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   544篇
  免费   24篇
电工技术   6篇
化学工业   156篇
金属工艺   7篇
机械仪表   6篇
建筑科学   18篇
矿业工程   3篇
能源动力   14篇
轻工业   92篇
水利工程   6篇
石油天然气   7篇
无线电   38篇
一般工业技术   73篇
冶金工业   91篇
原子能技术   3篇
自动化技术   48篇
  2024年   1篇
  2023年   1篇
  2022年   8篇
  2021年   19篇
  2020年   12篇
  2019年   20篇
  2018年   14篇
  2017年   12篇
  2016年   16篇
  2015年   12篇
  2014年   27篇
  2013年   33篇
  2012年   32篇
  2011年   36篇
  2010年   23篇
  2009年   28篇
  2008年   22篇
  2007年   26篇
  2006年   17篇
  2005年   11篇
  2004年   17篇
  2003年   16篇
  2002年   12篇
  2001年   10篇
  2000年   5篇
  1999年   6篇
  1998年   41篇
  1997年   16篇
  1996年   16篇
  1995年   13篇
  1994年   6篇
  1993年   9篇
  1992年   2篇
  1991年   4篇
  1990年   2篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   3篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1976年   2篇
  1973年   1篇
  1972年   2篇
  1971年   1篇
  1969年   1篇
排序方式: 共有568条查询结果,搜索用时 15 毫秒
71.
Twenty-six patients with relapsed or refractory Hodgkin's disease (HD) were treated with an intensive salvage regimen combining ifosfamide (3000 mg/m2/d, days 1-4 through continuous intravenous infusion) and vinorelbine (25 mg/m2, i.v. days 1 and 5) with mesna uroprotection and G-CSF support. Courses were given at 3-week intervals. Ten patients achieved a complete and 10 patients a partial response, yielding an overall response rate of 77%. The main toxic effect was neutropenia and the combination was well tolerated.  相似文献   
72.
73.
A novel microporous templated carbon material doped with nitrogen is synthesized by using a two‐step nanocasting process using acrylonitrile (AN) and propylene as precursors, and Na–Y zeolite as a scaffold. Liquid‐phase impregnation and in situ polymerization of the nitrogenated precursor inside the nanochannels of the inorganic scaffold, followed by gas‐phase impregnation with propylene, enables pore‐size control and functionality tuning of the resulting carbon material. The material thereby obtained has a narrow pore‐size distribution (PSD), within the micropore range, and a large amount of heteroatoms (i.e., oxygen and nitrogen). In addition, the carbon material inherits the ordered structure of the inorganic host. Such features simultaneously present in the carbon result in it being ideal for use as an electrode in a supercapacitor. Although presenting a moderately developed specific surface area (SBET = 1680 m2 g–1), the templated carbon material displays a large gravimetric capacitance (340 F g–1) in aqueous media because of the combined electrochemical activity of the heteroatoms and the accessible porosity. This material can operate at 1.2 V in an aqueous medium with good cycleability—‐beyond 10 000 cycles—and is extremely promising for use in the development of high‐energy‐density supercapacitors.  相似文献   
74.
A case study from the chemical and pharmaceutical industries is used to show the value of the repeated measures design in developing processes for drug substances. This article advocates the use of the repeated measures design in situations that commonly arise in the chemical and pharmaceutical industries when repeated measurements are taken on the same experimental unit, instead of the common practice of comparing only individual conditions, a procedure that is inappropriate in many cases. One of the most important advantages of applying the repeated measures design is the abundance of data that can be obtained by taking into account the entire response curve instead of only isolated individual points on it.  相似文献   
75.
Summary Acenaphthylene was polymerized in methylenedichloride at 273, 291 and 308 K by sulphuric acid. The initiation step takes place by addition of the proton of sulphuric acid to the monomer. The propagation step is through ion-pairs, and the propagation constants are first-order with respect to the monomer and initiator(kp = 0.22 M–1. s–1(273K), kp=0.88 M–1. s–1(291K), kp = 2.81 M–1. s–1 (308K)). There is not appreciable loss of active centres, being this confirmed by experiments carried out with succesive additions of monomer. The molecular weights obtained confirm the importance of processes to monomer in this polymerization.  相似文献   
76.
