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   9237篇
  免费   552篇
  国内免费   21篇
电工技术   126篇
综合类   18篇
化学工业   2374篇
金属工艺   178篇
机械仪表   211篇
建筑科学   332篇
矿业工程   47篇
能源动力   224篇
轻工业   402篇
水利工程   76篇
石油天然气   44篇
无线电   774篇
一般工业技术   2320篇
冶金工业   1012篇
原子能技术   86篇
自动化技术   1586篇
  2023年   153篇
  2022年   382篇
  2021年   423篇
  2020年   288篇
  2019年   249篇
  2018年   308篇
  2017年   263篇
  2016年   358篇
  2015年   306篇
  2014年   441篇
  2013年   559篇
  2012年   551篇
  2011年   627篇
  2010年   426篇
  2009年   416篇
  2008年   435篇
  2007年   423篇
  2006年   329篇
  2005年   253篇
  2004年   224篇
  2003年   205篇
  2002年   196篇
  2001年   125篇
  2000年   115篇
  1999年   122篇
  1998年   194篇
  1997年   159篇
  1996年   106篇
  1995年   88篇
  1994年   76篇
  1993年   91篇
  1992年   54篇
  1991年   51篇
  1990年   51篇
  1989年   38篇
  1988年   44篇
  1987年   41篇
  1986年   34篇
  1985年   45篇
  1984年   42篇
  1983年   36篇
  1982年   30篇
  1981年   29篇
  1980年   24篇
  1979年   23篇
  1978年   30篇
  1977年   26篇
  1976年   63篇
  1975年   27篇
  1974年   19篇
排序方式: 共有9810条查询结果,搜索用时 10 毫秒
71.
Graph-Theoretical Analysis of the Swiss Road and Railway Networks Over Time   总被引:2,自引:1,他引:1  
Recent research of complex networks has significantly contributed to the understanding how networks can be classified according to its topological characteristics. However, transport networks attracted less attention although their importance to economy and daily life. In this work the development of the Swiss road and railway network during the years 1950–2000 is investigated. The main difference between many of the recently studied complex networks and transport networks is the spatial structure. Therefore, some of the well-established complex network measures may not be applied directly to characterise transport networks but need to be adapted to fulfil the requirements of spatial networks. Additionally, new approaches to cover basic network characteristics such as local network densities are applied. The focus of the interest hereby is always not only to classify the transport network but also to provide the basis for further applications such as vulnerability analysis or network development. It could be showed that the proposed measures are able to characterise the growth of the Swiss road network. To proof the use of local density measures to explain the robustness of a network however needs further research.
Kay W. AxhausenEmail:
  相似文献   
72.
Patientinnen und Patienten vertrauen sich heutzutage nicht mehr nur ihrem Haus- oder Facharzt, sondern immer h?ufiger auch einer Gro?klinik („Krankenhausmaschine“) an. Schon dort entsteht die Frage, wie die ?rztliche Schweigepflicht oder besser: das Patientengeheimnis, noch aufrechterhalten werden kann. Weitere Risiken drohen dem Patientengeheimnis in der zunehmend vernetzten Verarbeitung von medizinischen Befunden z.B. in Praxisnetzen und auch in der Online-Welt, die zweifellos gro?e Vorteile für die behandlungsbedürftigen Menschen bringen. Sie werfen aber auch die Frage nach der Verantwortung für die Sicherheit, Richtigkeit und Verfügbarkeit dieser Daten auf, die nicht selten lebenswichtig sein k?nnen.  相似文献   
73.
Eosinophils (EOSs) are granular leukocytes that have significant roles in many inflammatory and immunoregulatory responses, especially asthma and allergic diseases. We have undertaken a fairly comprehensive proteomic analysis of purified peripheral blood EOSs from normal human donors primarily employing 2‐DE with protein spot identification by MALDI‐MS. Protein subfractionation methods employed included IEF (Zoom® Fractionator) and subcellular fractionation using differential protein solubilization. We have identified 3141 proteins, which had Mascot expectation scores of 10?3 or less. Of these 426 were unique and non‐redundant of which 231 were novel proteins not previously reported to occur in EOSs. Ingenuity Pathway Analysis showed that some 70% of the non‐redundant proteins could be subdivided into categories that are clearly related to currently known EOS biological activities. Cytoskeletal and associated proteins predominated among the proteins identified. Extensive protein posttranslational modifications were evident, many of which have not been previously reported that reflected the dynamic character of the EOS. This data set of eosinophilic proteins will prove valuable in comparative studies of disease versus normal states and for studies of gender differences and polymorphic variation among individuals.  相似文献   
74.
75.

