全文获取类型
收费全文 | 4164篇 |
免费 | 286篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 89篇 |
妇产科学 | 85篇 |
基础医学 | 535篇 |
口腔科学 | 112篇 |
临床医学 | 330篇 |
内科学 | 881篇 |
皮肤病学 | 85篇 |
神经病学 | 673篇 |
特种医学 | 96篇 |
外科学 | 744篇 |
综合类 | 16篇 |
预防医学 | 200篇 |
眼科学 | 40篇 |
药学 | 190篇 |
中国医学 | 2篇 |
肿瘤学 | 351篇 |
出版年
2024年 | 8篇 |
2023年 | 38篇 |
2022年 | 82篇 |
2021年 | 150篇 |
2020年 | 70篇 |
2019年 | 117篇 |
2018年 | 153篇 |
2017年 | 120篇 |
2016年 | 101篇 |
2015年 | 126篇 |
2014年 | 174篇 |
2013年 | 179篇 |
2012年 | 332篇 |
2011年 | 342篇 |
2010年 | 203篇 |
2009年 | 142篇 |
2008年 | 223篇 |
2007年 | 220篇 |
2006年 | 199篇 |
2005年 | 213篇 |
2004年 | 205篇 |
2003年 | 170篇 |
2002年 | 144篇 |
2001年 | 49篇 |
2000年 | 51篇 |
1999年 | 68篇 |
1998年 | 39篇 |
1997年 | 26篇 |
1996年 | 24篇 |
1995年 | 31篇 |
1994年 | 21篇 |
1993年 | 13篇 |
1992年 | 37篇 |
1991年 | 31篇 |
1990年 | 29篇 |
1989年 | 33篇 |
1988年 | 28篇 |
1987年 | 29篇 |
1986年 | 24篇 |
1985年 | 12篇 |
1984年 | 26篇 |
1983年 | 21篇 |
1982年 | 10篇 |
1980年 | 8篇 |
1979年 | 16篇 |
1978年 | 15篇 |
1977年 | 10篇 |
1975年 | 10篇 |
1974年 | 13篇 |
1969年 | 9篇 |
排序方式: 共有4471条查询结果,搜索用时 15 毫秒
71.
Rachel Wells Deborah Ejem J. Nicholas Dionne-Odom Gulcan Bagcivan Konda Keebler Jennifer Frost Andres Azuero Alan Kono Keith M. Swetz Marie Bakitas 《Heart & lung : the journal of critical care》2018,47(6):533-538
Background
Little has been reported about protocol-driven outpatient palliative care consultation (OPCC) for advanced heart failure (HF).Objectives
To describe evaluation practices and treatment recommendations made during protocol-driven OPCCs for advanced HF.Methods
We performed content analysis of OPCCs completed as part of ENABLE CHF-PC, an early palliative care HF intervention, conducted at sites in the Northeast and Southeast. T-tests, Fisher's exact, and Chi-square tests were used to evaluate sociodemographic, outcome measures, and site content differences.Results
Of 61 ENABLE CHF-PC participants, 39 (64%) had an OPCC (Northeast, n=27; Southeast, n=12). Social and medical history assessed most were close relationships (n=35, 90%), family support (n=33, 85%), advance directive status (n=33, 85%), functional status (n=30, 77%); and symptoms were mood (n= 35, 90%), breathlessness (n=28, 72%), and chest pain (n=24, 62%). Treatment recommendations focused on care coordination (n=13, 33%) and specialty referrals (n=12, 31%). Between-site OPCC differences included assessment of family support (Northeast vs. Southeast: 100% vs. 50%), code status (96% vs. 58%), goals of care discussions (89% vs. 41.7%), and prognosis understanding (85% vs. 33%).Conclusion
OPCCs for HF focused on evaluating medical and social history, along with goals of care and code status discussions. Symptom evaluation commonly included mood disorders, pain, dyspnea, and fatigue. Notable regional differences were found in topics evaluated and OPCC completion rates. 相似文献72.
Tyler F. Beck Philippe M. Campeau Shalini N. Jhangiani Tomasz Gambin Alexander H. Li Reem Abo‐Zahrah Valerie K. Jordan Andres Hernandez‐Garcia Wojciech K. Wiszniewski Donna Muzny Richard A. Gibbs Eric Boerwinkle James R. Lupski Brendan Lee Willie Reardon Daryl A. Scott 《American journal of medical genetics. Part A》2015,167(4):831-836
73.
74.
