全文获取类型
收费全文 | 152143篇 |
免费 | 10935篇 |
国内免费 | 704篇 |
专业分类
耳鼻咽喉 | 1802篇 |
儿科学 | 3715篇 |
妇产科学 | 2657篇 |
基础医学 | 19637篇 |
口腔科学 | 3364篇 |
临床医学 | 14992篇 |
内科学 | 31205篇 |
皮肤病学 | 2006篇 |
神经病学 | 13538篇 |
特种医学 | 6427篇 |
外科学 | 24400篇 |
综合类 | 2101篇 |
现状与发展 | 1篇 |
一般理论 | 189篇 |
预防医学 | 13467篇 |
眼科学 | 3383篇 |
药学 | 10602篇 |
2篇 | |
中国医学 | 197篇 |
肿瘤学 | 10097篇 |
出版年
2023年 | 728篇 |
2022年 | 929篇 |
2021年 | 3053篇 |
2020年 | 1753篇 |
2019年 | 2785篇 |
2018年 | 3367篇 |
2017年 | 2451篇 |
2016年 | 2605篇 |
2015年 | 3195篇 |
2014年 | 4668篇 |
2013年 | 6834篇 |
2012年 | 10144篇 |
2011年 | 10731篇 |
2010年 | 6008篇 |
2009年 | 5521篇 |
2008年 | 9469篇 |
2007年 | 10128篇 |
2006年 | 9549篇 |
2005年 | 9639篇 |
2004年 | 9251篇 |
2003年 | 8633篇 |
2002年 | 8297篇 |
2001年 | 1554篇 |
2000年 | 1314篇 |
1999年 | 1619篇 |
1998年 | 1768篇 |
1997年 | 1414篇 |
1996年 | 1338篇 |
1995年 | 1284篇 |
1994年 | 1092篇 |
1993年 | 1064篇 |
1992年 | 951篇 |
1991年 | 979篇 |
1990年 | 858篇 |
1989年 | 819篇 |
1988年 | 842篇 |
1987年 | 832篇 |
1986年 | 827篇 |
1985年 | 915篇 |
1984年 | 998篇 |
1983年 | 927篇 |
1982年 | 1191篇 |
1981年 | 1202篇 |
1980年 | 1010篇 |
1979年 | 718篇 |
1978年 | 725篇 |
1977年 | 655篇 |
1976年 | 567篇 |
1975年 | 508篇 |
1974年 | 507篇 |
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
41.
Marlen Z. Gonzalez Lane Beckes Joanna Chango Joseph P. Allen James A. Coan 《Social cognitive and affective neuroscience》2015,10(7):921-928
Neuroimaging studies using the social-exclusion paradigm Cyberball indicate increased dorsal anterior cingulate cortex (dACC) and right insula activity as a function of exclusion. However, comparatively less work has been done on how social status factors may moderate this finding. This study used the Cyberball paradigm with 85 (45 females) socio-economically diverse participants from a larger longitudinal sample. We tested whether neighborhood quality during adolescence would predict subsequent neural responding to social exclusion in young adulthood. Given previous behavioral studies indicating greater social vigilance and negative evaluation as a function of lower status, we expected that lower adolescent neighborhood quality would predict greater dACC activity during exclusion at young adulthood. Our findings indicate that young adults who lived in low-quality neighborhoods in adolescence showed greater dACC activity to social exclusion than those who lived in higher quality neighborhoods. Lower neighborhood quality also predicted greater prefrontal activation in the superior frontal gyrus, dorsal medial prefrontal cortex and the middle frontal gyrus, possibly indicating greater regulatory effort. Finally, this effect was not driven by subsequent ratings of distress during exclusion. In sum, adolescent neighborhood quality appears to potentiate neural responses to social exclusion in young adulthood, effects that are independent of felt distress. 相似文献
42.
Anthony R. Flores Brittany E. Jewell Erika M. Versalovic Randall J. Olsen Beth A. Bachert Slawomir Lukomski James M. Musser 《Infection and immunity》2015,83(3):1122-1129
Group A Streptococcus (GAS) predominantly exists as a colonizer of the human oropharynx that occasionally breaches epithelial barriers to cause invasive diseases. Despite the frequency of GAS carriage, few investigations into the contributory molecular mechanisms exist. To this end, we identified a naturally occurring polymorphism in the gene encoding the streptococcal collagen-like protein A (SclA) in GAS carrier strains. All previously sequenced invasive serotype M3 GAS possess a premature stop codon in the sclA gene truncating the protein. The carrier polymorphism is predicted to restore SclA function and was infrequently identified by targeted DNA sequencing in invasive strains of the same serotype. We demonstrate that a strain with the carrier sclA allele expressed a full-length SclA protein, while the strain with the invasive sclA allele expressed a truncated variant. An isoallelic mutant invasive strain with the carrier sclA allele exhibited decreased virulence in a mouse model of invasive disease and decreased multiplication in human blood. Further, the isoallelic invasive strain with the carrier sclA allele persisted in the mouse nasopharynx and had increased adherence to cultured epithelial cells. Repair of the premature stop codon in the invasive sclA allele restored the ability to bind the extracellular matrix proteins laminin and cellular fibronectin. These data demonstrate that a mutation in GAS carrier strains increases adherence and decreases virulence and suggest selection against increased adherence in GAS invasive isolates. 相似文献
43.
