全文获取类型
收费全文 | 1748篇 |
免费 | 117篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 79篇 |
妇产科学 | 26篇 |
基础医学 | 300篇 |
口腔科学 | 54篇 |
临床医学 | 135篇 |
内科学 | 392篇 |
皮肤病学 | 39篇 |
神经病学 | 303篇 |
特种医学 | 48篇 |
外科学 | 134篇 |
综合类 | 2篇 |
预防医学 | 112篇 |
眼科学 | 19篇 |
药学 | 97篇 |
中国医学 | 11篇 |
肿瘤学 | 118篇 |
出版年
2024年 | 6篇 |
2023年 | 21篇 |
2022年 | 52篇 |
2021年 | 74篇 |
2020年 | 42篇 |
2019年 | 55篇 |
2018年 | 57篇 |
2017年 | 68篇 |
2016年 | 64篇 |
2015年 | 78篇 |
2014年 | 85篇 |
2013年 | 94篇 |
2012年 | 149篇 |
2011年 | 155篇 |
2010年 | 85篇 |
2009年 | 67篇 |
2008年 | 110篇 |
2007年 | 94篇 |
2006年 | 113篇 |
2005年 | 74篇 |
2004年 | 69篇 |
2003年 | 64篇 |
2002年 | 62篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 15篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1996年 | 13篇 |
1995年 | 10篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1990年 | 5篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1969年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有1879条查询结果,搜索用时 62 毫秒
11.
12.
Silvia Ferri Bernardo Stefanini Lorenzo Mulazzani Margherita Alvisi Francesco Tovoli Simona Leoni Luca Muratori Tommaso Lotti Alessandro Granito Luigi Bolondi Fabio Piscaglia 《Nutrients》2022,14(12)
The role of moderate alcohol consumption in the evolution of NAFLD is still debated. The aim of this study is to evaluate the impact of current and lifelong alcohol consumption in patients with NAFLD. From 2015 to 2020, we enrolled 276 consecutive patients fulfilling criteria of NAFLD (alcohol consumption up to 140 g/week for women and 210 g/week for men). According to their current alcohol intake per week, patients were divided in: abstainers, very low consumers (C1: <70 g/week) and moderate consumers (C2). We created a new tool, called LACU (Lifetime Alcohol Consuming Unit) to estimate the alcohol exposure across lifetime: 1 LACU was defined as 7 alcohol units per week for 1 drinking year. Patients were divided into lifelong abstainers and consumers and the latter furtherly divided into quartiles: Q1-Q4. Stratification according to alcohol intake, both current and cumulative as estimated by LACU, showed that very low consumers (C1 and Q1-Q3) displayed lower frequency of cirrhosis and hepatocellular carcinoma compared to abstainers and moderate consumers (C2 and Q4). We can speculate that up to one glass of wine daily in the context of a Mediterranean diet may be a long-term useful approach in selected NAFLD patients. 相似文献
13.
