全文获取类型
收费全文 | 2645篇 |
免费 | 184篇 |
出版年
2024年 | 2篇 |
2023年 | 15篇 |
2022年 | 46篇 |
2021年 | 93篇 |
2020年 | 46篇 |
2019年 | 67篇 |
2018年 | 89篇 |
2017年 | 77篇 |
2016年 | 108篇 |
2015年 | 162篇 |
2014年 | 209篇 |
2013年 | 225篇 |
2012年 | 300篇 |
2011年 | 254篇 |
2010年 | 154篇 |
2009年 | 139篇 |
2008年 | 135篇 |
2007年 | 144篇 |
2006年 | 119篇 |
2005年 | 105篇 |
2004年 | 94篇 |
2003年 | 76篇 |
2002年 | 68篇 |
2001年 | 12篇 |
2000年 | 6篇 |
1999年 | 17篇 |
1998年 | 10篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 13篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有2829条查询结果,搜索用时 15 毫秒
31.
Alberto Baldini Alessandro Nota Valentina Assi Fabiana Ballanti Paola Cozza 《Journal of electromyography and kinesiology》2013,23(6):1474-1479
Aim of the studyTo evaluate the intersession reliability of a posturo-stabilometric examination.MethodsSingle blind clinical trial conducted in two sessions over two weeks.44 healthy volunteers free from postural and temporomandibular disorders. All the subjects complied with the criteria for completing the study.All the subjects underwent two sessions of posturo-stabilometric examinations in different visual and mandibular conditions.Sway area, sway length and the coordinates of the center of pressure were evaluated and statistically analyzed using the Intraclass correlation coefficient (ICC).ResultsAll the posturo-stabilometric parameters seemed to have an excellent reproducibility with overall ICCs higher than 70% and good confidence intervals except for the sway area (ICC 0.422 with CI 0.283–0.560 with open eyes and ICC 0.554 with CI 0.424–0.683 with closed eyes).ConclusionsThe posturo-stabilometric examination carried out using a force platform has a good intrasession and intersession reliability, especially considering sway velocity, COP X and COP Y parameters. The force platform usefulness in analyzing static posture is confirmed in any medical field. 相似文献
32.
Valentina Gambino Giulia De Michele Oriella Venezia Pierluigi Migliaccio Valentina Dall'Olio Loris Bernard Simone Paolo Minardi Maria Agnese Della Fazia Daniela Bartoli Giuseppe Servillo Myriam Alcalay Lucilla Luzi Marco Giorgio Heidi Scrable Pier Giuseppe Pelicci Enrica Migliaccio 《Aging cell》2013,12(3):435-445
33.
Valentina Sanghez Maria Teresa Russo Maria Antonietta Ajmone‐Cat Emanuele Cacci Alberto Martire Patrizia Popoli Germana Falcone Flavia Michelini Marco Crescenzi Paolo Degan Luisa Minghetti Margherita Bignami Gemma Calamandrei 《Aging cell》2013,12(4):695-705
The contribution that oxidative damage to DNA and/or RNA makes to the aging process remains undefined. In this study, we used the hMTH1‐Tg mouse model to investigate how oxidative damage to nucleic acids affects aging. hMTH1‐Tg mice express high levels of the hMTH1 hydrolase that degrades 8‐oxodGTP and 8‐oxoGTP and excludes 8‐oxoguanine from both DNA and RNA. Compared to wild‐type animals, hMTH1‐overexpressing mice have significantly lower steady‐state levels of 8‐oxoguanine in both nuclear and mitochondrial DNA of several organs, including the brain. hMTH1 overexpression prevents the age‐dependent accumulation of DNA 8‐oxoguanine that occurs in wild‐type mice. These lower levels of oxidized guanines are associated with increased longevity and hMTH1‐Tg animals live significantly longer than their wild‐type littermates. Neither lipid oxidation nor overall antioxidant status is significantly affected by hMTH1 overexpression. At the cellular level, neurospheres derived from adult hMTH1‐Tg neural progenitor cells display increased proliferative capacity and primary fibroblasts from hMTH1‐Tg embryos do not undergo overt senescence in vitro. The significantly lower levels of oxidized DNA/RNA in transgenic animals are associated with behavioral changes. These mice show reduced anxiety and enhanced investigation of environmental and social cues. Longevity conferred by overexpression of a single nucleotide hydrolase in hMTH1‐Tg animals is an example of lifespan extension associated with healthy aging. It provides a link between aging and oxidative damage to nucleic acids. 相似文献
34.
