全文获取类型
收费全文 | 47078篇 |
免费 | 3257篇 |
国内免费 | 203篇 |
专业分类
耳鼻咽喉 | 662篇 |
儿科学 | 1116篇 |
妇产科学 | 962篇 |
基础医学 | 6245篇 |
口腔科学 | 737篇 |
临床医学 | 4532篇 |
内科学 | 10446篇 |
皮肤病学 | 776篇 |
神经病学 | 4484篇 |
特种医学 | 2086篇 |
外科学 | 6955篇 |
综合类 | 468篇 |
一般理论 | 70篇 |
预防医学 | 3594篇 |
眼科学 | 1294篇 |
药学 | 3005篇 |
中国医学 | 59篇 |
肿瘤学 | 3047篇 |
出版年
2023年 | 374篇 |
2022年 | 736篇 |
2021年 | 1543篇 |
2020年 | 868篇 |
2019年 | 1297篇 |
2018年 | 1490篇 |
2017年 | 1042篇 |
2016年 | 1117篇 |
2015年 | 1353篇 |
2014年 | 1809篇 |
2013年 | 2329篇 |
2012年 | 3441篇 |
2011年 | 3628篇 |
2010年 | 1960篇 |
2009年 | 1689篇 |
2008年 | 2741篇 |
2007年 | 2813篇 |
2006年 | 2561篇 |
2005年 | 2497篇 |
2004年 | 2222篇 |
2003年 | 2011篇 |
2002年 | 1889篇 |
2001年 | 521篇 |
2000年 | 414篇 |
1999年 | 490篇 |
1998年 | 384篇 |
1997年 | 362篇 |
1996年 | 310篇 |
1995年 | 251篇 |
1994年 | 193篇 |
1993年 | 190篇 |
1992年 | 303篇 |
1991年 | 267篇 |
1990年 | 265篇 |
1989年 | 226篇 |
1988年 | 209篇 |
1987年 | 223篇 |
1986年 | 220篇 |
1985年 | 221篇 |
1984年 | 225篇 |
1983年 | 206篇 |
1982年 | 205篇 |
1981年 | 233篇 |
1980年 | 186篇 |
1979年 | 175篇 |
1978年 | 152篇 |
1977年 | 135篇 |
1975年 | 147篇 |
1974年 | 138篇 |
1973年 | 167篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Jean Ngou Mahlape P. Magooa Clare Gilham Florencia Djigma Marie-Noelle Didelot Helen Kelly Albert Yonli Bernard Sawadogo David A. Lewis Sinead Delany-Moretlwe Philippe Mayaud Michel Segondy 《Journal of clinical microbiology》2013,51(12):4240-4242
The careHPV and HC2 assays were compared for high-risk human papillomavirus (HR-HPV) DNA detection in cervical samples from 149 HIV-1-infected African women. The HR-HPV DNA detection rates were 37.6% and 34.9% for careHPV and HC2, respectively. Agreement between the two tests was 94.6% (95% confidence interval [CI], 89.7% to 97.7%) with a kappa value of 0.88 (95% CI, 0.81 to 0.96), indicating an excellent agreement. careHPV may be considered as suitable as HC2 for cervical cancer screening among HIV-infected African women. 相似文献
992.
Paul S. Foster Maximilian Plank Adam Collison Hock L. Tay Gerard E. Kaiko JingJing Li Sebastian L. Johnston Philip M. Hansbro Rakesh K. Kumar Ming Yang Joerg Mattes 《Immunological reviews》2013,253(1):198-215
Chronic inflammatory diseases of the lung are leading causes of morbidity and mortality worldwide. Many of these disorders can be attributed to abnormal immune responses to environmental stimuli and infections. As such, understanding the innate host defense pathways and their regulatory systems will be critical to developing new approaches to treatment. In this regard, there is increasing interest in the role of microRNAs (miRNAs) in the regulation of pulmonary innate host defense responses and the inflammatory sequelae in respiratory disease. In this review, we discuss recent findings that indicate an important role for miRNAs in the regulation in mouse models of various respiratory diseases and in host defense against bacterial and viral infection. We also discuss the potential utility and limitations of targeting these molecules as anti-inflammatory strategies and also as a means to improve pathogen clearance from the lung. 相似文献
993.
