全文获取类型
收费全文 | 9253篇 |
免费 | 619篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 85篇 |
综合类 | 6篇 |
化学工业 | 1790篇 |
金属工艺 | 136篇 |
机械仪表 | 136篇 |
建筑科学 | 408篇 |
矿业工程 | 10篇 |
能源动力 | 279篇 |
轻工业 | 1595篇 |
水利工程 | 100篇 |
石油天然气 | 32篇 |
无线电 | 576篇 |
一般工业技术 | 1501篇 |
冶金工业 | 1627篇 |
原子能技术 | 42篇 |
自动化技术 | 1561篇 |
出版年
2024年 | 11篇 |
2023年 | 88篇 |
2022年 | 91篇 |
2021年 | 219篇 |
2020年 | 184篇 |
2019年 | 211篇 |
2018年 | 304篇 |
2017年 | 290篇 |
2016年 | 315篇 |
2015年 | 275篇 |
2014年 | 355篇 |
2013年 | 672篇 |
2012年 | 607篇 |
2011年 | 635篇 |
2010年 | 528篇 |
2009年 | 467篇 |
2008年 | 498篇 |
2007年 | 453篇 |
2006年 | 355篇 |
2005年 | 284篇 |
2004年 | 251篇 |
2003年 | 229篇 |
2002年 | 198篇 |
2001年 | 135篇 |
2000年 | 120篇 |
1999年 | 116篇 |
1998年 | 560篇 |
1997年 | 318篇 |
1996年 | 230篇 |
1995年 | 131篇 |
1994年 | 120篇 |
1993年 | 103篇 |
1992年 | 45篇 |
1991年 | 39篇 |
1990年 | 31篇 |
1989年 | 40篇 |
1988年 | 29篇 |
1987年 | 41篇 |
1986年 | 31篇 |
1985年 | 33篇 |
1984年 | 29篇 |
1983年 | 24篇 |
1982年 | 24篇 |
1981年 | 25篇 |
1980年 | 20篇 |
1979年 | 19篇 |
1978年 | 14篇 |
1977年 | 22篇 |
1976年 | 27篇 |
1973年 | 8篇 |
排序方式: 共有9884条查询结果,搜索用时 46 毫秒
1.
Claudia Paredes Francisco J. Martínez-Vázquez Hamada Elsayed Paolo Colombo Antonia Pajares Pedro Miranda 《Journal of the European Ceramic Society》2021,41(1):892-900
Bioactive ceramic scaffolds for bone regeneration consisting of a three-dimensional mesh of interpenetrating struts with square section were fabricated via Digital Light Processing (DLP). The ability of the technique to manufacture 3D porous structures from β-tricalcium phosphate (β-TCP) powders with different dimensions of struts and pores was evaluated, identifying the possibilities and limitations of the manufacturing process. Small pore sizes were found to seriously complicate the elimination of excess slurry from the scaffold’s innermost pores. The effect of the strut/pore size on the mechanical performance of the scaffolds under compressive stresses was also evaluated, but no significant influence was found. Under compressive stresses, the structures resulted weaker when tested perpendicularly to the printing plane due to interlayer shear failure. Interlayer superficial grooves are proposed as potential failure-controlling defects, which could also explain the lack of a Weibull size effect on the mechanical strength of the fabricated DLP scaffolds. 相似文献
2.
Romero-Garcés A. Salles De Freitas R. Marfil R. Vicente-Chicote C. Martínez J. Inglés-Romero J. F. Bandera A. 《Multimedia Tools and Applications》2022,81(3):3603-3628
Multimedia Tools and Applications - The design of robots capable of operating autonomously in changing and unstructured environments, requires using complex software architectures in which,... 相似文献
3.
4.
5.
Nicholas Caffes David B. Kurland Volodymyr Gerzanich J. Marc Simard 《International journal of molecular sciences》2015,16(3):4973-4984
Ischemic and hemorrhagic strokes are associated with severe functional disability and high mortality. Except for recombinant tissue plasminogen activator, therapies targeting the underlying pathophysiology of central nervous system (CNS) ischemia and hemorrhage are strikingly lacking. Sur1-regulated channels play essential roles in necrotic cell death and cerebral edema following ischemic insults, and in neuroinflammation after hemorrhagic injuries. Inhibiting endothelial, neuronal, astrocytic and oligodendroglial sulfonylurea receptor 1–transient receptor potential melastatin 4 (Sur1–Trpm4) channels and, in some cases, microglial KATP (Sur1–Kir6.2) channels, with glibenclamide is protective in a variety of contexts. Robust preclinical studies have shown that glibenclamide and other sulfonylurea agents reduce infarct volumes, edema and hemorrhagic conversion, and improve outcomes in rodent models of ischemic stroke. Retrospective studies suggest that diabetic patients on sulfonylurea drugs at stroke presentation fare better if they continue on drug. Additional laboratory investigations have implicated Sur1 in the pathophysiology of hemorrhagic CNS insults. In clinically relevant models of subarachnoid hemorrhage, glibenclamide reduces adverse neuroinflammatory and behavioral outcomes. Here, we provide an overview of the preclinical studies of glibenclamide therapy for CNS ischemia and hemorrhage, discuss the available data from clinical investigations, and conclude with promising preclinical results that suggest glibenclamide may be an effective therapeutic option for ischemic and hemorrhagic stroke. 相似文献
6.
7.
8.
9.
Previous experimental results indicate that the humidification conditions at the anode have an impact on the liquid water distribution in the cathode gas diffusion layer. Numerical simulations are developed to reproduce and analyze this effect. Results consistent with the experimental results are first obtained by playing with the partition coefficients of an advanced pore network model computing the liquid water formation and transfer in the cathode gas diffusion layer (GDL) for a large range of operating conditions. Then, a model for the full anode – cathode assembly is developed by combining the pore network model of the cathode GDL and a 1D model describing the heat and water transfer in the various components of the anode-cathode assembly. This enables one to generalize the dry – wet regime diagram introduced in a previous work by incorporating the effect of the humidity condition at the anode. 相似文献
10.
Iratxe Perez-Arnedo María J. Cantalejo Alba Martínez-Laorden Elena Gonzalez-Fandos 《International Journal of Food Science & Technology》2021,56(4):1855-1864
Microbiological contamination of chicken meat depends on the conditions under which the animals are reared, slaughtered and processed. The aim of this study was to determine the influence of farm origin and processing stages at slaughterhouse on the microbial safety and quality of chicken. Samples of chicken carcasses from three different farms were taken from a slaughterhouse. Mesophiles, Escherichia coli, coagulase positive Staphylococcci counts, presence of Listeria monocytogenes,Campylobacter and Salmonella were determined at five sampling points: after defeathering, after evisceration, after washing, after chilling and after cutting. Chilling reduced log numbers of mesophiles, coagulase positive Staphylococci and E. coli by 0.85, 1.52 and 2.2 log units, respectively. Salmonella was not detected after chilling. High prevalence of Campylobacter spp was observed at all the stages ranging between 84% and 100%. L. monocytogenes was not detected in chicken carcasses after defeathering. However, it was detected after evisceration and after washing and chilling. The most critical stage for L. monocytogenes contamination was the portioning operation, the prevalence in breast and legs being 88% and 84%, respectively. 相似文献