全文获取类型
收费全文 | 3172篇 |
免费 | 213篇 |
出版年
2024年 | 3篇 |
2023年 | 25篇 |
2022年 | 42篇 |
2021年 | 94篇 |
2020年 | 59篇 |
2019年 | 73篇 |
2018年 | 98篇 |
2017年 | 90篇 |
2016年 | 121篇 |
2015年 | 213篇 |
2014年 | 207篇 |
2013年 | 267篇 |
2012年 | 310篇 |
2011年 | 295篇 |
2010年 | 188篇 |
2009年 | 159篇 |
2008年 | 196篇 |
2007年 | 169篇 |
2006年 | 147篇 |
2005年 | 136篇 |
2004年 | 123篇 |
2003年 | 88篇 |
2002年 | 57篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 21篇 |
1998年 | 20篇 |
1997年 | 17篇 |
1996年 | 10篇 |
1995年 | 4篇 |
1994年 | 13篇 |
1993年 | 10篇 |
1992年 | 13篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1968年 | 2篇 |
排序方式: 共有3385条查询结果,搜索用时 125 毫秒
941.
Rocio Aroca Cristina Chamorro Antonio Vega Inmaculada Ventura Elisa Gómez Ramón Pérez-Cano Miguel Blanca Javier Monteseirín 《PloS one》2014,9(4)
CD66b is a member of the carcinoembryonic antigen family, which mediates the adhesion between neutrophils and to endothelial cells. Allergen-specific immunotherapy is widely used to treat allergic diseases, and the molecular mechanisms underlying this therapy are poorly understood. The present work was undertaken to analyze A) the in vitro effect of allergens and immunotherapy on cell-surface CD66b expression of neutrophils from patients with allergic asthma and rhinitis and B) the in vivo effect of immunotherapy on cell-surface CD66b expression of neutrophils from nasal lavage fluid during the spring season. Myeloperoxidase expression and activity was also analyzed in nasal lavage fluid as a general marker of neutrophil activation.
Results
CD66b cell-surface expression is upregulated in vitro in response to allergens, and significantly reduced by immunotherapy (p<0.001). Myeloperoxidase activity in nasal lavage fluid was also significantly reduced by immunotherapy, as were the neutrophil cell-surface expression of CD66b and myeloperoxidase (p<0.001). Interestingly, CD66b expression was higher in neutrophils from nasal lavage fluid than those from peripheral blood, and immunotherapy reduced the number of CD66+MPO+ cells in nasal lavage fluid. Thus, immunotherapy positive effects might, at least in part, be mediated by the negative regulation of the CD66b and myeloperoxidase activity in human neutrophils. 相似文献942.
Elisa Raffaella Ferrè Mariia Kaliuzhna Bruno Herbelin Patrick Haggard Olaf Blanke 《PloS one》2014,9(1)
Vestibular signals are strongly integrated with information from several other sensory modalities. For example, vestibular stimulation was reported to improve tactile detection. However, this improvement could reflect either a multimodal interaction or an indirect interaction driven by vestibular effects on spatial attention and orienting. Here we investigate whether natural vestibular activation induced by passive whole-body rotation influences tactile detection. In particular, we assessed the ability to detect faint tactile stimuli to the fingertips of the left and right hand during spatially congruent or incongruent rotations. We found that passive whole-body rotations significantly enhanced sensitivity to faint shocks, without affecting response bias. Critically, this enhancement of somatosensory sensitivity did not depend on the spatial congruency between the direction of rotation and the hand stimulated. Thus, our results support a multimodal interaction, likely in brain areas receiving both vestibular and somatosensory signals. 相似文献
943.
Juan Carlos Castilla Patricio H. Manríquez Alejandro Delgado Verónica Ortiz María Elisa Jara Manuel Varas 《PloS one》2014,9(10)
Background
Biological invasions affecting rocky intertidal zonation patterns, yield information on species interactions. In the Bay of Antofagasta, northern Chile, the non-indigenous tunicate Pyura praeputialis, originally from Australia, has invaded (in the past century or so) and monopolized a major portion of the mid-intertidal rocky shore, displacing upshore the native mussel Perumytilus purpuratus. In Antofagasta the tunicate is subjected to intensive exploitation. Monitoring protocols show that in the past 10 years Antofagasta''s tunicate population has experienced a drastic decline, affecting the intertidal zonation pattern.Methodology/Principal Findings
A 12.5 km of coastline, on the southern eastern shore of the Bay of Antofagasta, was studied. Eight sites were systematically (1993–1994) or sporadically (2003–2014) monitored for the seaward-shoreward expansion or reduction of the tunicate Pyura praeputialis, and native mussel and barnacle bands. A notable reduction in the mid-intertidal band of P. praeputialis and a seaward expansion of the mussel, Perumytilus purpuratus, and barnacle bands was observed. We suggest that the major cause for the decline in the tunicate is due to its intensive exploitation by rocky shore Pyura-gathers. The rate of extraction of tunicates by professional Pyura-gathers ranged between 256–740 tunicates hour−1. Between 2009–2014 the density of professional Pyura-gather ranged between 0.5–4.5 km−1 per low tide. Hence, 10 professional Pyura-gathers working 1 h for 10 low tides per month, during 6 months, will remove between 307–888 m2 of tunicates. A drastic decline in tunicate recruitment was observed and several P. praeputialis ecosystems services have been lost.Conclusion and Significance
In Antofagasta, the continuous and intensive intertidal gathering of the invasive tunicate Pyura praeputialis, has caused a drastic reduction of its population modifying the zonation pattern. Thereby, native mussel Perumytilus purpuratus has regained its ecological center in the intertidal zone. We recorded a Pyura recruitment failure and loss of ecosystem services. 相似文献944.
