全文获取类型
收费全文 | 841篇 |
免费 | 48篇 |
专业分类
电工技术 | 14篇 |
化学工业 | 260篇 |
金属工艺 | 24篇 |
机械仪表 | 17篇 |
建筑科学 | 38篇 |
能源动力 | 29篇 |
轻工业 | 88篇 |
水利工程 | 12篇 |
石油天然气 | 1篇 |
无线电 | 51篇 |
一般工业技术 | 200篇 |
冶金工业 | 33篇 |
原子能技术 | 4篇 |
自动化技术 | 118篇 |
出版年
2024年 | 4篇 |
2023年 | 7篇 |
2022年 | 28篇 |
2021年 | 32篇 |
2020年 | 23篇 |
2019年 | 22篇 |
2018年 | 29篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 23篇 |
2014年 | 40篇 |
2013年 | 65篇 |
2012年 | 52篇 |
2011年 | 55篇 |
2010年 | 41篇 |
2009年 | 41篇 |
2008年 | 48篇 |
2007年 | 40篇 |
2006年 | 29篇 |
2005年 | 32篇 |
2004年 | 37篇 |
2003年 | 19篇 |
2002年 | 18篇 |
2001年 | 8篇 |
2000年 | 16篇 |
1999年 | 8篇 |
1998年 | 12篇 |
1997年 | 12篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 12篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1971年 | 4篇 |
1968年 | 1篇 |
排序方式: 共有889条查询结果,搜索用时 31 毫秒
881.
Mohammed S. I. Mansour Karina Malmros Ulrich Mager Kajsa Ericson Lindquist Kim Hejny Benjamin Holmgren Tomas Seidal Annika Dejmek Katalin Dobra Maria Planck Hans Brunnstrm 《International journal of molecular sciences》2022,23(9)
Immune checkpoint inhibitors (ICI) targeting programmed cell death-1 or its ligand (PD-L1) have improved outcomes in non-small cell lung cancer (NSCLC). High tumor PD-L1 expression, detected by immunohistochemistry (IHC) typically on formalin-fixed paraffin-embedded (FFPE) histological specimens, is linked to better response. Following our previous investigation on PD-L1 in cytological samples, the aim of this study was to further explore the potential impacts of various clinicopathological and molecular factors on PD-L1 expression. Two retrospective NSCLC cohorts of 1131 and 651 specimens, respectively, were investigated for PD-L1 expression (<1%/1–49%/≥50%), sample type, sample site, histological type, and oncogenic driver status. In both cohorts, PD-L1 was positive (≥1%) in 55% of the cases. Adenocarcinomas exhibited lower PD-L1 expression than squamous cell carcinomas (p < 0.0001), while there was no difference between sample types, tumor locations, or between the two cohorts in multivariate analysis (all p ≥ 0.28). Mutational status correlated significantly with PD-L1 expression (p < 0.0001), with the highest expression for KRAS-mutated cases, the lowest for EGFR-mutated, and the KRAS/EGFR wild-type cases in between. There was no difference in PD-L1 levels between different prevalent KRAS mutations (all p ≥ 0.44), while mucinous KRAS-mutated adenocarcinomas exhibited much lower PD-L1 expression than non-mucinous (p < 0.0001). Our data indicate that cytological and histological specimens are comparable for PD-L1 evaluation. Given the impact of KRAS mutations and the mucinous growth pattern on PD-L1 expression, these factors should be further investigated in studies on ICI response. 相似文献
882.
Jorge Rico-Fontalvo Gustavo Aroca Jose Cabrales Rodrigo Daza-Arnedo Tomas Ynez-Rodríguez María Cristina Martínez-vila Isabella Uparella-Gulfo María Raad-Sarabia 《International journal of molecular sciences》2022,23(15)
The inflammatory component of diabetic kidney disease has become of great interest in recent years, with genetic and epigenetic variants playing a fundamental role in the initiation and progression of the disease. Cells of the innate immune system play a major role in the pathogenesis of diabetic kidney disease, with a lesser contribution from the adaptive immune cells. Other components such as the complement system also play a role, as well as specific cytokines and chemokines. The inflammatory component of diabetic kidney disease is of great interest and is an active research field, with the hope to find potential innovative therapeutic targets. 相似文献
883.
Kristina Repova Tomas Baka Kristina Krajcirovicova Peter Stanko Silvia Aziriova Russel J. Reiter Fedor Simko 《International journal of molecular sciences》2022,23(24)
Anxiety disorders are the most common mental diseases. Anxiety and the associated physical symptoms may disturb social and occupational life and increase the risk of somatic diseases. The pathophysiology of anxiety development is complex and involves alterations in stress hormone production, neurosignaling pathways or free radical production. The various manifestations of anxiety, its complex pathophysiological background and the side effects of available treatments underlie the quest for constantly seeking therapies for these conditions. Melatonin, an indolamine produced in the pineal gland and released into the blood on a nightly basis, has been demonstrated to exert anxiolytic action in animal experiments and different clinical conditions. This hormone influences a number of physiological actions either via specific melatonin receptors or by receptor-independent pleiotropic effects. The underlying pathomechanism of melatonin’s benefit in anxiety may reside in its sympatholytic action, interaction with the renin–angiotensin and glucocorticoid systems, modulation of interneuronal signaling and its extraordinary antioxidant and radical scavenging nature. Of importance, the concentration of this indolamine is significantly higher in cerebrospinal fluid than in the blood. Thus, ensuring sufficient melatonin production by reducing light pollution, which suppresses melatonin levels, may represent an endogenous neuroprotective and anxiolytic treatment. Since melatonin is freely available, economically undemanding and has limited side effects, it may be considered an additional or alternative treatment for various conditions associated with anxiety. 相似文献
884.
