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   10031篇
  免费   153篇
  国内免费   9篇
电工技术   87篇
综合类   8篇
化学工业   1198篇
金属工艺   103篇
机械仪表   86篇
建筑科学   505篇
矿业工程   17篇
能源动力   98篇
轻工业   5749篇
水利工程   32篇
石油天然气   11篇
无线电   316篇
一般工业技术   711篇
冶金工业   559篇
原子能技术   32篇
自动化技术   681篇
  2021年   80篇
  2016年   110篇
  2015年   98篇
  2014年   176篇
  2013年   227篇
  2012年   216篇
  2011年   216篇
  2010年   184篇
  2009年   204篇
  2008年   254篇
  2007年   267篇
  2006年   197篇
  2005年   169篇
  2004年   144篇
  2003年   131篇
  1998年   93篇
  1993年   83篇
  1990年   96篇
  1989年   107篇
  1988年   92篇
  1987年   109篇
  1985年   121篇
  1984年   117篇
  1981年   96篇
  1980年   100篇
  1979年   93篇
  1978年   95篇
  1977年   129篇
  1976年   127篇
  1974年   88篇
  1973年   114篇
  1972年   96篇
  1971年   99篇
  1970年   102篇
  1969年   92篇
  1968年   85篇
  1917年   85篇
  1916年   110篇
  1915年   109篇
  1914年   98篇
  1913年   110篇
  1912年   143篇
  1911年   119篇
  1910年   129篇
  1909年   137篇
  1908年   139篇
  1907年   132篇
  1906年   130篇
  1905年   140篇
  1904年   130篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
123.
124.
125.
1. Background The use of engineering tools, design, research, and thinking to create environments and capabilities whereby individuals who are currently under-e...  相似文献   
126.
The functional requirements of proteins for foods   总被引:4,自引:0,他引:4  
As a growing amount of research attention has been diverted, for a number of reasons, from the traditional protein foods to the so-called unconventional food proteins, an awareness has increased of the need to understand the functional properties of these proteins. Some empirical functionality tests have been devised, but it is submitted that many of these could yield misleading information, inasmuch as they often ignore or even run counter to the environmental interactions to which proteins are exposed in food systems. Some examples are given of the influence of the ionic environment upon one basic functional property of proteins, their solubility in aqueous solution. One of 21 papers presented at the Symposium, “Oilseed Processors Challenged by World Protein Need,” ISF-AOCS World Congress, Chicago, September 1970.  相似文献   
127.
The SUPRENUM idea, the project, and the system has generally been described and presented in several papers. There is also a great deal of more detailed technical papers describing SUPRENUM as a whole or certain elements of it.

Here we want to give only a very general and rough survey on the essentials of the SUPRENUM system in order to enable the reader to categorize and understand the more specific SUPRENUM papers in this special issue.

Most of the supercomputer applications today are based on grid or grid-like data structures. Grid applications play also an essential role in the SUPRENUM development: in the top-down design of the architecture, in the programming environment, in the parallelization concept of algorithms, and, of course, in the application software development itself. We therefore place some emphasis on this grid orientation in our presentation.  相似文献   

128.
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that has the potential to treat a variety of neurologic and psychiatric disorders. The extent of rTMS-induced neuroplasticity may be dependent on a subject’s brain state at the time of stimulation. Chronic low intensity rTMS (LI-rTMS) has previously been shown to induce beneficial structural and functional reorganisation within the abnormal visual circuits of ephrin-A2A5-/- mice in ambient lighting. Here, we administered chronic LI-rTMS in adult ephrin-A2A5-/- mice either in a dark environment or concurrently with voluntary locomotion. One day after the last stimulation session, optokinetic responses were assessed and fluorescent tracers were injected to map corticotectal and geniculocortical projections. We found that LI-rTMS in either treatment condition refined the geniculocortical map. Corticotectal projections were improved in locomotion+LI-rTMS subjects, but not in dark + LI-rTMS and sham groups. Visuomotor behaviour was not improved in any condition. Our results suggest that the beneficial reorganisation of abnormal visual circuits by rTMS can be significantly influenced by simultaneous, ambient visual input and is enhanced by concomitant physical exercise. Furthermore, the observed pathway-specific effects suggest that regional molecular changes and/or the relative proximity of terminals to the induced electric fields influence the outcomes of LI-rTMS on abnormal circuitry.  相似文献   
129.
Estrogen receptors (ERs) play a key role in many biochemical and physiological processes, that are involved in maintaining organism homeostasis. At the most basic level, they can be divided into nuclear estrogen receptors and membrane estrogen receptors that imply their effect in two ways: slower genomic, and faster non-genomic. In these ways, estrogens and xenoestrogens can negatively affect animal health and welfare. Most of the available literature focuses on human and mammalian physiology, and clearly, we can observe a need for further research focusing on complex mutual interactions between different estrogens and xenoestrogens in aquatic animals, primarily fishes. Understanding the mechanisms of action of estrogenic compounds on the ERs in fishes and their negative consequences, may improve efforts in environmental protection of these animals and their environment and benefit society in return. In this review, we have summarized the ER-mediated effects of xenoestrogens and estrogens on teleost fishes metabolism, their carcinogenic potential, immune, circulatory, and reproductive systems.  相似文献   
130.
SLC26A9 is an epithelial anion transporter with a poorly defined function in airways. It is assumed to contribute to airway chloride secretion and airway surface hydration. However, immunohistochemistry showing precise localization of SLC26A9 in airways is missing. Some studies report localization near tight junctions, which is difficult to reconcile with a chloride secretory function of SLC26A9. We therefore performed immunocytochemistry of SLC26A9 in sections of human and porcine lungs. Obvious apical localization of SLC26A9 was detected in human and porcine superficial airway epithelia, whereas submucosal glands did not express SLC26A9. The anion transporter was located exclusively in ciliated epithelial cells. Highly differentiated BCi-NS1 human airway epithelial cells grown on permeable supports also expressed SLC26A9 in the apical membrane of ciliated epithelial cells. BCi-NS1 cells expressed the major Cl transporting proteins CFTR, TMEM16A and SLC26A9 in about equal proportions and produced short-circuit currents activated by increases in intracellular cAMP or Ca2+. Both CFTR and SLC26A9 contribute to basal chloride currents in non-stimulated BCi-NS1 airway epithelia, with CFTR being the dominating Cl conductance. In wtCFTR-expressing CFBE human airway epithelial cells, SLC26A9 was partially located in the plasma membrane, whereas CFBE cells expressing F508del-CFTR showed exclusive cytosolic localization of SLC26A9. Membrane localization of SLC26A9 and basal chloride currents were augmented by interleukin 13 in wild-type CFTR-expressing cells, but not in cells expressing the most common disease-causing mutant F508del-CFTR. The data suggest an upregulation of SLC26A9-dependent chloride secretion in asthma, but not in the presence of F508del-CFTR.  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