Magali Saint-Geniez Elisa Ghelfi Xiaoliang Liang Chenwei Yu Carrie Spencer Stephanie Abend Gokhan Hotamisligil Sule Cataltepe 《PloS one》2014,9(5)
Retinopathy of prematurity (ROP) is a leading cause of blindness in children worldwide due to increasing survival rates of premature infants. Initial suppression, followed by increased production of the retinal vascular endothelial growth factor-A (VEGF) expression are key events that trigger the pathological neovascularization in ROP. Fatty acid binding protein 4 (FABP4) is an intracellular lipid chaperone that is induced by VEGF in a subset of endothelial cells. FABP4 exhibits a pro-angiogenic function in cultured endothelial cells and in airway microvasculature, but whether it plays a role in modulation of retinal angiogenesis is not known. We hypothesized that FABP4 deficiency could ameliorate pathological retinal vascularization and investigated this hypothesis using a well-characterized mouse model of oxygen-induced retinopathy (OIR). We found that FABP4 was not expressed in retinal vessels, but was present in resident macrophages/microglial cells and endothelial cells of the hyaloid vasculature in the immature retina. While FABP4 expression was not required for normal development of retinal vessels, FABP4 expression was upregulated and localized to neovascular tufts in OIR. FABP4−/− mice demonstrated a significant decrease in neovessel formation as well as a significant improvement in physiological revascularization of the avascular retinal tissues. These alterations in retinal vasculature were accompanied by reduced endothelial cell proliferation, but no effect on apoptosis or macrophage/microglia recruitment. FABP4−/− OIR samples demonstrated decreased expression of genes involved in angiogenesis, such as Placental Growth Factor, and angiopoietin 2. Collectively, our findings suggest FABP4 as a potential target of pathologic retinal angiogenesis in proliferative retinopathies. 相似文献
945.
Albená Nunes-Silva Priscila T. T. Bernardes Bárbara M. Rezende Fernando Lopes Elisa C. Gomes Pedro E. Marques Paulo M. A. Lima Candido C. Coimbra Gustavo B. Menezes Mauro M. Teixeira Vanessa Pinho 《PloS one》2014,9(5)
Intense exercise is a physiological stress capable of inducing the interaction of neutrophils with muscle endothelial cells and their transmigration into tissue. Mechanisms driving this physiological inflammatory response are not known. Here, we investigate whether production of reactive oxygen species is relevant for neutrophil interaction with endothelial cells and recruitment into the quadriceps muscle in mice subjected to the treadmill fatiguing exercise protocol. Mice exercised until fatigue by running for 56.3±6.8 min on an electric treadmill. Skeletal muscle was evaluated by intravital microscopy at different time points after exercise, and then removed to assess local oxidative stress and histopathological analysis. We observed an increase in plasma lactate and creatine kinase (CK) concentrations after exercise. The numbers of monocytes, neutrophils, and lymphocytes in blood increased 12 and 24 hours after the exercise. Numbers of rolling and adherent leukocytes increased 3, 6, 12, and 24 hours post-exercise, as assessed by intravital microscopy. Using LysM-eGFP mice and confocal intravital microscopy technology, we show that the number of transmigrating neutrophils increased 12 hours post-exercise. Mutant gp91phox-/- (non-functional NADPH oxidase) mice and mice treated with apocynin showed diminished neutrophil recruitment. SOD treatment promoted further adhesion and transmigration of leukocytes 12 hours after the exercise. These findings confirm our hypothesis that treadmill exercise increases the recruitment of leukocytes to the postcapillary venules, and NADPH oxidase-induced ROS plays an important role in this process. 相似文献
946.
