全文获取类型
收费全文 | 203篇 |
免费 | 14篇 |
专业分类
217篇 |
出版年
2024年 | 2篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 9篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
排序方式: 共有217条查询结果,搜索用时 15 毫秒
1.
Emilie M. M. Santos Wiro J. Niessen Albert J. Yoo Olvert A. Berkhemer Ludo F. Beenen Charles B. Majoie Henk. A. Marquering MR CLEAN investigators 《PloS one》2016,11(1)
Background and Purpose
In acute ischemic stroke (AIS) management, CT-based thrombus density has been associated with treatment success. However, currently used thrombus measurements are prone to inter-observer variability and oversimplify the heterogeneous thrombus composition. Our aim was first to introduce an automated method to assess the entire thrombus density and then to compare the measured entire thrombus density with respect to current standard manual measurements.Materials and Method
In 135 AIS patients, the density distribution of the entire thrombus was determined. Density distributions were described using medians, interquartile ranges (IQR), kurtosis, and skewedness. Differences between the median of entire thrombus measurements and commonly applied manual measurements using 3 regions of interest were determined using linear regression.Results
Density distributions varied considerably with medians ranging from 20.0 to 62.8 HU and IQRs ranging from 9.3 to 55.8 HU. The average median of the thrombus density distributions (43.5 ± 10.2 HU) was lower than the manual assessment (49.6 ± 8.0 HU) (p<0.05). The difference between manual measurements and median density of entire thrombus decreased with increasing density (r = 0.64; p<0.05), revealing relatively higher manual measurements for low density thrombi such that manual density measurement tend overestimates the real thrombus density.Conclusions
Automatic measurements of the full thrombus expose a wide variety of thrombi density distribution, which is not grasped with currently used manual measurement. Furthermore, discrimination of low and high density thrombi is improved with the automated method. 相似文献2.
Tianhua Niu Changzhong Chen Heather Cordell Jianhua Yang Binyan Wang Zhaoxi Wang Zhian Fang Nicholas J. Schork Clifford J. Rosen X. Xu 《Human genetics》1999,104(3):226-233
Osteoporosis is a chronic disorder characterized by low bone mass and fragility fractures. It affects more than 25 million men and women in the United States alone. Although several candidate genes, such as the vitamin-D-receptor gene or the estrogen-receptor gene, have been suggested in the pathogenesis of osteoporosis, the genetic dissection of this disorder remains a daunting task. To search systematically for chromosomal regions containing genes that regulate bone mineral density (BMD), we scanned the entire autosomal genome by using 367 polymorphic markers among 218 individuals (153 sibpairs) from 96 nuclear families collected from three townships of Anqing, China. In these 96 families, DNA samples from both parents were available for 82 (85.4%) families. By using age- and gender-adjusted forearm BMD measurements, a peak on chromosome 2 near D2S2141, D2S1400, and D2S405, a region previously linked to spinal BMD, showed evidence of linkage to both proximal and distal forearm BMD (multipoint LOD=2.15 and 2.14 for proximal and distal forearm BMD, respectively). One region on chromosome 13 (multipoint LOD=1.67) in the proximity of D13S788 and D13S800 showed evidence of linkage to distal forearm BMD only. Possible candidate genes included CALM2 (calmodulin 2) at 2p21.3-p21.1, a putative STK (serine/threonine kinase) at 2p23–24, POMC (pro-opiomelanocortin) at 2p23.3, and COL4A1 and COL4A2 (collagen IV alpha-1 and alpha-2 subunits) at 13q34. Because of the limited sample size, the suggestive evidence of linkage of this study should be considered as tentative and needs to be replicated in other larger populations. Received: 19 November 1998 / Accepted: 22 January 1999 相似文献
3.
