全文获取类型
收费全文 | 4186篇 |
免费 | 144篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 57篇 |
综合类 | 18篇 |
化学工业 | 940篇 |
金属工艺 | 122篇 |
机械仪表 | 67篇 |
建筑科学 | 197篇 |
矿业工程 | 31篇 |
能源动力 | 65篇 |
轻工业 | 410篇 |
水利工程 | 27篇 |
石油天然气 | 9篇 |
无线电 | 326篇 |
一般工业技术 | 574篇 |
冶金工业 | 1048篇 |
原子能技术 | 39篇 |
自动化技术 | 403篇 |
出版年
2023年 | 31篇 |
2022年 | 63篇 |
2021年 | 80篇 |
2020年 | 71篇 |
2019年 | 66篇 |
2018年 | 82篇 |
2017年 | 59篇 |
2016年 | 90篇 |
2015年 | 76篇 |
2014年 | 102篇 |
2013年 | 119篇 |
2012年 | 143篇 |
2011年 | 174篇 |
2010年 | 139篇 |
2009年 | 128篇 |
2008年 | 136篇 |
2007年 | 136篇 |
2006年 | 115篇 |
2005年 | 145篇 |
2004年 | 90篇 |
2003年 | 84篇 |
2002年 | 92篇 |
2001年 | 92篇 |
2000年 | 86篇 |
1999年 | 85篇 |
1998年 | 304篇 |
1997年 | 179篇 |
1996年 | 129篇 |
1995年 | 116篇 |
1994年 | 85篇 |
1993年 | 91篇 |
1992年 | 56篇 |
1991年 | 55篇 |
1990年 | 54篇 |
1989年 | 48篇 |
1988年 | 37篇 |
1987年 | 34篇 |
1986年 | 35篇 |
1985年 | 42篇 |
1984年 | 30篇 |
1983年 | 31篇 |
1982年 | 38篇 |
1981年 | 37篇 |
1980年 | 31篇 |
1979年 | 50篇 |
1978年 | 21篇 |
1977年 | 48篇 |
1976年 | 91篇 |
1975年 | 23篇 |
1972年 | 18篇 |
排序方式: 共有4333条查询结果,搜索用时 15 毫秒
21.
22.
Mirjana D. Timotijevi Tanja Ili Bojan Markovi Danijela Randjelovi Neboja Ceki Ines Nikoli Sneana Savi Ivana Panteli 《International journal of molecular sciences》2022,23(11)
Polymeric film-forming systems have emerged as an esthetically acceptable option for targeted, less frequent and controlled dermal drug delivery. However, their dynamic nature (rapid evaporation of solvents leading to the formation of thin films) presents a true characterization challenge. In this study, we tested a tiered characterization approach, leading to more efficient definition of the quality target product profiles of film-forming systems. After assessing a number of physico-chemico-mechanical properties, thermal, spectroscopic and microscopic techniques were introduced. Final confirmation of betamethasone dipropionate-loaded FFS biopharmaceutical properties was sought via an in vitro skin permeation study. A number of applied characterization methods showed complementarity. The sample based on a combination of hydrophobic Eudragit® RS PO and hydroxypropyl cellulose showed higher viscosity (47.17 ± 3.06 mPa·s) and film thickness, resulting in sustained skin permeation (permeation rate of 0.348 ± 0.157 ng/cm2 h), and even the pH of the sample with Eudragit® NE 30D, along with higher surface roughness and thermal analysis, implied its immediate delivery through the epidermal membrane. Therefore, this study revealed the utility of several methods able to refine the number of needed tests within the final product profile. 相似文献
23.
Alexandra Pum Maria Ennemoser Tanja Gerlza Andreas J. Kungl 《International journal of molecular sciences》2022,23(12)
Proinflammatory chemokine ligand 26 (CCL26, eotaxin-3) mediates transendothelial cell migration of eosinophils by binding and activating the G-protein-coupled (GPC) chemokine receptor 3 on the surface of eosinophilic cells. Here we have investigated the role of glycosaminoglycans (GAGs) as potential co-receptors in the process of CCL26-induced eosinophil chemotaxis. For this purpose, we have first identified the GAG-binding site of CCL26 by a site-directed mutagenesis approach in the form of an alanine screening. A panel of GAG-binding-deficient mutants has been designed, generated, and analyzed with respect to their binding affinities to heparan sulphate (HS) by isothermal fluorescence titration studies. This showed that basic amino acids in the α-helical part of CCL26 are strongly involved in GAG-binding. In chemotaxis experiments, we found that decreased GAG-binding affinity correlated with decreased chemotactic activity, which indicates an involvement of GAGs in eosinophil migration. This was further proven by the negative impact of heparinase III treatment and, independently, by the incubation of eosinophils with an anti heparan sulfate antibody. We finally investigated eosinophils’ proteoglycan (PG) expression patterns by real-time PCR, which revealed the highest expression level for serglycin. Including an anti-serglycin antibody in CCL26-induced eosinophil migration experiments reduced the chemotaxis of these immune cells, thereby proving the dependence of eosinophil mobilization on the proteoglycan serglycin. 相似文献
24.