Laura Bonfili Massimiliano Cuccioloni Valentina Cecarini Matteo Mozzicafreddo Francesco Alessandro Palermo Paolo Cocci Mauro Angeletti Anna Maria Eleuteri 《Apoptosis : an international journal on programmed cell death》2013,18(10):1188-1200
Ghrelin is a metabolism-regulating hormone recently investigated for its role in cancer survival and progression. Controversially, ghrelin may act as either anti-apoptotic or pro-apoptotic factor in different cancer cells, suggesting that the effects are cell type dependent. Limited data are currently available on the effects exerted by ghrelin on intracellular proteolytic pathways in cancer. Both the lysosomal and the proteasomal systems are fundamental in cellular proliferation and apoptosis regulation. With the aim of exploring if the proteasome and autophagy may be possible targets of ghrelin in cancer, we exposed human colorectal adenocarcinoma cells to ghrelin. Preliminary in vitro fluorimetric assays evidenced for the first time a direct inhibition of 20S proteasomes by ghrelin, particularly evident for the trypsin-like activity. Moreover, 1 μM ghrelin induced apoptosis in colorectal adenocarcinoma cells by inhibiting the ubiquitin–proteasome system and by activating autophagy, with p53 having an “interactive” role. 相似文献
35.
Mauro Paschetta Valentina La Morgia Dario Masante Matteo Negro Antonio Rolando Marco Isaia 《Journal of Insect Conservation》2013,17(2):339-356
Alpine pastures are typical examples of “high nature value farmlands”, representing important habitats harbouring unique biological communities. Disturbance induced by overgrazing influences significantly ecosystem processes, in which invertebrates play a major role. To develop new models of sustainable management of pastures, more knowledge is needed of the animal communities, essential to the ecological functioning of pasture ecosystems. The apparent poor ecological state of several pastures in the Natural Regional Park of Alpi Marittime (NW-Italy) lead us to evaluate the influence of grazing history on biodiversity, using spider and harvestmen assemblages as key groups. Four different pastoral types characterized by four different grazing histories were identified using the Daget-Poissonet method. Spiders and harvestmen were collected by means of pitfall traps. Arachnid assemblages were characterized in terms of composition, abundance, species richness, richness of endemic species and taxonomic relatedness. Generalized linear mixed models (GLMM) were used to test differences among assemblages occurring in each pastoral type. Furthermore, we tested differences in terms of plant communities (species richness and percentage of zoogenic species). Specificity and fidelity of every spider and harvestmen species within pastoral types were explored by the IndVal (Indicator Value) procedure. Fifty-eight species of spiders and seven species of harvestmen were collected (2,304 individuals). Pastoral types related to intensive grazing were characterized by the dominance of diurnal wanderer spiders (namely Lycosidae) while, conversely, nocturnal wanderers (mainly Gnaphosidae) were more abundant in extensive pastoral types. Results show that both species richness and spider abundance were higher in abandoned areas of extensive grazing, while endemic assemblages were richer in extensive grazed areas, which also hosted the most diverse plant community. Furthermore, most of the indicator species of spiders of this type were endemic, characterized by more demanding ecological requirements. 相似文献
36.
37.
