全文获取类型
收费全文 | 368篇 |
免费 | 26篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 189篇 |
金属工艺 | 5篇 |
机械仪表 | 4篇 |
建筑科学 | 6篇 |
矿业工程 | 2篇 |
能源动力 | 3篇 |
轻工业 | 65篇 |
水利工程 | 3篇 |
无线电 | 22篇 |
一般工业技术 | 45篇 |
冶金工业 | 20篇 |
原子能技术 | 5篇 |
自动化技术 | 23篇 |
出版年
2023年 | 2篇 |
2022年 | 39篇 |
2021年 | 90篇 |
2020年 | 18篇 |
2019年 | 17篇 |
2018年 | 20篇 |
2017年 | 12篇 |
2016年 | 17篇 |
2015年 | 9篇 |
2014年 | 21篇 |
2013年 | 20篇 |
2012年 | 24篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 13篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1989年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有394条查询结果,搜索用时 15 毫秒
11.
The Asteraceae family is one of the largest flowering plant families, with over 1600 genera and 2500 species worldwide. Some of its most well-known taxa are lettuce, chicory, artichoke, daisy and dandelion. The members of the Asteraceae have been used in the diet and for medicine for centuries. Despite their wide diversity, most family members share a similar chemical composition: for example, all species are good sources of inulin, a natural polysaccharide with strong prebiotic properties. They also demonstrate strong antioxidant, anti-inflammatory and antimicrobial activity, as well as diuretic and wound healing properties. Their pharmacological effects can be attributed to their range of phytochemical compounds, including polyphenols, phenolic acids, flavonoids, acetylenes and triterpenes. One such example is arctiin: a ligand with numerous antioxidant, antiproliferative and desmutagenic activities. The family is also a source of sesquiterpene lactones: the secondary metabolites responsible for the bitter taste of many plants. This mini review examines the current state of literature regarding the positive effect of the Asteraceae family on human health. 相似文献
12.
Sonia R. Merritt Agata A. Exner Zhenghong Lee Horst A. von Recum 《Advanced Engineering Materials》2012,14(5):B266-B278
Polymer processing via electrospinning is a cost effective and scalable method for preparing nanofibers with industrial, electrical, and biomedical applications, particularly tissue engineering and drug delivery. Characterization methods for these fibers include microscopy techniques for vitro surface morphology information, spectroscopy methods to determine in vitro chemical composition, and medical imaging tools for in vivo assessment of morphology and efficacy of implanted material. The focus of this paper is be on recent applications for electrospun nanofibers, in vitro characterization methods, and medical imaging modalities that can be used for in vivo assessment of the fibers, as well as insights in how to adapt existing techniques toward the characterization of electrospun materials. 相似文献
13.
14.
15.
The effect of stocking density (16 rabbits/m2, 5 rabbits/m2, 2.5 rabbits/m2, n = 60, Experiment 1) and group size (4 rabbits/cage, 8 rabbits/cage, 16 rabbits/cage, n = 88, Experiment 2) on productive performance, carcass and meat quality of a slow-growing rabbit population reared outdoors was investigated in two experiments. The highest stocking density induced the highest skin percentage. Lower stocking densities showed lower lightness of Biceps femoris and higher redness of Longissimus lumborum muscles. Four rabbits/cage group (Experiment 2) showed the highest daily weight gain and slaughter weight and the lowest skin percentage. The muscles of 16 rabbits/cage showed significantly higher pHu than 8 and 4 rabbits/cage. BF of 16 and 4 rabbits/cage showed higher L* value. Productive performance and meat quality of rabbits reared outdoors improved in low group size while stocking density needs more experiments. The best combination of density, group size and total available surface that showed the best production and carcass traits was of 5 rabbits/m2, 4 rabbits/cage, and 0.8 m2. 相似文献
16.
Traumatic Acid Reduces Oxidative Stress and Enhances Collagen Biosynthesis in Cultured Human Skin Fibroblasts 下载免费PDF全文
Traumatic acid (TA) is a plant hormone (cytokinin) that in terms of chemical structure belongs to the group of fatty acids derivatives. It was isolated from Phaseolus vulgaris. TA activity and its influence on human cells and organism has not previously been the subject of research. The aim of this study was to examine the effects of TA on collagen content and basic oxidative stress parameters, such as antioxidative enzyme activity, reduced glutathione, thiol group content, and lipid peroxidation in physiological conditions. The results show a stimulatory effect of TA on tested parameters. TA caused a decrease in membrane phospholipid peroxidation and exhibited protective properties against ROS production. It also increases protein and collagen biosynthesis and its secretion into the culture medium. The present findings reveal that TA exhibits multiple and complex activity in fibroblast cells in vitro. TA, with its activity similar to unsaturated fatty acids, shows antioxidant and stimulatory effects on collagen biosynthesis. It is a potentially powerful agent with applications in the treatment of many skin diseases connected with oxidative stress and collagen biosynthesis disorders. 相似文献
17.
