首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2943篇
  免费   205篇
  国内免费   2篇
工业技术   3150篇
  2024年   7篇
  2023年   50篇
  2022年   34篇
  2021年   179篇
  2020年   92篇
  2019年   111篇
  2018年   127篇
  2017年   97篇
  2016年   116篇
  2015年   71篇
  2014年   104篇
  2013年   188篇
  2012年   167篇
  2011年   258篇
  2010年   171篇
  2009年   189篇
  2008年   165篇
  2007年   165篇
  2006年   125篇
  2005年   85篇
  2004年   92篇
  2003年   80篇
  2002年   52篇
  2001年   44篇
  2000年   38篇
  1999年   27篇
  1998年   36篇
  1997年   25篇
  1996年   24篇
  1995年   26篇
  1994年   18篇
  1993年   12篇
  1992年   13篇
  1991年   9篇
  1990年   14篇
  1989年   15篇
  1988年   8篇
  1987年   8篇
  1986年   6篇
  1985年   5篇
  1984年   6篇
  1983年   5篇
  1979年   5篇
  1976年   6篇
  1947年   8篇
  1946年   5篇
  1945年   6篇
  1944年   11篇
  1943年   7篇
  1942年   10篇
排序方式: 共有3150条查询结果,搜索用时 31 毫秒
101.
102.
In cake filtration processes with an air-blowing step, cracking is an undesirable phenomenon as it leads to deterioration of the filtration process by highly increasing gas throughput. This leads to higher residual moisture if the pressure difference cannot be maintained and an increase in overall cost. Crack formation can be avoided by compacting the filter cake before desaturation. While this action will make the separation process applicable by highly reducing gas consumption, there are also potential negative effects. Compaction increases filter cake resistance and might therefore slow down desaturation kinetics. Therefore, the authors investigated how the filter cake characteristics governing desaturation change from the nonconsolidated to the consolidated state of the filter cake and compared these findings to the actual dewatering kinetics. The results showed that for the case where cracking could be oppressed, dewatering kinetics of the consolidated cake are actually faster than for the nonconsolidated cake, despite higher resistance of the consolidated cake. Thus, compaction is an appropriate action when dealing with filter cake cracking.  相似文献   
103.
Microneedles are small needle‐like structures that are almost invisible to the naked eye. They have an immense potential to serve as a valuable tool in many medical applications, such as painless vaccination. Microneedles work by breaking through the stratum corneum, the outermost barrier layer of the skin, and providing a direct path for drug delivery into the skin. A lot of research has been presented over the past two decades on the applications of microneedles, yet the fundamental mechanism of how they interact, pressure, and penetrate the skin in its native state is worth examining further. As such, a major difficulty with understanding the mechanism of microneedle–skin interaction is the lack of an artificial mechanical human skin model to use as a standardized substrate. In this research news, the development of an artificial mechanical skin model based on a thorough mechanical study of fresh human and porcine skin samples is presented. The artificial mechanical skin model can be used to study the mechanical interactions between microneedles and skin, but not diffusion of molecules across skin. This model can assist in improving the performance of microneedles by enhancing the reproducibility of microneedle depth insertions for optimal drug delivery and biosensing.

  相似文献   

104.
The development of chronic kidney disease (CKD) following an episode of acute kidney injury (AKI) is an increasingly recognized clinical problem. Inhibition of toll-like receptor 4 (TLR4) protects renal function in animal models of AKI and has become a viable therapeutic strategy in AKI. However, the impact of TLR4 inhibition on the chronic sequelae of AKI is unknown. Consequently, we examined the chronic effects of TLR4 inhibition in a model of ischemic AKI. Mice with a TLR4-deletion on a C57BL/6 background and wild-type (WT) background control mice (C57BL/6) were subjected to bilateral renal artery clamping for 19 min and reperfusion for up to 6 weeks. Despite the acute protective effect of TLR4 inhibition on renal function (serum creatinine 1.6 ± 0.4 mg/dL TLR4-deletion vs. 2.8 ± 0.3 mg/dL·WT) and rates of tubular apoptosis following ischemic AKI, we found no difference in neutrophil or macrophage infiltration. Furthermore, we observed significant protection from microvascular rarefaction at six weeks following injury with TLR4-deletion, but this did not alter development of fibrosis. In conclusion, we validate the acute protective effect of TLR4 signal inhibition in AKI but demonstrate that this protective effect does not mitigate the sequential fibrogenic response in this model of ischemic AKI.  相似文献   
105.
Buildings feature a prominent role in electric grid loading, as they use about 75% of the total electricity generated in the United States and are main drivers of electric peak demand in the summer due to electrically driven air conditioning systems. Energy storage is a key technology that can increase energy cost savings, and add flexibility to the grid. However, cost is an important factor to consider. This study proposes a rapid approach that allows for visualization of potential cost savings by introducing energy storage as a peak load control for residential buildings in California. A combination of EnergyPlus load data generation, Matlab post-processing, and Google Fusion Tables data presentation analyses the potential cost savings when energy storage is implemented and TOU rates are applied. The study presents potential annual cost savings of $420 per home with storage capacities of 24?kWh.  相似文献   
106.

Two green nanocomposites of Co3O4 decorated CTAB/bentonite (Co@CT/BE) and chitosan/bentonite (Co@CH/BE) were synthesized as enhanced and environmental photocatalysts and antibacterial agents. As photocatalysts, the products were applied in the effective oxidation of toxic methyl parathion pesticide (MP) in wastewater under a visible light source. The application of Co@CH/BE (0.02 g) resulted in the complete oxidation of MP (50 mg/L) after 40 min and complete mineralization after 60 min. while the complete oxidation and mineralization of MP (50 mg/L) by Co@CT/BE was recognized after 75 min and 100 min, respectively. The Co@CH/BE composite is of higher activity than Co@CT/BE and can cause complete oxidation for MP at high concentrations up to 100 mg/L after 75 min. The oxidation pathway was illustrated considering the existence of the hydroxyl radicals as the active oxidizing species and the identified secondary organic compounds during the oxidation tests. The detected intermediate converted into end products of CO2 and inorganic anions of SO4?2, NO3?, and PO4?3 at the final stages of the oxidation processes. As antibacterial agents, the two composites exhibit considerable inhabitation zones of about 20 mm against both the Gram-positive Staphylococcus aureus and Gram-negative bacterium Vibrio Sp. The synthetic Co@CH/BE showed the best antibacterial properties with 200 μg/mL as minimum inhibitory against Staphylococcus aureus.

  相似文献   
107.
108.
Metallurgical and Materials Transactions A - Gas atomization is the most used powder production technique since it provides good control on particles shape, surface oxidation and dimension. It is a...  相似文献   
109.
110.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号