全文获取类型
收费全文 | 24028篇 |
免费 | 2722篇 |
国内免费 | 1515篇 |
专业分类
电工技术 | 1931篇 |
技术理论 | 1篇 |
综合类 | 1736篇 |
化学工业 | 3636篇 |
金属工艺 | 1468篇 |
机械仪表 | 1609篇 |
建筑科学 | 1832篇 |
矿业工程 | 795篇 |
能源动力 | 760篇 |
轻工业 | 1502篇 |
水利工程 | 690篇 |
石油天然气 | 1071篇 |
武器工业 | 195篇 |
无线电 | 2860篇 |
一般工业技术 | 2796篇 |
冶金工业 | 1102篇 |
原子能技术 | 456篇 |
自动化技术 | 3825篇 |
出版年
2024年 | 127篇 |
2023年 | 402篇 |
2022年 | 764篇 |
2021年 | 1131篇 |
2020年 | 811篇 |
2019年 | 751篇 |
2018年 | 722篇 |
2017年 | 852篇 |
2016年 | 817篇 |
2015年 | 998篇 |
2014年 | 1324篇 |
2013年 | 1438篇 |
2012年 | 1589篇 |
2011年 | 1797篇 |
2010年 | 1598篇 |
2009年 | 1529篇 |
2008年 | 1408篇 |
2007年 | 1360篇 |
2006年 | 1366篇 |
2005年 | 1027篇 |
2004年 | 876篇 |
2003年 | 876篇 |
2002年 | 1028篇 |
2001年 | 792篇 |
2000年 | 583篇 |
1999年 | 522篇 |
1998年 | 348篇 |
1997年 | 266篇 |
1996年 | 215篇 |
1995年 | 166篇 |
1994年 | 154篇 |
1993年 | 121篇 |
1992年 | 104篇 |
1991年 | 92篇 |
1990年 | 81篇 |
1989年 | 55篇 |
1988年 | 51篇 |
1987年 | 20篇 |
1986年 | 20篇 |
1985年 | 14篇 |
1984年 | 12篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1959年 | 7篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
论化工企业建筑的的防爆设计 总被引:1,自引:0,他引:1
对于防爆设计问题要特别重视,认真,具体设计中,除了必须遵照现行颁布的国家规范,法规及有关规定外,同时也要注意新型的建筑材料在建筑设计中的运用,使之不断发展,不断地研究和创新,臻于完善,使我们的设计工作创造出更多的化工建筑设计作品. 相似文献
3.
4.
5.
Chen Guodong 《International Journal of Pressure Vessels and Piping》1985,19(1):19-30
In this paper, according to the theory of thin shells, a basic equation in complex form is derived for conical thin shells with linearly varying wall thickness under symmetric loads, and the uniformly valid asymptotic solutions are given. 相似文献
6.
In this study, distribution and history of residual stresses in plaque-like geometries are simulated based on linear thermoviscoelastic
model, which helps to understand the mechanics and evolution of the residual stresses in the injection molding process. The
numerical calculation of direction, combined with the specified boundary conditions. Results show that the stress variation
across the thickness exhibits a high surface tensile value changing to a compressive peak value close to the surface, with
the core region experiencing a parabolic tensile peak. Residual stress distribution throughout the thickness is almost same
along the flowpath and the final residual stresses value near the gate is lower than the value near the end of flowpath. 相似文献
7.
The molecular mechanisms underlying the clustering and localization of K+ channels in specific microdomains on the neuronal surface are largely unknown. The Shaker subclass of voltage-gated K+ channel alpha-subunits interact through their cytoplasmic C-terminus with a family of membrane-associated putative guanylate kinases, including PSD-95 and SAP97. We show here that heterologous coexpression of either sap97 or PSD-95 with various Shaker-type subunits results in the coclustering of these proteins with the K+ channels. Mutation of the C-terminal sequence (-ETDV) of the Shaker subunit Kv1.4 abolishes its binding to, and prevents its clustering with, SAP97 and PSD-95. Whereas PSD-95 induces plaque-like clusters of K+ channels at the cell surface; however, SAP97 coexpression results in the formation of large round intracellular aggregates into which both SAP97 and the K+ channel proteins are colocalized. The efficiency of surface clustering by PSD-95 varies with different Shaker subunits: striking Kv1.4 clustering occurs in > 60% of cotransfected cells, whereas Kv1.1 and Kv1.2 form convincing clusters with PSD-95 only in approximately 10% of cells. 相似文献
8.
In this paper, according to the theory of thin shells, the uniformly valid asymptotic homogeneous solution and the exact particular solution are derived for spherical thin shell segments with a circular hole under transverse load and moment . 相似文献
9.
重大技术装备的制造水平是一个国家综合实力的直接体现,因此从上个世纪八十年代初开始,历届国务院领导人均兼任国家重大技术装备领导小组组长,通过推进重大技术装备的发展,促进 相似文献
10.
Designing circuits with partial scan 总被引:1,自引:0,他引:1
Agrawal V.D. Kwang-Ting Cheng Johnson D.D. Sheng Lin T. 《Design & Test of Computers, IEEE》1988,5(2):8-15
In this scan design methodology, only selected faults are targeted for detection. These faults are those not detected by the designer's functional vectors. The test generator decides exactly which flip-flops should be scanned using one of two methods. In the first method, all possible tests are generated for each target fault, and the set of tests requiring the fewest flip-flops is selected. In the second method, only one test is generated for each fault, and the use of flip-flops is avoided as much as possible during test generation. Examples of actual VLSI circuits show a savings of at least a 40% in full-scan overhead 相似文献