisms in order to develop management and life support guidelines from a trauma and emergency medicine perspective.  相似文献   
44.
Various intact and post‐injury bone phenotypes are heritable traits. In this study, we sought to determine if intramembranous bone regeneration following marrow ablation differed among common inbred mouse strains and to identify how early the differences appear. We found a ~four‐fold difference in the regenerated bone volume 21 days after marrow ablation in females from four inbred mouse strains: FVB/N (15.7 ± 8.1%, mean and standard deviation), C3H/He (15.5 ± 4.2%), C57BL/6 (12.2 ± 5.2%), and BALB/c (4.0 ± 4.4%); with BALB/c different from FVB/N (p = 0.007) and C3H/He (p = 0.002). A second experiment showed that FVB/N compared to BALB/c mice had more regenerated bone 7 and 14 days after ablation (p < 0.001), while at 21 days FVB/N mice had a greater fraction of mineralizing surface (p = 0.008) without a difference in mineral apposition rate. Thus, differences among strains are evident early during intramembranous bone regeneration following marrow ablation and appear to be associated with differences in osteogenic cell recruitment, but not osteoblast activity. The amount of regenerating bone was not correlated with other heritable traits such as the intact bone phenotype or soft tissue wound healing, suggesting that there may be independent genetic pathways for these traits. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1374–1381, 2015.  相似文献   
45.
Brentuximab vedotin (BV) shows a high overall response rate (ORR) in relapsed/refractory (R/R) Hodgkin lymphoma (HL) after autologous transplant (ASCT). The aim of this multicenter study, conducted in nine Hematology Departments of Rete Ematologica Pugliese, was to retrospectively evaluate the efficacy and safety of BV as salvage therapy and as bridge regimen to ASCT or allogeneic transplant (alloSCT) in R/R HL patients. Seventy patients received BV. Forty-five patients (64%) were treated with BV as bridge to transplant:16 (23%) patients as bridge to ASCT and 29 (41%) as bridge to alloSCT. Twenty-five patients (36%), not eligible for transplant, received BV as salvage treatment. The ORR was 59% (CR 26%). The ORR in transplant naïve patients was 75% (CR 31%). In patients treated with BV as bridge to alloSCT, the ORR was 62% (CR 24%). In a multivariate analysis, the ORR was lower in refractory patients (p?<?0.005). The 2y-OS was 70%. The median PFS was 17 months. Ten of the 16 (63%) naïve-transplant patients received ASCT, with 50% in CR before ASCT. In the 29 patients treated with BV as bridge to alloSCT, 28 (97%) proceeded to alloSCT with 25% in CR prior to alloSCT. The most common adverse events were peripheral neuropathy (50%), neutropenia (29%) and anemia (12%). These data suggest that BV is well tolerated and very effective in R/R HL, producing a substantial level of CR. BV may also be a key therapeutic agent to achieve good disease control before transplant, improving post- transplant outcomes, also in refractory and heavily pretreated patients, without significant overlapping toxicities with prior therapies.  相似文献   
46.
Macrophages and arterial smooth muscle cells comprise the cellular components of the atherosclerotic plaque. The vessel wall accumulation of macrophages occurs by a process of increased circulating monocyte migration into the vessel wall. In these studies it is demonstrated that human macrophages and arterial smooth muscle cells in culture secrete potent chemotactic factors for freshly isolated human monocytes. In contrast, human fibroblast-conditioned medium has no chemotactic activity. The effect of macrophage-conditioned medium is a function of macrophage differentiation and can be potentiated by macrophage activation. These results suggest that secretory products of human macrophages and arterial smooth muscle cells may be important stimuli for increased monocyte migration into the vessel wall in vivo.  相似文献   
47.
Summary Two 5 g glucose loads at 1-h interval were given to healthy controls and obese subjects with slightly altered or normal OGTT in order to explore the capacity of restoration of the ‘rapid insulin response’ to i.v. glucose. In the normal subjects, the two successive loads gave rise to identical responses as far as maximum increase (Δmax), average increase at 2–5 min (Δ2–5 min), area of increase 0–15 min (Δ0–15 min) for both glucose and IRI, were concerned. Obese subjects could be divided on the basis of their insulin response to the first load into normal responders (group I) and high-responders (group II). In group I obese subjects, the responses to the second load were identical to those to the first. In group II obese subjects Δmax, Δ2–5 min and Δ0–15 min of the insulin response to the second load were reduced as compared to the first.  相似文献   
48.
Hepatitis C virus (HCV) may be associated with the mixed cryoglobulinemia syndrome and other B-cell lymphoproliferative disorders (LPDs). The t(14;18) translocation may play a pathogenetic role. Limited data are available regarding the effects of antiviral therapy on rearranged B-cell clones. We evaluated the effects of interferon and ribavirin on serum, B-lymphocyte HCV RNA, and t(14; 18) in 30 HCV+, t(14;18)+ patients without either mixed cryoglobulinemia syndrome or other LPDs. The t(14;18) translocation was analyzed by both bcl-2/JH polymerase chain reaction and bcl-2/JH junction sequencing in peripheral blood mononuclear cells in all patients. Fifteen untreated patients with comparable characteristics served as controls. Throughout the study, the presence or absence of both t(14;18) and HCV RNA sequences were, in most cases, associated in the same cell samples. At the end of treatment, t(14;18) was no longer detected in 15 patients (50%) with complete or partial virologic response, whereas it was persistently detected in nonresponders (P <.05), as well as in 14 of 15 control patients. In 4 responder patients, t(14;18) and HCV RNA sequences were no longer detected in blood cells after treatment, but were again detected after viral relapse; the same B-cell clones were involved in the pretreatment and posttreatment periods. In conclusion, this study suggests that antiviral therapy may induce regression of t(14;18)-bearing B-cell clones in HCV+ patients and that this phenomenon may be related, at least in part, to the antiviral effect of therapy. This in turn suggests that antiviral treatment may help prevent or treat HCV-related LPDs.  相似文献   
49.
