全文获取类型
收费全文 | 2134篇 |
免费 | 156篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 62篇 |
妇产科学 | 42篇 |
基础医学 | 331篇 |
口腔科学 | 52篇 |
临床医学 | 163篇 |
内科学 | 377篇 |
皮肤病学 | 45篇 |
神经病学 | 347篇 |
特种医学 | 103篇 |
外科学 | 242篇 |
综合类 | 8篇 |
一般理论 | 2篇 |
预防医学 | 152篇 |
眼科学 | 46篇 |
药学 | 170篇 |
中国医学 | 2篇 |
肿瘤学 | 127篇 |
出版年
2024年 | 5篇 |
2023年 | 22篇 |
2022年 | 26篇 |
2021年 | 62篇 |
2020年 | 49篇 |
2019年 | 50篇 |
2018年 | 58篇 |
2017年 | 37篇 |
2016年 | 72篇 |
2015年 | 73篇 |
2014年 | 96篇 |
2013年 | 94篇 |
2012年 | 149篇 |
2011年 | 200篇 |
2010年 | 103篇 |
2009年 | 105篇 |
2008年 | 129篇 |
2007年 | 116篇 |
2006年 | 108篇 |
2005年 | 97篇 |
2004年 | 89篇 |
2003年 | 69篇 |
2002年 | 66篇 |
2001年 | 37篇 |
2000年 | 34篇 |
1999年 | 27篇 |
1998年 | 13篇 |
1997年 | 17篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1993年 | 5篇 |
1992年 | 15篇 |
1991年 | 14篇 |
1990年 | 24篇 |
1989年 | 21篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1974年 | 13篇 |
1973年 | 6篇 |
1972年 | 9篇 |
1971年 | 8篇 |
1970年 | 6篇 |
1959年 | 5篇 |
排序方式: 共有2301条查询结果,搜索用时 78 毫秒
1.
Georg Prokop Benedikt Wiestler Daniel Hieber Fynn Withake Karoline Mayer Jens Gempt Claire Delbridge Friederike Schmidt-Graf Nicole Pfarr Bruno Märkl Jürgen Schlegel Friederike Liesche-Starnecker 《International journal of cancer. Journal international du cancer》2023,153(9):1658-1670
Intratumor heterogeneity is a main cause of the dismal prognosis of glioblastoma (GBM). Yet, there remains a lack of a uniform assessment of the degree of heterogeneity. With a multiscale approach, we addressed the hypothesis that intratumor heterogeneity exists on different levels comprising traditional regional analyses, but also innovative methods including computer-assisted analysis of tumor morphology combined with epigenomic data. With this aim, 157 biopsies of 37 patients with therapy-naive IDH-wildtype GBM were analyzed regarding the intratumor variance of protein expression of glial marker GFAP, microglia marker Iba1 and proliferation marker Mib1. Hematoxylin and eosin stained slides were evaluated for tumor vascularization. For the estimation of pixel intensity and nuclear profiling, automated analysis was used. Additionally, DNA methylation profiling was conducted separately for the single biopsies. Scoring systems were established to integrate several parameters into one score for the four examined modalities of heterogeneity (regional, cellular, pixel-level and epigenomic). As a result, we could show that heterogeneity was detected in all four modalities. Furthermore, for the regional, cellular and epigenomic level, we confirmed the results of earlier studies stating that a higher degree of heterogeneity is associated with poorer overall survival. To integrate all modalities into one score, we designed a predictor of longer survival, which showed a highly significant separation regarding the OS. In conclusion, multiscale intratumor heterogeneity exists in glioblastoma and its degree has an impact on overall survival. In future studies, the implementation of a broadly feasible heterogeneity index should be considered. 相似文献
2.
3.
The vagal nerve as a link between the nervous and immune system in the instance of polymicrobial sepsis 总被引:5,自引:0,他引:5
Wolfram Kessler Tobias Traeger Alexandra Westerholt Friederike Neher Marlene Mikulcak Antje Müller Stefan Maier Claus-Dieter Heidecke 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2006,391(2):83-87
Background The role of the vagal nerve in the autonomic nervous system is widely well known. Recently, an additional function was revealed
serving as a connector between the nervous and immune system. This connection is called the “cholinergic inflammatory pathway.”
