首页 | 本学科首页   官方微博 | 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   380篇
  免费   14篇
电工技术   10篇
综合类   1篇
化学工业   69篇
金属工艺   6篇
机械仪表   7篇
建筑科学   12篇
能源动力   8篇
轻工业   14篇
无线电   70篇
一般工业技术   86篇
冶金工业   56篇
原子能技术   2篇
自动化技术   53篇
  2024年   3篇
  2023年   7篇
  2022年   12篇
  2021年   15篇
  2020年   14篇
  2019年   12篇
  2018年   17篇
  2017年   11篇
  2016年   12篇
  2015年   10篇
  2014年   9篇
  2013年   16篇
  2012年   7篇
  2011年   17篇
  2010年   10篇
  2009年   18篇
  2008年   11篇
  2007年   10篇
  2006年   13篇
  2005年   11篇
  2004年   5篇
  2003年   5篇
  2002年   3篇
  2001年   8篇
  2000年   6篇
  1999年   9篇
  1998年   13篇
  1997年   13篇
  1996年   12篇
  1995年   11篇
  1994年   6篇
  1993年   4篇
  1992年   9篇
  1991年   5篇
  1990年   8篇
  1989年   6篇
  1988年   7篇
  1987年   1篇
  1986年   1篇
  1983年   4篇
  1982年   1篇
  1980年   2篇
  1979年   7篇
  1978年   2篇
  1976年   4篇
  1975年   1篇
  1973年   1篇
  1970年   3篇
  1968年   2篇
排序方式: 共有394条查询结果,搜索用时 15 毫秒
101.
PERCE's GRIPES (Purdue Engineering Research Center's Grip Evaluation System) is an offline robot grasp planner for three-fingered grippers. The planner is based on a generate and test paradigm. Candidate triples of faces (or grasp configurations) are generated using heuristics. The precise coordinates of grip points are selected for each configuration by numerical solution of optimization problems. The constraints imposed by stability considerations are built into the optimization formulations. The accessibility of each candidate grasp is checked based on swept volume computation. Other criteria are used to rank the feasible grasps. This paper describes the modular design and the implementation of PERCE's GRIPES.  相似文献   
102.
The bactericidal actions of ofloxacin and sulbactam-ampicillin, alone and in combination with rifampin and isoniazid, on exponential-phase and stationary-phase cultures of a drug-susceptible isolate of Mycobacterium tuberculosis were studied in vitro. In exponential-phase cultures, all drugs were bactericidal, with the higher concentrations of ofloxacin (5 micrograms/ml) and sulbactam-ampicillin (15 micrograms of ampicillin per ml) being as bactericidal as 1 microgram of isoniazid per ml or 1 microgram of rifampin per ml. In two-drug combinations, both drugs increased the levels of activity of isoniazid and rifampin and were almost as bactericidal as isoniazid-rifampin; they also appeared to increase the level of activity of isoniazid-rifampin in three-drug combinations. In contrast, ofloxacin and sulbactam-ampicillin had little bactericidal activity against stationary-phase cultures and were less active than isoniazid or rifampin alone. Furthermore, in two-drug or three-drug combinations, they did not increase the level of activity of isoniazid, rifampin, or isoniazid-rifampin. These findings suggest that ofloxacin and sulbactam-ampicillin are likely to be most useful in the early stages of treatment and in preventing the emergence of resistance to other drugs but are unlikely to be effective as sterilizing drugs helping to kill persisting lesional bacilli.  相似文献   
103.
104.
105.
Several polyamideimides have been synthesised by the interaction of a number of aromatic diamines with an imidedicarboxylic acid. Since these polymers incorporated a preformed imide group, they did not pose the common problems encountered in imidisation of polyamic acids. They were synthesised by low temperature (<5°C) polycondensation, in 75–92% yields and had viscosities in the range 0.18–0.39 dl/g. They were characterised by IR spectra, elemental analysis, X-ray and thermal methods, and possessed very high solubility in polar aprotic solvents.  相似文献   
106.
International Journal of Information Security - The increasing use of smart metering infrastructure invites security threats through trusted insiders in spite of the devices’ authentication...  相似文献   
107.
The Journal of Supercomputing - Mobile users frequently change their location and often desire to avail of location-based services (LBS). LBS server provides services to users at the service...  相似文献   
108.
Corrosion behavior of mild steel plain bar embedded in concrete with 28 days compressive strength of 40 N/mm2 exposed to natural marine environment at a location in the Gulf of Mannar was studied. This paper reports the results of 1-year study conducted on the reinforced concrete specimens exposed to three different levels. The performance of three different types of corrosion protection by specialty coatings to rebars, namely cement polymer composite, interpenetrating polymer network coating and epoxy coating was also evaluated periodically by measuring open circuit potential measurements and the results are discussed. Biofouling was predominant on completion of 3 months immersion.  相似文献   
109.
Acetoxy butyl esters prepared from estolides (derived from castor oil fatty acids) were evaluated as plasticizers for poly (vinyl chloride) (PVC) resin. They showed limited compatibility. They were useful as secondary plasticizers for PVC along with dioctyl phthalate plasticizer. The properties of the plasticized stocks were generally comparable to the ones obtained by incorporating 12-acetoxy butyl oleate, the commercial secondary plasticizer. Among the estolides derivatives tried, the acetoxy butyl ester obtained from estolides of acid value 83 showed better performance. 1For parts I and II in the series ,see Refference 3 and 4  相似文献   
110.
The wave propagation in a generalized thermoelastic solid cylinder of arbitrary cross-section immersed in a fluid is discussed in this paper. The solid medium is assumed to be linear, isotropic, temperature rate-dependent thermoelastic and the fluid medium is assumed to be inviscid. By imposing the continuity conditions on the interface between solid and fluid mediums, the frequency equation corresponding to the problem is obtained using the Fourier expansion collocation method. To compare the model with the existing literature, the results of a generalized thermoelastic solid cylinder without fluid are obtained and they show very good agreement. Also graphs and tables for various values of the material parameters are furnished.  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