全文获取类型
收费全文 | 522篇 |
免费 | 36篇 |
国内免费 | 1篇 |
出版年
2023年 | 6篇 |
2022年 | 11篇 |
2021年 | 13篇 |
2020年 | 14篇 |
2019年 | 16篇 |
2018年 | 19篇 |
2017年 | 14篇 |
2016年 | 23篇 |
2015年 | 37篇 |
2014年 | 34篇 |
2013年 | 44篇 |
2012年 | 63篇 |
2011年 | 44篇 |
2010年 | 26篇 |
2009年 | 42篇 |
2008年 | 22篇 |
2007年 | 33篇 |
2006年 | 17篇 |
2005年 | 19篇 |
2004年 | 11篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1965年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有559条查询结果,搜索用时 15 毫秒
11.
Christian Milani Arancha Hevia Elena Foroni Sabrina Duranti Francesca Turroni Gabriele Andrea Lugli Borja Sanchez Rebeca Martín Miguel Gueimonde Douwe van Sinderen Abelardo Margolles Marco Ventura 《PloS one》2013,8(7)
Assessing the distribution of 16S rRNA gene sequences within a biological sample represents the current state-of-the-art for determination of human gut microbiota composition. Advances in dissecting the microbial biodiversity of this ecosystem have very much been dependent on the development of novel high-throughput DNA sequencing technologies, like the Ion Torrent. However, the precise representation of this bacterial community may be affected by the protocols used for DNA extraction as well as by the PCR primers employed in the amplification reaction. Here, we describe an optimized protocol for 16S rRNA gene-based profiling of the fecal microbiota. 相似文献
12.
Alex Gutteridge J. Michael Rukstalis Daniel Ziemek Mark Tié Lin Ji Rebeca Ramos-Zayas Nancy A. Nardone Lisa D. Norquay Martin B. Brenner Kim Tang John D. McNeish Rebecca K. Rowntree 《PloS one》2013,8(2)
We have used a previously unavailable model of pancreatic development, derived in vitro from human embryonic stem cells, to capture a time-course of gene, miRNA and histone modification levels in pancreatic endocrine cells. We investigated whether it is possible to better understand, and hence control, the biological pathways leading to pancreatic endocrine formation by analysing this information and combining it with the available scientific literature to generate models using a casual reasoning approach. We show that the embryonic stem cell differentiation protocol is highly reproducible in producing endocrine precursor cells and generates cells that recapitulate many aspects of human embryonic pancreas development, including maturation into functional endocrine cells when transplanted into recipient animals. The availability of whole genome gene and miRNA expression data from the early stages of human pancreatic development will be of great benefit to those in the fields of developmental biology and diabetes research. Our causal reasoning algorithm suggested the involvement of novel gene networks, such as NEUROG3/E2F1/KDM5B and SOCS3/STAT3/IL-6, in endocrine cell development We experimentally investigated the role of the top-ranked prediction by showing that addition of exogenous IL-6 could affect the expression of the endocrine progenitor genes NEUROG3 and NKX2.2. 相似文献
13.
Daniel Lucas José M. Delgado-García Beatriz Escudero Carmen Albo Ana Aza Rebeca Acín-Pérez Yaima Torres Paz Moreno José Antonio Enríquez Enrique Samper Luis Blanco Alfonso Fairén Antonio Bernad Agnès Gruart 《PloS one》2013,8(1)
A definitive consequence of the aging process is the progressive deterioration of higher cognitive functions. Defects in DNA repair mechanisms mostly result in accelerated aging and reduced brain function. DNA polymerase µ is a novel accessory partner for the non-homologous end-joining DNA repair pathway for double-strand breaks, and its deficiency causes reduced DNA repair. Using associative learning and long-term potentiation experiments, we demonstrate that Polµ−/− mice, however, maintain the ability to learn at ages when wild-type mice do not. Expression and biochemical analyses suggest that brain aging is delayed in Polµ−/− mice, being associated with a reduced error-prone DNA oxidative repair activity and a more efficient mitochondrial function. This is the first example in which the genetic ablation of a DNA-repair function results in a substantially better maintenance of learning abilities, together with fewer signs of brain aging, in old mice. 相似文献
14.
