全文获取类型
收费全文 | 1642篇 |
免费 | 71篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 12篇 |
综合类 | 17篇 |
化学工业 | 404篇 |
金属工艺 | 37篇 |
机械仪表 | 23篇 |
建筑科学 | 68篇 |
矿业工程 | 5篇 |
能源动力 | 36篇 |
轻工业 | 204篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 176篇 |
一般工业技术 | 224篇 |
冶金工业 | 277篇 |
原子能技术 | 23篇 |
自动化技术 | 200篇 |
出版年
2023年 | 20篇 |
2022年 | 45篇 |
2021年 | 51篇 |
2020年 | 34篇 |
2019年 | 31篇 |
2018年 | 39篇 |
2017年 | 42篇 |
2016年 | 41篇 |
2015年 | 38篇 |
2014年 | 49篇 |
2013年 | 83篇 |
2012年 | 58篇 |
2011年 | 90篇 |
2010年 | 58篇 |
2009年 | 65篇 |
2008年 | 65篇 |
2007年 | 58篇 |
2006年 | 55篇 |
2005年 | 64篇 |
2004年 | 44篇 |
2003年 | 28篇 |
2002年 | 37篇 |
2001年 | 26篇 |
2000年 | 24篇 |
1999年 | 33篇 |
1998年 | 83篇 |
1997年 | 53篇 |
1996年 | 46篇 |
1995年 | 29篇 |
1994年 | 36篇 |
1993年 | 37篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 15篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 16篇 |
1976年 | 17篇 |
1974年 | 8篇 |
1940年 | 6篇 |
排序方式: 共有1714条查询结果,搜索用时 15 毫秒
41.
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
42.
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
43.
DIELS -ALDER -Reactions. VI. Further Studies of the Reaction Products Formed by the Homodimerization of Acyclic 1,3-Diolefines with Five Carbon Atoms The distribution of the products of homodimerization of isoprene, trans-piperylene and cis-piperylene in toluene as solvent was determined as a function of the reaction temperature; the products formed by concurrent reactions were obtained by extrapolating the conversion to zero. From the data obtained the rate constants and the activation parameters were calculated for the six-membered ring dimers formed as the only products of the thermal homodimerization of transpiperylene, and for the four membered, six-membered and eight-membered cyclic compounds formed from isoprene. As was already found in similar studies of 1,3-butadiene, also in the case of homodimerization of isoprene, the activation parameters of the symmetry-allowed six-membered ring formation and of the symmetry-forbidden formation of four-membered and eight-membered cyclic dimers do not differ much from each other. 相似文献
44.
Tanja E. J. Vos Felix F. Lindlar Benjamin Wilmes Andreas Windisch Arthur I. Baars Peter M. Kruse Hamilton Gross Joachim Wegener 《Software Quality Journal》2013,21(2):259-288
During the past years, evolutionary testing research has reported encouraging results for automated functional (i.e. black-box) testing. However, despite promising results, these techniques have hardly been applied to complex, real-world systems and as such, little is known about their scalability, applicability, and acceptability in industry. In this paper, we describe the empirical setup used to study the use of evolutionary functional testing in industry through two case studies, drawn from serial production development environments at Daimler and Berner & Mattner Systemtechnik, respectively. Results of the case studies are presented, and research questions are assessed based on them. In summary, the results indicate that evolutionary functional testing in an industrial setting is both scalable and applicable. However, the creation of fitness functions is time-consuming. Although in some cases, this is compensated by the results, it is still a significant factor preventing functional evolutionary testing from more widespread use in industry. 相似文献
45.
46.
47.
48.
Peter Zimmermann 《Concurrency and Computation》1991,3(4):399-412
Visual simulation is one of the most important parts of a driving simulator. Unfortunately it is in general the most expensive part too. CGI-manufacturers tend to develop more complex systems because of the demands of the military market. The common systems are strongly hardware-oriented. On the basis of a new type of microprocessor, the transputer, a more software-oriented approach is introduced. Transputers in connection with the new high-level language occam are well suited for pipelining and parallelization owing to their communication concept. The advantages of this approach are reduced costs and development time, and also the capability for fast and cheap changes in algorithms. The achievable performance meets the requirements for a driving simulator very well. 相似文献
49.
Pyrylium Compounds. 45. 4-Aroyl-fluorenes from 2,4,6-Triaryl-pyrylium Salts and Indan-1-one via 2-(5-Oxo-pent-2-en-1-yliden)-indan-1-ones 2,4,6-Triarylpyrylium salts 1 react with indan-1-one in the presence of an appropriate buffer system (e.g. piperidine acetate, triethylamine/acetic acid, triethylamine or sodium acetate) to yield the 2-(1,3,5-triaryl-5-oxo-pent-2-en-1-yliden)-indan-1-ones 2 . For the reaction medium aliphatic alcohols (methanol, ethanol), dipolar aprotic solvents (acetonitrile) or chlorinated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride) can be used. On treating 2 with sodium methanolate in methanol, a cyclization reaction occurs giving rise to the 4-aroyl-1,3-diaryl-fluorenes 3 . As by-products 1,3-diaryl-fluorenes 8 (e.g. 1,3-diphenyl-fluorene) are formed. - I.r., n.m.r. and u.v. spectroscopic data of the novel compounds 2 and 3 are reported. 相似文献
50.
Marie Ebeyer-Masotta Tanja Eichhorn Ren Weiss Vladislav Semak Lucia Laukov Michael B. Fischer Viktoria Weber 《International journal of molecular sciences》2022,23(3)
Inflammation and thrombosis are closely intertwined in numerous disorders, including ischemic events and sepsis, as well as coronavirus disease 2019 (COVID-19). Thrombotic complications are markers of disease severity in both sepsis and COVID-19 and are associated with multiorgan failure and increased mortality. Immunothrombosis is driven by the complement/tissue factor/neutrophil axis, as well as by activated platelets, which can trigger the release of neutrophil extracellular traps (NETs) and release further effectors of immunothrombosis, including platelet factor 4 (PF4/CXCL4) and high-mobility box 1 protein (HMGB1). Many of the central effectors of deregulated immunothrombosis, including activated platelets and platelet-derived extracellular vesicles (pEVs) expressing PF4, soluble PF4, HMGB1, histones, as well as histone-decorated NETs, are positively charged and thus bind to heparin. Here, we provide evidence that adsorbents functionalized with endpoint-attached heparin efficiently deplete activated platelets, pEVs, PF4, HMGB1 and histones/nucleosomes. We propose that this elimination of central effectors of immunothrombosis, rather than direct binding of pathogens, could be of clinical relevance for mitigating thrombotic complications in sepsis or COVID-19 using heparin-functionalized adsorbents. 相似文献