全文获取类型
收费全文 | 1891篇 |
免费 | 118篇 |
出版年
2023年 | 8篇 |
2022年 | 22篇 |
2021年 | 40篇 |
2020年 | 28篇 |
2019年 | 41篇 |
2018年 | 60篇 |
2017年 | 49篇 |
2016年 | 116篇 |
2015年 | 258篇 |
2014年 | 212篇 |
2013年 | 298篇 |
2012年 | 216篇 |
2011年 | 114篇 |
2010年 | 107篇 |
2009年 | 111篇 |
2008年 | 58篇 |
2007年 | 52篇 |
2006年 | 48篇 |
2005年 | 44篇 |
2004年 | 20篇 |
2003年 | 31篇 |
2002年 | 19篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有2009条查询结果,搜索用时 296 毫秒
111.
E. Flaño P. López-Fierro F. Álvarez B. Razquin A. Villena 《Fish & shellfish immunology》1998,8(8):589-606
This study describes the culture conditions and the phenotypic features of different types of splenic cultures established from explants. Using the same culture technique it was possible to grow splenic explants from which monolayers of reticular origin, long-term haematopoietic cultures, and subcultures were obtained. The cultures were characterised by light and electron microscopy, cytochemical and immuno-cytochemical analyses, phagocytic activity and susceptibility to virus. The cultures comprised multilayers of epithelioid and fibroblastoid cells with haemopoietic foci, melanomacrophages and eosinophilic granular cells. The cytochemical and immuno-cytochemical analyses revealed that the stromal cells were always positive for ANAE activity. The stromal cells in primary cultures were negatively or weakly stained by antibodies directed against cytokeratins and S-100, but in the subcultures they were strongly stained by these antibodies. The stromal cells had very poor phagocytic activity and were susceptible to VHS virus. 相似文献
112.
113.
L. Pérez-Pardal L. J. Royo I. Álvarez F. A. Ponce de León I. Fernández R. Casais F. Goyache 《Animal genetics》2009,40(4):560-564
Here we tested the segregation and paternal compatibility of markers INRA124 and INRA126 on female DNA in 10 different cattle families, in order to clarify the usefulness of these microsatellites for the study of male-mediated population processes in cattle. Their performance was compared with that of four microsatellites located in the PAR-BTAY ( UMN0108 , UMN0803 , UMN0929 and UMN0905 ) and another one male-specific microsatellite ( INRA189 ). INRA124 and INRA126 amplified the same sized fragment in both sexes. Same size alleles were sequenced and the high homology found allowed us to rule out non-specific female amplification. INRA124 showed full parental compatibility, whilst the locus INRA126 showed 55% parental incompatibility. Based on these observations, it is recommended that markers INRA124 and INRA126 should not be used in studies to characterize male-mediated genetic events in cattle. 相似文献
114.
Eduard Solà Marta álvarez-Presas Cristina Frías-López D. Timothy J. Littlewood Julio Rozas Marta Riutort 《PloS one》2015,10(3)
Mitochondrial genomes (mitogenomes) are useful and relatively accessible sources of molecular data to explore and understand the evolutionary history and relationships of eukaryotic organisms across diverse taxonomic levels. The availability of complete mitogenomes from Platyhelminthes is limited; of the 40 or so published most are from parasitic flatworms (Neodermata). Here, we present the mitogenomes of two free-living flatworms (Tricladida): the complete genome of the freshwater species Crenobia alpina (Planariidae) and a nearly complete genome of the land planarian Obama sp. (Geoplanidae). Moreover, we have reanotated the published mitogenome of the species Dugesia japonica (Dugesiidae). This contribution almost doubles the total number of mtDNAs published for Tricladida, a species-rich group including model organisms and economically important invasive species. We took the opportunity to conduct comparative mitogenomic analyses between available free-living and selected parasitic flatworms in order to gain insights into the putative effect of life cycle on nucleotide composition through mutation and natural selection. Unexpectedly, we did not find any molecular hallmark of a selective relaxation in mitogenomes of parasitic flatworms; on the contrary, three out of the four studied free-living triclad mitogenomes exhibit higher A+T content and selective relaxation levels. Additionally, we provide new and valuable molecular data to develop markers for future phylogenetic studies on planariids and geoplanids. 相似文献
115.