Making a firm diagnosis of chronic heart failure with preserved ejection fraction (HFpEF) remains a challenge. We recommend a new stepwise diagnostic process, the ‘HFA–PEFF diagnostic algorithm’. Step 1 (P=Pre‐test assessment) is typically performed in the ambulatory setting and includes assessment for heart failure symptoms and signs, typical clinical demographics (obesity, hypertension, diabetes mellitus, elderly, atrial fibrillation), and diagnostic laboratory tests, electrocardiogram, and echocardiography. In the absence of overt non‐cardiac causes of breathlessness, HFpEF can be suspected if there is a normal left ventricular (LV) ejection fraction, no significant heart valve disease or cardiac ischaemia, and at least one typical risk factor. Elevated natriuretic peptides support, but normal levels do not exclude a diagnosis of HFpEF. The second step (E: Echocardiography and Natriuretic Peptide Score) requires comprehensive echocardiography and is typically performed by a cardiologist. Measures include mitral annular early diastolic velocity (e′), LV filling pressure estimated using E/e′, left atrial volume index, LV mass index, LV relative wall thickness, tricuspid regurgitation velocity, LV global longitudinal systolic strain, and serum natriuretic peptide levels. Major (2 points) and Minor (1 point) criteria were defined from these measures. A score ≥5 points implies definite HFpEF; ≤1 point makes HFpEF unlikely. An intermediate score (2–4 points) implies diagnostic uncertainty, in which case Step 3 (F1: Functional testing) is recommended with echocardiographic or invasive haemodynamic exercise stress tests. Step 4 (F2: Final aetiology) is recommended to establish a possible specific cause of HFpEF or alternative explanations. Further research is needed for a better classification of HFpEF.  相似文献   
50.
Respiratory diseases in Italy already now represent an emergency (they are the 3rd ranking cause of death in the world, and the 2nd if Lung cancer is included). In countries similar to our own, they result as the principal cause for a visit to the general practitioner (GP) and the second main cause after injury for recourse to Emergency Care. Their frequency is probably higher than estimated (given that respiratory diseases are currently underdiagnosed). The trend is towards a further increase due to epidemiologic and demographic factors (foremost amongst which are the widespread diffusion of cigarette smoking, the increasing mean age of the general population, immigration, and pollution). Within the more general problem of chronic disease care, chronic respiratory diseases (CRDs) constitute one of the four national priorities in that they represent an important burden for society in terms of mortality, invalidity, and direct healthcare costs. The strategy suggested by the World Health Organization (WHO) is an integrated approach consisting of three goals: inform about health, reduce risk exposure, improve patient care. The three goals are translated into practice in the three areas of prevention (1-primary, 2-secondary, 3-tertiary) as: 1) actions of primary (universal) prevention targeted at the general population with the aim to control the causes of disease, and actions of Predictive Medicine - again addressing the general population but aimed at measuring the individual’s risk for disease insurgence; 2) actions of early diagnosis targeted at groups or - more precisely - subgroups identified as at risk; 3) continuous improvement and integration of care and rehabilitation support - destined at the greatest possible number of patients, at all stages of disease severity. In Italy, COPD care is generally still inadequate. Existing guidelines, institutional and non-institutional, are inadequately implemented: the international guidelines are not always adaptable to the Italian context; the document of the Agency for Regional Healthcare Services (AGE.NA.S) is a more suited compendium for consultation, and the recent joint statement on integrated COPD management of the three major Italian scientific Associations in the respiratory area together with the contribution of a Society of General Medicine deals prevalently with some critical issues (appropriateness of diagnosis, pharmacological treatment, rehabilitation, continuing care); also the document “Care Continuity: Chronic Obstructive Pulmonary Disease (COPD)” of the Global Alliance against chronic Respiratory Diseases (GARD)-Italy does not treat in depth the issue of early diagnosis. The present document – produced by the AIMAR (Interdisciplinary Association for Research in Lung Disease) Task Force for early diagnosis of chronic respiratory disease based on the WHO/GARD model and on available evidence and expertise –after a general examination of the main epidemiologic aspects, proposes to integrate the above-mentioned existing documents. In particular: a) it formally indicates on the basis of the available evidence the modalities and the instruments necessary for carrying out secondary prevention at the primary care level (a pro-active,‘case-finding’approach; assessment of the individual’s level of risk of COPD; use of short questionnaires for an initial screening based on symptoms; use of simple spirometry for the second level of screening); b) it identifies possible ways of including these activities within primary care practice; c) it places early diagnosis within the “systemic”, consequential management of chronic respiratory diseases, which will be briefly described with the aid of schemes taken from the Italian and international reference documents.  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