全文获取类型
| 收费全文 | 2967篇 |
| 免费 | 53篇 |
| 国内免费 | 2篇 |
专业分类
| 电工技术 | 12篇 |
| 综合类 | 4篇 |
| 化学工业 | 833篇 |
| 金属工艺 | 7篇 |
| 机械仪表 | 42篇 |
| 建筑科学 | 113篇 |
| 矿业工程 | 1篇 |
| 能源动力 | 50篇 |
| 轻工业 | 592篇 |
| 水利工程 | 24篇 |
| 石油天然气 | 13篇 |
| 无线电 | 110篇 |
| 一般工业技术 | 328篇 |
| 冶金工业 | 617篇 |
| 原子能技术 | 12篇 |
| 自动化技术 | 264篇 |
出版年
| 2024年 | 40篇 |
| 2023年 | 40篇 |
| 2022年 | 130篇 |
| 2021年 | 151篇 |
| 2020年 | 64篇 |
| 2019年 | 85篇 |
| 2018年 | 107篇 |
| 2017年 | 98篇 |
| 2016年 | 117篇 |
| 2015年 | 79篇 |
| 2014年 | 116篇 |
| 2013年 | 180篇 |
| 2012年 | 144篇 |
| 2011年 | 171篇 |
| 2010年 | 132篇 |
| 2009年 | 127篇 |
| 2008年 | 126篇 |
| 2007年 | 113篇 |
| 2006年 | 103篇 |
| 2005年 | 89篇 |
| 2004年 | 68篇 |
| 2003年 | 60篇 |
| 2002年 | 60篇 |
| 2001年 | 33篇 |
| 2000年 | 36篇 |
| 1999年 | 33篇 |
| 1998年 | 47篇 |
| 1997年 | 39篇 |
| 1996年 | 42篇 |
| 1995年 | 26篇 |
| 1994年 | 32篇 |
| 1993年 | 24篇 |
| 1992年 | 34篇 |
| 1990年 | 24篇 |
| 1989年 | 23篇 |
| 1988年 | 20篇 |
| 1987年 | 25篇 |
| 1986年 | 16篇 |
| 1985年 | 17篇 |
| 1984年 | 22篇 |
| 1983年 | 9篇 |
| 1982年 | 8篇 |
| 1981年 | 23篇 |
| 1980年 | 7篇 |
| 1979年 | 16篇 |
| 1978年 | 11篇 |
| 1977年 | 11篇 |
| 1976年 | 7篇 |
| 1975年 | 7篇 |
| 1972年 | 6篇 |
排序方式： 共有3022条查询结果，搜索用时 15 毫秒
991.
Marcela de Sá Barreto da Cunha Natália Aboudib Campos Hankins Sandra Fernandes Arruda 《Critical reviews in food science and nutrition》2019,59(11):1767-1781
Anemia is a worldwide public health problem that can be related to many causes, including vitamin A deficiency. The aim of this study was to assess and estimate the effect of vitamin A supplementation (VAS) on iron status biomarkers and anemia in humans. Six databases, including Cochrane, EMBASE, LILACS, Pubmed, Scopus and Web of Science, were searched for clinical trials and cohort studies that investigated the effect of vitamin A supplementation alone on iron status and anemia, without time-restriction. The search yielded 23 eligible studies, 21 clinical trials and 2 cohort studies, with children, teenagers, pregnant or lactating women. The meta-analysis of the clinical trials showed that VAS reduces the risk of anemia by 26% and raises hemoglobin levels, compared to non-treated group, independent of the life stage. VAS did not alter the prevalence of iron deficiency among the clinical trials conducted with children and teenagers (RR 0.82, 95% CI 0.60 to 1.12, p = 0.204), whereas a significant increase in serum ferritin levels was observed in trials conducted with pregnant and lactating women (WMD 6.61 μg/L; 95% CI 6.00 to 7.21 μg/L; p < 0.001). Therefore, vitamin A supplementation alone may reduce the risk of anemia, by improving hemoglobin and ferritin levels in individuals with low serum retinol levels. 相似文献
992.
Sandra Ricart Antonio Rico Nick Kirk Franca Bülow Anna Ribas-Palom David Pavón 《国际水资源开发杂志》2019,35(3):491-524
AbstractThe aim of this article is to conduct an evidence-based analysis of stakeholder engagement in decision-making processes affecting multifunctional irrigation systems. The selection of case studies has allowed us to examine different tools that promote stakeholder engagement and good governance. The case studies show how stakeholder engagement in irrigation systems shapes hydrosocial territories: (1) by reducing tension between stakeholders, (2) by redirecting regional planning and strategy, (3) by highlighting water crises, (4) by decentralizing water responsibilities, and (5) by integrating values and beliefs from different stakeholders. 相似文献
993.
Sandra Petersmann Martin Spoerk Philipp Huber Margit Lang Gerald Pinter Florian Arbeiter 《大分子材料与工程》2019,304(11)
Material extrusion‐based additive manufacturing, also known as fused filament fabrication (FFF) or 3D printing facilitates the fabrication of cranial implants with different materials and complex internal structures. The impact behavior plays a key role in the designing process of cranial implants. Therefore, the performance of impact tests on novel implant materials is of utmost importance. This research focuses on investigating the dependency of the infill density and pattern on the impact properties of 3D‐printed poly(methyl methacrylate) (PMMA) sandwich specimens including internal rectilinear, gyroid, and 3D‐honeycomb (3D‐HC) structures. 3D‐HC structures show higher impact forces and dissipated energies as well as dynamic stiffness values compared to rectilinear and gyroid structures at the same infill density. 70% infill 3D‐HC and 100% infill rectilinear structures prove to be most promising. In addition, two different optimization techniques to further improve the impact properties of these specimens, namely a material and a topology optimization, are applied. Topology optimization shows promising results until first damage and material optimization regarding dissipated energies. However, both are not able to outperform the 3D‐HC pattern. 相似文献
994.
