全文获取类型
收费全文 | 88894篇 |
免费 | 9008篇 |
国内免费 | 5428篇 |
专业分类
电工技术 | 6326篇 |
技术理论 | 7篇 |
综合类 | 7280篇 |
化学工业 | 13032篇 |
金属工艺 | 5602篇 |
机械仪表 | 6156篇 |
建筑科学 | 6291篇 |
矿业工程 | 3270篇 |
能源动力 | 2673篇 |
轻工业 | 7904篇 |
水利工程 | 2120篇 |
石油天然气 | 4610篇 |
武器工业 | 1215篇 |
无线电 | 9850篇 |
一般工业技术 | 9605篇 |
冶金工业 | 3968篇 |
原子能技术 | 1506篇 |
自动化技术 | 11915篇 |
出版年
2024年 | 544篇 |
2023年 | 1657篇 |
2022年 | 3143篇 |
2021年 | 4118篇 |
2020年 | 3103篇 |
2019年 | 2358篇 |
2018年 | 2595篇 |
2017年 | 2958篇 |
2016年 | 2680篇 |
2015年 | 3851篇 |
2014年 | 4883篇 |
2013年 | 5786篇 |
2012年 | 6667篇 |
2011年 | 6898篇 |
2010年 | 6170篇 |
2009年 | 5883篇 |
2008年 | 5948篇 |
2007年 | 5869篇 |
2006年 | 5365篇 |
2005年 | 4314篇 |
2004年 | 3121篇 |
2003年 | 2353篇 |
2002年 | 2273篇 |
2001年 | 2075篇 |
2000年 | 1830篇 |
1999年 | 1420篇 |
1998年 | 1030篇 |
1997年 | 852篇 |
1996年 | 791篇 |
1995年 | 611篇 |
1994年 | 513篇 |
1993年 | 351篇 |
1992年 | 295篇 |
1991年 | 214篇 |
1990年 | 182篇 |
1989年 | 155篇 |
1988年 | 119篇 |
1987年 | 66篇 |
1986年 | 73篇 |
1985年 | 40篇 |
1984年 | 29篇 |
1983年 | 30篇 |
1982年 | 30篇 |
1981年 | 19篇 |
1980年 | 24篇 |
1979年 | 9篇 |
1976年 | 6篇 |
1973年 | 3篇 |
1959年 | 5篇 |
1951年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
设备前期翻料钩摆臂角度设计错误,导致该处液压缸事故频繁,经改造后,将过渡篦条和中间过渡装置拆除。整体标高再次进行定位,实现穿孔出来的毛管直接过渡到轧机入口,无需中间翻料钩装置,以保证设备的正常运转和生产连续性。 相似文献
3.
In vivo Kinetic Biodistribution of Nano‐Sized Outer Membrane Vesicles Derived from Bacteria 下载免费PDF全文
Su Chul Jang Sae Rom Kim Yae Jin Yoon Kyong‐Su Park Ji Hyun Kim Jaewook Lee Oh Youn Kim Eun‐Jeong Choi Dae‐Kyum Kim Dong‐Sic Choi Yoon‐Keun Kim Jaesung Park Dolores Di Vizio Yong Song Gho 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(4):456-461
Evaluation of kinetic distribution and behaviors of nanoparticles in vivo provides crucial clues into their roles in living organisms. Extracellular vesicles are evolutionary conserved nanoparticles, known to play important biological functions in intercellular, inter‐species, and inter‐kingdom communication. In this study, the first kinetic analysis of the biodistribution of outer membrane vesicles (OMVs)—bacterial extracellular vesicles—with immune‐modulatory functions is performed. OMVs, injected intraperitoneally, spread to the whole mouse body and accumulate in the liver, lung, spleen, and kidney within 3 h of administration. As an early systemic inflammation response, increased levels of TNF‐α and IL‐6 are observed in serum and bronchoalveolar lavage fluid. In addition, the number of leukocytes and platelets in the blood is decreased. OMVs and cytokine concentrations, as well as body temperature are gradually decreased 6 h after OMV injection, in concomitance with the formation of eye exudates, and of an increase in ICAM‐1 levels in the lung. Following OMV elimination, most of the inflammatory signs are reverted, 12 h post‐injection. However, leukocytes in bronchoalveolar lavage fluid are increased as a late reaction. Taken together, these results suggest that OMVs are effective mediators of long distance communication in vivo. 相似文献
4.
在国标法GB 7494—1987的基础上,将在线萃取、在线分离技术与分光光度法相结合,研究了自动测定水中阴离子表面活性剂的新方法,使国标法中的各个操作步骤完全实现自动化。结果表明,新的自动测定法在0.034~2.00 mg/L浓度范围内,线性相关系数为0.999 9,检出限为0.008 6 mg/L,相对标准偏差3.8%(n=6),实际样品加标回收率为88.3%~100.0%。测定全过程相对密闭,人体不接触三氯甲烷,保护了分析人员的自身安全,方法操作简便,测定时间也较短,单个样品测定时间7 min。 相似文献
5.
Multimedia Tools and Applications - In Wyner-Ziv (WZ) video coding, decoder side information (SI) takes a key role in a WZ video codec among other building blocks. In this paper, we review the... 相似文献
6.
7.
The effect of biochar substituted for anthracite as reductant on magnetizing-roasting pyrite cinder was investigated.The key of magnetizing-roasting is the gasification reaction between reductants and CO2.Since biochar could react with CO2 more rapidly at lower temperature,the reactivity of biochar is better than that of anthracite.The gasification of biochar could produce reducing condition ofφCO/(φCO+φCO2)about 10%-20% between 700-800 ℃,which is in accord with the atmosphere and temperature of Fe2O3 reduction.So it is beneficial to the reduction of iron mineral of pyrite cinder.Compared with anthracite,biochar could decrease the roasting temperature from825 to 750 ℃ and roasting time from 20 to 15min,which shows that a better effect of magnetization could be obtained in the condition of lower temperature and shorter time.Using biochar as reductant,iron concentrate extracted from pyrite cinder as about 64%iron grade could be produced,and the recovery is over 90% under the condition of above 90% grinding particle less than 0.045 mm and magnetic intensity of 0.124-0.194 T. 相似文献
8.
9.
Ye Wan Jun Tan Guangling Song Chuanwei Yan 《Metallurgical and Materials Transactions A》2006,37(7):2313-2316
The focused ion beam technique was employed to investigate the atmospheric corrosion morphology of AZ91D. It was found that
the α matrix of the alloy was preferentially corroded in the areas adjacent to intermetallic phases. The most interesting
finding was that the corrosion products in corrosion cavities were pelletlike, which has never been reported before. 相似文献
10.