全文获取类型
收费全文 | 3791篇 |
免费 | 408篇 |
国内免费 | 161篇 |
专业分类
电工技术 | 390篇 |
综合类 | 269篇 |
化学工业 | 585篇 |
金属工艺 | 270篇 |
机械仪表 | 207篇 |
建筑科学 | 220篇 |
矿业工程 | 113篇 |
能源动力 | 151篇 |
轻工业 | 211篇 |
水利工程 | 65篇 |
石油天然气 | 125篇 |
武器工业 | 17篇 |
无线电 | 408篇 |
一般工业技术 | 495篇 |
冶金工业 | 301篇 |
原子能技术 | 53篇 |
自动化技术 | 480篇 |
出版年
2024年 | 8篇 |
2023年 | 65篇 |
2022年 | 100篇 |
2021年 | 181篇 |
2020年 | 149篇 |
2019年 | 115篇 |
2018年 | 133篇 |
2017年 | 126篇 |
2016年 | 122篇 |
2015年 | 155篇 |
2014年 | 189篇 |
2013年 | 211篇 |
2012年 | 249篇 |
2011年 | 298篇 |
2010年 | 196篇 |
2009年 | 201篇 |
2008年 | 200篇 |
2007年 | 162篇 |
2006年 | 164篇 |
2005年 | 118篇 |
2004年 | 114篇 |
2003年 | 132篇 |
2002年 | 167篇 |
2001年 | 147篇 |
2000年 | 84篇 |
1999年 | 73篇 |
1998年 | 78篇 |
1997年 | 47篇 |
1996年 | 68篇 |
1995年 | 55篇 |
1994年 | 46篇 |
1993年 | 20篇 |
1992年 | 25篇 |
1991年 | 12篇 |
1990年 | 22篇 |
1989年 | 19篇 |
1988年 | 7篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1980年 | 4篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1971年 | 5篇 |
1962年 | 4篇 |
排序方式: 共有4360条查询结果,搜索用时 15 毫秒
1.
Marco Bocchetti Maria Grazia Ferraro Filippo Ricciardiello Alessandro Ottaiano Amalia Luce Alessia Maria Cossu Marianna Scrima Wing-Yan Leung Marianna Abate Paola Stiuso Michele Caraglia Silvia Zappavigna Tung On Yau 《International journal of molecular sciences》2021,22(8)
Colorectal cancer (CRC) is the third most deadly cancer worldwide, and inflammatory bowel disease (IBD) is one of the critical factors in CRC carcinogenesis. IBD is responsible for an unphysiological and sustained chronic inflammation environment favoring the transformation. MicroRNAs (miRNAs) belong to a class of highly conserved short single-stranded segments (18–25 nucleotides) non-coding RNA and have been extensively discussed in both CRC and IBD. However, the role of miRNAs in the development of colitis-associated CRC (CAC) is less clear. The aim of this review is to summarize the major upregulated (miR-18a, miR-19a, miR-21, miR-31, miR-155 and miR-214) and downregulated (miR-124, miR-193a-3p and miR-139-5p) miRNAs in CAC, and their roles in genes’ expression modulation in chronic colonic-inflammation-induced carcinogenesis, including programmed cell-death pathways. These miRNAs dysregulation could be applied for early CAC diagnosis, to predict therapy efficacy and for precision treatment. 相似文献
2.
济阳坳陷下古生界潜山油气藏特征及成藏模式 总被引:1,自引:1,他引:0
济阳坳陷下古生界潜山具有多样性、复杂性的特点,潜山差异性的形成演化、油气成藏主控因素和控藏模式不明确,严重制约了该区潜山油气勘探。在潜山分类的基础上,综合利用系统恢复、分类对比和典型解剖等方法,揭示了济阳坳陷下古生界不同类型潜山的形成演化过程和油气成藏主控因素差异性,分类建立了油气成藏模式。研究表明,济阳坳陷下古生界主要发育高位新盖侵蚀残丘潜山、中位古盖拉张断块潜山、中位新古盖拉张剪切断块潜山、中位中古盖挤压拉张断块潜山和低位古盖拉张滑脱断块潜山5种潜山类型。不同类型潜山的形成演化和油气成藏各具特色,其中,高位新盖侵蚀残丘潜山的发育受隆升、侵蚀作用控制,油气成藏主要受控于油源和盖层条件,表现为"单向供烃、砂体-不整合岩溶体联合输导、残丘控藏"的成藏模式;中位古盖拉张断块潜山的发育受掀斜、断裂作用控制,油气成藏主要受控于储集条件,表现为"单向供烃、顺向断层输导、反向断层控藏"的成藏模式;中位新古盖拉张剪切断块潜山的发育受反转、翘倾和走滑切割作用控制,油气成藏主要受控于输导条件,表现为"多源供烃、断溶体立体输导、断裂控藏"的成藏模式;中位中古盖挤压拉张断块潜山的形成受强烈挤压、拉张滑脱作用控制,油气成藏主要受控于储集条件,表现为"多源供烃、断缝体输导、断褶控藏"的成藏模式;低位古盖拉张滑脱断块潜山的形成受强烈拉张滑脱作用控制,油气成藏主要受控于输导条件,表现为"顶部供烃、断缝体输导、断裂控藏"的成藏模式。 相似文献
3.