77.
To investigate the developmental distribution of cochlear nucleus (CN) astrocytes, we used immunocytochemical localization of glial fibrillary acidic protein (GFAP) and S100beta in rats at 0, 5, 10, 15, 21, 30 postnatal days plus the adult. Differential developmental trends were observed for both proteins. The spatial distribution showed a progressive increase of the number of GFAP-immunoreactive (GFAP-IR) astrocytes during development. GFAP positive cells occurred first in the granule cell domain of the ventral CN and in the molecular cell layer of the dorsal CN, then followed an outside to inside pattern of progression. The GFAP-IR reached an adult distribution 1 month after birth. By contrast with GFAP, the apparition of S100beta-immunoreactivity (S100beta-IR) was abrupt (between 0 and 5 days) followed by a rapid stabilization of density and distribution of IR cells (between 15 and 21 days). The developmental distribution of S100beta-IR cells occurred from the posterodorsal region and progressed toward a rostroventral direction. With contrast to GFAP-IR astrocytes, S100beta-positive cells were mainly restricted to the central part of the CN, while only few IR astrocytes were observed in the granule cell domain of the ventral CN or in the molecular cell layer of the dorsal CN. This differential distribution suggests that both antigens were expressed by two different cell populations at least, it is obvious during the first postnatal week. The gradual expression of GFAP and S100beta is interpreted as reflecting the time course of astrocytic maturation. These data suggest that the maturation of CN astrocytes may be linked to the final maturation of CN neurons.  相似文献   
78.
The use of two different types of liposome suspensions (multilamellar vesicles, MLV, and large unilamellar vesicles, LUV) as carriers in the commercial dyeing of untreated wool with a milling acid dye is described. Liposomes prepared with egg phosphatidylcholine and containing the dye CI Acid Blue 90 were used. The physico-chemical stability of liposomes was studied by measuring the mean particle size distribution of phospholipidic vesicles during dyeing. The possible hydrolysis of phospholipid molecules was also determined. Kinetic aspects involving dye adsorption and bonding were investigated. Dye exhaustion on untreated wool fibres was inhibited and dye bonding was improved. The lipid concentration and type of liposomes were important factors in this process.  相似文献   
79.
OBJECTIVE: To find the reliability of the coding of diagnoses in the doctor's note in this computer system and to analyse where there are most discrepancies. DESIGN: An observational study. The concordance between the reason for consultation, codified by an external assessor, and the coding of the main diagnosis. SETTING: Health Districts 17 (Murcia/Barrio del Carmen) and 66 (Molina de Segura/La Ribera) in the Autonomous Community of Murcia. PATIENTS: A sub-sample of 228 consultations, belonging to a larger study of 1,904 general medical consultations (total: 98,768 consultations). MEASUREMENTS AND MAIN RESULTS: There were discrepancies between the coding of the reason for consultation and the diagnosis in 23% of the consultations recorded. The reason for consultation was not correctly recorded in 12.3%. The diagnostic group or section with the highest level of agreement was number XVIII or the supplementary section; and with the least agreement in XVII (injuries and adverse side-effects) and Number V covering mental disorders. CONCLUSIONS: Quality control of information and its validation enables errors and problems in the systems to be identified and corrected. This study points to the need to improve the filling-out of the reason for consultation and activity carried out, in order to obtain afterwards a more reliable coding of the diagnosis.  相似文献   
80.
Assistant robots have received special attention from the research community in the last years. One of the main applications of these robots is to perform care tasks in indoor environments such as houses, nursing homes or hospitals, and therefore they need to be able to navigate robustly for long periods of time. This paper focuses on the navigation system of SIRA, a robotic assistant for elderly and/or blind people based on a Partially Observable Markov Decision Process (POMDP) to global localize the robot and to direct its goal-oriented actions. The main novel feature of our approach is that it combines sonar and visual information in a natural way to produce state transitions and observations in the framework of Markov Decision Processes. Besides this multisensorial fusion, a two-level layered planning architecture that combines several planning objectives (such as guiding to a goal room and reducing locational uncertainty) improves the robustness of the navigation system, as its shown in our experiments with SIRA navigating corridors.  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