D Y Mason J L Cordell A G Tse J J van Dongen C J van Noesel K Micklem K A Pulford F Valensi W M Comans-Bitter J Borst 《Journal of immunology (Baltimore, Md. : 1950)》1991,147(11):2474-2482
Recent evidence indicates that the transmembrane form of IgM on murine and human B lymphocytes is physically associated with at least two proteins, forming a disulfide-linked dimer, which may control cell surface expression of IgM and also play a role in signal transduction after Ag binding (by analogy with the TCR-associated CD3 components in T lymphocytes). We have used mAb and polyclonal antibodies against an intracytoplasmic epitope on one of these polypeptides (previously identified in murine B cells as the product of the B cell specific mb-1 gene) to study the distribution of the IgM-associated dimer in human cells. By immunocytochemical staining of normal and neoplastic B cells, we show that the human mb-1 protein appears early in B cell differentiation, probably before expression of cytoplasmic mu-chain, and persists until the plasma cell stage, where it is seen as an intracytoplasmic component. According to immunohistologic analysis of reactive lymphoid tissue and lymphoma samples, mb-1 protein is completely B cell specific. Anti-mb-1 also labels B cell areas in tissues from seven different mammalian species. Finally, the Ig-associated dimer could be isolated from human hairy-cell leukemia cells in high purity and yield by affinity chromatography using anti-mb-1 antibody. Mice immunized with this material have produced a strong polyclonal response, so that it should now be possible to prepare a panel of new mAb reactive with different epitopes on both mb-1 and on its associated polypeptide(s). 相似文献
4.
Treatment of PC12 and C6 cell cultures with recombinant basic fibroblast growth factor results in approximately a five to ten-fold stimulation of beta-amyloid precursor mRNA in the C6 astrocytoma cell line but only a slight induction of precursor mRNA in the PC-12 neuronal cell line. Stimulation of expression occurred at a hormone concentration of approximately 0.5 to 1 nM and was seen after 2 days. These results suggest that basic fibroblast growth factor may contribute to amyloidosis of Alzheimer's disease. 相似文献
5.
6.
Karen Bersine Valance E. F. Brenneis Robyn C. Draheim A. Michelle Wargo Rub Jeannette E. Zamon Rodney K. Litton Susan A. Hinton Mark D. Sytsma Jeffery R. Cordell John W. Chapman 《Biological invasions》2008,10(8):1381-1388
Estuaries play an important role as nurseries and migration corridors for Chinook salmon and other fishes. The invasive New
Zealand mudsnail, Potamopyrgus antipodarum (Gray, 1843), has been noted in the Columbia River Estuary and other estuaries in the western USA, yet no studies have addressed
the estuarine impacts of this invader. Our data show P. antipodarum is currently found in five peripheral bays and many tributaries of the Columbia River Estuary, where it can constitute a
major portion of the benthic invertebrate biomass and where it co-occurs with native amphipod species. We review the history
of the P. antipodarum invasion in the Columbia River Estuary and discuss potential impacts on estuarine food webs. We also report the first occurrence
of P. antipodarum in the diet of juvenile Chinook salmon from the Columbia River Estuary. Although present in Chinook diets at very low frequencies,
our observations of P. antipodarum in Chinook gut contents may represent early stages of food web change due to the establishment of dense estuarine snail populations.
Additional research is needed to determine the effects of P. antipodarum on benthic resources, native benthic invertebrates, and benthic predators. We encourage biologists working in western USA
estuaries to be alert to the possibility of encountering P. antipodarum in benthic habitats and predator diets.
相似文献
Jeannette E. ZamonEmail: |
7.
D Y Mason J L Cordell Z Abdulaziz M Naiem G Bordenave 《The journal of histochemistry and cytochemistry》1982,30(11):1114-1122
The production of mouse peroxidase:antiperoxidase (PAP) complexes suitable for immunohistological use in conjunction with monoclonal antibodies is described. Three approaches were explored: 1) production of conventional polyclonal PAP complexes; 2) conversion of rabbit PAP to \"pseudo-mouse PAP\" by incubation with monoclonal mouse anti-rabbit immunoglobulin; 3) formation of PAP complexes from monoclonal mouse antiperoxidase. PAP complexes prepared by the latter technique gave the best immunohistological labeling reactions, being stable on storage and compatible with a wide range of human monoclonal antibodies. Gel filtration revealed that monoclonal PAP is of lower molecular weight than conventional PAP complexes (fulfilling theoretical predictions based on the monospecificity of monoclonal antibodies). 相似文献
8.