Roberto Lorusso Samuel Heuts Federica Jiritano Roberto Scrofani Carlo Antona Guglielmo Actis Dato Paolo Centofanti Sandro Ferrarese Matteo Matteucci Antonio Miceli Mattia Glauber Enrico Vizzardi Sandro Sponga Igor Vendramin Andrea Garatti Carlo de Vincentis Michele De Bonis Silvia Ajello Giovanni Troise Margherita Dalla Tomba Filiberto Serraino 《Interactive Cardiovascular and Thoracic Surgery》2022,35(1)
Open in a separate window OBJECTIVESAlthough the intra-aortic balloon pump (IABP) has been the most widely adopted temporary mechanical support device in cardiac surgical patients, its use has declined. The current study aimed to evaluate the occurrence and predictors of early mortality and complication rates in contemporary cardiac surgery patients supported by an IABP.METHODSA multicentre, retrospective analysis was performed of all consecutive cardiac surgical patients receiving perioperative balloon pump support in 8 centres between January 2010 to December 2019. The primary outcome was early mortality, and secondary outcomes were balloon-associated complications. A multivariable binary logistic regression model was applied to evaluate predictors of the primary outcome.RESULTSThe study cohort consisted of 2615 consecutive patients. The median age was 68 years [25th percentile 61, 75th percentile 75 years], with the majority being male (76.9%), and a mean calculated 30-day mortality risk of 10.0%. Early mortality was 12.7% (n = 333), due to cardiac causes (n = 266), neurological causes (=22), balloon-related causes (n = 5) and other causes (n = 40). A composite end point of all vascular complications occurred in 7.2% of patients, and leg ischaemia was observed in 1.3% of patients. The most important predictors of early mortality were peripheral vascular disease [odds ratio (OR) 1.63], postoperative dialysis requirement (OR 10.40) and vascular complications (OR 2.57).CONCLUSIONSThe use of the perioperative IABP proved to be safe and demonstrated relatively low complication rates, particularly for leg ischaemia. As such, we believe that specialists should not be held back to use this widely available treatment in high-risk cardiac surgical patients when indicated. 相似文献
14.
15.
16.
Luca Comuzzi Margherita Tumedei Adriano Piattelli Gianluca Tartaglia Massimo Del Fabbro 《Materials》2022,15(9)
Background. The maxillary sinus lift is a popular and predictable technique associated with implant-supported rehabilitation of the severely atrophic maxilla. The aim of the present retrospective study was to investigate the effectiveness of transcrestal maxillary sinus augmentation and the graft resorption pattern using different heterologous bone substitutes. Methods. A total of 75 sinus-grafting procedures were performed and 89 implants were placed in 66 patients, 24 males and 42 females, with mean age 67.9 ± 10.64 years (range 43–84 years). Nineteen subjects were smokers. The mean follow-up period was 93.33 ± 54.71 months (range 14–240 months). Clinical and radiographical evaluations were performed. Graft height and width were measured at baseline and at the latest follow-up. Results. Mesiodistal and vertical resorption averaged 9.3 ± 20.7% (standard deviation), and 5.04 ± 9.9% of the postoperative size, respectively, considering the graft as the unit. Linear regression analysis showed that graft resorption in both the vertical and the mesiodistal dimension is independent of the follow-up time. Conversely, there was a trend for greater resorption when increasing the postoperative graft size, in both vertical (p = 0.001) and horizontal (p = 0.007) dimensions. When grouping the dimensional changes by graft particle size (only small (<300 μm) particles, combination of small and medium (>500 μm)/large (>1000 μm) particles, and only medium/large particles), there was a trend for greater resorption associated with smaller particles, but it was not significant; neither in the mesiodistal nor in the vertical dimension (p = 0.17 and p = 0.25, respectively). No implant was lost during the observation period. In conclusion, the transcrestal technique for maxillary sinus augmentation documented a high level of predictability. The low clinical morbidity and the contextual dental implant positioning is clinically useful in relation to a significant reduction of the time required for implant restoration, a consistent decrease of the number of surgical phases, and a cost-effectiveness approach for the rehabilitation. The graft resorption pattern in all cases was compatible with persistent implant protection and support. 相似文献
17.