Gloria Taliani Martina Spaziante Elisa Biliotti Marina Borro Donatella Palazzo Stefania Grieco Cristiana Franchi Giancarlo Iaiani Caterina Furlan Valentina Gallinaro Maurizio Simmaco 《PloS one》2013,8(8)
Background
Recent clinical studies have shown that the presence of CC genotype in the rs12979860 region of IL28B gene is associated with an increase in the probability of spontaneous clearance of hepatitis C virus (HCV). Moreover, IL28B polymorphism seems to influence the probability of developing liver steatosis in chronic HCV patients.Aims
The aims of our clinical study were 1) to verify the distribution of IL28B genotypes (CC, CT or TT) among subjects with spontaneous clearance of HCV infection and 2) to examine the correlation between IL28B polymorphism and hepatic steatosis among these subjects.Methods and patients
We enrolled 41 subjects with spontaneous resolution of HCV infection (detectable serum anti-HCV but undetectable HCV-RNA) and 134 healthy controls from the same geographical area. The IL28B single-nucleotide polymorphism (SNP) rs12979860 was genotyped by using a Pyrosequencing™ technique. The presence of steatosis was assessed by liver biopsy or ultrasound examination in the 41 study subjects.Results
CC, CT and TT-genotypes of the SNP rs1979860 were found in 66%, 24% and 10% of the subjects who spontaneously cleared HCV and in 31%, 54% and 15% of controls, respectively (p = 0.0003). Among the study subjects, females with CC-genotype were significantly more represented (p = 0.02). Hepatic steatosis did not correlate with IL28B genotype (p = 0,14) but only with a high body mass index (BMI) value (p = 0.03).Conclusions
Female subjects carrying IL28B CC-genotype are significantly more represented among Italian patients who spontaneously cleared HCV infection. In addition, among these subjects, the presence of liver steatosis does not correlate with IL28B genotype but is solely related to the occurrence of high BMI. Thus, the association between IL28B polymorphism and steatosis in chronic HCV patients requires the presence of active HCV replication to occur, while in subjects who have cleared the infection, the mechanism(s) inducing liver steatosis are independent from IL28B profile. 相似文献38.
MicroRNA-486-3p Regulates γ-Globin Expression in Human Erythroid Cells by Directly Modulating BCL11A
Valentina Lulli Paolo Romania Ornella Morsilli Paolo Cianciulli Marco Gabbianelli Ugo Testa Alessandro Giuliani Giovanna Marziali 《PloS one》2013,8(4)
MicroRNAs (miRNAs) play key roles in modulating a variety of cellular processes through repression of mRNAs target. The functional relevance of microRNAs has been proven in normal and malignant hematopoiesis. While analyzing miRNAs expression profile in unilineage serum-free liquid suspension unilineage cultures of peripheral blood CD34+ hematopoietic progenitor cells (HPCs) through the erythroid, megakaryocytic, granulocytic and monocytic pathways, we identified miR-486-3p as mainly expressed within the erythroid lineage. We showed that miR-486-3p regulates BCL11A expression by binding to the extra-long isoform of BCL11A 3′UTR. Overexpression of miR-486-3p in erythroid cells resulted in reduced BCL11A protein levels, associated to increased expression of γ-globin gene, whereas inhibition of physiological miR-486-3p levels increased BCL11A and, consequently, reduced γ-globin expression. Thus, miR-486-3p regulating BCL11A expression might contributes to fetal hemoglobin (HbF) modulation and arise the question as to what extent this miRNA might contribute to different HbF levels observed among β-thalassemia patients. Erythroid cells, differentiated from PB CD34+ cells of a small cohort of patients affected by major or intermedia β-thalassemia, showed miR-486-3p levels significantly higher than those observed in normal counterpart. Importantly, in these patients, miR-486-3p expression correlates with increased HbF synthesis. Thus, our data indicate that miR-486-3p might contribute to different HbF levels observed among thalassemic patients and, possibly, to the clinical severity of the disease. 相似文献
39.
40.