全文获取类型
收费全文 | 579篇 |
免费 | 38篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 314篇 |
金属工艺 | 3篇 |
机械仪表 | 11篇 |
建筑科学 | 22篇 |
矿业工程 | 1篇 |
能源动力 | 14篇 |
轻工业 | 84篇 |
水利工程 | 6篇 |
无线电 | 17篇 |
一般工业技术 | 86篇 |
冶金工业 | 7篇 |
原子能技术 | 2篇 |
自动化技术 | 46篇 |
出版年
2024年 | 1篇 |
2023年 | 25篇 |
2022年 | 118篇 |
2021年 | 107篇 |
2020年 | 33篇 |
2019年 | 25篇 |
2018年 | 32篇 |
2017年 | 22篇 |
2016年 | 24篇 |
2015年 | 22篇 |
2014年 | 23篇 |
2013年 | 33篇 |
2012年 | 20篇 |
2011年 | 31篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 15篇 |
2007年 | 8篇 |
2006年 | 11篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有617条查询结果,搜索用时 15 毫秒
51.
Giulia Della Pelle Andrea Delgado Lpez Marina Salord Fiol Nina Kostevek 《International journal of molecular sciences》2021,22(13)
Cyanine fluorescent dyes are attractive diagnostic or therapeutic agents due to their excellent optical properties. However, in free form, their use in biological applications is limited due to the short circulation time, instability, and toxicity. Therefore, their encapsulation into nano-carriers might help overcome the above-mentioned issues. In addition to indocyanine green (ICG), which is clinically approved and therefore the most widely used fluorescent dye, we tested the structurally similar and cheaper alternative called IR-820. Both dyes were encapsulated into liposomes. However, due to the synthetic origin of liposomes, they can induce an immunogenic response. To address this challenge, we proposed to use erythrocyte membrane vesicles (EMVs) as “new era” nano-carriers for cyanine dyes. The optical properties of both dyes were investigated in different biological relevant media. Then, the temperature stability and photo-stability of dyes in free form and encapsulated into liposomes and EMVs were evaluated. Nano-carriers efficiently protected dyes from thermal degradation, as well as from photo-induced degradation. Finally, a hemotoxicity study revealed that EMVs seem less hemotoxic dye carriers than clinically approved liposomes. Herein, we showed that EMVs exhibit great potential as nano-carriers for dyes with improved stability and hemocompatibility without losing excellent optical properties. 相似文献
52.
Benedetta Angeloni Rachele Bigi Gianmarco Bellucci Rosella Mechelli Chiara Ballerini Carmela Romano Emanuele Morena Giulia Pellicciari Roberta Reni Virginia Rinaldi Maria Chiara Buscarinu Silvia Romano Giovanni Ristori Marco Salvetti 《International journal of molecular sciences》2021,22(7)
Multiple sclerosis is a complex, multifactorial, dysimmune disease prevalent in women. Its etiopathogenesis is extremely intricate, since each risk factor behaves as a variable that is interconnected with others. In order to understand these interactions, sex must be considered as a determining element, either in a protective or pathological sense, and not as one of many variables. In particular, sex seems to highly influence immune response at chromosomal, epigenetic, and hormonal levels. Environmental and genetic risk factors cannot be considered without sex, since sex-based immunological differences deeply affect disease onset, course, and prognosis. Understanding the mechanisms underlying sex-based differences is necessary in order to develop a more effective and personalized therapeutic approach. 相似文献
53.
Marcello Candelli Laura Franza Giulia Pignataro Veronica Ojetti Marcello Covino Andrea Piccioni Antonio Gasbarrini Francesco Franceschi 《International journal of molecular sciences》2021,22(12)
Lipopolysaccharides (LPSs) are bacterial surface glycolipids, produced by Gram-negative bacteria. LPS is known to determine acute inflammatory reactions, particularly in the context of sepsis. However, LPS can also trigger chronic inflammation. In this case, the source of LPS is not an external infection, but rather an increase in endogenous production, which is usually sustained by gut microbiota (GM), and LPS contained in food. The first site in which LPS can exert its inflammatory action is the gut: both GM and gut-associated lymphoid tissue (GALT) are influenced by LPS and shift towards an inflammatory pattern. The changes in GM and GALT induced by LPS are quite similar to the ones seen in IBD: GM loses diversity, while GALT T regulatory (Tregs) lymphocytes are reduced in number, with an increase in Th17 and Th1 lymphocytes. Additionally, the innate immune system is triggered, through the activation of toll-like receptor (TLR)-4, while the epithelium is directly damaged, further triggering inflammation. In this review, we will discuss the importance of the crosstalk between LPS, GM, and GALT, and discuss the possible implications. 相似文献
54.
Ownership, Investment Policies and Funding Choices of Italian Water Utilities: An Empirical Analysis
Nowadays, the efficient management of water has become the focus of vast debate, both in the academic literature and in the practical and regulatory field. Due to the growing importance and scarcity of water resources, it has become crucial to better understand how to improve the organizational efficiency of water utilities. By adopting an accounting perspective and using statistical methods, this paper analyzes whether and to what extent investment and financial strategies differ among clusters of water utilities with different ownership structures. The paper focuses on the Italian water industry, a context considered particularly appropriate due to the coexistence of utilities with different ownership structures. The main results of the paper show that ownership affects the level of investment as well as the financial structure and costs of water utilities. The evidence provided by this study should encourage national governments and regulatory authorities to select water utilities with the greatest investment potential measured in terms of financial efficiency and effectiveness. 相似文献
55.
