全文获取类型
收费全文 | 23890篇 |
免费 | 1865篇 |
国内免费 | 61篇 |
专业分类
耳鼻咽喉 | 504篇 |
儿科学 | 742篇 |
妇产科学 | 399篇 |
基础医学 | 2941篇 |
口腔科学 | 391篇 |
临床医学 | 2934篇 |
内科学 | 4515篇 |
皮肤病学 | 456篇 |
神经病学 | 2022篇 |
特种医学 | 1261篇 |
外科学 | 3619篇 |
综合类 | 432篇 |
一般理论 | 20篇 |
预防医学 | 2068篇 |
眼科学 | 442篇 |
药学 | 1513篇 |
1篇 | |
中国医学 | 15篇 |
肿瘤学 | 1541篇 |
出版年
2023年 | 249篇 |
2022年 | 380篇 |
2021年 | 934篇 |
2020年 | 543篇 |
2019年 | 846篇 |
2018年 | 983篇 |
2017年 | 615篇 |
2016年 | 629篇 |
2015年 | 707篇 |
2014年 | 957篇 |
2013年 | 1477篇 |
2012年 | 1691篇 |
2011年 | 1603篇 |
2010年 | 890篇 |
2009年 | 779篇 |
2008年 | 1127篇 |
2007年 | 1163篇 |
2006年 | 1026篇 |
2005年 | 875篇 |
2004年 | 875篇 |
2003年 | 678篇 |
2002年 | 630篇 |
2001年 | 385篇 |
2000年 | 435篇 |
1999年 | 367篇 |
1998年 | 248篇 |
1997年 | 237篇 |
1996年 | 221篇 |
1995年 | 170篇 |
1994年 | 170篇 |
1993年 | 187篇 |
1992年 | 271篇 |
1991年 | 231篇 |
1990年 | 236篇 |
1989年 | 268篇 |
1988年 | 258篇 |
1987年 | 217篇 |
1986年 | 285篇 |
1985年 | 197篇 |
1984年 | 168篇 |
1983年 | 138篇 |
1982年 | 108篇 |
1981年 | 118篇 |
1980年 | 106篇 |
1979年 | 164篇 |
1978年 | 101篇 |
1977年 | 86篇 |
1976年 | 93篇 |
1975年 | 83篇 |
1971年 | 75篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Ryan Malosh Suzanne E. Ohmit Joshua G. Petrie Mark G. Thompson Allison E. Aiello Arnold S. Monto 《Vaccine》2014
Background
Factors associated with influenza vaccine receipt are well studied in healthcare personnel, pregnant women, and the elderly. There has been substantially less research in community dwelling adults and children, and none among entire households. Many studies determine vaccination status by self-report or behavioral intention, outcomes susceptible to misclassification. Given that vaccine is recommended for everyone over six months, re-evaluating these factors is warranted.Methods
The Household Influenza Vaccine Effectiveness (HIVE) study is a prospective cohort of households with children. In 2010–2011, 549 adults representing 312 households completed surveys evaluating knowledge, attitudes, and practices regarding influenza vaccination for themselves and their children. Using the health belief model (HBM) as a framework, we examined factors associated with documented seasonal influenza vaccine receipt using log-binomial regression models.Results
In multivariate models, cues to action such as doctor recommendation, (RR 1.62, 95% CI: 1.25–2.10), perceived benefits (RR 1.25, 95% CI: 1.04–1.50), and perceived susceptibility (RR 1.21, 95% CI: 1.03–1.42) were significantly associated with increased likelihood of vaccine receipt among adults while high perceived barriers were associated with decreased likelihood (RR 0.38, 95% CI: 0.25–0.59). Similarly, parents reporting higher barriers were less likely (RR 0.58, 95% CI: 0.42–0.79) and those perceiving greater benefits (RR 4.16, 95% CI: 2.28–7.59) and severity (RR 1.13, 95% CI: 1.00–1.27 were more likely to vaccinate their children. The observed effects of perceptions of susceptibility, severity, and benefits were more pronounced at low cues to action for children, as were the effects of perceptions of barriers and severity among adults.Conclusion
Perceived benefits and barriers are most strongly associated with vaccine receipt. However, the effects of various factors were most pronounced in the absence of cues to action, which may be an important component of targeted interventions. 相似文献993.
