全文获取类型
收费全文 | 20682篇 |
免费 | 772篇 |
国内免费 | 22篇 |
专业分类
电工技术 | 142篇 |
综合类 | 13篇 |
化学工业 | 7372篇 |
金属工艺 | 279篇 |
机械仪表 | 446篇 |
建筑科学 | 639篇 |
矿业工程 | 30篇 |
能源动力 | 540篇 |
轻工业 | 4648篇 |
水利工程 | 185篇 |
石油天然气 | 105篇 |
无线电 | 877篇 |
一般工业技术 | 2925篇 |
冶金工业 | 1077篇 |
原子能技术 | 72篇 |
自动化技术 | 2126篇 |
出版年
2024年 | 256篇 |
2023年 | 332篇 |
2022年 | 1355篇 |
2021年 | 1552篇 |
2020年 | 742篇 |
2019年 | 807篇 |
2018年 | 782篇 |
2017年 | 819篇 |
2016年 | 863篇 |
2015年 | 652篇 |
2014年 | 864篇 |
2013年 | 1300篇 |
2012年 | 1276篇 |
2011年 | 1399篇 |
2010年 | 1033篇 |
2009年 | 1028篇 |
2008年 | 922篇 |
2007年 | 849篇 |
2006年 | 656篇 |
2005年 | 515篇 |
2004年 | 421篇 |
2003年 | 378篇 |
2002年 | 343篇 |
2001年 | 217篇 |
2000年 | 171篇 |
1999年 | 205篇 |
1998年 | 275篇 |
1997年 | 207篇 |
1996年 | 188篇 |
1995年 | 132篇 |
1994年 | 109篇 |
1993年 | 97篇 |
1992年 | 87篇 |
1991年 | 63篇 |
1990年 | 48篇 |
1989年 | 59篇 |
1988年 | 44篇 |
1987年 | 43篇 |
1986年 | 56篇 |
1985年 | 45篇 |
1984年 | 41篇 |
1983年 | 28篇 |
1982年 | 21篇 |
1981年 | 23篇 |
1980年 | 24篇 |
1979年 | 28篇 |
1978年 | 20篇 |
1977年 | 18篇 |
1976年 | 19篇 |
1975年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Francesca Piccapane Mario Bonomini Giuseppe Castellano Andrea Gerbino Monica Carmosino Maria Svelto Arduino Arduini Giuseppe Procino 《International journal of molecular sciences》2021,22(1)
The main reason why peritoneal dialysis (PD) still has limited use in the management of patients with end-stage renal disease (ESRD) lies in the fact that the currently used glucose-based PD solutions are not completely biocompatible and determine, over time, the degeneration of the peritoneal membrane (PM) and consequent loss of ultrafiltration (UF). Here we evaluated the biocompatibility of a novel formulation of dialytic solutions, in which a substantial amount of glucose is replaced by two osmometabolic agents, xylitol and l-carnitine. The effect of this novel formulation on cell viability, the integrity of the mesothelial barrier and secretion of pro-inflammatory cytokines was evaluated on human mesothelial cells grown on cell culture inserts and exposed to the PD solution only at the apical side, mimicking the condition of a PD dwell. The results were compared to those obtained after exposure to a panel of dialytic solutions commonly used in clinical practice. We report here compelling evidence that this novel formulation shows better performance in terms of higher cell viability, better preservation of the integrity of the mesothelial layer and reduced release of pro-inflammatory cytokines. This new formulation could represent a step forward towards obtaining PD solutions with high biocompatibility. 相似文献
2.
Priyanka Dhar Maria Thornhill Hanumantha Rao Kota 《Mineral Processing and Extractive Metallurgy Review》2019,40(6):380-389
ABSTRACTNorway has seen an upsurge of interest in exploiting its mineral deposits during the last decade. One of the major areas of interest is a huge copper deposit, operated by Nussir ASA located in the Repparfjord tectonic window in the Caledonides of west Finnmark. Nussir ASA is evaluating the Nussir and Ulveryggen mineral resources that contain copper sulfides with a small amount of gold and silver bearing minerals. The performance of flotation operations is generally evaluated on the basis of degree of liberation of minerals or the surface interactions between the collector and mineral. Firstly, size-by-size mineralogical characterization of the flotation feed and cumulative final product using Zeiss automated mineralogy techniques (Mineralogic) revealed that mineral liberation heavily influenced the flotation behavior of the ore. Furthermore, in order to assess the role of pH, collector concentration and flotation time, bench scale flotation experiments were performed. The metallurgical results were maximum between pH 6 and 8 and at collector concentration 6 × 10?5 M. A correlation is established using the zeta potential and Hallimond flotation tests to assess the role of operating parameters in flotation. The distinctive role of process mineralogy and flotation chemical influence for copper mineral flotation of Nussir ore is presented in this article. 相似文献
3.