Biochemical and biomechanical extracellular matrix (ECM) cues have recently been shown to play a role in stimulating stem cell differentiation towards several lineages, though how they combine to induce adipogenesis has been less well studied. The objective of this study was to recapitulate both the ECM composition and mechanical properties of adipose tissue in vitro to stimulate adipogenesis of human adipose-derived stem cells (ASCs) in the absence of exogenous adipogenic growth factors and small molecules. Adipose specific ECM biochemical cues have been previously shown to influence adipogenic differentiation; however, the ability of biomechanical cues to promote adipogenesis has been less defined. Decellularized human lipoaspirate was used to functionalize polyacrylamide gels of varying stiffness to allow the cells to interact with adipose-specific ECM components. Culturing ASCs on gels that mimicked the native stiffness of adipose tissue (2 kPa) significantly upregulated adipogenic markers, in the absence of exogenous adipogenic growth factors and small molecules. As substrate stiffness increased, the cells became more spread, lost their rounded morphology, and failed to upregulate adipogenic markers. Together these data imply that as with other lineages, mechanical cues are capable of regulating adipogenesis in ASCs. 相似文献
994.
Duong D. Tu Yeun Goo Chung Eun Seok Gil Abhishek Seth Debra Franck Vivian Cristofaro Maryrose P. Sullivan Dolores Di Vizio Pablo Gomez III Rosalyn M. Adam David L. Kaplan Carlos R. Estrada Jr. Joshua R. Mauney 《Biomaterials》2013
Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a porcine model of augmentation cystoplasty. Two bi-layer matrix configurations were fabricated by solvent-casting/salt leaching either alone (Group 1) or in combination with silk film casting (Group 2) to yield porous foams buttressed by heterogeneous surface pore occlusions or homogenous silk films, respectively. Bladder augmentation was performed with each scaffold group (6 × 6 cm2) in juvenile Yorkshire swine for 3 m of implantation. Augmented animals exhibited high rates of survival (Group 1: 5/6, 83%; Group 2: 4/4, 100%) and voluntary voiding over the course of the study period. Urodynamic evaluations demonstrated mean increases in bladder capacity over pre-operative levels (Group 1: 277%; Group 2: 153%) which exceeded nonsurgical control gains (144%) encountered due to animal growth. Similarly, elevations in bladder compliance were substantially higher in augmented animals from baseline (Group 1: 357%; Group 2: 147%) in comparison to controls (41%). Gross tissue evaluations revealed that both matrix configurations supported extensive de novo tissue formation throughout the entire original implantation site which exhibited ultimate tensile strength similar to nonsurgical counterparts. Histological and immunohistochemical analyses showed that both implant groups promoted comparable extents of smooth muscle regeneration and contractile protein (α-smooth muscle actin and SM22α) expression within defect sites similar to controls. Parallel evaluations demonstrated the formation of a transitional, multi-layered urothelium with prominent cytokeratin, uroplakin, and p63 protein expression in both matrix groups. De novo innervation and vascularization processes were evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Ex vivo organ bath studies demonstrated that regenerated tissues supported by both silk matrices displayed contractile responses to carbachol, α,β-methylene-ATP, KCl, and electrical field stimulation similar to controls. Our data detail the ability of acellular silk scaffolds to support regeneration of innervated, vascularized smooth muscle and urothelial tissues within 3 m with structural, mechanical, and functional properties comparable to native tissue in a porcine model of bladder repair. 相似文献
995.
Umberto Albert David De Cori Andrea Aguglia Francesca Barbaro Fabio Lanfranco Filippo Bogetto Giuseppe Maina 《Journal of affective disorders》2013
Background
Lithium is recommended as a first-line treatment for Bipolar Disorder (BD). Thyroid and renal alterations are well known lithium side-effects, while effects on parathyroids are less studied. The aim of this case-control cross-sectional study is to compare parathyroid hormone (PTH) and calcium levels in lithium-exposed bipolar patients and in subjects who had never been exposed to lithium.Methods
112 BD patients were enrolled, 58 on lithium since at least 1 month (mean exposure 60.8±74.8 months) and 54 in the control group. Blood exams included complete blood count, PTH, total and ionized calcium, TSH, T3 and T4, creatinine, urea, sodium and potassium, and lithium serum levels. The Student's t-test and the Pearson's Chi-square test were used for bivariate analyses. A linear regression model was used to analyze the relationship between the duration of exposure to lithium and PTH and calcium levels.Results
PTH and ionized calcium levels were significantly higher in lithium-exposed patients; the proportions of subjects with hyperparathyroidism (8.6%) and hypercalcaemia (24.1%) were significantly greater in lithium-exposed patients. The linear regression analyses showed a significant effect of exposure to lithium in months on ionized calcium levels but not on PTH levels.Limitations
Given the cross-sectional design of the study we could not identify the exact time of occurrence of hyperparathyroidism.Conclusions
Our results indicate that lithium-associated stimulation of parathyroid function is more common than assumed to date. Among parameters to be evaluated prior to lithium implementation and during long-term lithium maintenance, calcium (and eventually PTH) should be added. 相似文献996.