PURPOSE: To study the effect of the antiepileptic drug levetiracetam (LEV) on the patterns of intrinsic optical signals (IOSs) generated by slices of the somatosensory cortex obtained from 3- and 6-month-old WAG/Rij and age-matched, nonepileptic control (NEC) rats. METHODS: WAG/Rij and NEC animals were anesthetized with enfluorane and decapitated. Brains were quickly removed, and neocortical slices were cut coronally with a vibratome, transferred to a submerged tissue chamber, and superfused with oxygenated artificial cerebrospinal fluid (aCSF). Slices were illuminated with a dark-field condensor and examined with a x2.5 objective; images were processed with a real time digital video image-enhancement system. Images were acquired before (background) and during electrical stimulation with a temporal resolution of 10 images/s and were displayed in pseudocolors. Extracellular stimuli (200 micros; <4 V) were delivered through bipolar stainless steel electrodes placed in the white matter. RESULTS: IOSs recorded in NEC slices bathed in control aCSF became less intense and of reduced size with age (p < 0.05); this trend was not seen in WAG/Rij slices. Age-dependent decreases in IOS intensity and area size were also seen in NEC slices superfused with aCSF containing the convulsant 4-aminopyridine (4-AP, 5 microM); in contrast, significant increases in both parameters occurred with age in 4-AP-treated WAG/Rij slices (p < 0.05). Under any of these conditions, the IOS intensity and area size slices were larger in WAG/Rij than in NEC slices. LEV (50-500 microM) application to WAG/Rij slices caused dose-dependent IOS reductions that were evident both in control and in 4-AP-containing aCSF and were more pronounced in 6-month-old tissue. CONCLUSIONS: These data demonstrate age-dependent IOS modifications in NEC and WAG/Rij rat slices and identify a clear pattern of hyperexcitability that occurs in 6-month-old WAG/Rij neocortical tissue, an age when absence seizures occur in all animals. The ability of LEV to reduce these patterns of network hyperexcitability supports the potential use of this new antiepileptic drug in primary generalized epileptic disorders. 相似文献
18.
Badami E Sorini C Coccia M Usuelli V Molteni L Bolla AM Scavini M Mariani A King C Bosi E Falcone M 《Diabetes》2011,60(8):2120-2124
OBJECTIVE
The gut environment modulates the pathogenesis of type 1 diabetes (T1D), but how it affects autoimmunity toward pancreatic β-cells, a self-tissue located outside the intestine, is still unclear. In the small intestine, lamina propria dendritic cells (LPDCs) induce peripheral differentiation of FoxP3+ regulatory T (Treg) cells. We tested the hypothesis that the intestinal milieu impinges on human T1D by affecting differentiation of FoxP3+ Treg cells.RESEARCH DESIGN AND METHODS
We collected duodenal biopsies of 10 T1D patients, 16 healthy subjects, and 20 celiac individuals and performed a fluorescent-activated cell sorter analysis to measure percentages of various immune cell subsets, including CD4+ and CD8+ T cells, NK cells, γδ T cells, CD103+CD11c+ LPDCs, and CD4+CD25+FoxP3+CD127− Treg cells. In parallel, we assessed the tolerogenic function (i.e., capacity to induce differentiation of FoxP3+ Treg cells) by LPDCs of T1D patients and control subjects.RESULTS
Our analysis revealed a significant reduction in the percentage of intestinal CD4+CD25+FoxP3+CD127− Treg cells in T1D patients compared with healthy subjects (P = 0.03) and celiac individuals (P = 0.003). In addition, we found that LPDCs from T1D patients completely lacked their tolerogenic function; they were unable to convert CD4+CD25− T cells into CD4+CD25+FoxP3+CD127− Treg cells.CONCLUSIONS