Eric Dexter Stephen M. Bollens Jeffery Cordell Ho Young Soh Gretchen Rollwagen-Bollens Susanne P. Pfeifer Jérôme Goudet Séverine Vuilleumier 《Biological invasions》2018,20(6):1577-1595
The rate of aquatic invasions by planktonic organisms has increased considerably in recent decades. In order to effectively direct funding and resources to control the spread of such invasions, a methodological framework for identifying high-risk transport vectors, as well as ruling out vectors of lesser concern will be necessary. A number of estuarine ecosystems on the North American Pacific Northwest coast have experienced a series of high impact planktonic invasions that have slowly unfolded across the region in recent decades, most notably, that of the planktonic copepod crustacean Pseudodiaptomus inopinus. Although introduction of P. inopinus to the United States almost certainly occurred through the discharge of ballast water from commercial vessels originating in Asia (the species’ native range), the mechanisms and patterns of subsequent spread remain unknown. In order to elucidate the migration events shaping this invasion, we sampled the genomes of copepods from seven invasive and two native populations using restriction-site associated DNA sequencing. This genetic data was evaluated against spatially-explicit genetic simulation models to evaluate competing scenarios of invasion spread. Our results indicate that invasive populations of P. inopinus exhibit a geographically unstructured genetic composition, likely arising from infrequent and large migration events. This pattern of genetic patchiness was unexpected given the linear geographic structure of the sampled populations, and strongly contrasts with the clear invasion corridors observed in many aquatic systems. 相似文献
9.
Cordell HJ 《Genomics》2009,93(1):5-9
Gene-environment interactions are of interest in genetic association studies for several reasons. First, the power to detect genetic effects may be substantially decreased if those effects differ according to environmental exposure and if no account is taken of this interaction with environmental exposure in the analysis. Second, such interactions may indicate a phenomenon of genuine biological interest (whereby a particular genetic effect operates only in the presence of an environmental trigger, or vice versa), understanding of which can lead us to a greater understanding of possible mechanisms and pathways in disease progression. Here I discuss the testing and estimation of gene-environment interactions via the case/pseudocontrol and related approaches. As originally proposed, the case/pseudocontrol approach applies to case/parents trios with no missing genotype data. I discuss some recent extensions that allow larger pedigree structures with some missing genotype data and present computer simulations to compare the performance of several competing approaches. 相似文献
10.
Jorge Esparza-Gordillo Anja Matanovic Ingo Marenholz Anja Bauerfeind Klaus Rohde Katja Nemat Min-Ae Lee-Kirsch Magnus Nordenskj?ld Marten C. G. Winge Thomas Keil Renate Krüger Susanne Lau Kirsten Beyer Birgit Kalb Bodo Niggemann Norbert Hübner Heather J. Cordell Maria Bradley Young-Ae Lee 《PLoS genetics》2015,11(3)
Epidemiological studies suggest that allergy risk is preferentially transmitted through mothers. This can be due to genomic imprinting, where the phenotype effect of an allele depends on its parental origin, or due to maternal effects reflecting the maternal genome''s influence on the child during prenatal development. Loss-of-function mutations in the filaggrin gene (FLG) cause skin barrier deficiency and strongly predispose to atopic dermatitis (AD). We investigated the 4 most prevalent European FLG mutations (c.2282del4, p.R501X, p.R2447X, and p.S3247X) in two samples including 759 and 450 AD families. We used the multinomial and maximum-likelihood approach implemented in the PREMIM/EMIM tool to model parent-of-origin effects. Beyond the known role of FLG inheritance in AD (R1meta-analysis = 2.4, P = 1.0 x 10−36), we observed a strong maternal FLG genotype effect that was consistent in both independent family sets and for all 4 mutations analysed. Overall, children of FLG-carrier mothers had a 1.5-fold increased AD risk (S1 = 1.50, Pmeta-analysis = 8.4 x 10−8). Our data point to two independent and additive effects of FLG mutations: i) carrying a mutation and ii) having a mutation carrier mother. The maternal genotype effect was independent of mutation inheritance and can be seen as a non-genetic transmission of a genetic effect. The FLG maternal effect was observed only when mothers had allergic sensitization (elevated allergen-specific IgE antibody plasma levels), suggesting that FLG mutation-induced systemic immune responses in the mother may influence AD risk in the child. Notably, the maternal effect reported here was stronger than most common genetic risk factors for AD recently identified through genome-wide association studies (GWAS). Our study highlights the power of family-based studies in the identification of new etiological mechanisms and reveals, for the first time, a direct influence of the maternal genotype on the offspring’s susceptibility to a common human disease. 相似文献