全文获取类型
收费全文 | 350篇 |
免费 | 43篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 12篇 |
2014年 | 13篇 |
2013年 | 14篇 |
2012年 | 17篇 |
2011年 | 27篇 |
2010年 | 9篇 |
2009年 | 11篇 |
2008年 | 16篇 |
2007年 | 19篇 |
2006年 | 9篇 |
2005年 | 10篇 |
2004年 | 14篇 |
2003年 | 18篇 |
2002年 | 13篇 |
2001年 | 12篇 |
2000年 | 7篇 |
1999年 | 8篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1970年 | 2篇 |
1968年 | 7篇 |
1966年 | 4篇 |
1965年 | 3篇 |
1959年 | 2篇 |
排序方式: 共有393条查询结果,搜索用时 15 毫秒
51.
The structure of the glycopeptides of a human M-immunoglobulin 总被引:9,自引:0,他引:9
S Hickman R Kornfeld C K Osterland S Kornfeld 《The Journal of biological chemistry》1972,247(7):2156-2163
52.
53.
The role of sialic acid in determining the survival of glycoproteins in the circulation 总被引:58,自引:0,他引:58
A G Morell G Gregoriadis I H Scheinberg J Hickman G Ashwell 《The Journal of biological chemistry》1971,246(5):1461-1467
54.
In connection with the estimation of the average fecundability of a group of women, it has been assumed in the past that the waiting time for a conception follows a type I geometric distribution, and its two parameters have been estimated by the method of moments and the method of maximum likelihood. In a follow-up study, starting with a group of women, there is always the possibility that some women will remain nonpregnant in the limited period of time they are observed, and the problem arises as to how to estimate the same parameters if the follow-up experiment is terminated after a fixed period of time. The present paper deals with this truncation problem, and provides three different methods for estimating the parameters, which are applied to data from the Menstrual and Reproductive History Study at the University of Minnesota. In the last section, an extended model is presented which incorporates the possibility of dropout cases. 相似文献
55.
Nampally Sreenivasachary Heiko Kroth Pascal Benderitter Anne Hamel Yvan Varisco David T. Hickman Wolfgang Froestl Andrea Pfeifer Andreas Muhs 《Bioorganic & medicinal chemistry letters》2017,27(6):1405-1411
The aggregation of amyloid-β peptides into cytotoxic oligomeric and fibrillary aggregates is believed to be one of the major pathological events in Alzheimer disease. Here we report the design and synthesis of a novel series of indole and 7-azaindole derivatives containing, nitrile, piperidine and N-methyl-piperidine substituents at the 3-position to prevent the pathological self-assembly of amyloid-β. We have further demonstrated that substitution of the azaindole and indole derivatives at the 3 positions is required to obtain compounds with improved physicochemical properties to allow brain penetration. 相似文献
56.
57.
Question: Does understory vegetation cover and richness decline along a gradient of increasing Juniperus virginiana midstory canopy cover and is that decline best correlated with litter accumulation? Location: Cross Timbers Forest in Payne County, OK, USA. Methods: We measured vegetation in forest gaps as well as forest areas without J. virginiana, at the inner and outer edge of J. virginiana canopies and near J. virginiana trunks (200 plots) and compared vegetation differences among location to light, litter, soil and microclimate variables. Results: Species richness (11 spp m?2 to 6 spp m?2) and summer vegetation cover (53.3% to 12.7%) declined with proximity to trunks. Regression indicated that richness declines (R2=0.08) and cover (R2=0.18) were best correlated with J. virginiana litter accumulation. Partial canonical correspondence analysis (pCCA) revealed two strong canonical axes, one related to litter/light and another to cover of Quercus spp. versus J. virginiana. Tree seedlings and woody vines dominated near J. virginiana. Forbs, graminoids and Quercus spp. seedlings were more common in areas without J. virginiana. Conclusions: Increasing J. virginiana and consequent litter additions alter understory biomass and composition and, through inhibiting Quercus spp. recruitment, may lead to changes in overstory composition. Decreases in herbaceous litter, which historically contributed to fuel accumulation, may have positive feedback effects on midstory encroachment by reducing the potential for prescribed burning. 相似文献
58.
Sakya SM Cheng H Lundy Demello KM Shavnya A Minich ML Rast B Dutra J Li C Rafka RJ Koss DA Li J Jaynes BH Ziegler CB Mann DW Petras CF Seibel SB Silvia AM George DM Hickman A Haven ML Lynch MP 《Bioorganic & medicinal chemistry letters》2006,16(5):1202-1206
Structure-activity relationship (SAR) studies of novel 2-[3-trifluoromethyl-5-alkyl(thio)ether pyrazo-1-yl]-5-methanesulfonyl pyridine derivatives for canine COX enzymes are described. The 4-cyano-5-alkyl ethers were found to have excellent potency and selectivity, whereas the 5-thioethers were potent but less selective than the ether analogs in a canine whole blood (CWB) COX-2 assay. 相似文献
59.
Sakya SM DeMello KM Minich ML Rast B Shavnya A Rafka RJ Koss DA Cheng H Li J Jaynes BH Ziegler CB Mann DW Petras CF Seibel SB Silvia AM George DM Lund LA St Denis S Hickman A Haven ML Lynch MP 《Bioorganic & medicinal chemistry letters》2006,16(2):288-292
Structure-activity relationship (SAR) studies of the novel 2-[3-di and trifluoromethyl-5-alkylamino pyrazo-1-yl]-5-methanesulfonyl (SO(2)Me)/sulfamoyl (SO(2)NH(2))-pyridine derivatives for canine COX enzymes are described. The studies led to the identification of 2e as lead with potent in vitro activity, selectivity, and in vivo activity in dogs and cats. 相似文献
60.
Kucku Varghese Peter Molnar Mainak Das Neelima Bhargava Stephen Lambert Mark S. Kindy James J. Hickman 《PloS one》2010,5(1)