全文获取类型
收费全文 | 908篇 |
免费 | 62篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2019年 | 9篇 |
2018年 | 13篇 |
2017年 | 16篇 |
2016年 | 36篇 |
2015年 | 40篇 |
2014年 | 49篇 |
2013年 | 71篇 |
2012年 | 67篇 |
2011年 | 51篇 |
2010年 | 43篇 |
2009年 | 30篇 |
2008年 | 40篇 |
2007年 | 61篇 |
2006年 | 56篇 |
2005年 | 51篇 |
2004年 | 47篇 |
2003年 | 55篇 |
2002年 | 46篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 12篇 |
1997年 | 4篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 8篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1969年 | 3篇 |
1967年 | 4篇 |
1966年 | 2篇 |
1958年 | 2篇 |
1937年 | 2篇 |
排序方式: 共有970条查询结果,搜索用时 15 毫秒
911.
Venturi V Venuti C Devescovi G Lucchese C Friscina A Degrassi G Aguilar C Mazzucchi U 《FEMS microbiology letters》2004,241(2):179-183
We report for the first time the production of acyl homoserine lactones (AHLs) by Erwina amylovora, an important quarantine bacterial pathogen that causes fire blight in plants. E. amylovora produces one N-acyl homoserine lactone [a N-(3-oxo-hexanoyl)-homoserine lactone or a N-(3-hydroxy-hexanoyl)-homoserine lactone] quorum sensing signal molecule both in vitro and in planta (pear plant). Given the involvement of AHLs in plant pathogenesis, we speculate that AHL-dependent quorum sensing could play an important role in the regulation of E. amylovora virulence. 相似文献
912.
913.
914.
915.
Valentino Braitenberg Vittorio Guglielmotti Enrico Sada 《Biotechnic & histochemistry》1967,42(6):277-283
The surface of the specimens subjected to a modified Golgi technique (formalin fixed material; specimens in the following solution for 8-10 days at 27 C: 3% K2Cr2O7, 100 ml, with the addition of 2.5-10 ml of 10% formalin and 6-25 gm of sucrose; then in 0.75% AgNO3 for at least 2 days at 27 C) is sometimes covered with a fur of filamentous crystals and sometimes with a powdery precipitate of laminar crystals. In a series of experiments in which about 500 blocks of tissue were treated with variations of the staining procedure, good axonal stain was positively correlated with the appearance of filamentous crystals. These filaments have a thickness of 1-4 μ and grow at a rate of 160-330 μ/hr, reaching a length of 2-7 mm. 相似文献
916.
917.
Alessia Pasqualato Vittorio Lei Alessandra Cucina Simona Dinicola Fabrizio D'Anselmi Sara Proietti Maria Grazia Masiello Alessandro Palombo Mariano Bizzarri 《Cell Adhesion & Migration》2013,7(5):450-459
Unsuccessful cytotoxic anticancer treatments may contribute to tumor morphologic instability and consequent tissue invasion, promoting the selection of a more malignant phenotype. Indeed, morphological changes have been demonstrated to be more pronounced in strongly vs. weakly metastatic cells.By means of normalized bending energy, we have previously quantitatively defined the link between cell shape modifications and the acquisition of a more malignant phenotype by 5-FU-resistant colon cancer cells (HCT-8FUres). Such changes were significantly correlated with an increase in motility speed. Herein, we propose a method to quantitatively analyze the shape of wild and chemoresistant HCT-8 migration front cells during wound healing assay. We evaluated the reliability of parameters (area/perimeter ratio [A/p], circularity, roundness, fractal dimension, and solidity) in describing the biological behavior of the two cell lines, enabling hence in distinguishing the chemoresistant line from the other one. We found solidity index the parameter that better described the difference between chemoresistant and wild cells. Moreover, solidity is able to capture the differences between chemoresistant and wild cells at each time point of the migration process. Indeed, motility speed was found to be inversely correlated with solidity, a quantitative index of cell deformability. Deformability is an outstanding hallmark of the process leading to metastatic spread; consequently, solidity may be considered a marker of acquired metastatic property. 相似文献
918.
Mutations in the Extracellular Domain Cause RET Loss of Function by a Dominant Negative Mechanism 总被引:5,自引:0,他引:5
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)
Maria Pia Cosma Monica Cardone Francesca Carlomagno Vittorio Colantuoni 《Molecular and cellular biology》1998,18(6):3321-3329
The RET proto-oncogene encodes a tyrosine kinase receptor expressed in neuroectoderm-derived cells. Mutations in specific regions of the gene are responsible for the tumor syndromes multiple endocrine neoplasia types 2A and 2B (MEN 2A and 2B), while mutations along the entire gene are involved in a developmental disorder of the gastrointestinal tract, Hirschsprung’s disease (HSCR disease). Two mutants in the extracellular domain of RET, one associated with HSCR disease and one carrying a flag epitope, were analyzed to investigate the impact of the mutations on RET function. Both mutants were impeded in their maturation, resulting in the lack of the 170-kDa mature form and the accumulation of the 150-kDa immature form in the endoplasmic reticulum. Although not exposed on the cell surface, the 150-kDa species formed dimers and aggregates; this was more pronounced in a double mutant bearing a MEN 2A mutation. Tyrosine phosphorylation and the transactivation potential were drastically reduced in single and double mutants. Finally, in cotransfection experiments both mutants exerted a dominant negative effect over protoRET and RET2A through the formation of a heteromeric complex that prevents their maturation and function. These results suggest that HSCR mutations in the extracellular region cause RET loss of function through a dominant negative mechanism. 相似文献
919.
920.
Delia Cavallo Alessandro Marinaccio Barbara Perniconi Paola Tomao Vittorio Pecoriello Roberto Moccaldi Sergio Iavicoli 《Mutation research》2002,513(1-2):11-15
The increasing use of air travel suggests the need for risk assessment and cytogenetic analysis of flight personnel, to check for the risk of developing cancer. Taking into consideration occupational risk and possible confounding factors, we used traditional cytogenetics, the micronucleus test and fluorescent in situ hybridization (FISH) analysis to study 48 male crew members working on long-haul flights and a control group of 48 ground staff. Compared to controls, we detected a significant increase in the relative risk of gaps and breaks (adjusted odds ratio (OR(adj))--7.8; 95% confidence interval (CI) - 2.4-24.9) and of translocations (OR(adj)--5.1; 95% CI 1.5-17.3) in crew members, with a non-significant difference in the other chromosomal aberrations. The possibility of a correlation between translocations and cancer risk highlights the need for preventive measures for aircraft personnel. 相似文献