首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5977篇
  免费   507篇
  国内免费   197篇
工业技术   6681篇
  2024年   13篇
  2023年   93篇
  2022年   267篇
  2021年   313篇
  2020年   157篇
  2019年   154篇
  2018年   159篇
  2017年   175篇
  2016年   224篇
  2015年   267篇
  2014年   367篇
  2013年   346篇
  2012年   359篇
  2011年   409篇
  2010年   337篇
  2009年   363篇
  2008年   261篇
  2007年   316篇
  2006年   316篇
  2005年   246篇
  2004年   194篇
  2003年   194篇
  2002年   169篇
  2001年   338篇
  2000年   138篇
  1999年   87篇
  1998年   75篇
  1997年   61篇
  1996年   54篇
  1995年   37篇
  1994年   27篇
  1993年   26篇
  1992年   28篇
  1991年   16篇
  1990年   6篇
  1989年   12篇
  1988年   11篇
  1987年   8篇
  1986年   7篇
  1985年   5篇
  1984年   6篇
  1983年   8篇
  1982年   3篇
  1981年   4篇
  1980年   2篇
  1979年   4篇
  1978年   3篇
  1976年   3篇
  1975年   2篇
  1973年   3篇
排序方式: 共有6681条查询结果,搜索用时 0 毫秒
1.
Cif2000平台下的核磁共振测井解谱方法研究   总被引:3,自引:0,他引:3  
王才志  李宁 《测井技术》2002,26(5):360-363
介绍了在Cif2000多井解释平台下的核磁共振解谱方法与编程实现。解谱采用加入平滑因子后在特征矩阵的奇异值分解中截去小的非零奇异值的方法,可以在低信噪比时得到稳定的弛豫谱,在油田实际应用中证明了该方法的有效性。根据该方法在Cif2000平台上编制了完整的解谱处理程序,可以直接用于油田的生产实际。  相似文献   
2.
应用当前景流行的图形设计软件Coredraw9.0和Photoshop5.0,设计针织面料T恤花型,进一步利用SCC4F-548型电脑提花圆机相配套的图形设计软件Aupaint处理,生成提花花型图案,为夏季T恤花型图案设计提供了一条简便快捷的设计方法和新的设计思路。  相似文献   
3.
Kinetics of radiation induced segregation and precipitation in binary alloys are studied by Monte Carlo simulations. The simulations are based on a simple atomic model of diffusion under electron irradiation, which takes into account the creation of point defects, the recombination of close vacancy-interstitial pairs and the point defect annihilation at sinks. They can reproduce the coupling between point defect fluxes towards sinks and atomic fluxes, which controls the segregation tendency. In pure metals and ideal solid solutions, the Monte Carlo results are found to be in very good agreement with classical models based on rate equations. In alloys with an unmixing tendency, we show how the interaction between the point defect distribution, the solute segregation and the precipitation driving force can generate complex microstructural evolutions, which depend on the very details of atomic-scale diffusion properties.  相似文献   
4.
An experiment to remove re-deposited layers and to release hydrogen using a glow discharge in oxygen (O-GDC) has been performed in the HT-7 superconducting tokamak. In the absence of magnetic fields, the O-GDC wall conditioning had produced rapid, controlled co-deposit removal. Average removal rates, 5.2 × 1022 H-atoms/h, 5.65 × 1021 D-atoms/h and 5.53 × 1022 C-atoms/h, respectively, were obtained during 145 min O-GDC experiment in the pressure range 0.5-1.5 Pa. The corresponding removal rate of co-deposited films was ∼1.19 μm/day (26.5 g/day for carbon) based on an area of 12 m2. Compared to thermo-oxidation and O-ICR experiment, high pressure O-GDC wall conditioning promoted the oxidation and improved the C and D atoms removal. In the O-GDC experiment, the removal rates of H-atoms and D-atoms as H2O, HDO and D2O were higher than that of H2 and D2 by factors of about 20 and 50, respectively. During the 145 min O-GDC experiment, about 14.5% O-atoms were converted into carbon oxides and hydroxides, and about 5.37 × 1022 O-atoms were adsorbed on the walls corresponding to a coverage of 4.5 × 1021 O/m2 on an wall area of 12 m2. In a 100 min helium glow discharge (He-GDC) following the O-GDC experiment, 1.53 × 1022 O-atoms, about 28.5% oxygen retained on the walls, were removed. The removal rate of H-atoms in He-GDC cleaning after O-GDC experiment was lower than that in He-GDC cleaning before O-GDC experiment, which indicates that the O-GDC wall conditioning had effectively reduced hydrogen retention on the walls.  相似文献   
5.