Douglas Carroll Anna C. Phillips Geoff Der Kate Hunt Adam Bibbey Michaela Benzeval Annie T. Ginty 《International journal of psychophysiology》2013
It has been argued recently that blunted cardiovascular reactions to acute psychological stress have adverse behavioural and health corollaries that reflect dysregulation of the neural systems that support motivation. We examined the association between cardiovascular reactions to a standard stress task, the paced auditory serial arithmetic rest, and forced expiratory volume in one second, an effort, hence motivation, dependent assessment of lung function measured by spirometry. Low forced expiratory volume, expressed as a ratio to height squared was associated with blunted heart rate, but not blood pressure, stress reactivity, r = .17, p < .001. The association survived adjustment for smoking, a range of anthropometric and sociodemographic covariates, resting heart rate and stress task performance, β = .11, p = .005. As such, our results provide support for the hypothesis that blunted stress reactivity may be a peripheral marker of a dysfunction in the brain systems that support motivated behaviour. 相似文献
997.
Adam Bibbey Douglas Carroll Tessa J. Roseboom Anna C. Phillips Susanne R. de Rooij 《International journal of psychophysiology》2013
Stable personality traits have long been presumed to have biological substrates, although the evidence relating personality to biological stress reactivity is inconclusive. The present study examined, in a large middle aged cohort (N = 352), the relationship between key personality traits and both cortisol and cardiovascular reactions to acute psychological stress. Salivary cortisol and cardiovascular activity were measured at rest and in response to a psychological stress protocol comprising 5 min each of a Stroop task, mirror tracing, and a speech task. Participants subsequently completed the Big Five Inventory to assess neuroticism, agreeableness, openness to experience, extraversion, and conscientiousness. Those with higher neuroticism scores exhibited smaller cortisol and cardiovascular stress reactions, whereas participants who were less agreeable and less open had smaller cortisol and cardiac reactions to stress. These associations remained statistically significant following adjustment for a range of potential confounding variables. Thus, a negative personality disposition would appear to be linked to diminished stress reactivity. These findings further support a growing body of evidence which suggests that blunted stress reactivity may be maladaptive. 相似文献
998.
999.
1000.
Fiona Lobban Adam Postlethwaite David Glentworth Vanessa Pinfold Laura Wainwright Graham Dunn Anna Clancy Gillian Haddock 《Clinical psychology review》2013
Relatives play a key role in supporting people with psychosis at all stages of recovery, but this can be associated with high levels of distress. Family interventions, with an international evidence base, improve outcomes for service users but little is known about their impact on relatives' outcomes. This review of published evaluations aimed to assess whether family interventions are effective in improving outcomes for relatives of people with psychosis, to identify the key components of effective intervention packages, and to identify methodological limitations to be addressed in future research. Fifty studies were identified which evaluated an intervention to support relatives against a control group, and in which outcomes for the relatives were reported. Thirty (60%) studies showed a statistically significant positive impact of the intervention on at least one relatives' outcome category. Eleven key intervention components were identified across all 50 studies, but there was no evidence that the presence or absence of any of these key components reliably distinguished effective from ineffective interventions. Methodological quality of studies was generally poor with only 11 studies rated as adequate using the Clinical Trial Assessment Measure (CTAM). Recommendations to improve future research include larger samples; better defined interventions and controls; true randomisation and blind assessors; clearly specified primary outcomes; pre-published analysis plans that account appropriately for missing data and clustering of data; a consensus on the most relevant outcomes to assess and valid and reliable measures to do so. Alternative research designs need to be considered to evaluate more recent approaches which focus on family support, personalised to meet individual need, and offered as an integral part of complex clinical services. 相似文献