全文获取类型
收费全文 | 183490篇 |
免费 | 13053篇 |
国内免费 | 419篇 |
专业分类
耳鼻咽喉 | 1826篇 |
儿科学 | 4991篇 |
妇产科学 | 3659篇 |
基础医学 | 27509篇 |
口腔科学 | 4944篇 |
临床医学 | 15976篇 |
内科学 | 36849篇 |
皮肤病学 | 3033篇 |
神经病学 | 18073篇 |
特种医学 | 8095篇 |
外国民族医学 | 26篇 |
外科学 | 24458篇 |
综合类 | 1148篇 |
现状与发展 | 1篇 |
一般理论 | 162篇 |
预防医学 | 18883篇 |
眼科学 | 3379篇 |
药学 | 11043篇 |
中国医学 | 311篇 |
肿瘤学 | 12596篇 |
出版年
2023年 | 761篇 |
2022年 | 1288篇 |
2021年 | 2800篇 |
2020年 | 2061篇 |
2019年 | 2913篇 |
2018年 | 3620篇 |
2017年 | 3044篇 |
2016年 | 3416篇 |
2015年 | 3814篇 |
2014年 | 5261篇 |
2013年 | 7019篇 |
2012年 | 10668篇 |
2011年 | 10984篇 |
2010年 | 5868篇 |
2009年 | 5899篇 |
2008年 | 9913篇 |
2007年 | 10208篇 |
2006年 | 9912篇 |
2005年 | 9530篇 |
2004年 | 8431篇 |
2003年 | 8108篇 |
2002年 | 7465篇 |
2001年 | 5464篇 |
2000年 | 5348篇 |
1999年 | 4946篇 |
1998年 | 2326篇 |
1997年 | 1922篇 |
1996年 | 1927篇 |
1995年 | 1626篇 |
1994年 | 1470篇 |
1993年 | 1353篇 |
1992年 | 3335篇 |
1991年 | 3045篇 |
1990年 | 2900篇 |
1989年 | 2753篇 |
1988年 | 2530篇 |
1987年 | 2263篇 |
1986年 | 2148篇 |
1985年 | 2080篇 |
1984年 | 1555篇 |
1983年 | 1383篇 |
1982年 | 902篇 |
1981年 | 811篇 |
1980年 | 715篇 |
1979年 | 1181篇 |
1978年 | 809篇 |
1977年 | 700篇 |
1974年 | 680篇 |
1973年 | 646篇 |
1972年 | 632篇 |
排序方式: 共有10000条查询结果,搜索用时 276 毫秒
31.
Sex chromosome trisomies (SCT) are among the most common chromosomal duplications in humans. Due to recent technological advances in non-invasive screening, SCT can already be detected during pregnancy. This calls for more knowledge about the development of (young) children with SCT. This review focused on neurocognitive functioning of children with SCT between 0 and 18 years, on domains of global intellectual functioning, language, executive functioning, and social cognition, in order to identify targets that could benefit from early treatment. Online databases were used to identify peer-reviewed scientific articles using specific search terms. In total 18 studies were included. When applicable, effect sizes were calculated to indicate clinical significance. Results of the reviewed studies show that although traditionally, the focus has been on language and intelligence (IQ) in this population, recent studies suggest that executive functioning and social cognition may also be significantly affected already in childhood. These findings suggest that neuropsychological screening of children diagnosed with SCT should be extended, to also include executive functioning and social cognition. Knowledge about these neurocognitive risks is important to improve clinical care and help identify targets for early support and intervention programs to accommodate for the needs of individuals with SCT. 相似文献
32.
Rene S. Hendriksen Pimlapas Leekitcharoenphon Matthew Mikoleit Jacob Dyring Jensen Rolf Sommer Kaas Louise Roer Heena B. Joshi Srirat Pornruangmong Chaiwat Pulsrikarn Gladys D. Gonzalez-Aviles E. Ascelijn Reuland Nashwan Al Naiemi Astrid Louise Wester Frank M. Aarestrup Henrik Hasman 《Journal of clinical microbiology》2015,53(2):677-680
One unreported case of extended-spectrum-beta-lactamase (ESBL)-producing Salmonella enterica serovar Typhi was identified, whole-genome sequence typed, among other analyses, and compared to other available genomes of S. Typhi. The reported strain was similar to a previously published strain harboring blaSHV-12 from the Philippines and likely part of an undetected outbreak, the first of ESBL-producing S. Typhi. 相似文献
33.
