全文获取类型
收费全文 | 482篇 |
免费 | 29篇 |
专业分类
511篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 22篇 |
2014年 | 18篇 |
2013年 | 33篇 |
2012年 | 25篇 |
2011年 | 19篇 |
2010年 | 18篇 |
2009年 | 20篇 |
2008年 | 23篇 |
2007年 | 25篇 |
2006年 | 22篇 |
2005年 | 15篇 |
2004年 | 13篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 15篇 |
2000年 | 15篇 |
1999年 | 12篇 |
1998年 | 16篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1978年 | 3篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1968年 | 4篇 |
1967年 | 5篇 |
1966年 | 4篇 |
1962年 | 2篇 |
1961年 | 6篇 |
1959年 | 2篇 |
1911年 | 2篇 |
排序方式: 共有511条查询结果,搜索用时 15 毫秒
11.
M. F. Carruthers 《BMJ (Clinical research ed.)》1960,2(5216):1845-1847
12.
13.
14.
A novel disorder caused by defective biosynthesis of N-linked oligosaccharides due to glucosidase I deficiency 总被引:11,自引:0,他引:11 下载免费PDF全文
De Praeter CM Gerwig GJ Bause E Nuytinck LK Vliegenthart JF Breuer W Kamerling JP Espeel MF Martin JJ De Paepe AM Chan NW Dacremont GA Van Coster RN 《American journal of human genetics》2000,66(6):1744-1756
Glucosidase I is an important enzyme in N-linked glycoprotein processing, removing specifically distal alpha-1,2-linked glucose from the Glc3Man9GlcNAc2 precursor after its en bloc transfer from dolichyl diphosphate to a nascent polypeptide chain in the endoplasmic reticulum. We have identified a glucosidase I defect in a neonate with severe generalized hypotonia and dysmorphic features. The clinical course was progressive and was characterized by the occurrence of hepatomegaly, hypoventilation, feeding problems, seizures, and fatal outcome at age 74 d. The accumulation of the tetrasaccharide Glc(alpha1-2)Glc(alpha1-3)Glc(alpha1-3)Man in the patient's urine indicated a glycosylation disorder. Enzymological studies on liver tissue and cultured skin fibroblasts revealed a severe glucosidase I deficiency. The residual activity was <3% of that of controls. Glucosidase I activities in cultured skin fibroblasts from both parents were found to be 50% of those of controls. Tissues from the patient subjected to SDS-PAGE followed by immunoblotting revealed strongly decreased amounts of glucosidase I protein in the homogenate of the liver, and a less-severe decrease in cultured skin fibroblasts. Molecular studies showed that the patient was a compound heterozygote for two missense mutations in the glucosidase I gene: (1) one allele harbored a G-->C transition at nucleotide (nt) 1587, resulting in the substitution of Arg at position 486 by Thr (R486T), and (2) on the other allele a T-->C transition at nt 2085 resulted in the substitution of Phe at position 652 by Leu (F652L). The mother was heterozygous for the G-->C transition, whereas the father was heterozygous for the T-->C transition. These base changes were not seen in 100 control DNA samples. A causal relationship between the alpha-glucosidase I deficiency and the disease is postulated. 相似文献
15.
16.
In July the yield of protein extractable from potato haulm could be 600 kg/ha and the beginning of September it is 200 kg/ha. The yield of fiber containing 1 to 2% N is less affected by maturity. The annual waste of extractable protein, suitable for feeding nonruminants, is about 60,000 tons. The contribution that some small changes in conventional potato husbandry might make to minimizing this waste is discussed. 相似文献
17.
G. Cabrera Walsh Y. Magalí Dalto Federico M. Mattioli Raymond I. Carruthers Lars W. Anderson 《BioControl》2013,58(1):133-147
Egeria densa (Hydrocharitaceae) is a submerged macrophyte from South America that is a weed in several countries. It crowds out native plants and hinders water use, causing economic and environmental damage. The leafminer fly Hydrellia sp. 1 (Diptera: Ephydridae), was found feeding in E. densa throughout its Argentine distribution, and is currently the only known specialist herbivore of E. densa. It was reared in the laboratory and tested on 25 plant species. This herbivore can cause heavy defoliation in the laboratory and in the field. Hydrellia sp. 1 was found only on E. densa, but in the laboratory it also developed on two other Hydrocharitaceae species in the same family; Egeria naias, and Elodea callitrichoides. Significant oviposition and feeding were only observed on its primary natural host, and to a lesser degree on E. naias. Field studies indicate Hydrellia sp. 1 is present in the field year round, unless the host plant is prostrate for long periods, or covered by floating macrophytes. These results indicate Hydrellia sp. 1 may be a suitable biocontrol candidate for E. densa. 相似文献
18.
Rebuilding depleted fish populations is a priority of modern fisheries management. In the U.S., strong statutory mandates extend to both the goals and process by which stocks are to be rebuilt. However, the National Standard Guidelines that govern the implementation of the Magnuson-Stevens Fishery Conservation and Management Act may change to increase flexibility in rebuilding requirements. In this study we evaluate performance of the status quo approach to fish stock rebuilding in the United States against 3 alternatives that have been proposed to improve rebuilding outcomes. These alternatives either simplify the analytical requirements of rebuilding analyses or apply ‘best practices’ in fisheries management, thereby avoiding the need for rebuilding analyses altogether. We use a Management Strategy Evaluation framework to evaluate rebuilding options across 6 fish life history types and 5 possible real-world fishery scenarios that include options for stock assessment quality, multiple fleets, and the degree to which the stocks are overfished at the start of the analysis. We show that the status quo rebuilding plan and a harvest control rule that reduces harvest rates at low stock size generally achieve the best rebuilding outcomes across all life-history types and fishery scenarios. Both approaches constrain fishing in the short term, but achieve high catches in the medium and long term as stocks rebuild to productive levels. These results support a growing body of literature that indicates that efforts to end overfishing early pay off in the medium- to long-term with higher cumulative catches than the alternative. 相似文献
19.
20.
Juan Manuel Herrero-Medrano Hendrik-Jan Megens Martien AM Groenen Mirte Bosse Miguel Pérez-Enciso Richard PMA Crooijmans 《BMC genomics》2014,15(1)