全文获取类型
收费全文 | 9437篇 |
免费 | 668篇 |
国内免费 | 2篇 |
出版年
2022年 | 41篇 |
2021年 | 101篇 |
2020年 | 68篇 |
2019年 | 85篇 |
2018年 | 106篇 |
2017年 | 96篇 |
2016年 | 188篇 |
2015年 | 303篇 |
2014年 | 358篇 |
2013年 | 507篇 |
2012年 | 536篇 |
2011年 | 561篇 |
2010年 | 397篇 |
2009年 | 333篇 |
2008年 | 484篇 |
2007年 | 543篇 |
2006年 | 490篇 |
2005年 | 531篇 |
2004年 | 494篇 |
2003年 | 476篇 |
2002年 | 487篇 |
2001年 | 131篇 |
2000年 | 98篇 |
1999年 | 124篇 |
1998年 | 164篇 |
1997年 | 105篇 |
1996年 | 111篇 |
1995年 | 125篇 |
1994年 | 119篇 |
1993年 | 122篇 |
1992年 | 92篇 |
1991年 | 87篇 |
1990年 | 106篇 |
1989年 | 98篇 |
1988年 | 76篇 |
1987年 | 79篇 |
1986年 | 72篇 |
1985年 | 76篇 |
1984年 | 81篇 |
1983年 | 79篇 |
1982年 | 66篇 |
1981年 | 80篇 |
1980年 | 61篇 |
1979年 | 57篇 |
1978年 | 50篇 |
1977年 | 51篇 |
1976年 | 47篇 |
1975年 | 43篇 |
1974年 | 42篇 |
1968年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
Ebner S Lang R Mueller EE Eder W Oeller M Moser A Koller J Paulweber B Mayr JA Sperl W Kofler B 《PloS one》2011,6(12):e27192
Background
Because mitochondria play an essential role in energy metabolism, generation of reactive oxygen species (ROS), and apoptosis, sequence variation in the mitochondrial genome has been postulated to be a contributing factor to the etiology of multifactorial age-related diseases, including cancer. The aim of the present study was to compare the frequencies of mitochondrial DNA (mtDNA) haplogroups as well as control region (CR) polymorphisms of patients with malignant melanoma (n = 351) versus those of healthy controls (n = 1598) in Middle Europe.Methodology and Principal Findings
Using primer extension analysis and DNA sequencing, we identified all nine major European mitochondrial haplogroups and known CR polymorphisms. The frequencies of the major mitochondrial haplogroups did not differ significantly between patients and control subjects, whereas the frequencies of the one another linked CR polymorphisms A16183C, T16189C, C16192T, C16270T and T195C were significantly higher in patients with melanoma compared to the controls. Regarding clinical characteristics of the patient cohort, none of the nine major European haplogroups was associated with either Breslow thickness or distant metastasis. The CR polymorphisms A302CC-insertion and T310C-insertion were significantly associated with mean Breslow thickness, whereas the CR polymorphism T16519C was associated with metastasis.Conclusions and Significance
Our results suggest that mtDNA variations could be involved in melanoma etiology and pathogenesis, although the functional consequence of CR polymorphisms remains to be elucidated. 相似文献972.
Kornhuber J Erhard G Lenz B Kraus T Sperling W Bayerlein K Biermann T Stoessel C 《PloS one》2011,6(4):e19332
The ratio of the lengths of the second and fourth finger (2D∶4D) has been described as reflecting the degree of prenatal androgen exposure in humans. 2D∶4D is smaller for males than females and is associated with traits such as left-handedness, physical aggression, attention-deficit-hyperactivity disorder and a genetic polymorphism of the androgen receptor. All of these traits are known to be correlated to the vulnerability for alcohol dependency. We therefore hypothesized low 2D∶4D in patients with alcohol dependency. In the present study on 131 patients suffering from alcohol dependency and 185 healthy volunteers, we found that alcohol dependent patients had smaller 2D∶4D ratios compared to controls with preserved sexual dimorphism but with reduced right-left differences. The detection of alcohol dependency based on 2D∶4D ratios was most accurate using the right hand of males (ROC-analysis: AUC 0.725, sensitivity 0.667, specificity 0.723). These findings provide novel insights into the role of prenatal androgen exposure in the development of alcohol dependency and for the use of 2D∶4D as a possible trait marker in identifying patients with alcohol dependency. 相似文献
973.
The flowers of Erythrina brucei afforded, in addition to known compounds, a new erythrina alkaloid, 8-oxoerythrinine. Its structure was elucidated by spectroscopic investigations as well as by chemical transformations. 相似文献
974.
975.
The painted shrimp exhibits a social system of “relative monogamy”. The selective consequences of mate attachment for the individuals have been studied by long term observations and experiments. 相似文献
976.
977.
978.
979.
980.
Cytoplasmic thioredoxin reductase is essential for embryogenesis but dispensable for cardiac development
下载免费PDF全文
![点击此处可从《Molecular and cellular biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jakupoglu C Przemeck GK Schneider M Moreno SG Mayr N Hatzopoulos AK de Angelis MH Wurst W Bornkamm GW Brielmeier M Conrad M 《Molecular and cellular biology》2005,25(5):1980-1988
Two distinct thioredoxin/thioredoxin reductase systems are present in the cytosol and the mitochondria of mammalian cells. Thioredoxins (Txn), the main substrates of thioredoxin reductases (Txnrd), are involved in numerous physiological processes, including cell-cell communication, redox metabolism, proliferation, and apoptosis. To investigate the individual contribution of mitochondrial (Txnrd2) and cytoplasmic (Txnrd1) thioredoxin reductases in vivo, we generated a mouse strain with a conditionally targeted deletion of Txnrd1. We show here that the ubiquitous Cre-mediated inactivation of Txnrd1 leads to early embryonic lethality. Homozygous mutant embryos display severe growth retardation and fail to turn. In accordance with the observed growth impairment in vivo, Txnrd1-deficient embryonic fibroblasts do not proliferate in vitro. In contrast, ex vivo-cultured embryonic Txnrd1-deficient cardiomyocytes are not affected, and mice with a heart-specific inactivation of Txnrd1 develop normally and appear healthy. Our results indicate that Txnrd1 plays an essential role during embryogenesis in most developing tissues except the heart. 相似文献