全文获取类型
收费全文 | 692篇 |
免费 | 35篇 |
出版年
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 16篇 |
2016年 | 9篇 |
2015年 | 30篇 |
2014年 | 30篇 |
2013年 | 42篇 |
2012年 | 48篇 |
2011年 | 53篇 |
2010年 | 26篇 |
2009年 | 23篇 |
2008年 | 26篇 |
2007年 | 31篇 |
2006年 | 37篇 |
2005年 | 38篇 |
2004年 | 38篇 |
2003年 | 29篇 |
2002年 | 37篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 9篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有727条查询结果,搜索用时 546 毫秒
701.
Tomasz Kosmala Horacio Coy Diaz Hannu‐Pekka Komsa Yujing Ma Arkady V. Krasheninnikov Matthias Batzill Stefano Agnoli 《Liver Transplantation》2018,8(20)
The hydrogen evolution reaction (HER) is a fundamental process that impacts several important clean energy technologies. Great efforts have been taken to identify alternative materials that could replace Pt for this reaction or that may present additional functional properties such as optical activity and advanced electronic properties. Herein, a comparative study of the HER activity for ultrathin films of MoTe2, MoSe2, and their solid solutions on highly oriented pyrolytic graphite is reported. Combining advanced characterization techniques and density functional theory calculations with electrochemical measurements, it is shown that the chemical activity of the scarcely reactive 2H phases can be boosted by the presence of metallic twin boundaries. These defects, which are thermodynamically stable and naturally present in Mo‐enriched MoTe2 and MoSe2, endow the basal plane of the 2H phase with a high chemical activity, which is comparable to the metastable 1T polymorph. 相似文献
703.
Masato Mitome Pang Low Hoi Horacio O. de la Iglesia William J. Schwartz 《Biological Rhythm Research》2013,44(2):221-232
We introduce a new transplantation technique for analyzing suprachiasmatic nucleus (SCN) development and function. Neural precursor (‘stem’) cells are harvested from the brains of mice engineered to express the green fluorescent protein, propagated in culture with growth factors, and injected into the forebrain ventricles of individual embryos in order to gain access to the ventricular germinal zone and the developing brain. Initial data indicate that such cells can incorporate within the SCN and appear to differentiate into astroglial phenotypes. In addition to applications in chronobiology, SCN chimeras may be a potentially powerful model system for analyzing the structural and functional plasticity of implanted precursor cells. 相似文献
704.
705.
706.
Maria Iracilda da Cunha Sampaio Maria Paula Cruz Schneider Horacio Schneider 《International journal of primatology》1993,14(6):895-903
We studied 20 electrophoretic loci in two populations ofAteles (Ateles paniscus paniscus andAteles paniscus chamek). We observed intrapopulational variation at the following loci: esterase D, glyoxalase 1, adenosine deaminase (A. p. chamek) and carbonic anhydrase 2 (A. p. paniscus). The two populations share the most frequent alleles at 17 loci, but we noted great differences in glyoxalase 1, adenosine deaminase and phosphoglucomutase 1.A. p. paniscus is monomorphic for theGLO1
*1 allele, which has a frequency of 6% inA. p.chamek. They did not share alleles in relation to the ADA and PGM1 loci. We found a CA2 allele, named hereCA2
*1, which has not been described previously in other neotropical primates (Sampaio et al., 1991a), inA. p. paniscus. The present results suggest that the geographical isolation represented by the Rio Amazonas has lasted long enough to support this level of divergence. These observations taken together with chromosomal findings, led us to endorse the proposal of two distinct species:Ateles paniscus andAteles chamek. 相似文献
707.
de Sousa João Leno Pereira de Araújo Bitencourt Jamille Sampaio Iracilda Schneider Horacio de Mello Affonso Paulo Roberto Antunes 《Conservation Genetics》2021,22(3):411-425
Conservation Genetics - The restricted range, taxonomic uncertainties and the apparent phylopatric behavior of Parotocinclus (dwarf plecos) make this fish group an excellent model to infer... 相似文献
708.