Patrizia Ciammella Maria Galeandro Nunziata D’Abbiero Tamara Palmieri Elisa Donini Cinzia Iotti 《Reports of Practical Oncology and Radiotherapy》2013,18(5):310-315
Introduction
Prostate embryonal rhabdomyosarcoma (ERMS) is a common tumour in infants and children, with a median occurrence age of 5 years, but it is rare in adults. It is characterized by a high degree of malignancy, both local rapid growth with formation of large pelvic masses, often leading to renal failure due to urethral obstruction, and systemic spread, commonly to the lungs, liver and bone. Several therapeutic approaches have been employed in the effort to treat prostate ERMS, but all of them have failed to gain a significant survival benefit in adult patients.Case report
We report on a case of a stage IV prostate ERMS, approached with combined-modality treatment, with the administration of 5 courses of doxorubicin, ifosfamide and 2-mercaptoethane sulfonate sodium (mesna), and, subsequent radiotherapy to the prostatic bed (60 Gy/30 fxs). The patient remained free of progression of disease for about 1 year to finally experience a systemic relapse with multiple lung metastases and pleural effusion. The patient died for metastatic disease 27 months following the initial diagnosis.Conclusion
While it remains questionable which therapeutic approach for prostate ERMS in adults is the most appropriate, our report demonstrates that a chemo-radiation combined treatment can control the prostate disease, reducing the symptoms and improving the quality of life of these patients, for the most part destined to die for systemic progression of disease. 相似文献947.
Anne Kathrin Müller-Rischart Anna Pilsl Patrick Beaudette Maria Patra Kamyar Hadian Maria Funke Regina Peis Alexandra Deinlein Carolin Schweimer Peer-Hendrik Kuhn Stefan F. Lichtenthaler Elisa Motori Silvana Hrelia Wolfgang Wurst Dietrich Trümbach Thomas Langer Daniel Krappmann Gunnar Dittmar Konstanze F. Winklhofer 《Molecular cell》2013,49(5):908-921
Highlights? The stress-protective prosurvival activity of parkin depends on NEMO ? Parkin binds to LUBAC and increases linear ubiquitination of NEMO ? OPA1 is upregulated via parkin/NEMO/NF-κB for maintaining mitochondrial integrity ? TNF-α signaling via NEMO/NF-κB is impaired in parkin-deficient cells 相似文献
948.
Elisa Giuliano 《Plant biosystems》2013,147(3-5):291-292
Abstract Researchs on the stamens of the healty and parasited flovers of Melandrium album. — The author has examined the structure of the stamens filaments in the healthy and parasited flowers of Melandrium album. The structural modifications induced by the mycelial hyphae of Ustilago violacea expecially in such filaments are pointed out. 相似文献
949.
Oriana Maggi Maria Angelova Elisa Lagostina Anna Adele Fabbri Lorenzo Pecoraro 《Plant biosystems》2013,147(1):247-258
A wide range of cold environments exist, with an equally broad variety of fungi and yeasts that have adapted to such environments. These adaptations, which affect membranes, enzymes and other cellular components, such as radical scavenging molecules, display a great potential for exploitation in biotechnology. Alterations have been detected in membrane lipids, with an increase in fatty acid unsaturated bonds that enhance their fluidity. We report new data on the different phospholipid composition in membrane lipids in the same fungal species from both Antarctic and temperate regions. The decrease in temperature causes intracellular oxidative stress by inducing the generation of reactive oxygen species. We report the results of the first analysis of the non-enzymatic antioxidant response and phenolic compound production by an Antarctic strain of Geomyces pannorum. A survey on yeasts from the cryosphere is reported with a focus on their adaptation to a cold environment. Some studies have shown that the number of macrofungi in glacier forefronts rises as deglaciation increases. The survival success of many plants in such areas may be attributed to their mycorrhizal associations. We highlighted the macrofungal biodiversity of some Italian alpine habitats, in which we Inocybe microfastigiata, Laccaria montana and Lactarius salicis-herbaceae were recorded for the first time in Lombardy (Italy). 相似文献
950.
Juliana F. Santos-Gandelman Olinda C. S. Santos Paula V. M. Pontes Cleyton Lage Andrade Elisa Korenblum Guilherme Muricy Marcia Giambiagi-deMarval Marinella S. Laport 《Marine biotechnology (New York, N.Y.)》2013,15(6):668-676
Among 1,236 colony-forming units (CFU) associated with 11 species of marine sponges collected from a Brazilian coast, a total of 100 morphologically different bacterial strains were analyzed. The phylogenetic diversity of the bacterial isolates was assessed by 16S rRNA gene amplification—restriction fragment length polymorphism (RFLP) analysis, using AluI restriction endonuclease. The RFLP fingerprinting resulted in 21 different patterns with good resolution for the identification of the bacterial isolates at the genus level. The genus Bacillus was the most commonly encountered genus, followed by Kocuria. Regarding the relationship between the morphotypes and species of marine sponges, Mycale microsigmatosa presented major diversity, followed by Dragmacidon reticulatum and Polymastia janeirensis. An antibiotic susceptibility profile of the 100 sponge-associated bacterial strains was determined by the disk diffusion method, and we observed a variable resistance profile, with 15 % of the bacteria being multiresistant. In addition, 71 of 100 strains were able to produce biofilm. These 71 strains were divided into 20 strong biofilm producers, 10 moderate biofilm producers, and 41 weak biofilm producers. The plasmid profile of the 100 bacterial strains was analyzed and 38 (38 %) of these samples possessed one or more plasmids. Studies like this are important to increase the information on these associated bacteria found off the coastline of Brazil, a place which has rich biodiversity that is still unknown. 相似文献