全文获取类型
收费全文 | 1095篇 |
免费 | 86篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 17篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 22篇 |
2017年 | 17篇 |
2016年 | 34篇 |
2015年 | 42篇 |
2014年 | 41篇 |
2013年 | 73篇 |
2012年 | 92篇 |
2011年 | 83篇 |
2010年 | 43篇 |
2009年 | 29篇 |
2008年 | 61篇 |
2007年 | 53篇 |
2006年 | 61篇 |
2005年 | 49篇 |
2004年 | 48篇 |
2003年 | 48篇 |
2002年 | 54篇 |
2001年 | 38篇 |
2000年 | 27篇 |
1999年 | 24篇 |
1998年 | 7篇 |
1997年 | 13篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 19篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1987年 | 5篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1982年 | 6篇 |
1980年 | 4篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1969年 | 5篇 |
1967年 | 6篇 |
1966年 | 4篇 |
1963年 | 4篇 |
1938年 | 5篇 |
1936年 | 4篇 |
1882年 | 3篇 |
排序方式: 共有1181条查询结果,搜索用时 31 毫秒
31.
Marco Binder Nurgazy Sulaimanov Diana Clausznitzer Manuel Schulze Christian M. Hüber Simon M. Lenz Johannes P. Schl?der Martin Trippler Ralf Bartenschlager Volker Lohmann Lars Kaderali 《PLoS pathogens》2013,9(8)
Hepatitis C virus (HCV) infection develops into chronicity in 80% of all patients, characterized by persistent low-level replication. To understand how the virus establishes its tightly controlled intracellular RNA replication cycle, we developed the first detailed mathematical model of the initial dynamic phase of the intracellular HCV RNA replication. We therefore quantitatively measured viral RNA and protein translation upon synchronous delivery of viral genomes to host cells, and thoroughly validated the model using additional, independent experiments. Model analysis was used to predict the efficacy of different classes of inhibitors and identified sensitive substeps of replication that could be targeted by current and future therapeutics. A protective replication compartment proved to be essential for sustained RNA replication, balancing translation versus replication and thus effectively limiting RNA amplification. The model predicts that host factors involved in the formation of this compartment determine cellular permissiveness to HCV replication. In gene expression profiling, we identified several key processes potentially determining cellular HCV replication efficiency. 相似文献
32.
Mary Nicolaou Anton E. Kunst Wim B. Busschers Irene G. van Valkengoed Henriette Dijkshoorn Linda Boateng Lizzy M. Brewster Marieke B. Snijder Karien Stronks Charles Agyemang 《PloS one》2013,8(6)
Background
Despite higher levels of obesity, West African migrant women appear to have lower rates of type 2 diabetes than their male counterparts. We investigated the role of body fat distribution in these differences.Methods
Cross-sectional study of Ghanaian migrants (97 men, 115 women) aged 18–60 years in Amsterdam, the Netherlands. Weight, height, waist and hip circumferences were measured. Logistic regression was used to explore the association of BMI, waist and hip measurements with elevated fasting glucose (glucose≥5.6 mmol/L). Linear regression was used to study the association of the same parameters with fasting glucose.Results
Mean BMI, waist and hip circumferences were higher in women than men while the prevalence of elevated fasting glucose was higher in men than in women, 33% versus 19%. With adjustment for age only, men were non-significantly more likely than women to have an elevated fasting glucose, odds ratio (OR) 1.81, 95% CI: 0.95, 3.46. With correction for BMI, the higher odds among men increased and were statistically significant (OR 2.84, 95% CI: 1.32, 6.10), but with consideration of body fat distribution (by adding both hip and waist in the analysis) differences were no longer significant (OR 1.56 95% CI: 0.66, 3.68). Analysis with fasting glucose as continuous outcome measure showed somewhat similar results.Conclusion
Compared to men, the lower rates of elevated fasting glucose observed among Ghanaian women may be partly due to a more favorable body fat distribution, characterized by both hip and waist measurements. 相似文献33.
Susan Ehinger Jana Seifert Andrea Kassahun Lorina Schmalz Nils Hoth Michael Schlömann 《Geomicrobiology journal》2013,30(5):326-338
The microbial communities in sulfate-rich, saline formation fluids of a natural gas reservoir in Lower Saxony, Germany were investigated to enhance the knowledge about microbial communities in potential carbon dioxide sequestration sites. This investigation of the initial state of the deep subsurface microbiota is necessary to predict their influence on the long-term stability and storage capacity of such sites. While the bacterial 16S rDNA gene library was comprised of sequences affiliating with the Firmicutes, the Alphaproteobacteria, the Gammaproteobacteria and the Thermotogales, the archaeal 16S rDNA libraries were simply dominated by two phylotypes related to the genera Methanolobus and Methanoculleus. The monitoring of the archaeal communities in different formation fluid samples by T-RFLP and Real-Time-PCR indicated that these two methanogenic genera dominated at all, whereas the proportion of the two groups varied. Thus, methylotrophic and autotrophic methanogenesis seems to be of importance in the reservoir fluids, dependent on the provided reduction equivalents and substrates and it also may influence the fate of CO2 in the subsurface. 相似文献
34.
