全文获取类型
收费全文 | 37958篇 |
免费 | 3490篇 |
国内免费 | 1833篇 |
专业分类
电工技术 | 2736篇 |
综合类 | 2675篇 |
化学工业 | 8830篇 |
金属工艺 | 6728篇 |
机械仪表 | 1647篇 |
建筑科学 | 4031篇 |
矿业工程 | 1093篇 |
能源动力 | 1251篇 |
轻工业 | 2482篇 |
水利工程 | 810篇 |
石油天然气 | 1226篇 |
武器工业 | 285篇 |
无线电 | 2096篇 |
一般工业技术 | 4559篇 |
冶金工业 | 1817篇 |
原子能技术 | 247篇 |
自动化技术 | 768篇 |
出版年
2024年 | 214篇 |
2023年 | 768篇 |
2022年 | 1508篇 |
2021年 | 1671篇 |
2020年 | 1484篇 |
2019年 | 1161篇 |
2018年 | 1101篇 |
2017年 | 1515篇 |
2016年 | 1422篇 |
2015年 | 1443篇 |
2014年 | 2005篇 |
2013年 | 2107篇 |
2012年 | 2541篇 |
2011年 | 2814篇 |
2010年 | 1939篇 |
2009年 | 2248篇 |
2008年 | 1828篇 |
2007年 | 2196篇 |
2006年 | 2184篇 |
2005年 | 1806篇 |
2004年 | 1497篇 |
2003年 | 1298篇 |
2002年 | 1068篇 |
2001年 | 931篇 |
2000年 | 772篇 |
1999年 | 710篇 |
1998年 | 570篇 |
1997年 | 490篇 |
1996年 | 367篇 |
1995年 | 366篇 |
1994年 | 304篇 |
1993年 | 207篇 |
1992年 | 169篇 |
1991年 | 144篇 |
1990年 | 99篇 |
1989年 | 89篇 |
1988年 | 58篇 |
1987年 | 43篇 |
1986年 | 25篇 |
1985年 | 14篇 |
1984年 | 16篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 6篇 |
1980年 | 13篇 |
1979年 | 5篇 |
1961年 | 2篇 |
1960年 | 3篇 |
1959年 | 6篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
单片机控制的托辊阻力参数及加载测试仪硬软件系统研发 总被引:1,自引:1,他引:0
论述了托辊阻力参数硬件测试系统的组成及工作过程,进行了系统硬件的电气原理电路的设计和测试软件系统及数据处理应用程序的设计。 相似文献
104.
316L不锈钢焊缝的点蚀行为 总被引:1,自引:0,他引:1
采用数显恒温水浴锅HH-4静态模拟点腐蚀的试验方法,研究316L奥氏体不锈钢焊缝在不同Cl^-浓度和温度下的三氯化铁溶液中点腐蚀行为,探讨不同的Cl^-浓度和温度变化对焊缝耐蚀性能的影响。结果表明:在三氯化铁溶液中,Cl^-浓度增加、温度升高,316L奥氏体不锈钢焊缝的耐点蚀性能下降,腐蚀速率增加,腐蚀后的表面形貌为不均匀点腐蚀。 相似文献
105.
106.
107.
Low energy arc discharge characteristics was analyzed based on dynamic V-A characteristics model. It draws conclusions that discharge time relates to the source voltage and the product of inductance and stable current, discharge time will increase when the source voltage increases; current reduce rate is in inverse proportion to the value of inductance; arc resistance when the arc occurs is the ratio of minimum arcing voltage to stable current. It also gains the expressions of arc resistance and arc power, arc resistance and arc power both increase as the source voltage increases and decrease as the value of inductance increases. Conclusions above mentioned are helpful to design intrinsically safe circuits. 相似文献
108.
Wei Meng Yanli Li Binshu Chai Xiaomin Liu Zhongliang Ma 《International journal of molecular sciences》2022,23(15)
Lung cancer is the leading cause of cancer death worldwide. miR-199a, which has two mature molecules: miR-199a-3p and miR-199a-5p, plays an important biological role in the genesis and development of tumors. We collected recent research results on lung cancer and miR-199a from Google Scholar and PubMed databases. The biological functions of miR-199a in lung cancer are reviewed in detail, and its potential roles in lung cancer diagnosis and treatment are discussed. With miR-199a as the core point and a divergence outward, the interplay between miR-199a and other ncRNAs is reviewed, and a regulatory network covering various cancers is depicted, which can help us to better understand the mechanism of cancer occurrence and provide a means for developing novel therapeutic strategies. In addition, the current methods of diagnosis and treatment of lung cancer are reviewed. Finally, a conclusion was drawn: miR-199a inhibits the development of lung cancer, especially by inhibiting the proliferation, infiltration, and migration of lung cancer cells, inhibiting tumor angiogenesis, increasing the apoptosis of lung cancer cells, and affecting the drug resistance of lung cancer cells. This review aims to provide new insights into lung cancer therapy and prevention. 相似文献
109.
110.
Ilaria Saltarella Concetta Altamura Aurelia Lamanuzzi Benedetta Apollonio Angelo Vacca Maria Antonia Frassanito Jean-Franois Desaphy 《International journal of molecular sciences》2022,23(13)
Ion channels are pore-forming proteins that allow ions to flow across plasma membranes and intracellular organelles in both excitable and non-excitable cells. They are involved in the regulation of several biological processes (i.e., proliferation, cell volume and shape, differentiation, migration, and apoptosis). Recently, the aberrant expression of ion channels has emerged as an important step of malignant transformation, tumor progression, and drug resistance, leading to the idea of “onco-channelopathy”. Here, we review the contribution of ion channels and transporters in multiple myeloma (MM), a hematological neoplasia characterized by the expansion of tumor plasma cells (MM cells) in the bone marrow (BM). Deregulation of ion channels sustains MM progression by modulating intracellular pathways that promote MM cells’ survival, proliferation, and drug resistance. Finally, we focus on the promising role of ion channels as therapeutic targets for the treatment of MM patients in a combination strategy with currently used anti-MM drugs to improve their cytotoxic activity and reduce adverse effects. 相似文献