Robotic process automation is a disruptive technology to automate already digital yet manual tasks and subprocesses as well as whole business processes rapidly. In contrast to other process automation technologies, robotic process automation is lightweight and only accesses the presentation layer of IT systems to mimic human behavior. Due to the novelty of robotic process automation and the varying approaches when implementing the technology, there are reports that up to 50% of robotic process automation projects fail. To tackle this issue, we use a design science research approach to develop a framework for the implementation of robotic process automation projects. We analyzed 35 reports on real-life projects to derive a preliminary sequential model. Then, we performed multiple expert interviews and workshops to validate and refine our model. The result is a framework with variable stages that offers guidelines with enough flexibility to be applicable in complex and heterogeneous corporate environments as well as for small and medium-sized companies. It is structured by the three phases of initialization, implementation, and scaling. They comprise eleven stages relevant during a project and as a continuous cycle spanning individual projects. Together they structure how to manage knowledge and support processes for the execution of robotic process automation implementation projects.

  相似文献   
76.

Organizations are increasingly delegating customer inquiries to speech dialog systems (SDSs) to save personnel resources. However, customers often report frustration when interacting with SDSs due to poorly designed solutions. Despite these issues, design knowledge for SDSs in customer service remains elusive. To address this research gap, we employ the design science approach and devise a design theory for SDSs in customer service. The design theory, including 14 requirements and five design principles, draws on the principles of dialog theory and undergoes validation in three iterations using five hypotheses. A summative evaluation comprising a two-phase experiment with 205 participants yields positive results regarding the user experience of the artifact. This study contributes to design knowledge for SDSs in customer service and supports practitioners striving to implement similar systems in their organizations.

  相似文献   
77.
International Journal of Computer Vision - Machine learning models are known to perpetuate and even amplify the biases present in the data. However, these data biases frequently do not become...  相似文献   
78.
79.
Ternary Ⅲ-Ⅴ nanowires (NWs) cover a wide range of wavelengths in the solar spectrum and would greatly benefit from being synthesized as position-controlled arrays for improved vertical yield,reprodudbility,and tunable optical absorption.Here,we report on successful selective-area epitaxy of metal-particle-free vertical InxGa1-xP NW arrays using metal-organic vapor phase epitaxy and detail their optical properties.A systematic growth study establishes the range of suitable growth parameters to obtain uniform NW growth over a large array.The optical properties of the NWs were characterized by room-temperature cathodoluminescence spectroscopy.Tunability of the emission wavelength from 870 nm to approximately 800 nm was achieved.Transmission electron microscopy and energy dispersive X-ray measurements performed on crosssection samples revealed a pure wurtzite crystal structure with very few stacking faults and a slight composition gradient along the NW growth axis.  相似文献   
80.
Colloidal quantum dots (CQDs) have attracted significant interest for applications in electronic and optoelectronic devices such as photodetectors, light-emitting diodes, and solar cells. However, a poor understanding of charge transport in these nanocrystalline films hinders their practical applications. The photocarrier radiometry (PCR) technique, a frequency-domain photoluminescence method spectrally gated for monitoring radiative recombination photon emissions while excluding thermal infrared photons due to non-radiative recombination, has been applied to PbS CQD thin films for the analysis of charge transport properties. Linear excitation intensity responses of PCR signals were found in the reported experimental conditions. The type and influence of trap states in the coupled PbS CQD thin film were analyzed with PCR temperature- and time-dependent results.  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