Peter Klepsatel Martina Gáliková Nicola De Maio Christian D. Huber Christian Schlötterer Thomas Flatt 《Evolution; international journal of organic evolution》2013,67(12):3573-3587
The major goal of evolutionary thermal biology is to understand how variation in temperature shapes phenotypic evolution. Comparing thermal reaction norms among populations from different thermal environments allows us to gain insights into the evolutionary mechanisms underlying thermal adaptation. Here, we have examined thermal adaptation in six wild populations of the fruit fly (Drosophila melanogaster) from markedly different natural environments by analyzing thermal reaction norms for fecundity, thorax length, wing area, and ovariole number under ecologically realistic fluctuating temperature regimes in the laboratory. Contrary to expectation, we found only minor differences in the thermal optima for fecundity among populations. Differentiation among populations was mainly due to differences in absolute (and partly also relative) thermal fecundity performance. Despite significant variation among populations in the absolute values of morphological traits, we observed only minor differentiation in their reaction norms. Overall, the thermal reaction norms for all traits examined were remarkably similar among different populations. Our results therefore suggest that thermal adaptation in D. melanogaster predominantly involves evolutionary changes in absolute trait values rather than in aspects of thermal reaction norms. 相似文献
35.
36.
Meirav Meiri Adrian M. Lister Thomas F. G. Higham John R. Stewart Lawrence G. Straus Henriette Obermaier Manuel R. González Morales Ana B. Marín‐Arroyo Ian Barnes 《Molecular ecology》2013,22(18):4711-4722
The Pleistocene was an epoch of extreme climatic and environmental changes. How individual species responded to the repeated cycles of warm and cold stages is a major topic of debate. For the European fauna and flora, an expansion–contraction model has been suggested, whereby temperate species were restricted to southern refugia during glacial times and expanded northwards during interglacials, including the present interglacial (Holocene). Here, we test this model on the red deer (Cervus elaphus) a large and highly mobile herbivore, using both modern and ancient mitochondrial DNA from the entire European range of the species over the last c. 40 000 years. Our results indicate that this species was sensitive to the effects of climate change. Prior to the Last Glacial Maximum (LGM) haplogroups restricted today to South‐East Europe and Western Asia reached as far west as the UK. During the LGM, red deer was mainly restricted to southern refugia, in Iberia, the Balkans and possibly in Italy and South‐Western Asia. At the end of the LGM, red deer expanded from the Iberian refugium, to Central and Northern Europe, including the UK, Belgium, Scandinavia, Germany, Poland and Belarus. Ancient DNA data cannot rule out refugial survival of red deer in North‐West Europe through the LGM. Had such deer survived, though, they were replaced by deer migrating from Iberia at the end of the glacial. The Balkans served as a separate LGM refugium and were probably connected to Western Asia with genetic exchange between the two areas. 相似文献
37.
Peter Bellstedt Thomas Seiboth Sabine Häfner Henriette Kutscha Ramadurai Ramachandran Matthias Görlach 《Journal of biomolecular NMR》2013,57(1):65-72
NMR-based structure determination of a protein requires the assignment of resonances as indispensable first step. Even though heteronuclear through-bond correlation methods are available for that purpose, challenging situations arise in cases where the protein in question only yields samples of limited concentration and/or stability. Here we present a strategy based upon specific individual unlabeling of all 20 standard amino acids to complement standard NMR experiments and to achieve unambiguous backbone assignments for the fast precipitating 23 kDa catalytic domain of human aprataxin of which only incomplete standard NMR data sets could be obtained. Together with the validation of this approach utilizing the protein GB1 as a model, a comprehensive insight into metabolic interconversion ("scrambling”) of NH and CO groups in a standard Escherichia coli expression host is provided. 相似文献
38.
Obesity and Age‐Related Changes in Markers of Oxidative Stress and Inflammation Across Four Generations
下载免费PDF全文
![点击此处可从《Obesity (Silver Spring, Md.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
39.
40.
Francisco Gómez Real Laura Pérez Barrionuevo Karl Franklin Eva Lindberg Randi Jacobsen Bertelsen Bryndís Benediktsdóttir Bertil Forsberg Thorarinn Gislason Rain J?gi Ane Johannessen Ernst Omenaas Eirunn Saure Vivi Schlünssen Trude Duelien Skorge Kjell Torén Antonio Pérez Saavedra ?istein Svanes Anne Nordrehaug ?str?m Christer Janson Cecilie Svanes 《PloS one》2016,11(1)