全文获取类型
收费全文 | 468篇 |
免费 | 34篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 18篇 |
2020年 | 17篇 |
2019年 | 15篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 17篇 |
2015年 | 27篇 |
2014年 | 19篇 |
2013年 | 35篇 |
2012年 | 46篇 |
2011年 | 30篇 |
2010年 | 19篇 |
2009年 | 20篇 |
2008年 | 22篇 |
2007年 | 41篇 |
2006年 | 24篇 |
2005年 | 18篇 |
2004年 | 24篇 |
2003年 | 14篇 |
2002年 | 15篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1952年 | 1篇 |
1943年 | 1篇 |
1921年 | 2篇 |
排序方式: 共有502条查询结果,搜索用时 31 毫秒
151.
Tricia Rowlison Timothy P. Cleland Mary Ann Ottinger Pierre Comizzoli 《Molecular & cellular proteomics : MCP》2020,19(12):2090-2104
- Download : Download high-res image (175KB)
- Download : Download full-size image
- •Several proteins were found to be unique to each male type.
- •Expression levels of seven proteins trended downward in teratospermic males.
- •Several proteins were related to sperm motility and subsequent oocyte binding.
152.
153.
Charlie Chandsawangbhuwana Linda Z. Shi Qingyuan Zhu Michael W. Berns 《Journal of biophotonics》2014,7(8):571-579
A system has been developed that allows for the real‐time measurement of calcium dynamics in swimming sperm. Specifically, the ratiometric dye Indo‐I is used as a fluorescent indicator of intracellular calcium dynamics. The dual emissions are collected by a high‐sensitivity back‐illuminated CCD camera coupled to a Dual‐View imaging system. From the CCD, the images are sent to a custom developed algorithm which processes the images and outputs the calcium measurements in real‐time. Additionally, sperm velocity and position data are processed and outputted in real‐time. The velocity and position data are obtained using a separate coupled red light (>670 nm) phase contrast imaging setup that does not optically interfere with the fluorescent imaging. Using this system the effects of optical trapping on calcium dynamics was determined. Optical trapping of sperm with a decaying focused laser power of 510 mW to 3 mW over 8 seconds causes a statistically insignificant change in calcium dynamics between in‐trap and out‐of‐trap conditions. Progesterone, a calcium activator, was added and sperm were trapped under the 8 second power decay conditions. Progesterone treated sperm has a statistically higher average calcium level than untreated sperm, but shows no statistical difference between progesterone treated in‐trap and out‐of‐trap conditions. Trapping at 16 seconds at 510 mW without decay, which have been shown to decrease sperm motility, shows a statistical difference between baseline pre‐trap and in‐trap intracellular calcium levels. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
154.
Paul D. Wes Amy Easton John Corradi Donna M. Barten Nino Devidze Lynn B. DeCarr Amy Truong Aiqing He Nestor X. Barrezueta Craig Polson Clotilde Bourin Marianne E. Flynn Stefanie Keenan Regina Lidge Jere Meredith Joanne Natale Sethu Sankaranarayanan Greg W. Cadelina Charlie F. Albright Angela M. Cacace 《PloS one》2014,9(8)
Filamentous inclusions of the microtubule-associated protein, tau, define a variety of neurodegenerative diseases known as tauopathies, including Alzheimer’s disease (AD). To better understand the role of tau-mediated effects on pathophysiology and global central nervous system function, we extensively characterized gene expression, pathology and behavior of the rTg4510 mouse model, which overexpresses a mutant form of human tau that causes Frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). We found that the most predominantly altered gene expression pathways in rTg4510 mice were in inflammatory processes. These results closely matched the causal immune function and microglial gene-regulatory network recently identified in AD. We identified additional gene expression changes by laser microdissecting specific regions of the hippocampus, which highlighted alterations in neuronal network activity. Expression of inflammatory genes and markers of neuronal activity changed as a function of age in rTg4510 mice and coincided with behavioral deficits. Inflammatory changes were tau-dependent, as they were reversed by suppression of the tau transgene. Our results suggest that the alterations in microglial phenotypes that appear to contribute to the pathogenesis of Alzheimer’s disease may be driven by tau dysfunction, in addition to the direct effects of beta-amyloid. 相似文献
155.
156.
Jin C Li J Green CD Yu X Tang X Han D Xian B Wang D Huang X Cao X Yan Z Hou L Liu J Shukeir N Khaitovich P Chen CD Zhang H Jenuwein T Han JD 《Cell metabolism》2011,14(2):161-172
Epigenetic modifications are thought to be important for gene expression changes during development and aging. However, besides the Sir2 histone deacetylase in somatic tissues and H3K4 trimethylation in germlines, there is scant evidence implicating epigenetic regulations in aging. The insulin/IGF-1 signaling (IIS) pathway is a major life span regulatory pathway. Here, we show that progressive increases in gene expression and loss of H3K27me3 on IIS components are due, at least in part, to increased activity of the H3K27 demethylase UTX-1 during aging. RNAi of the utx-1 gene extended the mean life span of C. elegans by ~30%, dependent on DAF-16 activity and not additive in daf-2 mutants. The loss of utx-1 increased H3K27me3 on the Igf1r/daf-2 gene and decreased IIS activity, leading to a more "naive" epigenetic state. Like stem cell reprogramming, our results suggest that reestablishment of epigenetic marks lost during aging might help "reset" the developmental age of animal cells. 相似文献
157.
