全文获取类型
收费全文 | 3958篇 |
免费 | 388篇 |
国内免费 | 164篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 25篇 |
妇产科学 | 22篇 |
基础医学 | 1043篇 |
口腔科学 | 67篇 |
临床医学 | 265篇 |
内科学 | 822篇 |
皮肤病学 | 60篇 |
神经病学 | 277篇 |
特种医学 | 81篇 |
外科学 | 150篇 |
综合类 | 368篇 |
预防医学 | 165篇 |
眼科学 | 225篇 |
药学 | 552篇 |
3篇 | |
中国医学 | 69篇 |
肿瘤学 | 291篇 |
出版年
2024年 | 12篇 |
2023年 | 98篇 |
2022年 | 185篇 |
2021年 | 241篇 |
2020年 | 168篇 |
2019年 | 167篇 |
2018年 | 173篇 |
2017年 | 150篇 |
2016年 | 135篇 |
2015年 | 173篇 |
2014年 | 289篇 |
2013年 | 270篇 |
2012年 | 292篇 |
2011年 | 302篇 |
2010年 | 236篇 |
2009年 | 205篇 |
2008年 | 234篇 |
2007年 | 190篇 |
2006年 | 182篇 |
2005年 | 160篇 |
2004年 | 130篇 |
2003年 | 100篇 |
2002年 | 65篇 |
2001年 | 61篇 |
2000年 | 40篇 |
1999年 | 38篇 |
1998年 | 44篇 |
1997年 | 34篇 |
1996年 | 32篇 |
1995年 | 16篇 |
1994年 | 16篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有4510条查询结果,搜索用时 93 毫秒
31.
大鼠重组IgE Fc区CH2-3的原核表达及活性研究 总被引:1,自引:0,他引:1
目的 研究大鼠IgE的Fc区CH2-3的生物学活性。方法 构建大鼠IgE的Fc区CH2-3的原核表达质粒pBAD/gⅢA/Ch2-3,并转化入TOP10中,阿拉伯糖诱导表达、周质腔抽提、Ni-NTA金属鳌合柱纯化获得大鼠IgE的Fc区CH2-3,细胞及动物水平检测蛋白质生物学活性。结果 原核系统表达出大鼠IgE的Fc区CH2-3,它能够阻断OVA激发的RBL-2H3的脱颗粒反应,阻断被动皮肤实验。结论 大鼠IgE的Fc区CH2-3能够封闭IgE高亲和力受体,阻断过敏反应。 相似文献
32.
The assessment of the mechanical properties of the respiratory system is typically done by oscillating flow into the lungs via the trachea, measuring the resulting pressure generated at the trachea, and relating the two signals to each other in terms of some suitable mathematical model. If the perturbing flow signal is broadband and not too large in amplitude, linear behavior is usually assumed and the input impedance calculated. Alternatively, some researchers have used flow signals that are narrow band but large in amplitude, and invoked nonlinear lumped-parameter models to account for the relationship between flow and pressure. There has been little attempt, however, to deal with respiratory data that are both broadband and reflective of system nonlinearities. In the present study, we collected such data from mice. To interpret these data, we first developed a time-domain approximation to a widely used model of respiratory input impedance. We then extended this model to include nonlinear resistive and elastic terms. We found that the nonlinear elastic term fit the data better than the linear model or the nonlinear resistance model when amplitudes were large. This model may be useful for detecting overinflation of the lung during mechanical ventilation. © 2003 Biomedical Engineering Society.
PAC2003: 8719Rr, 8719Uv 相似文献
33.
北京地区精神分裂症患者家属情感表达测查报告 总被引:10,自引:2,他引:10
目的;探讨北京地区的住院精神分裂症患者家属情感表达方式及测查方法的实用性、测查工具应用的一致性。方法:经过训练的研究人员,采用费氏修订的CFI-CV访谈提纲,对171例住院精神分裂症患者家庭的284位家属进行访谈和录音,并将录音打印成文字资料。 相似文献
34.