44.
45.
Oliver Sartor MD Daniel Heinrich MD Neil Mariados MD Maria José Méndez Vidal MD Daniel Keizman MD Camilla Thellenberg Karlsson MD Avivit Peer MD Giuseppe Procopio MD Stephen J. Frank MD Kalevi Pulkkanen MD Eli Rosenbaum MD Stefano Severi MD José Trigo MD Lucia Trandafir MD Volker Wagner MD Rui Li MS Luke T. Nordquist MD 《The Prostate》2019,79(14):1683-1691
46.
Sourajit M.Mustafi Jaroslaw Harezlak Chandana Kodiweera Jennifer S.Randolph James C.Ford Heather A.Wishart Yu-Chien Wu 《中国神经再生研究》2019,(1)
Multiple sclerosis is a neurodegenerative and inflammatory disease, a hallmark of which is demyelinating lesions in the white matter. We hypothesized that alterations in white matter microstructures can be non-invasively characterized by advanced diffusion magnetic resonance imaging. Seven diffusion metrics were extracted from hybrid diffusion imaging acquisitions via classic diffusion tensor imaging, neurite orientation dispersion and density imaging, and q-space imaging. We investigated the sensitivity of the diffusion metrics in 36 sets of regions of interest in the brain white matter of six female patients(age 52.8 ± 4.3 years) with multiple sclerosis. Each region of interest set included a conventional T2-defined lesion, a matched perilesion area, and normal-appearing white matter. Six patients with multiple sclerosis(n = 5) or clinically isolated syndrome(n = 1) at a mild to moderate disability level were recruited. The patients exhibited microstructural alterations from normal-appearing white matter transitioning to perilesion areas and lesions, consistent with decreased tissue restriction, decreased axonal density, and increased classic diffusion tensor imaging diffusivity. The findings suggest that diffusion compartment modeling and q-spa ce analysis appeared to be sensitive for detecting subtle microstructural alterations between perilesion areas and normal-appearing white matter. 相似文献
47.
James L. Dorling Alice E. Thackray James A. King Andrea Pucci Fernanda R. Goltz Rachel L. Batterham David J. Stensel 《Nutrients》2020,12(12)
The fat mass and obesity-associated gene (FTO) rs9939609 A-allele is linked to obesity and dyslipidemia, yet the independent influence of this polymorphism on blood lipids remains equivocal. We examined the influence of the FTO rs9939609 polymorphism on fasting and postprandial blood lipids in individuals homozygous for the risk A-allele or T-allele with similar anthropometric and demographic characteristics. 12 AA and 12 TT males consumed a standardized meal after fasting overnight. Blood samples were collected at baseline (−1.5 h), before the meal (0 h), and for five hours postprandially to measure lipid, glucose, and insulin concentrations. Time-averaged total area under the curve (TAUC) values (0–5 h) were calculated and compared between genotypes. Fasting triacylglycerol (TG), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, non-esterified fatty acid (NEFA), glucose, and insulin concentrations were similar between groups (p ≥ 0.293). TAUC for TG was similar in AAs and TTs (95% confidence interval (CI) −0.52 to 0.31 mmol/L/h; p = 0.606). Likewise, TAUC values were similar for NEFA (95% CI −0.04 to 0.03 mmol/L/h; p = 0.734), glucose (95% CI −0.41 to 0.44 mmol/L/h; p = 0.951), and insulin (95% CI −6.87 to 2.83 pmol/L/h; p = 0.395). Blood lipids are not influenced by the FTO rs9939609 polymorphism, suggesting the FTO-dyslipidemia link is mediated by adiposity and weight management is important in preventing FTO-related lipid variations. 相似文献
48.
49.
50.
Emmi Helle Aldo Córdova-Palomera Tiina Ojala Priyanka Saha Praneetha Potiny Stefan Gustafsson Erik Ingelsson Michael Bamshad Deborah Nickerson Jessica X. Chong University of Washington Center for Mendelian Genomics Euan Ashley James R. Priest 《Genetic epidemiology》2019,43(2):215-226
Loss of function variants in NOTCH1 cause left ventricular outflow tract obstructive defects (LVOTO). However, the risk conferred by rare and noncoding variants in NOTCH1 for LVOTO remains largely uncharacterized. In a cohort of 49 families affected by hypoplastic left heart syndrome, a severe form of LVOTO, we discovered predicted loss of function NOTCH1 variants in 6% of individuals. Rare or low-frequency missense variants were found in 16% of families. To make a quantitative estimate of the genetic risk posed by variants in NOTCH1 for LVOTO, we studied associations of 400 coding and noncoding variants in NOTCH1 in 1,085 cases and 332,788 controls from the UK Biobank. Two rare intronic variants in strong linkage disequilibrium displayed significant association with risk for LVOTO amongst European-ancestry individuals. This result was replicated in an independent analysis of 210 cases and 68,762 controls of non-European and mixed ancestry. In conclusion, carrying rare predicted loss of function variants in NOTCH1 confer significant risk for LVOTO. In addition, the two intronic variants seem to be associated with an increased risk for these defects. Our approach demonstrates the utility of population-based data sets in quantifying the specific risk of individual variants for disease-related phenotypes. 相似文献