Titi monkey biogeography: Parallel Pleistocene spread by Plecturocebus and Cheracebus into a post‐Pebas Western Amazon
下载免费PDF全文
![点击此处可从《Zoologica scripta》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hazel Byrne Jessica W. Lynch Alfaro Iracilda Sampaio Izeni Farias Horacio Schneider Tomas Hrbek Jean P. Boubli 《Zoologica scripta》2018,47(5):499-517
Titi monkeys, subfamily Callicebinae, are a diverse, species‐rich group of Neotropical primates with an extensive range across South America. Their distribution in space and time makes them an interesting primate model for addressing questions of Neotropical historical biogeography. Our aim was to reconstruct the biogeographic history of Callicebinae to better understand their diversification patterns and the history of their colonisation of South America since the late Miocene. We reconstructed a time‐calibrated phylogeny of 19 titi species under Bayesian inference using two mitochondrial and 11 nuclear loci. Species were assigned across eight Neotropical areas of endemism, and statistical biogeographic methods implemented in BioGeoBEARS were employed to estimate ancestral areas using 12 biogeographic models. Our results indicate that the most recent common ancestor to extant titi monkeys was widespread from the present‐day Andean foothills in the Colombian Amazon, through the wet and dry savannas of Bolivia and Brazil, to the southern Atlantic forest of eastern Brazil. Genus‐level divergences were characterised by vicariance of ancestral range in the late Miocene. Species‐level diversification in Cheracebus and the Plecturocebus moloch group occurred as they spread across the Amazon in the Pleistocene and were largely characterised by a sequential, long‐distance “island‐hopping” dispersal model of speciation from a narrow area of origin through jump dispersal across rivers. This study comprises the first large‐scale investigation of the evolutionary history of titi monkeys in the context of Amazonian and South American historical biogeography and sheds light on the processes that generated the great diversity found among Callicebinae. 相似文献
709.
Antonio G. González Antonio Gallindo Horacio Mansilla Angeles Gutiérrez 《Phytochemistry》1981,20(10):2367-2369
1-Keto-6β,7α,11β-H-selin-4(5)-en-6,12-olide, vulgarin and a new eudesmanolide, maritimin, were isolated from Artemisia maritima gallica. The structure and stereochemistry of this lactone have been determined by spectral studies and chemical transformations. 相似文献
710.
NM Macias-Gomez E Leal Ugarte M Gutiérrez-Angulo G Domínguez-Quezada H Rivera P Barros-Nuñez 《Journal of medical case reports》2012,6(1):301
ABSTRACT: INTRODUCTION: Beckwith--Wiedemann syndrome is an overgrowth syndrome that is characterized by hypoglycemia at birth, coarse face, hemihypertrophy and an increased risk to develop embryonal tumors. In approximately 15% of patients, the inheritance is autosomal dominant with variable expressivity and incomplete penetrance, whereas the remainder of Beckwith--Wiedemann syndrome cases are sporadic. Beckwith--Wiedemann syndrome molecular etiologies are complex and involve the two imprinting centers 1 (IC1) and 2 (IC2) of 11p15 region. This case report describes, for the first time, the unusual association of ovotesticular disorder in a patient from Morelia, Mexico with Wiedemann-Beckwith syndrome. CASE PRESENTATION: We report the case of a Mexican six-year-old girl with Beckwith--Wiedemann Syndrome, ambiguous genitalia, and bilateral ovotestes. She has a 46,XX karyotype without evidence of Y-chromosome sequences detected by fluorescence in situ hybridization with both SRY and wcp-Y probes. CONCLUSION: Although a random association between these two conditions cannot be excluded, future analysis of this patient with Beckwith--Wiedemann syndrome and 46,XX ovotesticular disorder may lead to new insights into these complex pathologies. We speculate that a possible misregulation in the imprinted genes network has a fundamental role in the coexistence of these two disorders. 相似文献