Analysis of highly cited papers provides unique insights into the status of research in a given field. We sought to identify the top 100 most highly cited papers in the field of anorexia nervosa (AN). A free, publically accessible software was used to conduct an online search of publications with accompanying citation data. Search terms were selected to focus on papers dealing predominantly with AN, and the results manually screened to exclude out‐of‐scope publications. Papers in bulimia nervosa, eating disorder not otherwise specified and binge‐eating disorder, were not included. The top 100 most highly cited papers in the AN field were identified. Of these, 34 garnered greater than 400 citations, classifying them as ‘citation classics’. These works were divided into five categories, those dealing with epidemiological trends, medical/psychiatric comorbidities, treatment, mechanisms of disease and measurement/classification. Publications examining the epidemiology and underlying mechanisms of AN account for the majority of the top 100 papers. Scales and measurement tools have had the greatest impact, garnering the greatest number of average citations per paper. Although reasonably diverse, the top 100 papers highlight areas still lagging behind, including the neuroscience of AN as well as research into novel treatment strategies. Copyright © 2013 John Wiley & Sons, Ltd and Eating Disorders Association. 相似文献
75.
Gai McMichael Santhosh Girirajan Andres Moreno-De-Luca Jozef Gecz Chloe Shard Lam Son Nguyen Jillian Nicholl Catherine Gibson Eric Haan Evan Eichler Christa Lese Martin Alastair MacLennan 《European journal of human genetics : EJHG》2014,22(1):40-45
Recent studies have established the role of rare copy number variants (CNVs) in several neurological disorders but the contribution of rare CNVs to cerebral palsy (CP) is not known. Fifty Caucasian families having children with CP were studied using two microarray designs. Potentially pathogenic, rare (<1% population frequency) CNVs were identified, and their frequency determined, by comparing the CNVs found in cases with 8329 adult controls with no known neurological disorders. Ten of the 50 cases (20%) had rare CNVs of potential relevance to CP; there were a total of 14 CNVs, which were observed in <0.1% (<8/8329) of the control population. Eight inherited from an unaffected mother: a 751-kb deletion including FSCB, a 1.5-Mb duplication of 7q21.13, a 534-kb duplication of 15q11.2, a 446-kb duplication including CTNND2, a 219-kb duplication including MCPH1, a 169-kb duplication of 22q13.33, a 64-kb duplication of MC2R, and a 135-bp exonic deletion of SLC06A1. Three inherited from an unaffected father: a 386-kb deletion of 12p12.2-p12.1, a 234-kb duplication of 10q26.13, and a 4-kb exonic deletion of COPS3. The inheritance was unknown for three CNVs: a 157-bp exonic deletion of ACOX1, a 693-kb duplication of 17q25.3, and a 265-kb duplication of DAAM1. This is the first systematic study of CNVs in CP, and although it did not identify de novo mutations, has shown inherited, rare CNVs involving potentially pathogenic genes and pathways requiring further investigation. 相似文献
76.
Katarzyna Walkiewicz Andres S. Benitez Cardenas Christine Sun Colin Bacorn Gerda Saxer Yousif Shamoo 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(52):21408-21413
In principle, evolutionary outcomes could be largely predicted if all of the relevant physicochemical variants of a particular protein function under selection were known and integrated into an appropriate physiological model. We have tested this principle by generating a family of variants of the tetracycline resistance protein TetX2 and identified the physicochemical properties most correlated with organismal fitness. Surprisingly, small changes in the Km(MCN), less than twofold, were sufficient to produce highly successful adaptive mutants over clinically relevant drug concentrations. We then built a quantitative model directly relating the in vitro physicochemical properties of the mutant enzymes to the growth rates of bacteria carrying a single chromosomal copy of the tet(X2) variants over a wide range of minocycline (MCN) concentrations. Importantly, this model allows the prediction of enzymatic properties directly from cellular growth rates as well as the physicochemical-fitness landscape of TetX2. Using experimental evolution and deep sequencing to monitor the allelic frequencies of the seven most biochemically efficient TetX2 mutants in 10 independently evolving populations, we showed that the model correctly predicted the success of the two most beneficial variants tet(X2)T280A and tet(X2)N371I. The structure of the most efficient variant, TetX2T280A, in complex with MCN at 2.7 Å resolution suggests an indirect effect on enzyme kinetics. Taken together, these findings support an important role for readily accessible small steps in protein evolution that can, in turn, greatly increase the fitness of an organism during natural selection. 相似文献
77.
