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   1852篇
  免费   1篇
化学工业   13篇
机械仪表   1篇
建筑科学   3篇
能源动力   1篇
轻工业   3篇
无线电   2篇
一般工业技术   4篇
冶金工业   1818篇
自动化技术   8篇
  2022年   1篇
  2021年   2篇
  2019年   1篇
  2017年   1篇
  2016年   2篇
  2015年   1篇
  2014年   1篇
  2013年   5篇
  2012年   1篇
  2011年   2篇
  2010年   2篇
  2008年   1篇
  2006年   2篇
  2005年   1篇
  2004年   1篇
  2003年   2篇
  1999年   46篇
  1998年   541篇
  1997年   275篇
  1996年   199篇
  1995年   112篇
  1994年   92篇
  1993年   101篇
  1992年   19篇
  1991年   29篇
  1990年   23篇
  1989年   36篇
  1988年   38篇
  1987年   31篇
  1986年   33篇
  1985年   18篇
  1984年   1篇
  1983年   2篇
  1982年   8篇
  1981年   11篇
  1980年   21篇
  1979年   2篇
  1978年   5篇
  1977年   55篇
  1976年   127篇
  1975年   1篇
  1955年   1篇
排序方式: 共有1853条查询结果,搜索用时 15 毫秒
71.
72.
Granulocytic sarcoma (chloroma) is a localized tumefaction of immature granulocytes that is typically seen in association with myelogenous leukemia. The primitive cell population seen in biopsy material may be misinterpreted as histiocytic lymphoma or other sarcoma unless additional studies are performed. We saw a 36-year-old woman with promyelocytic leukemia in remission who had the signs and symptoms of an acute coalescent mastoiditis. Histologic examination of the surgical specimen, however, demonstrated a granulocytic sarcoma. Our case exemplifies some of the difficulties that may be encountered in the diagnosis of granulocytic sarcoma and illustrates the point that symptoms of an inflammatory process in a patient with a diagnosis of leukemia must be regarded with a degree of suspicion.  相似文献   
73.
A case of multiple adenocarcinoma arising from the kidney, bladder, and prostate is presented with a relevant discussion of the possible factors of pathogenesis. A staged approach of radical extirpative surgery is suggested.  相似文献   
74.
75.
The largest human exposure to N-nitrosamines is in the industrial section. Leather tanners are exposed to N-nitrosodimethylamine at levels up to 47 microgram/m3, corresponding to 440 microgram/person/day. Workers in the curing area of tire factories are exposed to N-nitrosomorpholine at levels up to 27 microgram/m3, corresponding to a intake of 250 microgram/person/day. These industrial exposures are considerably greater than exposure via foodstuffs, beer, cosmetics, cutting fluids and herbicides.  相似文献   
76.
1. Part of the DNA extruded by cultured rat spleen cells occurs in the form of a low density lipid complex. 2. The present work indicates that this complex is also associated with protein but not with RNA and its elementary properties have been studied. 3. For example, it is destroyed by freezing and thawing or by deoxycholate treatment and small quantities of copper salts added to the medium may either inhibit or stimulate its release depending on the conditions.  相似文献   
77.
78.
79.
80.
The problems related to our strong dependency on fossil fuels, i.e. greenhouse effect, energy dependency, urban pollution, are of growing importance in recent years. European Union (EU) Action plan of 2003, which had originated from Kyoto Agreement, defined a strategy for substitution of 20% of conventional fuel with the alternative one by 2020. Proved advantages of biodiesel usage in the system of public transport of passengers, with regard to exhaust gases emission above all, have been the decisive determinants for the actual promotion of biodiesel as ecologically “clean” fuel, while its wider usage gives important contribution to sustainable development of cities. This paper presents results of biodiesel-test run in Belgrade, as a part of the project BIO-PEX, which relates to the usage of this alternative fuel in real operating conditions in urban public transport system, with special emphasis on technical, ecological and operational aspects of biofuel usage.  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