Jennifer C. Sasaki Ashley Allemang Steven M. Bryce Laura Custer Kerry L. Dearfield Yasmin Dietz Azeddine Elhajouji Patricia A. Escobar Albert J. Fornace Jr Roland Froetschl Sheila Galloway Ulrike Hemmann Giel Hendriks Heng-Hong Li Mirjam Luijten Gladys Ouedraogo Lauren Peel Stefan Pfuhler Daniel J. Roberts Véronique Thybaud Jan van Benthem Carole L. Yauk Maik Schuler 《Environmental and molecular mutagenesis》2020,61(1):114-134
In May 2017, the Health and Environmental Sciences Institute's Genetic Toxicology Technical Committee hosted a workshop to discuss whether mode of action (MOA) investigation is enhanced through the application of the adverse outcome pathway (AOP) framework. As AOPs are a relatively new approach in genetic toxicology, this report describes how AOPs could be harnessed to advance MOA analysis of genotoxicity pathways using five example case studies. Each of these genetic toxicology AOPs proposed for further development includes the relevant molecular initiating events, key events, and adverse outcomes (AOs), identification and/or further development of the appropriate assays to link an agent to these events, and discussion regarding the biological plausibility of the proposed AOP. A key difference between these proposed genetic toxicology AOPs versus traditional AOPs is that the AO is a genetic toxicology endpoint of potential significance in risk characterization, in contrast to an adverse state of an organism or a population. The first two detailed case studies describe provisional AOPs for aurora kinase inhibition and tubulin binding, leading to the common AO of aneuploidy. The remaining three case studies highlight provisional AOPs that lead to chromosome breakage or mutation via indirect DNA interaction (inhibition of topoisomerase II, production of cellular reactive oxygen species, and inhibition of DNA synthesis). These case studies serve as starting points for genotoxicity AOPs that could ultimately be published and utilized by the broader toxicology community and illustrate the practical considerations and evidence required to formalize such AOPs so that they may be applied to genetic toxicity evaluation schemes. Environ. Mol. Mutagen. 61:114–134, 2020. © 2019 Wiley Periodicals, Inc. 相似文献
34.
35.
36.
Imre W.K. Kouw Bart B.L. Groen Joey S.J. Smeets Irene Fleur Kramer Janneau M.X. van Kranenburg Rachél Nilwik Jan A.P. Geurts René H.M. ten Broeke Martijn Poeze Luc J.C. van Loon Lex B. Verdijk 《Journal of the American Medical Directors Association》2019,20(1):35-42
Objectives
Short successive periods of skeletal muscle disuse have been suggested to substantially contribute to the observed loss of skeletal muscle mass over the life span. Hospitalization of older individuals due to acute illness, injury, or major surgery generally results in a mean hospital stay of 5 to 7 days, during which the level of physical activity is strongly reduced. We hypothesized that hospitalization following elective total hip arthroplasty is accompanied by substantial leg muscle atrophy in older men and women.Design and participants
Twenty-six older patients (75 ± 1 years) undergoing elective total hip arthroplasty participated in this observational study.Measurements
On hospital admission and on the day of discharge, computed tomographic (CT) scans were performed to assess muscle cross-sectional area (CSA) of both legs. During surgery and on the day of hospital discharge, a skeletal muscle biopsy was taken from the m. vastus lateralis of the operated leg to assess muscle fiber type–specific CSA.Results
An average of 5.6 ± 0.3 days of hospitalization resulted in a significant decline in quadriceps (?3.4% ± 1.0%) and thigh muscle CSA (?4.2% ± 1.1%) in the nonoperated leg (P < .05). Edema resulted in a 10.3% ± 1.7% increase in leg CSA in the operated leg (P < .05). At hospital admission, muscle fiber CSA was smaller in the type II vs type I fibers (3326 ± 253 μm2 vs 4075 ± 279 μm2, respectively; P < .05). During hospitalization, type I and II muscle fiber CSA tended to increase, likely due to edema in the operated leg (P = .10).Conclusions
Six days of hospitalization following elective total hip arthroplasty leads to substantial leg muscle atrophy in older patients. Effective intervention strategies are warranted to prevent the loss of muscle mass induced by short periods of muscle disuse during hospitalization. 相似文献37.
38.
39.
The specific role of postsynaptic activity for the generation of a functional magnetic resonance imaging (fMRI) response was determined by a simultaneous measurement of generated field excitatory postsynaptic potentials (fEPSPs) and blood oxygen level-dependent (BOLD) response in the rat hippocampal CA1 region during electrical stimulation of the contralateral CA3 region. The stimulation electrode was placed either in the left CA3a/b or CA3c, causing the preferentially basal or apical dendrites of the pyramidal cells in the right CA1 to be activated. Consecutive stimulations with low-intensity stimulation trains (i.e., 16 pulses for 8 seconds) resulted in clear postsynaptic responses of CA1 pyramidal cells, but in no significant BOLD responses. In contrast, consecutive high-intensity stimulation trains resulted in stronger postsynaptic responses that came along with minor (during stimulation of the left CA3a/b) or substantial (during stimulation of the left CA3c) spiking activity of the CA1 pyramidal cells, and resulted in the generation of significant BOLD responses in the left and right hippocampus. Correlating the electrophysiologic parameters of CA1 pyramidal cell activity (fEPSP and spiking activity) with the resultant BOLD response revealed no positive correlation. Consequently, postsynaptic activity of pyramidal cells, the most abundant neurons in the CA1, is not directly linked to the measured BOLD response. 相似文献
40.