994.
Burke Q. Rosen Ryan O'HaraSanja Kovacevic Andrew SchulmanNevena Padovan Ksenija Marinkovic 《Alcohol》2014
It has been firmly established that opening and closing the eyes strongly modulate the electro- and magnetoencephalography (EEG and MEG) signals acquired during wakeful rest. Certain features of the resting EEG are altered in chronic alcoholics and their offspring, and have been proposed as biomarkers for alcoholism. Spontaneous brain oscillations are also affected by pharmacological manipulations, but the spectral and spatial characteristics of these changes are not clear. This study examined effects of the eyes-open (EO) and eyes-closed (EC) resting paradigm and alcohol challenge on the spatial profile of spontaneous MEG and EEG oscillations. Whole-head MEG and scalp EEG signals were acquired simultaneously from healthy social drinkers (n = 17) who participated in both alcohol (0.6 g/kg ethanol for men, 0.55 g/kg for women) and placebo conditions in a counterbalanced design. Power of the signal was calculated with Fast Fourier Transform and was decomposed into its constituent theta (4–7 Hz), alpha (8–12 Hz), and beta (15–20 Hz) frequency bands. High-resolution structural MRI images were additionally obtained from all participants and used to constrain distributed minimum norm inverse source power estimates. The spatial estimates of the main generator nodes were in agreement with studies using a combined fMRI-EEG approach. Alpha band oscillations dominated the spectral profile and their source was estimated to the medial parieto-occipital area. Power in theta and beta bands was weaker overall and their sources were estimated to a more focal medial prefrontal area. EO and EC manipulation most strongly modulated power in the alpha band, but a wide-band power increase was observed during the EC condition. Alcohol intoxication increased alpha power, particularly during the EC condition. Application of this methodology to cohorts of chronic alcoholics or individuals at risk could potentially provide insight into the neural basis of oscillatory differences that may be predictive of the vulnerability to alcoholism. 相似文献
995.
P. Urwyler I. Earnshaw M. Bermudez E. Perucha W. Wu S. Ryan L. Mcdonald S. N. Karagiannis L. S. Taams N. Powell A. Cope S. Papa 《Clinical and experimental immunology》2020,200(2):141-154
Immune checkpoint inhibition has revolutionized the treatment of several solid cancers, most notably melanoma and non-small-cell lung cancer (NSCLC). Drugs targeting cytotoxic T lymphocyte antigen (CTLA)-4 and programmed cell death 1 (PD-1) have made their way into routine clinical use; however, this has not been without difficulties. Stimulation of the immune system to target cancer has been found to result in a reduction of self-tolerance, leading to the development of adverse effects that resemble autoimmunity. These adverse effects are erratic in their onset and severity and can theoretically affect any organ type. Several mechanisms for immune-related toxicity have been investigated over recent years; however, no consensus on the cause or prediction of toxicity has been reached. This review seeks to examine reported evidence for possible mechanisms of toxicity, methods for prediction of those at risk and a discussion of future prospects within the field. 相似文献
996.
Christopher M. Richmond Richard Leventer Monique M. Ryan Martin B. Delatycki 《Clinical genetics》2020,97(3):516-520
Biallelic pathogenic variants in CA8 cause cerebellar ataxia, mental retardation and dysequilibrium syndrome 3 (CAMRQ3), a rare form of hereditary ataxia characterised by cerebellar hypoplasia/atrophy, variable intellectual disability and often quadrupedal gait. The few cases reported in the medical literature are all caused by pathogenic homozygous or compound heterozygous missense variants in CA8. We report a 9 year-old boy with marked gross motor delay, ataxia and progressive cerebellar atrophy with limited bipedal gait, but without intellectual disability. Singleton whole exome sequencing was performed. A novel homozygous truncating variant in CA8 (c.232C>T) with a predicted premature termination codon at position 78 (p.Arg78*) was identified. Both parents and the proband's healthy sister are heterozygous for the variant. This variant is likely pathogenic and the cause of the condition in this child. Functional evidence in the form of a spontaneous mouse model involving homozygous intragenic deletion of the mouse analogue of CA8 with nonsense-mediated decay and similar clinical features to the proband support pathogenicity. Identification of this truncating variant broadens the genotypic and phenotypic spectrum of CA8-related cerebellar ataxia. 相似文献
997.