目前存在3个关键因素导致环锭纺产量无法进一步提高。介绍了一些有利于未来环锭纺技术进一步发展的基本情况。详细分析了环锭纺工序中的能耗问题,这是性能能否提高的基础。环锭纺产量的提高,不仅是技术上是否可行的问题,更重要的是能够获得良好的经济效益。 相似文献
25.
Daniel H. Mendelsohn Katja Schnabel Andreas Mamilos Samuel Sossalla Steffen Pabel Georg Daniel Duerr Karsten Keller Volker H. Schmitt Friedrich Barsch Nike Walter Ronald Man Yeung Wong Thaqif El Khassawna Tanja Niedermair Volker Alt Markus Rupp Christoph Brochhausen 《International journal of molecular sciences》2022,23(9)
Mitochondria play a crucial role in cell physiology and pathophysiology. In this context, mitochondrial dynamics and, subsequently, mitochondrial ultrastructure have increasingly become hot topics in modern research, with a focus on mitochondrial fission and fusion. Thus, the dynamics of mitochondria in several diseases have been intensively investigated, especially with a view to developing new promising treatment options. However, the majority of recent studies are performed in highly energy-dependent tissues, such as cardiac, hepatic, and neuronal tissues. In contrast, publications on mitochondrial dynamics from the orthopedic or trauma fields are quite rare, even if there are common cellular mechanisms in cardiovascular and bone tissue, especially regarding bone infection. The present report summarizes the spectrum of mitochondrial alterations in the cardiovascular system and compares it to the state of knowledge in the musculoskeletal system. The present paper summarizes recent knowledge regarding mitochondrial dynamics and gives a short, but not exhaustive, overview of its regulation via fission and fusion. Furthermore, the article highlights hypoxia and its accompanying increased mitochondrial fission as a possible link between cardiac ischemia and inflammatory diseases of the bone, such as osteomyelitis. This opens new innovative perspectives not only for the understanding of cellular pathomechanisms in osteomyelitis but also for potential new treatment options. 相似文献
26.
Miha Renko Tanja Zupan David F. Plaza Stefanie S. Schmieder Milica Perii Nanut Janko Kos Duan Turk Markus Künzler Jerica Saboti
《International journal of molecular sciences》2022,23(9)
We introduce a new family of fungal protease inhibitors with β-trefoil fold from the mushroom Coprinopsis cinerea, named cocaprins, which inhibit both cysteine and aspartic proteases. Two cocaprin-encoding genes are differentially expressed in fungal tissues. One is highly transcribed in vegetative mycelium and the other in the stipes of mature fruiting bodies. Cocaprins are small proteins (15 kDa) with acidic isoelectric points that form dimers. The three-dimensional structure of cocaprin 1 showed similarity to fungal β-trefoil lectins. Cocaprins inhibit plant C1 family cysteine proteases with Ki in the micromolar range, but do not inhibit the C13 family protease legumain, which distinguishes them from mycocypins. Cocaprins also inhibit the aspartic protease pepsin with Ki in the low micromolar range. Mutagenesis revealed that the β2-β3 loop is involved in the inhibition of cysteine proteases and that the inhibitory reactive sites for aspartic and cysteine proteases are located at different positions on the protein. Their biological function is thought to be the regulation of endogenous proteolytic activities or in defense against fungal antagonists. Cocaprins are the first characterized aspartic protease inhibitors with β-trefoil fold from fungi, and demonstrate the incredible plasticity of loop functionalization in fungal proteins with β-trefoil fold. 相似文献
27.
28.
29.
In this paper, we identify two cases in which the proposition for calculating time window penalties presented in Nagata, Y., Bräysy, O. and Dullaert, W. A penalty-based edge assembly memetic algorithm for the vehicle routing problem with time windows, Computers & Operations Research 2010;37(4): 724–37 yields incorrect results. We derive the corrected proposition and use numerical studies to show that a significant proportion of the evaluations performed by a Tabu Search for VRPTW falls under the two incorrect cases. Moreover, we demonstrate that the incorrect time window handling has a significant negative impact on the solution quality of the Tabu Search. 相似文献
30.