Our data indicate that T1D patients have a reduced number of intestinal FoxP3+ Treg cells as a result of their defective differentiation in the gut. These findings suggest that intestinal immune regulation is not only calibrated to tolerate commensal bacteria and food components but also is instrumental in maintaining immune tolerance toward pancreatic β-cells and preventing T1D.Type 1 diabetes (T1D) is a destructive islet β-cell specific autoimmune disease resulting from a yet undefined interaction between genetic and environmental factors (1). A dramatic increase in T1D incidence was recorded in most developed countries in the past 40 years (e.g., a threefold increase in Western countries) (2,3). The steady and rapid increase in T1D incidence cannot be ascribed to genetic variations and, thus, it must be related to environmental changes. Environmental agents such as viral infections (i.e., enteroviruses and rotaviruses) (4,5), reactions to dietary antigens (i.e., cow’s milk and gluten) (6–8), and microbiota alterations (9) that act at the intestinal level have been observed in association with, or as risk factors for, the development of T1D. The observation that development of clinical diabetes in patients is preceded by intestinal alterations such as increased permeability, immune activation, and ultrastructural abnormalities of the epithelium (10–16) provides additional evidence on the crucial role of the gut environment in human T1D. Although existing evidence is suggestive of a causative link between the gut milieu and the pathogenesis of T1D, it is still unclear whether and by which mechanism(s) a dysfunction in the intestine promotes autoimmunity elsewhere (i.e., in the pancreatic β-cells) and if it does, how this process occurs.Important immune regulatory mechanisms reside in the intestinal mucosa. FoxP3+ regulatory T (Treg) cells, a Treg cell subset that is instrumental to controlling T1D (17), arise centrally in the thymus and peripherally in the gut (18). Specifically, lamina propria CD103+CD11c+ dendritic cells (LPDCs) are responsible for extrathymic FoxP3+ Treg cell development and expansion (18,19). Considering the key immune regulatory role of FoxP3+ Treg cells, it is clear that their defective peripheral differentiation in the gut could lead to failure of self-tolerance and autoimmune disease, particularly in tissues such as pancreatic islets and lymph nodes that are directly connected to the intestinal mucosa and gut-associated lymphoid tissue (20).Here we demonstrate that the extrathymic differentiation of FoxP3+ Treg cells by gut-resident CD103+CD11c+ dendritic cells (DCs) is selectively impaired in humans affected by T1D. Our findings indicate that organ-specific autoimmune diseases such as T1D could be initiated and possibly maintained by virtue of changes in peripheral FoxP3+ Treg cell differentiation and/or expansion in the gut. 相似文献19.
Mariarosaria Galeano MD ; Alessandra Bitto MD ; Domenica Altavilla PhD ; Letteria Minutoli MD ; Francesca Polito PhD ; Margherita Calò PhD ; Patrizia Lo Cascio PhD ; Francesco Stagno d'Alcontres MD ; Francesco Squadrito MD 《Wound repair and regeneration》2008,16(2):208-217
Healing of diabetic wounds still remains a critical medical problem. Polydeoxyribonucleotide (PDRN), a compound having a mixture of deoxyribonucleotide polymers, stimulates the A2 purinergic receptor with no toxic or adverse effect. We studied the effects of PDRN in diabetes‐related healing defect using an incisional skin‐wound model produced on the back of female diabetic mice (db+/db+) and their normal littermates (db+/+m). Animals were treated daily for 12 days with PDRN (8 mg/kg/ip) or its vehicle (100 μL 0.9%NaCl). Mice were killed 3, 6, and 12 days after skin injury to measure vascular endothelial growth factor (VEGF) mRNA expression and protein synthesis, to assay angiogenesis and tissue remodeling through histological evaluation, and to study CD31, Angiopoietin‐1 and Transglutaminase‐II. Furthermore, we measured wound breaking strength at day 12. PDRN injection in diabetic mice resulted in an increased VEGF message (vehicle=1.0±0.2 n‐fold vs. β‐actin; PDRN=1.5±0.09 n‐fold vs. β‐actin) and protein wound content on day 6 (vehicle=0.3±0.07 pg/wound; PDRN=0.9±0.1 pg/wound). PDRN injection improved the impaired wound healing and increased the wound‐breaking strength in diabetic mice. PDRN also caused a marked increase in CD31 immunostaining and induced Transglutaminase‐II and Angiopoietin‐1 expression. Furthermore, the concomitant administration of 3,7‐dimethyl‐1‐propargilxanthine, a selective adenosine A2A receptor antagonist, abolished PDRN positive effects on healing. However, 3,7‐dimethyl‐1‐propargilxanthine alone did not affect wound healing in both diabetic mice and normal littermates. These results suggest that PDRN might be useful in wound disorders associated with diabetes. 相似文献
20.