995.
996.
997.
Lorenna Lino Santos Pedro Costa Lima De Almeida Carla Aparecida Rodrigues Luís Felipe Franco De Battisti Lellis Henrique Costa Renan Gomes Bastos Carla Miguel De Oliveira Vany Perpétua Ferraz Ana Lúcia Leite Moraes Hudsara Aparecida de Almeida Paula Fernanda Borges de Araújo Paula Marcelo José Dias Silva Wagner Vilegas Sandra Maria Oliveira Morais Veiga Ana Flávia Da Silva Amorim Geraldo Alves Da Silva Marcelo Aparecido Da Silva 《International Journal of Food Science & Technology》2019,54(8):2595-2603
The increase in chronic diseases has arisen interest to search for alternative treatments so that people can improve their quality of life. Thus, Carya illinoinensis is the subject of the present work which aims at determining whether it has antidiabetic activity. The plant was collected and its nuts were separated from their peels, dried and grinded and incorporated into the feed, in concentration of 6% and 10%, for the treatment of animals. The centesimal composition of this diet was also determined. From the nut was also obtained the fixed oil, for the profile of fatty acids, and the 70% hydroethanolic extract for the phytochemical analysis. The results have shown that species presents hypoglycaemic effect, high fat composition of unsaturated fatty acids and the presence of some phenolic compounds, directly related to the antidiabetic activity. Therefore, the specie presente benefits that can contribute to the binomial diet/health. 相似文献
998.
Elias Salomão Helou Sandra A. Santos Lucas E. A. Simões 《Optimization methods & software》2016,31(5):983-1007
999.
Sandra Feijo-Bandín Alana Aragn-Herrera Manuel Otero-Santiago Laura Anido-Varela Sandra Moraa-Fernndez Estefanía Tarazn Esther Rosell-Lletí Manuel Portols Oreste Gualillo Jos Ramn Gonzlez-Juanatey Francisca Lago 《International journal of molecular sciences》2022,23(10)
Sodium-glucose co-transporter 2 inhibitors, also known as gliflozins, were developed as a novel class of anti-diabetic agents that promote glycosuria through the prevention of glucose reabsorption in the proximal tubule by sodium-glucose co-transporter 2. Beyond the regulation of glucose homeostasis, they resulted as being effective in different clinical trials in patients with heart failure, showing a strong cardio-renal protective effect in diabetic, but also in non-diabetic patients, which highlights the possible existence of other mechanisms through which gliflozins could be exerting their action. So far, different gliflozins have been approved for their therapeutic use in T2DM, heart failure, and diabetic kidney disease in different countries, all of them being diseases that have in common a deregulation of the inflammatory process associated with the pathology, which perpetuates and worsens the disease. This inflammatory deregulation has been observed in many other diseases, which led the scientific community to have a growing interest in the understanding of the biological processes that lead to or control inflammation deregulation in order to be able to identify potential therapeutic targets that could revert this situation and contribute to the amelioration of the disease. In this line, recent studies showed that gliflozins also act as an anti-inflammatory drug, and have been proposed as a useful strategy to treat other diseases linked to inflammation in addition to cardio-renal diseases, such as diabetes, obesity, atherosclerosis, or non-alcoholic fatty liver disease. In this work, we will review recent studies regarding the role of the main sodium-glucose co-transporter 2 inhibitors in the control of inflammation. 相似文献
1000.
Florine Seidel Robert Kleemann Wim van Duyvenvoorde Nikki van Trigt Nanda Keijzer Sandra van der Kooij Cees van Kooten Lars Verschuren Aswin Menke Amanda J. Kiliaan Johnathan Winter Timothy R. Hughes B. Paul Morgan Frank Baas Kees Fluiter Martine C. Morrison 《International journal of molecular sciences》2022,23(18)
Background: Chronic inflammation is an important driver in the progression of non-alcoholic steatohepatitis (NASH) and atherosclerosis. The complement system, one of the first lines of defense in innate immunity, has been implicated in both diseases. However, the potential therapeutic value of complement inhibition in the ongoing disease remains unclear. Methods: After 20 weeks of high-fat diet (HFD) feeding, obese Ldlr-/-.Leiden mice were treated twice a week with an established anti-C5 antibody (BB5.1) or vehicle control. A separate group of mice was kept on a chow diet as a healthy reference. After 12 weeks of treatment, NASH was analyzed histopathologically, and genome-wide hepatic gene expression was analyzed by next-generation sequencing and pathway analysis. Atherosclerotic lesion area and severity were quantified histopathologically in the aortic roots. Results: Anti-C5 treatment considerably reduced complement system activity in plasma and MAC deposition in the liver but did not affect NASH. Anti-C5 did, however, reduce the development of atherosclerosis, limiting the total lesion size and severity independently of an effect on plasma cholesterol but with reductions in oxidized LDL (oxLDL) and macrophage migration inhibitory factor (MIF). Conclusion: We show, for the first time, that treatment with an anti-C5 antibody in advanced stages of NASH is not sufficient to reduce the disease, while therapeutic intervention against established atherosclerosis is beneficial to limit further progression. 相似文献