Through stimulation of the acetylcholine receptors located upon the macrophages, the “unspecific” immune system can be directly
influenced.
Methods The vagal nerve was completely transected directly posterior to its passage through the diaphragm. The effect of complete
vagotomy was analyzed using a murine model of polymicrobial peritonitis (colon ascendens stent peritonitis, CASP). Survival
and clinical course of vagotomized or sham-operated mice were analyzed in the CASP model.
Results After CASP surgery, vagotomy led to a significantly increased mortality (64.7%) in comparison to sham-vagotomized animals
(34%). No difference in the bacterial load of various tissues (lung, liver, spleen, blood, lavage fluid, and kidney) from
septic animals with or without vagotomy was observed. Vagotomized animals reveal elevated serum cytokine levels (TNF, IL-6,
IL-10, and MCP-1) 20 h after the induction of polymicrobial peritonitis.
Conclusion The vagal nerve is therefore an important modulator of the immune system.
W. Kessler and T. Traeger contributed equally to this work
Best of Forum Papers presented at the Annual Meeting of the German Society of Surgery, 2–5 May 2006, Berlin, Germany 相似文献
4.
Davangere P Devanand Christian G Habeck Matthias H Tabert Nikolaos Scarmeas Gregory H Pelton James R Moeller Brett D Mensh Tyler Tarabula Ronald L Van Heertum Yaakov Stern 《Neuropsychopharmacology》2006,31(6):1327-1334
Temporoparietal and posterior cingulate metabolism deficits characterize patients with Alzheimer's disease (AD). A H(2)(15)O resting PET scan covariance pattern, derived by using multivariate techniques, was previously shown to discriminate 17 mild AD patients from 16 healthy controls. This AD covariance pattern revealed hypoperfusion in bilateral inferior parietal lobule and cingulate; and left middle frontal, inferior frontal, precentral, and supramarginal gyri. The AD pattern also revealed hyperperfusion in bilateral insula, lingual gyri, and cuneus; left fusiform and superior occipital gyri; and right parahippocampal gyrus and pulvinar. In an independent sample of 23 outpatients with mild cognitive impairment (MCI) followed at 6-month intervals, the AD pattern score was evaluated as a predictor of cognitive decline. In this MCI sample, an H2(15)O resting PET scan was carried out at baseline. Mean duration of follow-up was 48.8 (SD 15.5) months, during which time six of 23 MCI patients converted to AD. In generalized estimating equations (GEE) analyses, controlling for age, sex, education, and baseline neuropsychological scores, increased AD pattern score was associated with greater decline in each neuropsychological test score over time (Mini Mental State Exam, Selective Reminding Test delayed recall, Animal Naming, WAIS-R digit symbol; Ps<0.01-0.001). In summary, a resting PET covariance pattern previously reported to discriminate AD patients from control subjects was applied prospectively to an independent sample of MCI patients and found to predict cognitive decline. Independent replication in larger samples is needed before clinical application can be considered. 相似文献
5.
6.
7.
Haupt SS Spengler F Husemann R Dinse HR 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2004,155(4):485-499
We recorded neurons extracellularly in layers II/III, IV, and V of the hindpaw representation of primary somatosensory cortex in anesthetized rats and studied laminar features of receptive fields (RFs) and representational maps. On average, RFs were smallest in layer IV and largest in layer V; however, for individual penetrations we found substantial deviations from this rule. Within the hindpaw representation, a distinct rostrocaudal gradient of RF size was present in all layers. While layer V RFs were generally largest independent of this gradient, layer IV RFs recorded caudally representing the proximal portions of the paw were larger than layer II/III RFs recorded rostrally representing the digits. The individual scatter of the locations of RFs across laminar groups was in the range of several millimeters, corresponding to about 25% of the average RF diameter. The cutaneous representations of the hindpaw in extragranular layers were confined to the areal extent defined by responsive sites in layer IV. Comparison between RFs determined quantitatively and by handplotting showed a reliable correspondence. Repeated measurements of RFs revealed spontaneous fluctuations of RF size of no more than 5% of the initial condition over an observation period of several hours. The topography and variability of cortical maps of the hindpaw representation were studied with a quantitative interpolation method taking into account the geometric centers of RFs and the corresponding cortical recording sites. On average, the overall topography in terms of preservation of neighborhood relations was present in all layers, although some individual maps showed severe distortions of topography. Factors contributing to map variability were overall position of the representation on the cortical surface, internal topography and spatial extent. Interindividual variability of map layout was always highest in the digit representations. Local topographic orderliness was lowest in layer V, but comparable in layers II/III and IV. Within layer IV, the lowest orderliness was observed in the digit representations. Our data emphasize a substantial variability of RF size, overlap and position across layers and within layers. At the level of representational maps, we found a similar degree of variability that often co-varied across layers, with little evidence for significant layer specificity. Laminar differences are likely to arise from the specific input-output pattern, layer-specific cell types and the connectivity between different layers. Our findings emphasizing similarities in the variability across layers support the notion of tightly coupled columnar interactions between different layers. 相似文献
8.