The effect of coherency loss on the development of precipitate size distribution under cascade-producing irradiation is considered. The nucleation of coherent precipitates, their growth followed by coherency loss and cascade-induced dissolution of large incoherent precipitates can occur simultaneously resulting in formation of a quasi-stationary size distribution of semicoherent precipitates. To describe this process we consider co-evolution of a mixed population of coherent, semicoherent and incoherent precipitates. Mathematically, the problem is formulated as a set of discrete rate equations of nucleation kinetics (the Master equation approach) which is also used for later stages of evolution. To solve the corresponding large set of equations (typically, more than 105 equations) an efficient numerical method is developed. The simulation results obtained for material parameters and irradiation conditions typical for nuclear reactors show that the coherency loss affects considerably evolution of the precipitate population. Under certain irradiation conditions, both in solution-annealed alloys and in aged ones, the mean precipitate size and the number density during prolonged irradiation tend to steady state values, whereas the size distribution function of large precipitates narrows. The width of the quasi-stationary size distribution is controlled by cascade parameters. It was found that the asymptotic quasi-stationary state of the precipitate population may depend on initial state of the alloy.  相似文献   
6.
坨五站中间乳化层快速增长原因及治理方案   总被引:1,自引:0,他引:1  
胜利采油厂坨五站高含水(95%)原油化学预脱水中,二级沉降罐内油水相之间的中间乳化层增长迅速,引起了一系列问题。现场调查和大量室内测试结果表明,产生这一现象的原因有:油溶性破乳剂WD-1加入点不合理。有2/3的含水原油在通过油水分离器之后才与破乳剂混合;二级沉降罐进油口伸入油相内,油流的冲击达不到中间层;WD-1对坨五站混合原油中的稠油破乳脱水性能欠佳,不能适应坨五站混合原油组成和含水的变化。针对上述各种原因筛选出了性能更好的一种破乳剂1916。根据确定的几种原因采取了相应的措施:将破乳剂加入点改在3个并联油水分离器之前;将二级沉降罐的进油口移到水相内;改用筛选出的破乳剂1916,结果使中间乳化层的增长受到了抑制。图2表4参2。  相似文献   
7.
The thermal expansion of a titanium modified, swelling resistant austenitic stainless steel designated as D9 is studied by measuring the lattice parameter as a function of temperature in the range 300-1300 K by high-temperature X-ray diffraction technique. The thermal expansion data thus obtained is in reasonable agreement with the typical thermal expansion values reported for similar nuclear grade austenitic stainless steels. However, at temperatures exceeding 900 K, the measured thermal expansivity exhibits a pronounced non-linear increase due partly to the precipitation of complex carbide and intermetallic phases. The high-temperature thermal expansion data obtained in the present study are augmented by modelling the low-temperature thermal expansion behaviour by Grüneisen formalism.  相似文献   
8.
我国石油开采与油井管生产概述   总被引:1,自引:1,他引:0  
概略介绍了我国石油开采及其专用管材的需求情况以及油井管的生产规划和要求,对发展国内油井管特别是焊接油井管生产提出了建议。  相似文献   
9.
本文分析了T/C府绸集色条花产生的原因。通过工艺条件和操作方法,染色条花疵病得到明显改善。  相似文献   
10.
方平 《钢管》1994,(1):18-20
定量描述了实际生产过程中三辊斜轧穿孔所产生的钢管壁厚极差和波浪形内螺纹,初步探讨了三辊轧管机对钢管壁厚极差和波浪形内螺纹的影响。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号