全文获取类型
收费全文 | 5188篇 |
免费 | 602篇 |
国内免费 | 505篇 |
出版年
2024年 | 7篇 |
2023年 | 34篇 |
2022年 | 89篇 |
2021年 | 175篇 |
2020年 | 172篇 |
2019年 | 206篇 |
2018年 | 198篇 |
2017年 | 163篇 |
2016年 | 209篇 |
2015年 | 303篇 |
2014年 | 314篇 |
2013年 | 334篇 |
2012年 | 472篇 |
2011年 | 415篇 |
2010年 | 293篇 |
2009年 | 282篇 |
2008年 | 336篇 |
2007年 | 281篇 |
2006年 | 255篇 |
2005年 | 260篇 |
2004年 | 248篇 |
2003年 | 252篇 |
2002年 | 227篇 |
2001年 | 178篇 |
2000年 | 119篇 |
1999年 | 108篇 |
1998年 | 53篇 |
1997年 | 45篇 |
1996年 | 29篇 |
1995年 | 19篇 |
1994年 | 29篇 |
1993年 | 10篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 14篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1983年 | 6篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1973年 | 6篇 |
1971年 | 6篇 |
1969年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有6295条查询结果,搜索用时 31 毫秒
201.
Jong Taik Moon Sung Hoon Ha So Hyung Lee Tae Hui Kwon Chun Rim Oh Young Deuk Kim Jungahn Kim Dong Joon Choo Jae Yeol Lee 《Bioorganic & medicinal chemistry letters》2010,20(1):52-55
First total synthesis of methylgerambullone (MGB, 1) isolated from Glycosmis angustifolia was completed via a convergent route. The effect of MGB on the contractile responses of the isolated guinea-pig ileum induced by acetylcholine was investigated. As a result, it showed a potent relaxation rate (78.66 ± 4.30% at 100 mg/L) in a concentration-dependent manner on longitudinal smooth muscle contraction of isolated guinea-pig ileum induced by 1 μM acetylcholine. 相似文献
202.
203.
青海可可西里地区鱼类资源及其保护的初步研究 总被引:5,自引:1,他引:5
青海可可西里地区是世界上最少研究的地区之一。通过多次零星的鱼类调查(1973-1986)和1990年5至8月间对本区进行的全面水生生物和鱼类考察。本文首次报道其有关的浮游植物、浮游动物和鱼类种类分布及生物学特性等问题。诸如浮游动、植物的水平分布、优势和群和生物量及鱼类食性、年龄、生长、繁殖等。 相似文献
204.
Novel dendritic kinesin sorting identified by different process targeting of two related kinesins: KIF21A and KIF21B 总被引:6,自引:0,他引:6
下载免费PDF全文
![点击此处可从《The Journal of cell biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Marszalek JR Weiner JA Farlow SJ Chun J Goldstein LS 《The Journal of cell biology》1999,145(3):469-479
Neurons use kinesin and dynein microtubule-dependent motor proteins to transport essential cellular components along axonal and dendritic microtubules. In a search for new kinesin-like proteins, we identified two neuronally enriched mouse kinesins that provide insight into a unique intracellular kinesin targeting mechanism in neurons. KIF21A and KIF21B share colinear amino acid similarity to each other, but not to any previously identified kinesins outside of the motor domain. Each protein also contains a domain of seven WD-40 repeats, which may be involved in binding to cargoes. Despite the amino acid sequence similarity between KIF21A and KIF21B, these proteins localize differently to dendrites and axons. KIF21A protein is localized throughout neurons, while KIF21B protein is highly enriched in dendrites. The plus end-directed motor activity of KIF21B and its enrichment in dendrites indicate that models suggesting that minus end-directed motor activity is sufficient for dendrite specific motor localization are inadequate. We suggest that a novel kinesin sorting mechanism is used by neurons to localize KIF21B protein to dendrites since its mRNA is restricted to the cell body. 相似文献
205.
206.
207.
Mitochondrial fatty acid -oxidation is an important energy resource for many mammal tissues. Acyl-CoA dehydrogenases (ACADs) are a family of flavoproteins that are involved in the -oxidation of the fatty acyl-CoA derivatives. Deficiency of these ACADs can cause metabolic disorders including muscle fatigue, hypoglycaemia, hepatic lipidosis and so on. By large scale sequencing, we identified a cDNA sequence of 3960 base pairs with a typical acyl-CoA dehydrogenase function domain. RT-PCR result shows that it is widely expressed in human tissues, especially high in liver, kidney, pancreas and spleen. It is hypothesized that this is a novel member of ACADs family.
Abbreviations: ACADs – acyl-CoA dehydrogenases, FAD – flavinadenine dinucleotide, SCAD – short-chain acyl-CoA dehydrogenase,MCAD – medium-chain acyl-CoA dehydrogenase, LCAD – long-chain acyl-CoAdehydrogenase, VLCAD – very long- chain acyl-CoA dehydrogenase, IVD –isocalery-CoA dehydrogenase, SBCAD – short/branched chain acyl-CoAdehydrogenase, GCD – glutaryl- CoA dehydrogenase, ETF – electron transferflavoprotein, ACAD8 – acyl-CoA dehydrogenase 8, ACAD9 – acyl-CoAdehydrogenase 9, ACAD10 – acyl-CoA dehydrogenase 10. 相似文献
208.
Chun JT Di Dato V D'Andrea B Zannini M Di Lauro R 《Molecular endocrinology (Baltimore, Md.)》2004,18(11):2817-2829
209.
A series of studies in black and white women and men have suggested that serum gamma-glutamyltransferase (GGT) within its normal range might be an early marker of oxidative stress. If serum GGT is a marker of oxidative stress, it might have important implications both clinically and epidemiologically because measurement of serum GGT is easy, reliable, and not expensive. We examined the cross-sectional association between deciles of serum GGT and concentrations of serum antioxidants among 9083 adult participants in the third U.S. National Health and Nutrition Examination Survey. After adjustment for race, sex, age, and total cholesterol, serum concentration of GGT across all deciles was inversely associated with serum concentrations of alpha-carotene, beta-carotene, beta-cryptoxanthin, zeaxanthin/lutein, lycopene, and vitamin C (p for trend <.01, respectively). Vitamin E was not associated with serum GGT. All these associations were not materially different after additional adjustment for total energy intake, body mass index, smoking status, smoking amount, alcohol intake, and exercise. These associations were similarly observed among most subgroups. In conclusion, the current and previous studies strongly suggest that serum GGT level within its normal range may be an early marker of oxidative stress. 相似文献
210.