全文获取类型
收费全文 | 1326篇 |
免费 | 165篇 |
出版年
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 13篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 22篇 |
2015年 | 33篇 |
2014年 | 37篇 |
2013年 | 53篇 |
2012年 | 60篇 |
2011年 | 80篇 |
2010年 | 42篇 |
2009年 | 38篇 |
2008年 | 52篇 |
2007年 | 54篇 |
2006年 | 65篇 |
2005年 | 64篇 |
2004年 | 53篇 |
2003年 | 60篇 |
2002年 | 55篇 |
2001年 | 43篇 |
2000年 | 39篇 |
1999年 | 40篇 |
1998年 | 18篇 |
1997年 | 15篇 |
1996年 | 15篇 |
1995年 | 18篇 |
1994年 | 18篇 |
1993年 | 10篇 |
1992年 | 31篇 |
1991年 | 32篇 |
1990年 | 25篇 |
1989年 | 33篇 |
1988年 | 25篇 |
1987年 | 18篇 |
1986年 | 23篇 |
1985年 | 16篇 |
1984年 | 16篇 |
1983年 | 19篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 13篇 |
1979年 | 22篇 |
1978年 | 15篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1974年 | 12篇 |
1973年 | 11篇 |
1972年 | 7篇 |
1970年 | 12篇 |
排序方式: 共有1491条查询结果,搜索用时 31 毫秒
71.
72.
Adipose tissue fibrosis,hypertrophy, and hyperplasia: Correlations with diabetes in human obesity 下载免费PDF全文
Lindsey A. Muir Christopher K. Neeley Kevin A. Meyer Nicki A. Baker Alice M. Brosius Alexandra R. Washabaugh Oliver A. Varban Jonathan F. Finks Brian F. Zamarron Carmen G. Flesher Joshua S. Chang Jennifer B. DelProposto Lynn Geletka Gabriel Martinez‐Santibanez Niko Kaciroti Carey N. Lumeng Robert W. O'Rourke 《Obesity (Silver Spring, Md.)》2016,24(3):597-605
73.
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74.
75.
Linda M. Delahanty Thomas A. Wadden Pamela J. Goodwin Catherine M. Alfano Cynthia A. Thomson Melinda L. Irwin Marian L. Neuhouser Tracy E. Crane Elizabeth Frank Patricia A. Spears Bonnie P. Gillis Dawn L. Hershman Electra D. Paskett Judith Hopkins Vanessa Bernstein Vered Stearns Julia White Clifford Hudis Eric P. Winer Lisa A. Carey Ann H. Partridge Jennifer A. Ligibel 《Obesity (Silver Spring, Md.)》2022,30(1):28-38
76.
77.
78.
Alpha-B crystallin gene (CRYAB) mutation causes dominant congenital posterior polar cataract in humans 总被引:10,自引:0,他引:10 下载免费PDF全文
Berry V Francis P Reddy MA Collyer D Vithana E MacKay I Dawson G Carey AH Moore A Bhattacharya SS Quinlan RA 《American journal of human genetics》2001,69(5):1141-1145
Congenital cataracts are an important cause of bilateral visual impairment in infants. In a four-generation family of English descent, we mapped dominant congenital posterior polar cataract to chromosome 11q22-q22.3. The maximum LOD score, 3.92 at recombination fraction 0, was obtained for marker D11S898, near the gene that encodes crystallin alpha-B protein (CRYAB). By sequencing the coding regions of CRYAB, we found in exon 3 a deletion mutation, 450delA, that is associated with cataract in this family. The mutation resulted in a frameshift in codon 150 and produced an aberrant protein consisting of 184 residues. This is the first report of a mutation, in this gene, resulting in isolated congenital cataract. 相似文献
79.
Cross-linking of surface Ig receptors with anti IgM (anti-mu heavy chain, anti-mu), but not anti-IgD (anti-delta heavy chain, anti-delta), Abs leads to growth arrest and apoptosis in several extensively characterized B cell lymphomas. By poorly understood mechanisms, both Igs transiently stimulate c-Myc protein expression. However, ultimately, only anti-mu causes a severe loss in c-Myc and a large induction of p27(Kip1) protein expression. Because phosphatidylinositol 3-kinase (PI3K) has been established as a major modulator of cellular growth and survival, we investigated its role in mediating anti-Ig-stimulated outcomes. Herein, we show that PI3K pathways regulate cell cycle progression and apoptosis in the ECH408 B cell lymphoma. Anti-mu and anti-delta driven c-Myc protein changes precisely follow their effects on the PI3K effector, p70(S6K). Upstream of p70(S6K), signaling through both Ig receptors depresses PI3K pathway phospholipids below control with time, which is followed by p27(Kip1) induction. Conversely, anti-delta, but not anti-mu stimulated PI3K-dependent phospholipid return to control levels by 4-8 h. Abrogation of the PI3K pathway with specific inhibitors mimics anti-mu action, potentiates anti-mu-induced cell death and, importantly, converts anti-delta to a death signal. Transfection with active PI3K kinase construct induces anti-mu resistance, whereas transfection with dominant negative PI3K augments anti-mu sensitivity. Our results show that prolonged disengagement of PI3K or down-regulation of its products by anti-mu (and not anti-delta) determines B cell fate. 相似文献
80.
Szwajkajzer D Dai L Fukayama JW Abramczyk B Fairman R Carey J 《Journal of molecular biology》2001,308(5):949-962
The cis-trans isomerisation of maleylacetoacetate to fumarylacetoacetate is the penultimate step in the tyrosine/phenylalanine catabolic pathway and has recently been shown to be catalysed by glutathione S-transferase enzymes belonging to the zeta class. Given this primary metabolic role it is unsurprising that zeta class glutathione S-transferases are well conserved over a considerable period of evolution, being found in vertebrates, plants, insects and fungi. The structure of this glutathione S-transferase, cloned from Arabidopsis thaliana, has been solved by single isomorphous replacement with anomalous scattering and refined to a final crystallographic R-factor of 19.6% using data from 25.0 A to 1.65 A. The zeta class enzyme adopts the canonical glutathione S-transferase fold and forms a homodimer with each subunit consisting of 221 residues. In agreement with structures of glutathione S-transferases from the theta and phi classes, a serine residue (Ser17) is present in the active site, at a position that would allow it to stabilise the thiolate anion of glutathione. Site-directed mutagenesis of this residue confirms its importance in catalysis. In addition, the role of a highly conserved cysteine residue (Cys19) present in the active site of the zeta class glutathione S-transferase enzymes is discussed. 相似文献