全文获取类型
收费全文 | 3723篇 |
免费 | 303篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 114篇 |
妇产科学 | 120篇 |
基础医学 | 574篇 |
口腔科学 | 59篇 |
临床医学 | 410篇 |
内科学 | 644篇 |
皮肤病学 | 88篇 |
神经病学 | 377篇 |
特种医学 | 141篇 |
外科学 | 413篇 |
综合类 | 46篇 |
一般理论 | 8篇 |
预防医学 | 492篇 |
眼科学 | 47篇 |
药学 | 185篇 |
中国医学 | 3篇 |
肿瘤学 | 276篇 |
出版年
2023年 | 35篇 |
2022年 | 55篇 |
2021年 | 118篇 |
2020年 | 76篇 |
2019年 | 100篇 |
2018年 | 111篇 |
2017年 | 82篇 |
2016年 | 122篇 |
2015年 | 110篇 |
2014年 | 142篇 |
2013年 | 172篇 |
2012年 | 276篇 |
2011年 | 293篇 |
2010年 | 142篇 |
2009年 | 138篇 |
2008年 | 222篇 |
2007年 | 214篇 |
2006年 | 201篇 |
2005年 | 213篇 |
2004年 | 172篇 |
2003年 | 168篇 |
2002年 | 162篇 |
2001年 | 48篇 |
2000年 | 57篇 |
1999年 | 40篇 |
1998年 | 30篇 |
1997年 | 20篇 |
1996年 | 18篇 |
1995年 | 25篇 |
1994年 | 14篇 |
1993年 | 14篇 |
1992年 | 35篇 |
1991年 | 30篇 |
1990年 | 32篇 |
1989年 | 20篇 |
1988年 | 26篇 |
1987年 | 16篇 |
1986年 | 21篇 |
1985年 | 26篇 |
1984年 | 12篇 |
1983年 | 18篇 |
1982年 | 12篇 |
1979年 | 21篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 15篇 |
1975年 | 12篇 |
1974年 | 17篇 |
1973年 | 12篇 |
1972年 | 12篇 |
排序方式: 共有4029条查询结果,搜索用时 35 毫秒
51.
Philip Moons Koen Luyckx Corina Thomet Werner Budts Junko Enomoto Maayke A. Sluman Chun-Wei Lu Jamie L. Jackson Paul Khairy Stephen C. Cook Shanthi Chidambarathanu Luis Alday Katrine Eriksen Mikael Dellborg Malin Berghammer Bengt Johansson Andrew S. Mackie Samuel Menahem Adrienne H. Kovacs 《The Canadian journal of cardiology》2021,37(2):215-223
BackgroundWe compared physical functioning, mental health, and quality of life (QoL) of patients with different subtypes of congenital heart disease (CHD) in a large international sample and investigated the role of functional class in explaining the variance in outcomes across heart defects.MethodsIn the cross-sectional Assessment of Patterns of Patient-Reported Outcome in Adults with Congenital Heart Disease-International Study (APPROACH-IS), we enrolled 4028 adult patients with CHD from 15 countries. Diagnostic groups with at least 50 patients were included in these analyses, yielding a sample of 3538 patients (median age: 32 years; 52% women). Physical functioning, mental health, and QoL were measured with the SF-12 health status survey, Hospital Anxiety and Depression Scale (HADS), linear analog scale (LAS) and Satisfaction with Life Scale, respectively. Functional class was assessed using the patient-reported New York Heart Association (NYHA) class. Multivariable general linear mixed models were applied to assess the relationship between the type of CHD and patient-reported outcomes, adjusted for patient characteristics, and with country as random effect.ResultsPatients with coarctation of the aorta and those with isolated aortic valve disease reported the best physical functioning, mental health, and QoL. Patients with cyanotic heart disease or Eisenmenger syndrome had worst outcomes. The differences were statistically significant, above and beyond other patient characteristics. However, the explained variances were small (0.6% to 4.1%) and decreased further when functional status was added to the models (0.4% to 0.9%).ConclusionsSome types of CHD predict worse patient-reported outcomes. However, it appears that it is the functional status associated with the heart defect rather than the heart defect itself that shapes the outcomes. 相似文献
52.
The hypergastrinemia and hyperacidity associated with Helicobacter pylori infection has been explained by either a primary excess of gastrin or a lack of inhibitory influence by somatostatin (SOM). The objective of the present study was to compare the concentrations of fundic and antral SOM- and antral progastrin-derived peptides in nonulcer dyspepsia (NUD) subjects with and without H. pylori infection. Antral and fundic mucosal biopsies were extracted and assayed for SOM and gastrin amide, glycine–extended gastrin (gastrin gly), progastrin, and total gastrin. There was a significant sixfold reduction in antral SOM but no change in fundic SOM content in H. pylori-infected subjects compared to uninfected subjects. Antral gastrin amide concentrations were significantly higher in infected subjects. However, the concentrations of the nonamidated gastrin forms (progastrin and glycine-extended gastrin) were significantly lower in the infected subjects, indicating an increased conversion of the precursor forms of gastrin to amidated gastrin, the type known to stimulate gastric acidity. The present study demonstrates that the elevated gastrin concentrations associated with H. pylori infection may be due to a reduction in the paracrine inhibitory effect of SOM on antral gastrin release. In addition, the posttranslational processing of gastrin to the amidated forms is increased in infected subjects, explaining why the elevation in antral gastrin is confined to the amidated form. 相似文献
53.
