全文获取类型
收费全文 | 872篇 |
免费 | 114篇 |
出版年
2022年 | 6篇 |
2021年 | 8篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 15篇 |
2015年 | 35篇 |
2014年 | 28篇 |
2013年 | 44篇 |
2012年 | 45篇 |
2011年 | 41篇 |
2010年 | 44篇 |
2009年 | 41篇 |
2008年 | 33篇 |
2007年 | 29篇 |
2006年 | 40篇 |
2005年 | 29篇 |
2004年 | 36篇 |
2003年 | 15篇 |
2002年 | 27篇 |
2001年 | 20篇 |
2000年 | 22篇 |
1999年 | 24篇 |
1998年 | 17篇 |
1997年 | 20篇 |
1996年 | 14篇 |
1995年 | 15篇 |
1994年 | 8篇 |
1993年 | 16篇 |
1992年 | 12篇 |
1991年 | 16篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 23篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 16篇 |
1984年 | 8篇 |
1983年 | 18篇 |
1982年 | 24篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1979年 | 16篇 |
1978年 | 11篇 |
1977年 | 15篇 |
1976年 | 7篇 |
1975年 | 10篇 |
1967年 | 6篇 |
1966年 | 7篇 |
1961年 | 5篇 |
排序方式: 共有986条查询结果,搜索用时 93 毫秒
111.
112.
S Chen AJ de Craen Y Raz E Derhovanessian AC Vossen WG Rudi G Pawelec AB Maier 《Immunity & ageing : I & A》2012,9(1):18-7
ABSTRACT: BACKGROUND: Cytomegalovirus (CMV) infection has been reported to contribute to the pathogenesis of type 1 diabetes and post-transplantation diabetes. However, CMV infection has not been evaluated as a possible risk factor for type 2 diabetes. Our aim was to investigate potential associations between CMV seropositivity, CMV IgG antibody level and glucose regulation in the oldest old. RESULTS: CMV seropositive subjects were more likely to have type 2 diabetes (17.2% vs 7.9%, p = 0.016), had a higher level of HbA1c (p = 0.014) and higher non-fasting glucose (p = 0.024) in the oldest olds. These associations remained significant after adjustment for possible confounders. CMV IgG antibody level was not significantly associated with glucose regulation (all p > 0.05). CONCLUSIONS: In the oldest old, CMV seropositivity is significantly associated with various indicators of glucose regulation. This finding suggests that CMV infection might be a risk factor for the development of type 2 diabetes in the elderly. 相似文献
113.
Study design
A prospective treatment study with a new brace was conducted Objective. To evaluate radiological and subjective clinical results after one year conservative brace treatment with pressure onto lordosis at the thoracolumbar joint in children with scoliosis and kyphosis.Summary of background data
Conservative brace treatment of adolescent scoliosis is not proven to be effective in terms of lasting correction. Conservative treatment in kyphotic deformities may lead to satisfactory correction. None of the brace or casting techniques is based on sagittal forces only applied at the thoracolumbar spine (TLI= thoracolumbar lordotic intervention). Previously we showed in patients with scoliosis after forced lordosis at the thoracolumbar spine a radiological instantaneous reduction in both coronal curves of double major scoliosis.Methods
A consecutive series of 91 children with adolescent scoliosis and kyphosis were treated with a modified symmetric 30 degrees Boston brace to ensure only forced lordosis at the thoracolumbar spine. Scoliosis was defined with a Cobb angle of at least one of the curves [greater than or equal to] 25 degrees and kyphosis with or without a curve <25 degrees in the coronal plane. Standing radiographs were made i) at start, ii) in brace at beginning and iii) after one year treatment without brace.Results
Before treatment start ??in brace?? radiographs showed a strong reduction of the Cobb angles in different curves in kyphosis and scoliosis groups (sagittal n = 5 all p < 0.001, pelvic obliquity p < 0.001). After one year of brace treatment in scoliosis and kyphosis group the measurements on radiographs made without brace revealed an improvement in 3 Cobb angles each.Conclusion
Conservative treatment using thoracolumbar lordotic intervention in scoliotic and kyphotic deformities in adolescence demonstrates a marked improvement after one year also in clinical and postural criteria. An effect not obtained with current brace techniques. 相似文献114.
Steven W Kembel Evan Jones Jeff Kline Dale Northcutt Jason Stenson Ann M Womack Brendan JM Bohannan G Z Brown Jessica L Green 《The ISME journal》2012,6(8):1469-1479
Buildings are complex ecosystems that house trillions of microorganisms interacting with each other, with humans and with their environment. Understanding the ecological and evolutionary processes that determine the diversity and composition of the built environment microbiome—the community of microorganisms that live indoors—is important for understanding the relationship between building design, biodiversity and human health. In this study, we used high-throughput sequencing of the bacterial 16S rRNA gene to quantify relationships between building attributes and airborne bacterial communities at a health-care facility. We quantified airborne bacterial community structure and environmental conditions in patient rooms exposed to mechanical or window ventilation and in outdoor air. The phylogenetic diversity of airborne bacterial communities was lower indoors than outdoors, and mechanically ventilated rooms contained less diverse microbial communities than did window-ventilated rooms. Bacterial communities in indoor environments contained many taxa that are absent or rare outdoors, including taxa closely related to potential human pathogens. Building attributes, specifically the source of ventilation air, airflow rates, relative humidity and temperature, were correlated with the diversity and composition of indoor bacterial communities. The relative abundance of bacteria closely related to human pathogens was higher indoors than outdoors, and higher in rooms with lower airflow rates and lower relative humidity. The observed relationship between building design and airborne bacterial diversity suggests that we can manage indoor environments, altering through building design and operation the community of microbial species that potentially colonize the human microbiome during our time indoors. 相似文献
115.