The Popdc2 gene is a member of the Popeye domain containing gene family encoding membrane proteins with prominent expression in striated and smooth muscle tissue. After introducing a LacZ reporter gene into the Popdc2 locus, expression was studied during embryonic development and postnatal life. At embryonic day (E) 7.5, expression was present in cardiac and extraembryonic mesoderm. At E10.5, expression was found in heart, somites, and mesothelial cells lining the coelom. At E12.5, expression was present in the coelomic mesothelium, pericardial and myocardial layer of the heart, skeletal muscle, bladder, gut, and umbilical vessels. Postnatal expression was found in cardiac and skeletal muscle and in the smooth muscle layer of colon, rectum, and bladder. In the stomach, Popdc2 was exclusively present in the pyloric epithelium. In conclusion, Popdc2 is expressed in various muscle and nonmuscle cell types during embryonic development and in postnatal life. 相似文献
35.
36.
37.
Anne Marie-Cardine Henning Kirchgessner Christoph Eckerskorn Stefan C. Meuer Burkhart Schraven 《European journal of immunology》1995,25(12):3290-3297
A glutathione-S-transferase-src-homology domain 2 (GST-SH2) fusion protein was employed to identify molecules interacting with the protein tyrosine kinase p59fyn. Among several proteins which bound to the fyn SH2 domain in lysates of human Jurkat T lymphocytes, α- and β-tubulin were identified by N-terminal sequencing. Further analysis established that α-tubulin exists as a tyrosine-phosphorylated protein in Jurkat cells, where it interacts with p59fyn, but not with p56lck. By contrast, in untransformed resting human T lymphocytes α-tubulin is not detectable as a tyrosine phosphorylated protein. However, following T cell activation, it becomes rapidly phosphorylated on tyrosine residues and subsequently associates with the SH2 domain of fyn. Interestingly, constitutively tyrosine-phosphorylated α-tubulin that is able to interact with the fyn-SH2 domain is expressed in peripheral blood T lymphoblasts isolated from leukemic patients in the absence of external stimulation. 相似文献
38.
Krämer J Aguirre-Arteta AM Thiel C Gross CM Dietz R Cardoso MC Leonhardt H 《Journal of molecular medicine (Berlin, Germany)》1999,77(2):294-298
Studies on smooth muscle cell differentiation and those on vascular development in mouse and humans have long been hampered
by the lack of suitable markers. Here we describe a novel, large isoform of smoothelin, a structural protein of differentiated,
contractile smooth muscle cells. The protein, which is highly conserved in mouse and humans, shows homology with other cytoskeleton-associated
smooth muscle cell proteins and contains an actinin-type actin-binding domain. Northern blot analysis from various mouse organs
identified short and long smoothelin mRNA forms, which exhibit distinct tissue expression patterns. The short form is highly
expressed in visceral muscle tissues such as intestine and stomach and is not detectable in brain, while the long mRNA form
is expressed in all vascularized organs. These results may provide new tools and approaches to study both smooth muscle cell
differentiation and proliferative vascular disease.
Received: 25 August 1998 / Accepted: 19 October 1998 相似文献
39.
Independent Component Analysis (ICA) is a promising tool for the analysis of functional magnetic resonance imaging (fMRI) time series. In these studies, mostly assumed is a spatially independent component map of fMRI data (spatial ICA). In this paper, we assume that the temporal courses of the signal and noises are independent within a Tiny spatial domain (temporal ICA). Then with fast-ICA algorithm, spatially neighboring fMRI data were blindly separated into several temporal courses and were preassumed to be formed by a signal time course and several noise time courses where the signal has the largest correlation coefficient with the reference signal. The final functional imaging was completed for the signals obtained from each voxel. Simulations showed that compared with the spatial ICA method, the new temporal ICA method is more effective than the spatial ICA in detecting weak signal in a fMRI dataset. As background noise, the simulations include simulated Gaussian noise and fMRI data without stimulation. Finally, vivo fMRI tests showed that the excited areas evoked by a visual stimuli are mainly in the region of the primary visual cortex and that evoked by auditory stimuli are mainly in the region of the primary temporal cortex. 相似文献
40.
We provide here 29 genetic variations, including 28 novel ones, in five genes that are potentially involved in the excitement
of cardiomyocytes: we found 4 in KCNA10, 2 in KCNK1, 8 in KCNK6, 11 in SLC18A1 (VMAT1), and 4 in SLC6A2 (norepinephrine transporter). We also examined their allelic frequencies in a Japanese population of long QT syndrome-affected
and nonaffected individuals. These data would be useful for genetic association studies designed to investigate acquired arrhythmias.
Received: May 22, 2001 / Accepted: June 8, 2001 相似文献