全文获取类型
收费全文 | 2584篇 |
免费 | 152篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 37篇 |
综合类 | 18篇 |
化学工业 | 633篇 |
金属工艺 | 65篇 |
机械仪表 | 46篇 |
建筑科学 | 86篇 |
矿业工程 | 8篇 |
能源动力 | 75篇 |
轻工业 | 384篇 |
水利工程 | 28篇 |
石油天然气 | 25篇 |
武器工业 | 2篇 |
无线电 | 236篇 |
一般工业技术 | 337篇 |
冶金工业 | 486篇 |
原子能技术 | 13篇 |
自动化技术 | 275篇 |
出版年
2023年 | 11篇 |
2022年 | 18篇 |
2021年 | 106篇 |
2020年 | 69篇 |
2019年 | 53篇 |
2018年 | 75篇 |
2017年 | 72篇 |
2016年 | 66篇 |
2015年 | 67篇 |
2014年 | 79篇 |
2013年 | 160篇 |
2012年 | 119篇 |
2011年 | 142篇 |
2010年 | 116篇 |
2009年 | 125篇 |
2008年 | 108篇 |
2007年 | 115篇 |
2006年 | 94篇 |
2005年 | 71篇 |
2004年 | 68篇 |
2003年 | 95篇 |
2002年 | 78篇 |
2001年 | 51篇 |
2000年 | 37篇 |
1999年 | 32篇 |
1998年 | 163篇 |
1997年 | 100篇 |
1996年 | 92篇 |
1995年 | 56篇 |
1994年 | 42篇 |
1993年 | 48篇 |
1992年 | 17篇 |
1991年 | 18篇 |
1990年 | 14篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 15篇 |
1986年 | 14篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1983年 | 11篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 12篇 |
1976年 | 22篇 |
1971年 | 8篇 |
1943年 | 2篇 |
排序方式: 共有2754条查询结果,搜索用时 182 毫秒
1.
Gianmarco Mangiaterra Elisa Carotti Salvatore Vaiasicca Nicholas Cedraro Barbara Citterio Anna La Teana Francesca Biavasco 《International journal of molecular sciences》2021,22(4)
The occurrence of Pseudomonas aeruginosa (PA) persisters, including viable but non-culturable (VBNC) forms, subpopulations of tolerant cells that can survive high antibiotic doses, is the main reason for PA lung infections failed eradication and recurrence in Cystic Fibrosis (CF) patients, subjected to life-long, cyclic antibiotic treatments. In this paper, we investigated the role of subinhibitory concentrations of different anti-pseudomonas antibiotics in the maintenance of persistent (including VBNC) PA cells in in vitro biofilms. Persisters were firstly selected by exposure to high doses of antibiotics and their abundance over time evaluated, using a combination of cultural, qPCR and flow cytometry assays. Two engineered GFP-producing PA strains were used. The obtained results demonstrated a major involvement of tobramycin and bacterial cell wall-targeting antibiotics in the resilience to starvation of VBNC forms, while the presence of ciprofloxacin and ceftazidime/avibactam lead to their complete loss. Moreover, a positive correlation between tobramycin exposure, biofilm production and c-di-GMP levels was observed. The presented data could allow a deeper understanding of bacterial population dynamics during the treatment of recurrent PA infections and provide a reliable evaluation of the real efficacy of the antibiotic treatments against the bacterial population within the CF lung. 相似文献
2.
Milena Jankovic Ivana Novakovic Dejan Nikolic Jasmina Mitrovic Maksic Slavko Brankovic Ivana Petronic Dragana Cirovic Sinisa Ducic Mirko Grajic Dragana Bogicevic 《International journal of molecular sciences》2021,22(9)
Diabetic neuropathy (DN), the most common chronic and progressive complication of diabetes mellitus (DM), strongly affects patients’ quality of life. DN could be present as peripheral, autonomous or, clinically also relevant, uremic neuropathy. The etiopathogenesis of DN is multifactorial, and genetic components play a role both in its occurrence and clinical course. A number of gene polymorphisms in candidate genes have been assessed as susceptibility factors for DN, and most of them are linked to mechanisms such as reactive oxygen species production, neurovascular impairments and modified protein glycosylation, as well as immunomodulation and inflammation. Different epigenomic mechanisms such as DNA methylation, histone modifications and non-coding RNA action have been studied in DN, which also underline the importance of “metabolic memory” in DN appearance and progression. In this review, we summarize most of the relevant data in the field of genetics and epigenomics of DN, hoping they will become significant for diagnosis, therapy and prevention of DN. 相似文献
3.