RH Andersson A Johnston PA Herman UH Winzer-Serhan I Karavanova D Vullhorst A Fisahn A Buonanno 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(32):13118-13123
The neuregulin/ErbB signaling network is genetically associated with schizophrenia and modulates hippocampal γ oscillations-a type of neuronal network activity important for higher brain processes and altered in psychiatric disorders. Because neuregulin-1 (NRG-1) dramatically increases extracellular dopamine levels in the hippocampus, we investigated the relationship between NRG/ErbB and dopamine signaling in hippocampal γ oscillations. Using agonists for different D1- and D2-type dopamine receptors, we found that the D4 receptor (D4R) agonist PD168077, but not D1/D5 and D2/D3 agonists, increases γ oscillation power, and its effect is blocked by the highly specific D4R antagonist L-745,870. Using double in situ hybridization and immunofluorescence histochemistry, we show that hippocampal D4R mRNA and protein are more highly expressed in GAD67-positive GABAergic interneurons, many of which express the NRG-1 receptor ErbB4. Importantly, D4 and ErbB4 receptors are coexpressed in parvalbumin-positive basket cells that are critical for γ oscillations. Last, we report that D4R activation is essential for the effects of NRG-1 on network activity because L-745,870 and the atypical antipsychotic clozapine dramatically reduce the NRG-1-induced increase in γ oscillation power. This unique link between D4R and ErbB4 signaling on γ oscillation power, and their coexpression in parvalbumin-expressing interneurons, suggests a cellular mechanism that may be compromised in different psychiatric disorders affecting cognitive control. These findings are important given the association of a DRD4 polymorphism with alterations in attention, working memory, and γ oscillations, and suggest potential benefits of D4R modulators for targeting cognitive deficits. 相似文献
78.
Loss of heterozygosity in 7q myeloid disorders: clinical associations and genomic pathogenesis 总被引:1,自引:0,他引:1
Jerez A Sugimoto Y Makishima H Verma A Jankowska AM Przychodzen B Visconte V Tiu RV O'Keefe CL Mohamedali AM Kulasekararaj AG Pellagatti A McGraw K Muramatsu H Moliterno AR Sekeres MA McDevitt MA Kojima S List A Boultwood J Mufti GJ Maciejewski JP 《Blood》2012,119(25):6109-6117
Loss of heterozygosity affecting chromosome 7q is common in acute myeloid leukemia and myelodysplastic syndromes, pointing toward the essential role of this region in disease phenotype and clonal evolution. The higher resolution offered by recently developed genomic platforms may be used to establish more precise clinical correlations and identify specific target genes. We analyzed a series of patients with myeloid disorders using recent genomic technologies (1458 by single-nucleotide polymorphism arrays [SNP-A], 226 by next-generation sequencing, and 183 by expression microarrays). Using SNP-A, we identified chromosome 7q loss of heterozygosity segments in 161 of 1458 patients (11%); 26% of chronic myelomonocytic leukemia patients harbored 7q uniparental disomy, of which 41% had a homozygous EZH2 mutation. In addition, we describe an SNP-A-isolated deletion 7 hypocellular myelodysplastic syndrome subset, with a high rate of progression. Using direct and parallel sequencing, we found no recurrent mutations in typically large deletion 7q and monosomy 7 patients. In contrast, we detected a markedly decreased expression of genes included in our SNP-A defined minimally deleted regions. Although a 2-hit model is present in most patients with 7q uniparental disomy and a myeloproliferative phenotype, haplodeficient expression of defined regions of 7q may underlie pathogenesis in patients with deletions and predominant dysplastic features. 相似文献
79.
Victoria C. Wing Mera S. Barr Caroline E. Wass Nir Lipsman Andres M. Lozano Zafiris J. Daskalakis Tony P. George 《Brain stimulation》2013,6(3):221-230
BackgroundTobacco smoking is the leading cause of preventable deaths worldwide, but many smokers are simply unable to quit. Psychosocial and pharmaceutical treatments have shown modest results on smoking cessation rates, but there is an urgent need to develop treatments with greater efficacy. Brain stimulation methods are gaining increasing interest as possible addiction therapeutics.ObjectivesThe purpose of this paper is to review the studies that have evaluated brain stimulation techniques on tobacco addiction, and discuss future directions for research in this novel area of addiction interventions.MethodsElectronic and manual literature searches identified fifteen studies that administered repetitive transcranial magnetic stimulation (rTMS), cranial electrostimulation (CES), transcranial direct current stimulation (tDCS) or deep brain stimulation (DBS).ResultsrTMS was found to be the most well studied method with respect to tobacco addiction. Results indicate that rTMS and tDCS targeted to the dorsolateral prefrontal cortex (DLPFC) were the most efficacious in reducing tobacco cravings, an effect that may be mediated through the brain reward system involved in tobacco addiction. While rTMS was shown to reduce consumption of cigarettes, as yet no brain stimulation technique has been shown to significantly increase abstinence rates. It is possible that the therapeutic effects of rTMS and tDCS may be improved by optimization of stimulation parameters and increasing the duration of treatment.ConclusionAlthough further studies are needed to confirm the ability of brain stimulation methods to treat tobacco addiction, this review indicates that rTMS and tDCS both represent potentially novel treatment modalities. 相似文献
80.