全文获取类型
收费全文 | 650篇 |
免费 | 40篇 |
国内免费 | 2篇 |
出版年
2023年 | 10篇 |
2022年 | 6篇 |
2021年 | 17篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 8篇 |
2016年 | 23篇 |
2015年 | 28篇 |
2014年 | 27篇 |
2013年 | 41篇 |
2012年 | 48篇 |
2011年 | 74篇 |
2010年 | 49篇 |
2009年 | 32篇 |
2008年 | 50篇 |
2007年 | 53篇 |
2006年 | 33篇 |
2005年 | 37篇 |
2004年 | 40篇 |
2003年 | 15篇 |
2002年 | 20篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有692条查询结果,搜索用时 15 毫秒
51.
Sidiropoulou MP Fotiadou EG Tsimaras VK Zakas AP Angelopoulou NA 《Journal of strength and conditioning research / National Strength & Conditioning Association》2007,21(2):446-450
A lot of emphasis has been placed in screening individuals with exercise-induced bronchospasm in order to avoid persistence bronchial hyperactivity and consequent chronic silent inflammation of the respiratory tract. The purpose of this study was to evaluate the effect of interval training on the respiratory function and endurance in children with exercise-induced asthma (EIA) participating in the sport of soccer. Twenty-nine boys ages 10-14, who developed EIA after a 6-minute free running test (decline in forced expiratory volume in 1 second: FEV(1)10%), participated in the study. They were divided into 2 groups (experimental: n = 18, and control: n = 11), fulfilling the same criteria (i.e., age, body height and weight, and severity of asthma). The experimental group exercised with the interval training method for a period of 8 weeks, (3 sessions per week), whereas the control group exercised with the usual football program. Measurements were made for FEV(1) and endurance in both groups, before and after the application of training (8 weeks). Following the implementation of the training program, a significant improvement in FEV(1) and endurance was documented in the experimental group, as well as significant differences between the 2 groups. In conclusion, duration and aerobic training via the interval method seems to be beneficial to soccer players with EIA. 相似文献
52.
Oxidative stress biomarkers responses to physical overtraining: implications for diagnosis 总被引:1,自引:0,他引:1
Margonis K Fatouros IG Jamurtas AZ Nikolaidis MG Douroudos I Chatzinikolaou A Mitrakou A Mastorakos G Papassotiriou I Taxildaris K Kouretas D 《Free radical biology & medicine》2007,43(6):901-910
Overtraining syndrome is characterized by declining performance and transient inflammation following periods of severe training with major health implications for the athletes. Currently, there is no single diagnostic marker for overtraining. The present investigation examined the responses of oxidative stress biomarkers to a resistance training protocol of progressively increased and decreased volume/intensity. Twelve males (21.3+/-2.3 years) participated in a 12-week resistance training consisting of five 3-week periods (T1, 2 tones/week; T2, 8 tones/week; T3, 14 tones/week; T4, 2 tones/week), followed by a 3-week period of complete rest. Blood/urine samples were collected at baseline and 96 h following the last training session of each period. Performance (strength, power, jumping ability) increased after T2 and declined thereafter, indicating an overtraining response. Overtraining (T3) induced sustained leukocytosis, an increase of urinary isoprostanes (7-fold), TBARS (56%), protein carbonyls (73%), catalase (96%), glutathione peroxidase, and oxidized glutathione (GSSG) (25%) and a decline of reduced glutathione (GSH) (31%), GSH/GSSG (56%), and total antioxidant capacity. Isoprostanes and GSH/GSSG were highly (r=0.764-0.911) correlated with performance drop and training volume increase. In conclusion, overtraining induces a marked response of oxidative stress biomarkers which, in some cases, was proportional to training load, suggesting that they may serve as a tool for overtraining diagnosis. 相似文献
53.
Different environmental stimuli cause bacteria to exchange the sigma subunit in the RNA polymerase (RNAP) and, thereby, tune their gene expression according to the newly emerging needs. Sigma factors are usually thought to recognize clearly distinguishable promoter DNA determinants, and thereby activate distinct gene sets, known as their regulons. In this review, we illustrate how the principle sigma factor in stationary phase and in stressful conditions in Escherichia coli, sigmaS (RpoS), can specifically target its large regulon in vivo, although it is known to recognize the same core promoter elements in vitro as the housekeeping sigma factor, sigma70 (RpoD). Variable combinations of cis-acting promoter features and trans-acting protein factors determine whether a promoter is recognized by RNAP containing sigmaS or sigma70, or by both holoenzymes. How these promoter features impose sigmaS selectivity is further discussed. Moreover, additional pathways allow sigmaS to compete more efficiently than sigma70 for limiting amounts of core RNAP (E) and thereby enhance EsigmaS formation and effectiveness. Finally, these topics are discussed in the context of sigma factor evolution and the benefits a cell gains from retaining competing and closely related sigma factors with overlapping sets of target genes. 相似文献
54.