116.
Jose M. Ayuso Haneen A. Basheer Rosa Monge Pablo Sánchez-álvarez Manuel Doblaré Steven D. Shnyder Victoria Vinader Kamyar Afarinkia Luis J. Fernández Ignacio Ochoa 《PloS one》2015,10(10)
We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS) was established across the central chamber by addition of growth media containing serum into one of the lateral channels. We observe that spheroids of oral squamous carcinoma cells OSC–19 invade collectively in the direction of the gradient of FBS. This invasion is more directional and aggressive than that observed for individual cells in the same experimental setup. In contrast to spheroids of OSC–19, U87-MG multicellular spheroids migrate as individual cells. A study of the exposure of spheroids to the chemoattractant shows that the rate of diffusion into the spheroid is slow and thus, the chemoattractant wave engulfs the spheroid before diffusing through it. 相似文献
117.
Dimitrios Draganidis Athanasios Chatzinikolaou Alexandra Avloniti José C. Barbero-álvarez Magni Mohr Paraskevi Malliou Vassilios Gourgoulis Chariklia K. Deli Ioannis I. Douroudos Konstantinos Margonis Asimenia Gioftsidou Andreas D. Flouris Athanasios Z. Jamurtas Yiannis Koutedakis Ioannis G. Fatouros 《PloS one》2015,10(7)
118.
Genomic Resources Development Consortium P. Álvarez Wolfgang Arthofer Maria M. Coelho D. Conklin A. Estonba Ana R. Grosso S. J. Helyar J. Langa Miguel P. Machado I. Montes Joana Pinho Alexander Rief Manfred Schartl Birgit C. Schlick‐Steiner Julia Seeber Florian M. Steiner C. Vilas 《Molecular ecology resources》2015,15(6):1510-1512
119.
Daniella Braz Parente Fernando Fernandes Paiva Jaime Araújo Oliveira Neto Lilian Machado-Silva Fatima Aparecida Ferreira Figueiredo Valeria Lanzoni Carlos Frederico Ferreira Campos Pedro Emmanuel Alvarenga Americano do Brasil Marilia de Brito Gomes Renata de Mello Perez Rosana Souza Rodrigues 《PloS one》2015,10(5)
ObjectiveTo evaluate the capability of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) to assess steatohepatitis and fibrosis determined by histopathology in type 2 diabetic patients.MethodsFifty-nine type 2 diabetic patients (49 women, 10 men; mean age, 54 ± 9 years) were submitted to liver biopsy for the evaluation of non-alcoholic fatty liver disease (NAFLD) and underwent DWI on a 3.0T MR system using 10 b values. Institutional approval and patient consent were obtained. Pure molecular-based (D), perfusion-related (D*), and vascular fraction (f) were calculated using a double exponential model and least squares curve fitting. D, D*, and f were compared between patients with and without steatohepatitis and between patients with and without fibrosis. The variables were compared by using the Ranksum test and Student t-test.ResultsSteatohepatitis was observed in 22 patients and fibrosis in 16 patients. A lower D median (0.70 s/mm2 vs. 0.83 s/mm2, p<0.05) and a lower D* median (34.39 s/mm2 vs. 45.23 s/mm2, p<0.05) were observed among those with steatohepatitis. A lower D median (0.70 s/mm2 vs. 0.82 s/mm2, p<0.05) and a lower D* median (35.01 s/mm2 vs. 44.76 s/mm2, p=0.05) were also observed among those with fibrosis.ConclusionIVIM-DWI has the potential to aid in the characterization of steatohepatitis and fibrosis. 相似文献
120.