Karch R Neumann F Neumann M Szawlowski P Schreiner W 《Annals of biomedical engineering》2003,31(5):548-563
Topological and metric properties of Voronoi polyhedra (VP) generated by the distal end points of terminal segments in arterial tree models grown by the method of constrained constructive optimization (CCO) are analyzed with the aim to characterize the spatial distribution of their supply sites relative to randomly distributed points as a reference model. The distributions of the number N
f
of Voronoi cell faces, cell volume V, surface area S, area A of individual cell faces, and asphericity parameter of the CCO models are all significantly different from the ones of random points, whereas the distributions of V, S, and are also significantly different among CCO models optimized for minimum intravascular volume and minimum segment length (p < 0.0001). The distributions of N
f
, V, and S of the CCO models are reasonably well approximated by two-parameter gamma distributions. We study scaling of intravascular blood volume and arterial cross-sectional area with the volume of supplied tissue, the latter being represented by the VP of the respective terminal segments. We observe scaling exponents from 1.20 ± 0.007 to 1.08 ± 0.005 for intravascular blood volume and 0.77 ± 0.01 for arterial cross-sectional area. Setting terminal flows proportional to the associated VP volumes during tree construction yields a relative dispersion of terminal flows of 37% and a coefficient of skewness of 1.12. © 2003 Biomedical Engineering Society.
PAC2003: 8719Uv, 8710+e, 4720Ky, 0260Pn, 0230Oz 相似文献
9.
Bruce R. Thorley Julie Milland Dale Christiansen Marc B. Lanteri Beth McInnes Ingrid Moeller Pierre Rivailler Branka Horvat Chantal Rabourdin-Combe Denis Gerlier Ian F. C. McKenzie Bruc. E. E. Loveland 《European journal of immunology》1997,27(3):726-734
CD46 (membrane cofactor protein) is a human cell-surface regulator of activated complement and a receptor for the measles virus. A CD46 transgenic mouse line with an expression pattern similar to that of human tissues has been produced, to develop an animal model of (i) the control of complement activation by complement regulators in hyperacute rejection of xenografts, and (ii) measles virus infection. The mouse line was made using a CD46 minigene that includes promoter sequence and the first two introns of genomic CD46, which was coinjected into mouse ova with chicken lysozyme matrix attachment region DNA. A high level of CD46 expression in homozygotic transgenic mice was obtained with spleen cells having approximately 75% of the level found on human peripheral blood mononuclear cells. CD46 was detected in all tissues examined by immunohistochemistry, radioimmunoassay and Western blotting, showing that these mice were suitable for transplantation and measles virus infection studies. It also indicated that the transgene included the important regulatory elements of the CD46 promoter. Transgenic spleen cells were significantly protected in vitro from human complement activated by either the classical or alternative pathways and from alternative pathway rat complement. Furthermore, transgenic mouse hearts transplanted to rats regulated complement deposition in an in vivo model of antibody-dependent hyperacute xenograft rejection. Similar to human lymphocytes, transgenic lymphoblasts could be infected in vitro with measles virus; infected cells expressed viral proteins and produced infectious viral particles. The data demonstrate the suitability of this minigene for obtaining high-level CD46 expression sufficient for enhanced resistance of transgenic cells to complement attack and for obtaining wide tissue distribution of CD46, analogous to human tissues and, therefore, useful for comparative studies. 相似文献
10.