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   15786篇
  免费   842篇
  国内免费   28篇
电工技术   168篇
综合类   43篇
化学工业   3444篇
金属工艺   315篇
机械仪表   316篇
建筑科学   695篇
矿业工程   52篇
能源动力   510篇
轻工业   1241篇
水利工程   131篇
石油天然气   55篇
无线电   1119篇
一般工业技术   3002篇
冶金工业   2302篇
原子能技术   125篇
自动化技术   3138篇
  2023年   166篇
  2022年   362篇
  2021年   579篇
  2020年   378篇
  2019年   386篇
  2018年   501篇
  2017年   471篇
  2016年   537篇
  2015年   474篇
  2014年   604篇
  2013年   1072篇
  2012年   982篇
  2011年   1171篇
  2010年   818篇
  2009年   763篇
  2008年   804篇
  2007年   794篇
  2006年   592篇
  2005年   515篇
  2004年   382篇
  2003年   387篇
  2002年   344篇
  2001年   215篇
  2000年   189篇
  1999年   213篇
  1998年   222篇
  1997年   207篇
  1996年   195篇
  1995年   184篇
  1994年   157篇
  1993年   152篇
  1992年   120篇
  1991年   75篇
  1990年   124篇
  1989年   117篇
  1988年   81篇
  1987年   94篇
  1986年   100篇
  1985年   100篇
  1984年   89篇
  1983年   76篇
  1982年   96篇
  1981年   90篇
  1980年   71篇
  1979年   70篇
  1978年   62篇
  1977年   74篇
  1976年   64篇
  1975年   45篇
  1974年   41篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
Color vision is used throughout medicine to interpret the health and status of tissue. Ionizing radiation used in radiation therapy produces broadband white lig...  相似文献   
122.
The Medical and Pharmaceutical industries have shown high interest in the precise engineering of protein hormones and enzymes that perform existing functions under a wide range of conditions. Proteins are responsible for the execution of different functions in the cell: catalysis in chemical reactions, transport and storage, regulation and recognition control. Computational Protein Design (CPD) investigates the relationship between 3-D structures of proteins and amino acid sequences and looks for all sequences that will fold into such 3-D structure. Many computational methods and algorithms have been proposed over the last years, but the problem still remains a challenge for Mathematicians, Computer Scientists, Bioinformaticians and Structural Biologists. In this article we present a new method for the protein design problem. Clustering techniques and a Dead-End-Elimination algorithm are combined with a SAT problem representation of the CPD problem in order to design the amino acid sequences. The obtained results illustrate the accuracy of the proposed method, suggesting that integrated Artificial Intelligence techniques are useful tools to solve such an intricate problem.  相似文献   
123.
Medication adherence—taking medication as prescribed—is critical for successful self-care, especially among older adults. Adherence depends on developing and implementing plans for taking medications. Age-related cognitive declines that affect adherence may be mitigated using external tools that support patient-provider collaboration needed to develop these adherence plans. We tested the effectiveness of structured collaborative medication tools to support better medication planning and adherence practices. Evidence for benefits of collaborative tools has been mixed in terms of their usefulness for medication-scheduling tasks, perhaps because the tools have not been explicitly designed to support patient-provider collaboration. A total of 144 community-dwelling older adults participated in pairs and performed the role of a patient or provider in a simulated patient-provider medication-scheduling task. Each pair worked with a structured (MedTable? and e-MedTable) or unstructured (Medcard) scheduling tool and completed four problems (2 simple and 2 complex). Performance was measured using the following: problem-solving (medication schedule) accuracy, problem-solving time, solution (schedule) optimality, tool usability, collaborative effectiveness, and subjective workload involved in creating the medication schedules. Participants using structured tools produced more accurate and optimal schedules. They also rated subjective workload as lower and thought that the structured tools were easier to use, reduced subjective workload associated with creating the schedules. There was also suggestive evidence that participants using the structured tools rated more highly the quality of their collaboration. Structured medication-scheduling tools have the potential to improve medication adherence among older adults because they support collaborative planning and reduce the cognitive load involved in creating these adherence plans.  相似文献   
124.
125.
A phase-sampling method has been developed to measure periodic flows at a high temporal resolution using conventional micro-particle image velocimetry (PIV). In this technique, the sampling is set such that each velocimetry dataset represents a unique point in phase of a periodic flow. The flow characteristics over a single cycle are reconstructed from measurements over a number of cycles, thus allowing measurement at a higher temporal resolution than the PIV system. The flow measurements were performed for AC electroosmotic flows and verified with results from the phase-locking technique. The temporal resolution is limited by the shortest camera exposure time and the time separation between laser pulses. The theoretical sampling resolution can be as low as 20 μs for 100 Hz periodic flows. A resolution of 200 μs was obtained in the experiment using 40 velocimetry datasets.  相似文献   
126.
127.
128.
129.
Metallic magnesium (Mg) and its alloys are highly suitable for medical applications as biocompatible and biodegradable implant materials. Magnesium has mechanical properties similar to bone, stimulates bone regeneration, is an essential non-toxic element for the human body and degrades completely within the body environment. In consequence, magnesium is a promising candidate as implant material for orthopaedic applications. Protocols using the guideline of current ISO standards should be carefully evaluated when applying them for the characterization of the cytotoxic potential of degradable magnesium materials. For as-cast material we recommend using 10 times more extraction medium than recommended by the ISO standards to obtain reasonable results for reliable cytotoxicity rankings of degradable materials in vitro. In addition primary isolated human osteoblasts or mesenchymal stem cells should be used to test magnesium materials.  相似文献   
130.
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