Manuel Pedrón Laura Villar Uxue Uria Liher Prieto Tomas Tejero Pedro Merino Jose L. Vicario 《Advanced Synthesis \u0026amp; Catalysis》2024,366(4):916-924
The mechanism of the enantioselective (4+3) cycloaddition between furan derivatives and oxyallylcations, which are generated from the corresponding oxiranes through in situ oxidation of allenamides, has been studied using DFT methods. The research has revealed that, under acid-catalysis by a chiral non-racemic phosphoramide, the epoxide ring-opening proceeds without any energy barrier, while the rate-limiting step is the electrophilic attack of the intermediate enaminium ion on the furan ring. The reaction exhibits low energy barriers when dealing with furan derivatives unsubstituted at C2 and C5. Calculations predict the formation of an achiral regioisomer for 2-substituted furans, a prediction that has been experimentally confirmed. Additionally, the calculations accurately predict the reaction with substituted allenamides. 相似文献
885.
Martin Tomas Valtchev Petko Roux Louis-Romain 《Knowledge and Information Systems》2023,65(8):3295-3335
Knowledge and Information Systems - Mining frequent itemsets (FIs) from data streams is a challenging task due to the limited resources available w.r.t. the typically large size of the result and... 相似文献
886.
887.
Carmen C. Mayorga-Martinez Marketa Castoralova Jaroslav Zelenka Tomas Ruml Martin Pumera 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(6):2205047
Bovine mastitis produced by Staphylococcus aureus (S. aureus) causes major problems in milk production due to the staphylococcal enterotoxins produced by this bacterium. These enterotoxins are stable and cannot be eradicated easily by common hygienic procedures once they are formed in dairy products. Here, magnetic microrobots (MagRobots) are developed based on paramagnetic hybrid microstructures loaded with IgG from rabbit serum that can bind and isolate S. aureus from milk in a concentration of 3.42 104 CFU g−1 (allowable minimum level established by the United States Food and Drug Administration, FDA). Protein A, which is present on the cell wall of S. aureus, selectively binds IgG from rabbit serum and loads the bacteria onto the surface of the MagRobots. The selective isolation of S. aureus is confirmed using a mixed suspension of S. aureus and Escherichia coli (E. coli). Moreover, this fuel-free system based on magnetic robots does not affect the natural milk microbiota or add any toxic compound resulting from fuel catalysis. This system can be used to isolate and transport efficiently S. aureus and discriminate it from nontarget bacteria for subsequent identification. Finally, this system can be scaled up for industrial use in food production. 相似文献
888.
Ahmad Jaradat Chengji Zhang Sanket Shashikant Sutar Nannan Shan Shuxi Wang Sachin Kumar Singh Taimin Yang Khagesh Kumar Kartikey Sharma Shahriar Namvar Ahmadiparidari Alireza Tomas Rojas Vikas Berry Jordi Cabana-Jimenez Zhehao Huang Arunkumar Subramanian Anh T. Ngo Larry A. Curtiss Amin Salehi-khojin 《Advanced functional materials》2023,33(21):2300814
Lithium-air batteries based on CO2 reactant (Li–CO2) have recently been of interest because it has been found that reversible Li/CO2 electrochemistry is feasible. In this study, a new medium-entropy cathode catalyst, (NbTa)0.5BiS3, that enables the reversible electrochemistry to operate at high rates is presented. This medium entropy cathode catalyst is combined with an ionic liquid-based electrolyte blend to give a Li–CO2 battery that operates at high current density of 5000 mA g−1 and capacity of 5000 mAh g−1 for up to 125 cycles, far exceeding reported values in the literature for this type of battery. The higher rate performance is believed to be due to the greater stability of the multi-element (NbTa)0.5BiS3 catalyst because of its higher entropy compared to previously used catalysts with a smaller number of elements with lower entropies. Evidence for this comes from computational studies giving very low surface energies (high surface stability) for (NbTa)0.5BiS3 and transmission electron microscopystudies showing the structure being retained after cycling. In addition, the calculations indicate that Nb-terminated surface promotes Li–CO2 electrochemistry resulting in Li2CO3 and carbon formation, consistent with the products found in the cell. These results open new direction to design and develop high-performance Li–CO2 batteries. 相似文献
889.
Lucas Gonzalez Pierre Lafleur Tomas Lozano Ana B. Morales Ricardo Garcia Marisela Angeles Francisco Rodriguez Saul Sanchez 《Polymer Composites》2014,35(1):1-9
The effects of stearic acid treatment on the crystallization, morphology, thermal, and mechanical properties of polypropylene (PP)/montmorillonite (Mm) nanocomposites were investigated. Stearic acid was used as a new surface modifier for Mm, and also small amounts of this acid were used as a new interface modifier. Nanocomposites containing 1.5, 2.5, 5, and 10% in weight of the unmodified and modified Mm were prepared by melt blending. The tensile and impact properties of nanocomposites were evaluated. Wide‐angle X‐ray diffraction was used to study both the generated PP β crystals and the dispersion state of the nanocomposites. Differential scanning calorimeter was used to detect the melting and crystallization behavior of the samples. The toughness of some nanocomposites was higher than the pure PP. β phase of PP was observed with the addition of Mm. Stearic acid favored the dispersion of the nanocomposites when used as interface modifier. Nanocomposites with better dispersion exhibited crystallization temperatures similar to pure PP. POLYM. COMPOS., 35:1–9, 2014. © 2013 Society of Plastics Engineers 相似文献