Sinico Michele; Parovel Giulia; Casco Clara; Anstis Stuart 《Canadian Metallurgical Quarterly》2009,35(4):948
We show that human observers strongly underestimate a linear or circular trajectory that a luminous spot follows in the dark. At slow speeds, observers are relatively accurate, but, as the speed increases, the size of the path is progressively underestimated, by up to 35%. The underestimation imposes little memory load and does not require tracking of the trajectory. Most importantly, we found that underestimation occurred only when successive motion vectors changed in direction. This suggests a perceptual rather than representational origin of the illusion, related to vector-sum integration over time of neural motion signals in different directions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
De Petris G 《Accounts of chemical research》2002,35(5):305-312
Recent mass spectrometric studies of species and processes relevant to the chemistry of atmospheres are reported. New species have been detected, including HO(3); a stratospheric reservoir of OH radicals; the [H(2)O(+)O(2)(-)] charge transfer complex, central to the atmospheric photonucleation theory; and the OSOSO oxide and its cation, likely present in the Io's atmosphere. As to ionic processes, a new route to tropospheric N(2)O in air ionized by lightning and coronas is reported, as well as the complex chemistry promoted by ionization of ozone/freon and ozone/carbonyl sulfide mixtures and the formation of O(5)(+), relevant to the problem of (18)O excess in stratospheric ozone. 相似文献
57.
Nanometre-sized diamond has been found in meteorites, protoplanetary nebulae and interstellar dusts, as well as in residues of detonation and in diamond films. Remarkably, the size distribution of diamond nanoparticles seems to be peaked around 2-5 nm, and to be largely independent of preparation conditions. We have carried out ab initio calculations of the stability of nanodiamond as a function of surface hydrogen coverage and of size. We have found that at about 3 nm, and for a broad range of pressures and temperatures, particles with bare, reconstructed surfaces become thermodynamically more stable than those with hydrogenated surfaces, thus preventing the formation of larger grains. Our findings provide an explanation of the size distribution of extraterrestrial and of terrestrial nanodiamond found in ultradispersed and ultracrystalline diamond films. They also provide an atomistic structural model of these films, based on the topology and structure of 2-3-nm dimond clusters consisting of a diamond core surrounded by a fullerene-like carbon network. 相似文献
58.
Nanocapsules: Ultrastable Liquid–Liquid Interface as Viable Route for Controlled Deposition of Biodegradable Polymer Nanocapsules (Small 22/2016) 下载免费PDF全文
59.
Ultrastable Liquid–Liquid Interface as Viable Route for Controlled Deposition of Biodegradable Polymer Nanocapsules 下载免费PDF全文
Raffaele Vecchione Giulia Iaccarino Paolo Bianchini Roberto Marotta Francesca D'autilia Vincenzo Quagliariello Alberto Diaspro Paolo A. Netti 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(22):3005-3013
Liquid–liquid interfaces are highly dynamic and characterized by an elevated interfacial tension as compared to solid–liquid interfaces. Therefore, they are gaining an increasing interest as viable templates for ordered assembly of molecules and nanoparticles. However, liquid–liquid interfaces are more difficult to handle compared to solid–liquid interfaces; their intrinsic instability may affect the assembly process, especially in the case of multiple deposition. Indeed, some attempts have been made in the deposition of polymer multilayers at liquid–liquid interfaces, but with limited control over size and stability. This study reports on the preparation of an ultrastable liquid–liquid interface based on an O/W secondary miniemulsion and its possible use as a template for the self‐assembly of polymeric multilayer nanocapsules. Such polymer nanocapsules are made of entirely biodegradable materials, with highly controlled size—well under 200 nm—and multi‐compartment and multifunctional features enriching their field of application in drug delivery, as well as in other bionanotechnology fields. 相似文献
60.
Serrano-Guisan S di Domenicantonio G Abid M Abid JP Hillenkamp M Gravier L Ansermet JP Félix C 《Nature materials》2006,5(9):730-734
The emerging field of spintronics explores the many possibilities offered by the prospect of using the spin of the electrons for fast, nanosized electronic devices. The effect of magnetization acting on a current is the essence of giant or tunnel magnetoresistance. Although such spintronics effects already find technological applications, much of the underlying physics remains to be explored. The aim of this article is to demonstrate the importance of spin mixing in metallic nanostructures. Here we show that magnetic clusters embedded in a metallic matrix exhibit a giant magnetic response of more than 500% at low temperature, using a recently developed thermoelectric measurement. This method eliminates the dominating resistivity component of the magnetic response and thus reveals an intrinsic spin-dependent process: the conduction-electron spin precession about the exchange field as the electron crosses the clusters, giving rise to a spin-mixing mechanism with strong field dependence. This effect appears sensibly only in the smallest clusters, that is, at the level of less than 100 atoms per cluster. 相似文献