Maria Koteko 《Thin》1998,30(1-4):239-250
In this work the results of the collapse behaviour analysis of thin-walled, trapezoidal box-section beams subject to pure bending are presented. The analysis emphasizes two problems: the strain-hardening effect in the structural material and different modes of stress distribution at yield lines, inducing different plastic moment capacities at those lines. The problem is solved by means of the energy method, based upon the plastic mechanism approach, applied for thin-walled structures. Two theoretical models of plastic mechanisms of failure are discussed. 相似文献
4.
Alisson Rodrigo Souza Reis Sineire Maria Silva Araújo Paulo Ricardo Rodrigues Piovesan 《Holz als Roh- und Werkstoff》2018,76(6):1761-1763
The objective of this study was to anatomically characterize the fibers of nine species of Fabaceae lianas, to determine their potential in papermaking and to define which biometric parameters can be used to distinguish and identify individuals. The species presented average values of 76.81, 57.45, 42.55, and 1.81 for the felting index, wall fraction, coefficient of flexibility, and Runkel index, respectively. It is concluded that only M. ferox and M. madeirense can be recommended for papermaking. 相似文献
5.
Iuliana Dumitrescu Ana Maria Mocioiu Emilia Visileanu 《The International journal of environmental studies》2013,70(4):549-562
This paper reports the changes resulting from adopting environmentally sensitive criteria in Novatextile Pitesti, Romania. The changes have improved the operation of the production plant and reduced costs at the same time. 相似文献
6.
The practice of architecture is very similar in different national settings despite what may be very different sociological and cultural origins of the profession, the attendant variances in how work is organized and distinctions in equality and gender roles. The aim of this paper is to examine the quest for equality in architecture for women in the UK and Spain reporting the findings of a comparative study into women architects’ careers in the two countries. Within the qualitative paradigm, semi-structured in-depth interviews were carried out with a total of 55 women architects in the UK and Spain. Findings indicate surprising differences in levels and terms of equality for women in the two countries and marked differences in women’s experiences of working as an architect. Women have come to the profession in Spain much later than their British counterparts and, somewhat surprisingly, are present in greater numbers. However, despite there being more of a ‘critical mass’ this has not served to improve their situation; they report much higher levels of discrimination and find it difficult to progress in their careers. Conclusions argue for a stronger approach by the professional bodies to help improve the position of women. 相似文献
7.
Zein‐based ultrathin fibers containing ceramic nanofillers obtained by electrospinning. II. Mechanical properties,gas barrier,and sustained release capacity of biocide thymol in multilayer polylactide films
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The combination of electrospinning technology and nanomaterials such as nanoclays can synergistically lead to novel materials with enhanced properties and functionalities for their usage in passive and active packaging applications. Part I of this work was focused on the development of ultrathin zein fibers containing nanoclays, which were oriented along the fiber axis and increased the thermal properties. Part II presents the use of the hybrid fibers as passive and active components in multilayer packaging structures. The hybrid fibers are incorporated in poly(lactic acid) films via a two‐step process: Electrospinning and compression molding. The composites thus produced presented improved mechanical and barrier properties than the unfilled material. The natural biocide extract thymol is then incorporated in the coating, and its sustained release properties are shown. The antimicrobial capacity of the hybrid fibers was also determined against foodborne bacteria. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40768. 相似文献
8.
9.
Renata Cardoso Magagnin Maria Solange Gurgel de Castro Fontes Rosio Fernandez Baca Salcedo 《土木工程与建筑:英文版》2014,(12):1567-1574
This paper presents an assessment of the spatial quality of a pedestrian street located in downtown Bauru, S~o Paulo State, Brazil, from the application of some urban sustainability indicators. Multi-method was used to evaluate the thermal comfort quality of users, urban accessibility and preservation of architectural heritage. The results show that the sustainability indicators, apart from being effective tools in identifying problems, can assist local managers in decision making, planning and monitoring of pedestrian public space. These indicators contribute to a broad diagnosis of the pedestrian street and also the formulation of programs, projects and municipal policies, aimed at providing a better life quality for pedestrians. 相似文献
10.