QTL mapping of yield, agronomic and quality traits in tetraploid potato (Solanum tuberosum subsp. tuberosum) 总被引:2,自引:0,他引:2
Bradshaw JE Hackett CA Pande B Waugh R Bryan GJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(2):193-211
Interval mapping of quantitative trait loci (QTL) for 16 yield, agronomic and quality traits in potato was performed on a
tetraploid full-sib family comprising 227 clones from a cross between processing clone 12601ab1 and table cultivar Stirling.
Thirty-eight AFLP primer combinations and six SSRs provided 514 informative markers which formed a molecular marker map comprising
12 linkage groups (LGs) in 12601ab1 (nine with four homologous chromosomes) which were aligned with 12 in Stirling (11 with
four homologous chromosomes), with four partial groups remaining in 12601ab1. Two LGs were identified unequivocally as chromosomes
IV and V and eight others were tentatively assigned with chromosomes VII and X unidentified. All of the traits scored had
moderately high heritabilities with 54–92% of the variation in clone means over 3 years and two replicates being due to genetic
differences. A total of 39 QTLs were identified. A QTL for maturity was identified on chromosome V which explained 56% of
the phenotypic variance, whereas the other QTLs individually explained between 5.4 and 16.5%. However, six QTLs were detected
for after-cooking blackening and four for each of regularity of tuber shape, fry colour both after storage at 4 and 10°C and
sprouting. Just two QTLs were found for each of yield, the two ‘overall’ scores, crop emergence, tuber size and common scab
and just one QTL was detected for each of dry matter content, keeping quality, growth cracks and internal condition. The implications
for practical potato breeding and for practical linkage and QTL analysis in autotetraploids are discussed. 相似文献
116.
117.
QTL detection experiments in livestock species commonly use the half-sib design. Each male is mated to a number of females, each female producing a limited number of progeny. Analysis consists of attempting to detect associations between phenotype and genotype measured on the progeny. When family sizes are limiting experimenters may wish to incorporate as much information as possible into a single analysis. However, combining information across sires is problematic because of incomplete linkage disequilibrium between the markers and the QTL in the population. This study describes formulæ for obtaining MLEs via the expectation maximization (EM) algorithm for use in a multiple-trait, multiple-family analysis. A model specifying a QTL with only two alleles, and a common within sire error variance is assumed. Compared to single-family analyses, power can be improved up to fourfold with multi-family analyses. The accuracy and precision of QTL location estimates are also substantially improved. With small family sizes, the multi-family, multi-trait analyses reduce substantially, but not totally remove, biases in QTL effect estimates. In situations where multiple QTL alleles are segregating the multi-family analysis will average out the effects of the different QTL alleles. 相似文献
118.
Judith van Holten Kris Reedquist Pascale Sattonet-Roche Tom JM Smeets Christine Plater-Zyberk Margriet J Vervoordeldonk Paul P Tak 《Arthritis research & therapy》2004,6(3):R239
We investigated the therapeutic potential and mechanism of action of IFN-β protein for the treatment of rheumatoid arthritis
(RA). Collagen-induced arthritis was induced in DBA/1 mice. At the first clinical sign of disease, mice were given daily injections
of recombinant mouse IFN-β or saline for 7 days. Disease progression was monitored by visual clinical scoring and measurement
of paw swelling. Inflammation and joint destruction were assessed histologically 8 days after the onset of arthritis. Proteoglycan
depletion was determined by safranin O staining. Expression of cytokines, receptor activator of NF-κB ligand, and c-Fos was
evaluated immunohistochemically. The IL-1-induced expression of IL-6, IL-8, and granulocyte/macrophage-colony-stimulating
factor (GM-CSF) was studied by ELISA in supernatant of RA and osteoarthritis fibroblast-like synoviocytes incubated with IFN-β.
We also examined the effect of IFN-β on NF-κB activity. IFN-β, at 0.25 μg/injection and higher, significantly reduced disease
severity in two experiments, each using 8–10 mice per treatment group. IFN-β-treated animals displayed significantly less
cartilage and bone destruction than controls, paralleled by a decreased number of positive cells of two gene products required
for osteoclastogenesis, receptor activator of NF-κB ligand and c-Fos. Tumor necrosis factor α and IL-6 expression were significantly
reduced, while IL-10 production was increased after IFN-β treatment. IFN-β reduced expression of IL-6, IL-8, and GM-CSF in
RA and osteoarthritis fibroblast-like synoviocytes, correlating with reduced NF-κB activity. The data support the view that
IFN-β is a potential therapy for RA that might help to diminish both joint inflammation and destruction by cytokine modulation. 相似文献
119.
120.