Anna Wajler Anna Kozłowska Magdalena Nakielska Kamila Leśniewska‐Matys Agata Sidorowicz Dariusz Podniesiński Piotr Putyra 《Journal of the American Ceramic Society》2014,97(6):1692-1695
Transparent cobalt‐doped magnesium aluminate spinel (Co:MgAl2O4) ceramics with a submicrometer grain size were prepared by spark plasma sintering. For the first time, the nonlinear absorption of Co:MgAl2O4 transparent ceramics was experimentally demonstrated. Both ground state absorption (σGSA) and excited state absorption (σESA) were estimated using the solid‐state slow saturable absorber model based on absorption saturation measurements performed at 1.535 μm. σGSA and σESA for 0.03 at.% Co:MgAl2O4 were found to be 4.1 × 10?19 cm2 and 4.0 × 10?20 cm2, respectively. In the case of 0.06 at.% Co:MgAl2O4 ceramics, σGSA = 2.6 × 10?19 cm2 and σESA= 5.3 × 10?20 cm2 were determined. 相似文献
18.
Research was conducted, which aim was to evaluate quantitative and qualitative PCB changes in sewage sludge during mesophilic digestion, and the influence of those compound concentration above acceptable level (1.9 mg kg−1 of sludge dry matter), also nickel and cadmium ions, on mesophilic digestion process. Before and after the digestion, concentration of seven PCB congeners, Ni and Cd in particular chemical fractions of the sludge was analyzed. 相似文献
19.
Dagmara Wojcik-Grzybek Magdalena Hubalewska-Mazgaj Marcin Surmiak Zbigniew Sliwowski Anna Dobrut Agata Mlodzinska Adrianna Wojcik Slawomir Kwiecien Marcin Magierowski Agnieszka Mazur-Bialy Jan Bilski Tomasz Brzozowski 《International journal of molecular sciences》2022,23(6)
Inflammatory bowel diseases (IBD) are commonly considered as Crohn’s disease and ulcerative colitis, but the possibility that the alterations in gut microbiota and oxidative stress may affect the course of experimental colitis in obese physically exercising mice treated with the intestinal alkaline phosphatase (IAP) has been little elucidated. Mice fed a high-fat-diet (HFD) or normal diet (ND) for 14 weeks were randomly assigned to exercise on spinning wheels (SW) for 7 weeks and treated with IAP followed by intrarectal administration of TNBS. The disease activity index (DAI), grip muscle strength test, oxidative stress biomarkers (MDA, SOD, GSH), DNA damage (8-OHdG), the plasma levels of cytokines IL-2, IL-6, IL-10, IL-12p70, IL-17a, TNF-α, MCP-1 and leptin were assessed, and the stool composition of the intestinal microbiota was determined by next generation sequencing (NGS). The TNBS-induced colitis was worsened in obese sedentary mice as manifested by severe colonic damage, an increase in DAI, oxidative stress biomarkers, DNA damage and decreased muscle strength. The longer running distance and weight loss was observed in mice given IAP or subjected to IAP + SW compared to sedentary ones. Less heterogeneous microbial composition was noticed in sedentary obese colitis mice and this effect disappeared in IAP + SW mice. Absence of Alistipes, lower proportion of Turicibacter, Proteobacteria and Faecalibacterium, an increase in Firmicutes and Clostridium, a decrease in oxidative stress biomarkers, 8-OHdG content and proinflammatory cytokines were observed in IAP + SW mice. IAP supplementation in combination with moderate physical activity attenuates the severity of murine colitis complicated by obesity through a mechanism involving the downregulation of the intestinal cytokine/chemokine network and oxidative stress, the modulation of the gut microbiota and an improvement of muscle strength. 相似文献
20.
Agata Buonacera Benedetta Stancanelli Michele Colaci Lorenzo Malatino 《International journal of molecular sciences》2022,23(7)
Over the last 10 years, the evaluation of the neutrophil-to-lymphocyte ratio (NLR) as an emerging marker of diseases has become a compelling field of bio-medical research. Although a precise and unique cut-off value has not been yet found, its role as a flag of immune system homeostasis is well established. NLR has a well-known prognostic value and independently correlates with mortality in the general population and in several specific subsets of disease (sepsis, pneumonia, COVID-19, cancer, etc.). Moreover, NLR was recently considered as part of the decision-making processes concerning the admission/recovery of patients with COVID-19 pneumonia. This review aims to provide an overview of the main use of this biomarker, focusing on the pathophysiology and the molecular basis underlying its central role as a reliable mirror of inflammatory status and adaptive immunity. 相似文献