全文获取类型
收费全文 | 20482篇 |
免费 | 2406篇 |
国内免费 | 1019篇 |
学科分类
工业技术 | 23907篇 |
出版年
2024年 | 115篇 |
2023年 | 346篇 |
2022年 | 526篇 |
2021年 | 634篇 |
2020年 | 759篇 |
2019年 | 651篇 |
2018年 | 669篇 |
2017年 | 852篇 |
2016年 | 904篇 |
2015年 | 915篇 |
2014年 | 1237篇 |
2013年 | 1267篇 |
2012年 | 1676篇 |
2011年 | 1806篇 |
2010年 | 1320篇 |
2009年 | 1228篇 |
2008年 | 1162篇 |
2007年 | 1375篇 |
2006年 | 1303篇 |
2005年 | 997篇 |
2004年 | 705篇 |
2003年 | 648篇 |
2002年 | 517篇 |
2001年 | 412篇 |
2000年 | 328篇 |
1999年 | 274篇 |
1998年 | 267篇 |
1997年 | 183篇 |
1996年 | 189篇 |
1995年 | 136篇 |
1994年 | 118篇 |
1993年 | 73篇 |
1992年 | 58篇 |
1991年 | 38篇 |
1990年 | 39篇 |
1989年 | 32篇 |
1988年 | 26篇 |
1987年 | 18篇 |
1986年 | 15篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 8篇 |
1982年 | 19篇 |
1981年 | 7篇 |
1980年 | 16篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1959年 | 2篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
预处理工艺对硬质合金与金刚石膜间粘结力的影响 总被引:1,自引:0,他引:1
在两种经不同预处理的硬质合金YG8基底上,采用微波等离子体化学气相沉积法,在微波功率2kW,压强4.0kPa和6.5kPa,CH4和H2流量分别为1.6cm/s和100.0cm/s的条件下生长金刚石薄膜。利用X射线衍射检测了金刚石薄膜是否存在,用拉曼光谱分析了薄膜的质量,用金相显微镜观察了薄膜的洛氏硬度压痕,标定并比较了不同预处理工艺膜与基底的结合力。实验结果表明,不同的预处理方法对于粘结力的影响不大,最主要的因素是钴含量的多少。 相似文献
6.
采用自行开发研制的超音速电弧喷设备,在45钢表面制成了钛铝合金复合涂层。并利用金相显微镜、X射线衍射仪、扫描电镜、电子探针,对涂层的成分、相结构、显微组织及其结合强度、显微硬度进行了研究。结果表明,利用超音速电弧喷涂设备,可以在45钢表面形成 度高、孔隙率低,结合强度较好和硬度高的Ti-Al合金涂层。 相似文献
7.
The aim of this study was to investigate the drug‐loading effects on release and mechanical properties of a scleroglucan gel, with the intention of considering them in delivery systems formulations. The rheological and kinetic properties of a 2 % w/w scleroglucan gel matrix loaded with 0, 0.02, 0.04, 0.06, 0.2 and 0.4 % w/w of theophylline (Th, used as a model drug) were investigated. Rheological measurements were performed in a controlled‐stress rotational‐shear rheometer under isothermal conditions. For theophylline release from the gel a flat Franz cell was used and the kinetic parameters were derived applying a semi‐empirical power law. The influence of scleroglucan molar weight on kinetic and rheological behaviour was also studied. Results suggest two possible effects of drug loading on the gel network: in the 0.04–0.06 % w/w Th range a plasticizing effect and in the 0.2–0.4 % w/w Th range a rigidization effect. In the first range mentioned, the changes in the gel structural properties tested by means of rheological measurements are coincident with changes in drug‐release kinetics. Copyright © 2005 Society of Chemical Industry 相似文献
8.
Reinforced concrete slabs are among the most common structural elements. In spite of the large number of slabs designed and built, the effect of their details on their behavior under impact loads are not always appreciated or properly taken into account. This experimental study was aimed at understanding the dynamic behavior of structural concrete slabs under impact loading to improve the state of the art of protective design. This study investigated the effects of different types of slab reinforcements and the applied impact loads on the dynamic response and behavior of reinforced concrete slabs. 相似文献
9.
The present study is an investigation on the behaviors of concrete-filled thin-walled steel tubular members subjected to combined loading, such as compression and torsion, bending and torsion, compression, bending and torsion. ABAQUS software is used in this paper for the finite element analysis (FEA). A comparison of results calculated using this modeling shows generally good agreement with test results. The FEA modeling is then used to investigate the influence of important parameters that determine the ultimate strength of the composite members under combined loading, such as compression and torsion, bending and torsion, compression, bending and torsion. The parametric studies provide information for the development of formulae for calculating the ultimate strength of the composite members subjected to combined loading. 相似文献
10.
We analyze specific features of the design of equipment used for mechanical testing of sheet structural materials under the conditions of biaxial static, cyclic, or dynamic loading. We propose original solutions of the problems related to the fatigue testing of crosslike specimens performed without using complex hydraulic systems and their dynamic testing carried out by using very simple testing machines for uniaxial tension–compression. 相似文献