Panagiotis M Kritonas K Irini NO Kiriaki C Nicolaos P Athanasios T 《Biomolecular engineering》2007,24(2):245-251
Many phytopathogenic species of the fungus Cercospora produce cercosporin, a photoactivated perylenequinone toxin that belongs to a family of photosensitizers, which absorb light energy and produce extremely cytotoxic, reactive oxygen species. The cpd1 (cercosporin photosensitizer detoxification) gene of yeast (Saccharomyces cerevisiae), which encodes for a novel protein with significant similarity to the FAD-dependent pyridine nucleotide reductases, confers resistance to cercosporin when over-expressed in yeast. The aim of this work was to investigate the potential ability of cpd1 gene to confer resistance to cercosporin when expressed in tobacco plants (Nicotiana tabacum). Transgenic tobacco plants were produced using Agrobacterium tumefaciens, with cpd1 integrated as the gene of interest. We report here that expression of cpd1 gene in tobacco can mediate resistance to cercosporin. The involvement of cpd1 gene in the detoxification of the cercosporin reinforces previous observations, which suggested that resistance to cercosporin is mediated by a mechanism involving toxin reduction. 相似文献
55.
56.
Disentangling the effects of land‐use change,climate and CO2 on projected future European habitat types 下载免费PDF全文
57.
Maria Braoudaki Fotini Tzortzatou-Stathopoulou Athanasios K. Anagnostopoulos Chrisa Papathanassiou Konstantinos Vougas Kalliopi Karamolegou George Th. Tsangaris 《Amino acids》2011,40(3):943-951
The aim of this study was to investigate the progression of myelodysplastic syndrome (MDS) to acute myeloid leukemia (AML)
and to provide additional data regarding the proteomic analysis of AML. The protein profiles obtained were correlated to cytogenetic
and molecular analyses. Bone marrow (BM) and peripheral blood (PB) samples were obtained during MDS diagnosis, at MDS transformation
to AML, at de novo AML diagnosis and 3 months following treatment. As controls, non-leukemic pediatric patients were studied.
Cytogenetic and molecular analyses were carried out by G banding and polymerase chain reaction followed by sequencing, respectively.
Differential proteomic analysis was performed by two-dimensional gel electrophoresis and protein identification by matrix-assisted
laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. No significant correlations were noted between protein
patterns and cytogenetic or molecular analyses. Certain suppressor genes, metabolic enzymes, immunoglobulins and actin-binding
proteins were differentially expressed by BM or PB plasma and cell lysates compared to controls. The obtained data showed
that vitamin D and gelsolin played contradicting roles in contributing and restraining leukemogenesis, while MOES, EZRI and
AIFM1 could be considered as biomarkers for AML. 相似文献
58.
59.
Anagnostopoulos AK Dimas KS Papathanassiou C Braoudaki M Anastasiadou E Vougas K Karamolegou K Kontos H Prodromou N Tzortzatou-Stathopoulou F Tsangaris GT 《Journal of proteome research》2011,10(5):2555-2565
Childhood pilocytic astrocytoma is the most frequent brain tumor affecting children. Proteomics analysis is currently considered a powerful tool for global evaluation of protein expression and has been widely applied in the field of cancer research. In the present study, a series of proteomics, genomics, and bioinformatics approaches were employed to identify, classify and characterize the proteome content of low-grade brain tumors as it appears in early childhood. Through bioinformatics database construction, protein profiles generated from pathological tissue samples were compared against profiles of normal brain tissues. Additionally, experiments of comparative genomic hybridization arrays were employed to monitor for genetic aberrations and sustain the interpretation and evaluation of the proteomic data. The current study confirms the dominance of MAPK pathway for the childhood pilocytic astrocytoma occurrence and novel findings regarding the ERK-2 expression are reported. 相似文献
60.
Chartoumpekis DV Habeos IG Ziros PG Psyrogiannis AI Kyriazopoulou VE Papavassiliou AG 《Molecular medicine (Cambridge, Mass.)》2011,17(7-8):736-740
Fibroblast growth factor-21 (FGF21) is a pleiotropic protein involved in glucose, lipid metabolism and energy homeostasis, with main tissues of expression being the liver and adipose tissue. Brown adipose tissue (BAT) is responsible for cold-induced thermogenesis in rodents. The role of FGF21 in BAT biology has not been investigated. In the present study, wild-type C57BL/6J mice as well as a brown adipocyte cell line were used to explore the potential role of cold exposure and β3-adrenergic stimulation in the expression of FGF21 in BAT. Our results demonstrate that short-term exposure to cold, as well as β3-adrenergic stimulation, causes a significant induction of FGF21 mRNA levels in BAT, without a concomitant increase in FGF21 plasma levels. This finding opens new routes for the potential use of pharmaceuticals that could induce FGF21 and, hence, activate BAT thermogenesis. 相似文献