Rebeca Martínez Teresa Núñez de Villavicencio-Díaz Aniel Sánchez Yassel Ramos Jesús Noda Ferro Lázaro Gil González Milagros Méndez Elsa Rodríguez Ernesto Marcos Belinda Sánchez Yordanka Masforrol Hilda Garay Fernando Albericio Lisset Hermida Luis Javier González Eva Vonasek Mario P Estrada Vladimir Besada 《Biochemistry and Biophysics Reports》2016
BackgroundGrowth hormone secretagogues (GHS), among other factors, regulate the release of GH. The biological activity of the secretagogue peptide A233 as a promoter of growth and innate immunity in teleost fish has previously been demonstrated, but its role in the immune system of mammals is not well understood.MethodsThe effect of the peptide was investigated in J774A.2 macrophage cells using a comparative proteomics approach after 6 and 12 h of peptide stimulation.ResultsThe functional analysis of differentially modulated proteins showed that A233 peptide treatment appears to promote activation and ROS-dependent cytotoxic functions in macrophages and enhanced expression of antiviral protein complexes such as MAVS. In accordance with this hypothesis, we found that A233 treatment enhanced superoxide anion production and the IFN-γ level in J774A.2 cells and mouse splenocytes, respectively, and reduced viral load in a dengue virus mouse model of infection.ConclusionsThe growth hormone secretagogue A233 peptide promotes activation of ROS-dependent cytotoxic functions and exerts immunomodulatory effects that enable an antiviral state in a dengue virus mouse model.General SignificanceThe increase of IFN-γ level and the differential modulation of antiviral proteins by the A233 peptide suggest that the molecule could activate an innate immune response with a possible further impact in the treatment of acute and chronic diseases. 相似文献
15.
16.
Juan Antonio Surez‐Cuenca Rogelio Robledo‐Nolasco Marco Antonio Alcntara‐Melndez Luis Javier Díaz Hernndez Eduardo Vera‐Gmez Alejandro Hernndez‐Patricio Karla Susana Snchez‐Díaz Juan Ariel Buendía‐Gutirrez Alejandra Contreras‐Ramos Atzin Su Ruíz‐Hernndez Rebeca Prez‐Cabeza de Vaca Paul Mondragn‐Tern 《Journal of cellular and molecular medicine》2019,23(7):4844-4849
17.
Arias-Real Rebeca Gutirrez-Cnovas Cayetano Muoz Isabel Pascoal Cludia Menndez Margarita 《Ecosystems》2022,25(4):780-794
Ecosystems - Investigating the influence of biodiversity on ecosystem functioning over environmental gradients is needed to anticipate ecosystem responses to global change. However, our... 相似文献
18.
Acácio F. Nogueira Francisco Langeani André L. Netto-Ferreira 《Journal of fish biology》2019,94(5):798-803
Hemiodus bimaculatus sp. nov., is described from tributaries of the Rio Juruena and Rio Teles Pires in the upper Rio Tapajós basin. The new species is diagnosed from most congeners, except Hemiodus jatuarana, by having a conspicuous circular or horizontally elongate dark blotch on the caudal peduncle (v. inconspicuous in H. iratapuru and absent in the other species). The new species differs from H. jatuarana by having a round midlateral spot on the flank (v. absent in H. jatuarana), 98–121 perforated scales in the lateral line (v. 66–72 in H. jatuarana), 23–28 scale series above and 14–19 below lateral line (v. 12–13 above and 6–7 below in H. jatuarana). Hemiodus bimaculatus is hypothesised to be related to species of the H. microlepis group, from which it also differs by having 11–25 epibranchial (v. 26–34 in H. argenteus, 29–39 in H. microlepis, 21–42 in H. orthonops and 27–35 in H. parnaguae) and 18–31 ceratobranchial (v. 38–50 in H. argenteus, 43–58 in H. microlepis, 32–52 in H. orthonops and 34–48 in H. parnaguae) gill rakers in the first arch. 相似文献
19.
20.
Willian Batista‐Silva David B. Medeiros Accio Rodrigues‐Salvador Danilo M. Daloso Rebeca P. Omena‐Garcia Franciele Santos Oliveira Lilian Ellen Pino Lzaro Eustquio Pereira Peres Adriano Nunes‐Nesi Alisdair R. Fernie Agustín Zsgn Wagner L. Araújo 《Plant, cell & environment》2019,42(2):448-465
Auxin modulates a range of plant developmental processes including embryogenesis, organogenesis, and shoot and root development. Recent studies have shown that plant hormones also strongly influence metabolic networks, which results in altered growth phenotypes. Modulating auxin signalling pathways may therefore provide an opportunity to alter crop performance. Here, we performed a detailed physiological and metabolic characterization of tomato (Solanum lycopersicum) mutants with either increased (entire) or reduced (diageotropica—dgt) auxin signalling to investigate the consequences of altered auxin signalling on photosynthesis, water use, and primary metabolism. We show that reduced auxin sensitivity in dgt led to anatomical and physiological modifications, including altered stomatal distribution along the leaf blade and reduced stomatal conductance, resulting in clear reductions in both photosynthesis and water loss in detached leaves. By contrast, plants with higher auxin sensitivity (entire) increased the photosynthetic capacity, as deduced by higher Vcmax and Jmax coupled with reduced stomatal limitation. Remarkably, our results demonstrate that auxin‐sensitive mutants (dgt) are characterized by impairments in the usage of starch that led to lower growth, most likely associated with decreased respiration. Collectively, our findings suggest that mutations in different components of the auxin signalling pathway specifically modulate photosynthetic and respiratory processes. 相似文献