Miroslava Horynová Michaela Remešová Lenka Klakurková Karel Dvořák Ivana Ročňáková Shaokun Yan Ladislav Čelko Guang-Ling Song 《Journal of the American Ceramic Society》2019,102(1):123-135
Magnesium, as a biodegradable metal, offers great potential for use as a temporary implant material, which dissolves in the course of bone tissue healing. It can sufficiently support the bone and promote the bone healing process. However, the corrosion resistance of magnesium implants must be enhanced before its application in clinical practice. A promising approach of enhancing the corrosion resistance is deposition of bioactive coating, which can reduce the corrosion rate of the implants and promote bone healing. Therefore, a well-designed substrate-coating system allowing a good control of the degradation behavior is highly desirable for tailored implants for specific groups of patients with particular needs. In this contribution, the influence of coating formation conditions on the characteristics of potentiostatically electrodeposited CaP coatings on magnesium substrate was evaluated. Results showed that potential variation led to formation of coatings with the same chemical composition, but very different morphologies. Parameters that mostly influence the coating performance, such as the thickness, uniformity, deposits size, and orientation, varied from produced coating to coating. These characteristics of CaP coatings on magnesium were controlled by coating formation potential, and it was demonstrated that the electrodeposition could be a promising coating technique for production of tailored magnesium-CaP implants. 相似文献
4.
Results of a study devoted to provide the pure enantiomers of isoflurane and desflurane from racemic mixtures using gas chromatography are presented. For that purpose, a cyclodextrin‐based selector described in earlier work was immobilized on porous glass beads. The adsorption isotherms were determined and applied to predict operating parameters which provide the highest possible productivity of the separation. The analysis included evaluation of the performance of larger columns applying simplifying scale‐up considerations. Using repetitive batches, the method can provide per day with a laboratory scale column approximately 1 g pure enantiomer. Selected model predictions were validated experimentally. 相似文献
5.
Maria Grazia Basanisi Gianfranco La Bella Gaia Nobili Rosa Coppola Annita Maria Damato Maria Assunta Cafiero Giovanna La Salandra 《International Journal of Food Science & Technology》2020,55(3):1145-1150
The authenticity and traceability of meat products are issues of primary importance to ensure food safety. Unfortunately, food adulteration (e.g. the addition of inexpensive cuts to minced meat products) and mislabelling (e.g. the inclusion of meat from species other than those declared) happens frequently worldwide. The aim of this study was to apply a droplet digital PCR assay for the detection and quantification (copies μL−1) of the beef, pork, horse, sheep, chicken and turkey in meat products. The analysis conducted on commercial meat showed the presence of traces of DNA from other animal species than those declared. We show that the method is highly sensitive, specific and accurate (accuracy = 100%). This method could be adopted by competent food safety authorities to verify compliance with the labelling of meat products and to ensure quality and safety throughout the meat supply chain, from primary production to consumption. 相似文献
6.
Test specimens following ASTM D638 standards are frequently used to measure the tensile properties of reinforced and unreinforced polymers machined with traditional machining and emerging manufacturing methods (additive manufacturing/3D printing). However, designs of large engineering structures may rely on mechanical properties based on ASTM D3039 for fiber-reinforced polymer composites. This parametric study examines the scaling effects present in uniaxial tensile test specimens of molded high-density polyethylene (HDPE), with geometries ranging from Types I to IV of ASTM D638 to ASTM D3039. HDPE is a thermoplastic polymer that is recyclable, can be 3D-printed, and has a wide range of engineering applications, from bottles to pipes to radiation protection shielding. The mechanical properties test results for the molded HDPE samples are validated using a Monte Carlo simulation to estimate uncertainties for the probability distribution of maximum stress at the yield point. A Finite Element study based on the empirical model shows how the proposed approach can be adopted for design purposes. The results of this work are a useful tool to enhance confidence in the tensile mechanical properties of ASTM D638 Types II and IV geometries as statistically similar to those of ASTM D3039 samples, impacting engineering designs with traditional and emerging manufacturing methods. 相似文献
7.
Vazquez-Velazquez Arturo R. Vazquez-Garcia Rosa . Hernandez-Bucio German Gonzalez-Gonzalez Virgilio A. Moggio Ivana Vazquez-Rodriguez Sofia 《Polymer Bulletin》2020,77(4):1781-1792
Polymer Bulletin - In this work, polypropylene films (PP) and maleic anhydride graft polypropylene (PPgMA) at different concentrations of a photoluminescent dye 2,2′-(1,4-phenylenedivinylene)... 相似文献
8.
9.
10.