158.
Zongxin Ling Xia Liu Weiguang Chen Yueqiu Luo Li Yuan Yaxian Xia Karen E Nelson Shaolei Huang Shaoen Zhang Yuezhu Wang Jieli Yuan Lanjuan Li Charlie Xiang 《Microbial ecology》2013,65(3):773-780
Whether or not treatment with antibiotics or probiotics for bacterial vaginosis (BV) is associated with a change in the diversity of vaginal microbiota in women was investigated. One hundred fifteen women, consisting of 30 healthy subjects, 30 BV-positive control subjects, 30 subjects with BV treated with a 7-day metronidazole regimen, and 25 subjects with BV treated with a 10-day probiotics regimen, were analyzed to determine the efficacy and disparity of diversity and richness of vaginal microbiota using 454 pyrosequencing. Follow-up visits at days 5 and 30 showed a greater BV cure rate in the probiotics-treated subjects (88.0 and 96 %, respectively) compared to the metronidazole-treated subjects (83.3 and 70 %, respectively [p?=?0.625 at day 5 and p?=?0.013 at day 30]). Treatment with metronidazole reduced the taxa diversity and eradicated most of the BV-associated phylotypes, while probiotics only suppressed the overgrowth and re-established vaginal homeostasis gradually and steadily. Despite significant interindividual variation, the microbiota of the actively treated groups or participants constituted a unique profile. Along with the decrease in pathogenic bacteria, such as Gardnerella, Atopobium, Prevotella, Megasphaera, Coriobacteriaceae, Lachnospiraceae, Mycoplasma, and Sneathia, a Lactobacillus-dominated vaginal microbiota was recovered. Acting as vaginal sentinels and biomarkers, the relative abundance of Lactobacillus and pathogenic bacteria determined the consistency of the BV clinical and microbiologic cure rates, as well as recurrent BV. Both 7-day intravaginal metronidazole and 10-day intravaginal probiotics have good efficacy against BV, while probiotics maintained normal vaginal microbiota longer due to effective and steady vaginal microbiota restoration, which provide new insights into BV treatment. 相似文献
159.
Recently, genome-wide associated studies (GWAS) have identified that host genetics IL28B SNPs rs12979860 and rs8099917 were significantly associated with SVR in patients infected with chronic HCV genotype 1 to PEG-INF/RBV therapy. Results from these studies remain conflicting. We conducted this meta-analysis to estimate the overall association of SVR with rs12979860 and rs8099917. We searched the PubMed, Embase, Scholar Google, ISI Web of Knowledge, and Chinese National Knowledge Infrastructure (CNKI) databases for all articles before July 30, 2012. The odds ratio (OR) corresponding to the 95% confidence interval (CI) was used to assess the association. The statistical heterogeneity among studies was assessed with the I2 statistics. Begg's test and Egger's test were performed to evaluate the publication bias. Eventually, twenty studies were selected for the meta-analysis. The IL-28B SNPs rs12979860 genotype CC and rs8099917 genotype TT significantly positive associated with SVR in patients infected chronic HCV genotype 1 to PEG-INF/RBV therapy (OR = 4.473, 95% CI = 3.814–5.246, OR = 5.171, 95% CI = 4.372–6.117 respectively). The results suggested that rs12979860 genotype CC and rs8099917 genotype TT could be used as independent predictors of the HCV-1 infected patients. 相似文献
160.
Kang JY Costyn LJ Nagy T Cowan EA Oldham CD May SW Arnold RD 《Archives of biochemistry and biophysics》2011,515(1-2):112-119
Anthracyclines are potent anticancer agents, but cardiotoxicity mediated by free radical generation limits their clinical use. This study evaluated the anticancer activity of phenyl-2-aminoethyl selenide (PAESe) and its potential to reduce doxorubicin (DOX)-induced cardiotoxicity. Growth inhibitory effects of PAESe with DOX, and vincristine, clinically used anticancer agents, and tert-butylhydroperoxide (TBHP), a known oxidant, on the growth of human prostate carcinoma (PC-3) cells was determined. PAESe (≤1μm) did not alter the growth of PC-3 cells, however, concomitant use of PAESe decreased the oxidative-mediated cytotoxicity of TBHP, but had limited effect on vincristine or DOX activity. Further, PAESe decreased the formation of intracellular reactive oxygen species from TBHP and DOX. The effect of PAESe on the activity of DOX was determined using a tumor (PC-3) xenograft model in mice. PAESe did not alter DOX antitumor activity and showed evidence of direct antitumor activity relative to controls. DOX treatment decreased mice body weight significantly, whereas concomitant administration of PAESe and DOX was similar to controls. Most importantly, PAESe decreased DOX-mediated infiltration of neutrophil and macrophages into the myocardium. These data suggest PAESe had in vivo antitumor activity and in combination with DOX decreased early signs of cardiotoxicity while preserving its antitumor activity. 相似文献