4.
针对高速率通信网络和Round-Robin(RR)协议影响下网络化时变系统的有限时域[H∞]控制问题,考虑到系统中存在乘性噪声、随机时滞和量化效应,提出了一种基于观测器的有限时域[H∞]控制器的设计方法。利用李雅普诺夫稳定性理论和线性矩阵不等式(Linear Matrix Inequality,LMI)技术得到有限时域[H∞]控制器存在的充分条件。基于锥补线性化(Cone Complementarity Linearization,CCL)方法通过求解一组递归矩阵不等式得到观测器和控制器参数。所设计的控制器保证闭环网络化时变系统在给定的时域内稳定,且满足预定的[H∞]性能指标。数值仿真验证了所提方法的有效性。 相似文献
6.
7.
Shuan-yang Zhang Zhi-guo Qu Hong-tao Xu Fariborz-Karimi Talkhoncheh Shun Liu Qiang Gao 《International Journal of Hydrogen Energy》2021,46(54):27700-27708
The gas flow field design has a significant influence on the overall performance of a proton exchange membrane fuel cell (PEMFC). A single-channel PEMFC with wedge-shaped fins in the cathode channel was proposed, and the effects of fin parameters such as volume (0.5 mm3, 1.0 mm3, and 1.5 mm3), number (3, 5, and 9), and porosity of the gas diffusion layer (GDL) (0.2, 0.4, 0.6, and 0.8) on the performance of PEMFC were numerically examined based on the growth rate of power density (GRPD) and polarization curve. It was shown that wedge-shaped fins could effectively improve the PEMFC performance. With an increase in fin volume, the distributions of oxygen mass fraction in the outlet area of the cathode channel were lower, the drainage effect of the PEMFC improved, and GRPD also increased accordingly. Similar results were obtained as the number of fins increased. The GDL porosity had a greater effect than the wedge-shaped fins on the improvement in PEMFC performance, but the influence of GDL porosity weakened and the GRPD of porosity decreased as the porosity increased. This study provides an effective guideline for the optimization of the cathode channel in a PEMFC. 相似文献
8.
锤击法在熔丝积材残余应力消除中具有非常重要的研究价值和学术意义。近年来该方法日趋完善,现已成为消除熔丝积材残余应力的重要方法之一。本文概括综述了消除残余应力的方法,并着重分析了锤击法消除残余应力的国内外研究现状和最新进展。希望能给相关工作者提供参考。 相似文献
9.
In situ electrokinetic remediation of toxic metal‐contaminated soil driven by solid phase microbial fuel cells with a wheat straw addition 下载免费PDF全文
10.
Simonas Ramanavičius Carla Bittencourt Arnas Naujokaitis Vidas Pakštas Arunas Jagminas 《International Journal of Hydrogen Energy》2021,46(27):14359-14368
Due to low hydrogen adsorption free energy at the edges of 2D-MoS2 layered sheets, nanostructured MoS2 materials recently are assigned to prospective electrocatalysts for hydrogen evolution reaction (HER) from water. However, the efficiency and stability of HER onto the MoS2 designed on the conductive substrates are poor. To significantly increase the number of active sites and achieve a long-time working stability, the design of hybrid-type electrodes is crucial. Here, we report the synthesis of a new hybrid material composed of molybdenum disulfide and molybdenum oxides heterostructured with strontium molybdate. For this, a facile one-pot hydrothermal process was developed directly onto the TiO2 nanotube carpet substrate. The interfacing of strontium molybdate at the electrode substrate verified by X-ray photoelectron spectroscopy and Time of flight secondary ions mass spectrometry (ToF SIMS) techniques. Considerable higher catalytic activity at the surface of this hybrid film, with the onset potential of 190 mV vs RHE and a Tafel slope of 66 mV dec?1 attaining ~80 mA cm?2 at 0.35 V overvoltage was ascertained. Exciting HER stability in comparison with the pure synthetic MoS2 was verified by a prolonged potential cycling from 0.05 to ?0.35 V versus RHE potential and 45 h continuous HER processing at a constant current density. 相似文献