998.
Jed A. Diekfuss Dustin R. Grooms Scott Bonnette Christopher A. DiCesare Staci Thomas Ryan P. MacPherson Jonathan D. Ellis Adam W. Kiefer Michael A. Riley Daniel K. Schneider Brooke Gadd Katie Kitchen Kim D. Barber Foss Jonathan A. Dudley Weihong Yuan Gregory D. Myer 《Psychophysiology》2020,57(5):e13545
Prospective evidence indicates that functional biomechanics and brain connectivity may predispose an athlete to an anterior cruciate ligament injury, revealing novel neural linkages for targeted neuromuscular training interventions. The purpose of this study was to determine the efficacy of a real-time biofeedback system for altering knee biomechanics and brain functional connectivity. Seventeen healthy, young, physically active female athletes completed 6 weeks of augmented neuromuscular training (aNMT) utilizing real-time, interactive visual biofeedback and 13 served as untrained controls. A drop vertical jump and resting state functional magnetic resonance imaging were separately completed at pre- and posttest time points to assess sensorimotor adaptation. The aNMT group had a significant reduction in peak knee abduction moment (pKAM) compared to controls (p = .03, d = 0.71). The aNMT group also exhibited a significant increase in functional connectivity between the right supplementary motor area and the left thalamus (p = .0473 after false discovery rate correction). Greater percent change in pKAM was also related to increased connectivity between the right cerebellum and right thalamus for the aNMT group (p = .0292 after false discovery rate correction, r2 = .62). No significant changes were observed for the controls (ps > .05). Our data provide preliminary evidence of potential neural mechanisms for aNMT-induced motor adaptations that reduce injury risk. Future research is warranted to understand the role of neuromuscular training alone and how each component of aNMT influences biomechanics and functional connectivity. 相似文献
999.
1000.
Santosh Gupta Daniel H. Hovelson Gabor Kemeny Susan Halabi Wen‐Chi Foo Monika Anand Jason A. Somarelli Scott A. Tomlins Emmanuel S. Antonarakis Jun Luo Ryan V. Dittamore Daniel J. George Colin Rothwell David M. Nanus Andrew J. Armstrong Simon G. Gregory 《Genes, chromosomes & cancer》2020,59(4):225-239
Circulating tumor cell (CTC) and cell‐free (cf) DNA‐based genomic alterations are increasingly being used for clinical decision‐making in oncology. However, the concordance and discordance between paired CTC and cfDNA genomic profiles remain largely unknown. We performed comparative genomic hybridization (CGH) on CTCs and cfDNA, and low‐pass whole genome sequencing (lpWGS) on cfDNA to characterize genomic alterations (CNA) and tumor content in two independent prospective studies of 93 men with mCRPC treated with enzalutamide/abiraterone, or radium‐223. Comprehensive analysis of 69 patient CTCs and 72 cfDNA samples from 93 men with mCRPC, including 64 paired samples, identified common concordant gains in FOXA1, AR, and MYC, and losses in BRCA1, PTEN, and RB1 between CTCs and cfDNA. Concordant PTEN loss and discordant BRCA2 gain were associated with significantly worse outcomes in Epic AR‐V7 negative men with mCRPC treated with abiraterone/enzalutamide. We identified and externally validated CTC‐specific genomic alternations that were discordant in paired cfDNA, even in samples with high tumor content. These CTC/cfDNA‐discordant regions included key genomic regulators of lineage plasticity, osteomimicry, and cellular differentiation, including MYCN gain in CTCs (31%) that was rarely detected in cfDNA. CTC MYCN gain was associated with poor clinical outcomes in AR‐V7 negative men and small cell transformation. In conclusion, we demonstrated concordance of multiple genomic alterations across CTC and cfDNA platforms; however, some genomic alterations displayed substantial discordance between CTC DNA and cfDNA despite the use of identical copy number analysis methods, suggesting tumor heterogeneity and divergent evolution associated with poor clinical outcomes. 相似文献