54.
55.
56.
Claudia A. Grillo Gerardo G. Piroli Robert C. Lawrence Shayna A. Wrighten Adrienne J. Green Steven P. Wilson Randall R. Sakai Sandra J. Kelly Marlene A. Wilson David D. Mott Lawrence P. Reagan 《Diabetes》2015,64(11):3927-3936
Insulin receptors (IRs) are expressed in discrete neuronal populations in the central nervous system, including the hippocampus. To elucidate the functional role of hippocampal IRs independent of metabolic function, we generated a model of hippocampal-specific insulin resistance using a lentiviral vector expressing an IR antisense sequence (LV-IRAS). LV-IRAS effectively downregulates IR expression in the rat hippocampus without affecting body weight, adiposity, or peripheral glucose homeostasis. Nevertheless, hippocampal neuroplasticity was impaired in LV-IRAS–treated rats. High-frequency stimulation, which evoked robust long-term potentiation (LTP) in brain slices from LV control rats, failed to evoke LTP in LV-IRAS–treated rats. GluN2B subunit levels, as well as the basal level of phosphorylation of GluA1, were reduced in the hippocampus of LV-IRAS rats. Moreover, these deficits in synaptic transmission were associated with impairments in spatial learning. We suggest that alterations in the expression and phosphorylation of glutamate receptor subunits underlie the alterations in LTP and that these changes are responsible for the impairment in hippocampal-dependent learning. Importantly, these learning deficits are strikingly similar to the impairments in complex task performance observed in patients with diabetes, which strengthens the hypothesis that hippocampal insulin resistance is a key mediator of cognitive deficits independent of glycemic control. 相似文献
57.
58.
Functionally deficient mesenchymal stem cells reside in the bone marrow niche with M2‐macrophages and amyloid‐β protein adjacent to loose total joint implants 下载免费PDF全文
Bryan S. Margulies Sean D. DeBoyace Adrienne M. Parsons Connor G. Policastro Jessica S.S. Ee Timothy S. Damron 《Journal of orthopaedic research》2015,33(5):615-624
We sought to demonstrate whether there is a difference in the local mesenchymal stem cells (MSC) niche obtained from patients undergoing their first total joint replacement surgery versus those patients undergoing a revision surgery for an failing total joint implant. Bone marrow aspirates collected from patients undergoing revision total joint arthroplasty were observed to be less clonal and the expression of PDGFRα, CD51, ALCAM, endoglin, CXCL12, nestin, and nucleostemin were decreased. Revision MSC were also less able to commit to an osteoblast‐lineage or an adipocyte‐lineage. Further, in revision MSC, OPG, and IL6 expression were increased. Monocytes, derived from revision whole marrow aspirates, were less capable of differentiating into osteoclasts, the cells implicated in the pathologic degradation of bone. Osteoclasts were also not observed in tissue samples collected adjacent to the implants of revision patients; however, the alternatatively activated M2‐macrophage phenotype was observed in parallel with pathologic accumulations of amyloid‐β, τ‐protien and 3‐nitrotyrosine. Despite the limited numbers of patients examined, our data suggest that nucleostemin may be a useful functional marker for MSC while the observation of M2‐macrophage infiltration around the implant lays the foundation for future investigation into a novel mechanism that we propose is associated with loose total joint implants. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:615–624, 2014. 相似文献
59.
Adrienne A. Taren Peter J. Gianaros Carol M. Greco Emily K. Lindsay April Fairgrieve Kirk Warren Brown Rhonda K. Rosen Jennifer L. Ferris Erica Julson Anna L. Marsland James K. Bursley Jared Ramsburg J. David Creswell 《Social cognitive and affective neuroscience》2015,10(12):1758-1768
Recent studies indicate that mindfulness meditation training interventions reduce stress and improve stress-related health outcomes, but the neural pathways for these effects are unknown. The present research evaluates whether mindfulness meditation training alters resting state functional connectivity (rsFC) of the amygdala, a region known to coordinate stress processing and physiological stress responses. We show in an initial discovery study that higher perceived stress over the past month is associated with greater bilateral amygdala-subgenual anterior cingulate cortex (sgACC) rsFC in a sample of community adults (n = 130). A follow-up, single-blind randomized controlled trial shows that a 3-day intensive mindfulness meditation training intervention (relative to a well-matched 3-day relaxation training intervention without a mindfulness component) reduced right amygdala-sgACC rsFC in a sample of stressed unemployed community adults (n = 35). Although stress may increase amygdala-sgACC rsFC, brief training in mindfulness meditation could reverse these effects. This work provides an initial indication that mindfulness meditation training promotes functional neuroplastic changes, suggesting an amygdala-sgACC pathway for stress reduction effects. 相似文献
60.