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   2052篇
  免费   4篇
  国内免费   1篇
电工技术   4篇
化学工业   96篇
金属工艺   7篇
机械仪表   21篇
建筑科学   8篇
矿业工程   31篇
能源动力   1篇
轻工业   5篇
水利工程   5篇
石油天然气   43篇
无线电   14篇
一般工业技术   119篇
冶金工业   1647篇
原子能技术   43篇
自动化技术   13篇
  2021年   10篇
  2019年   5篇
  2018年   10篇
  2017年   10篇
  2016年   16篇
  2014年   7篇
  2013年   15篇
  2012年   7篇
  2011年   15篇
  2010年   12篇
  2009年   10篇
  2008年   16篇
  2007年   16篇
  2006年   14篇
  2005年   10篇
  2004年   14篇
  2003年   16篇
  2002年   4篇
  2001年   6篇
  2000年   10篇
  1999年   47篇
  1998年   468篇
  1997年   284篇
  1996年   195篇
  1995年   118篇
  1994年   85篇
  1993年   101篇
  1992年   18篇
  1991年   21篇
  1990年   24篇
  1989年   31篇
  1988年   26篇
  1987年   24篇
  1986年   15篇
  1985年   20篇
  1984年   4篇
  1983年   7篇
  1982年   12篇
  1981年   24篇
  1980年   31篇
  1979年   12篇
  1978年   24篇
  1977年   57篇
  1976年   112篇
  1975年   11篇
  1974年   4篇
  1973年   8篇
  1972年   5篇
  1971年   6篇
  1969年   9篇
排序方式: 共有2057条查询结果,搜索用时 859 毫秒
1.
Nontuberculous mycobacteria are increasingly recognized as important pathogens in peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD). Mycobacterium gordonae rarely causes human infection and is the least likely mycobacterium to produce clinical infection in CAPD patients. We describe a patient with persistent M. gordonae peritonitis acquired while undergoing CAPD. During 18 months of treatment, clinical improvement occurred but a microbiological cure could not be achieved. Principles of therapy for mycobacterial peritonitis developing during CAPD are reviewed, and potential explanations for our patient's failure to respond to therapy are discussed.  相似文献   
2.
The results of computer simulations demonstrate the possibility of light energy transmission through band gaps of a one-dimensional photonic crystal with fluctuating lengths of individual layers. In the case of weak (±5%) fluctuations, the light pulse energy partly penetrates in depth a photonic crystal. If fluctuations of the layer length are strong (±20%), the light pulse energy can be partly transmitted through the crystal.  相似文献   
3.
Abstract— An all solid‐state photoelectrochromic element (PECE) was developed on the basis of electrochromic layers of WO3 and polyaniline with a layer of polymer electrolyte placed on a base of polyamidosulfoacid, in which a thin‐film CdSxSe1?x photoresistor was used as an electronic key. The dependence of the sensitometric characteristics of the PECE on the applied voltage was studied.  相似文献   
4.
Equations are proposed for calculating the molar volume of liquid hydrocarbons used in production of surfactants. With such data, it will be possible to calculate most of the physicochemical properties of these hydrocarbons to solve many process problems. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 6, pp. 39–41, Novemmber–December, 2006.  相似文献   
5.
6.
7.
Relapse after autologous bone marrow transplantation for chronic myelogenous leukemia (CML) can be due either to the persistence of leukemia cells in systemic tissues following preparative therapy, or due to the persistence of leukemia cells in the autologous marrow used to restore marrow function after intensive therapy. To help distinguish between these two possible causes of relapse, we used safety-modified retroviruses, which contain the bacterial resistance gene NEO, to mark autologous marrow cells that had been collected from patients early in the phase of hematopoietic recovery after in vivo chemotherapy. The cells were then subjected to ex vivo CD34 selection following collection and 30% of the bone marrow were exposed to a safety-modified virus. This marrow was infused after delivery of systemic therapy, which consisted of total body irradiation (1,020 cGy), cyclophosphamide (120 mg/kg), and VP-16 (750 mg/m2). RT PCR assays specific for the bacterial NEO mRNA, which was coded for by the virus, and the bcr-abl mRNA showed that in two evaluable CML patients transplanted with marked cells, sufficient numbers of leukemia cells remained in the infused marrow to contribute to systemic relapse. In addition, both normal and leukemic cells positive for the retroviral transgenome persisted in the systemic circulation of the patients for at least 280 days posttransplant showing that the infused marrow was responsible for the return of hematopoiesis following the preparative therapy. This observation shows that it is possible to use a replication-incompetent safety-modified retrovirus in order to introduce DNA sequences into the hematopoietic cells of patients undergoing autologous bone marrow transplantation. Moreover, this data suggested that additional fractionation procedures will be necessary to reduce the probability of relapse after bone marrow transplantation in at least the advanced stages of the disease in CML patients undergoing autologous bone marrow transplantation procedures.  相似文献   
8.
9.
10.
Glucose levels in rats with hyperglycemia induced by streptozotocin were determined after i.p. administration of marsupsin (1), pterosupin (2), and pterostilbene (3), three important phenolic constituents of the heartwood of Pterocarpus marsupium. Marsupsin and pterostilbene significantly lowered the blood glucose level of hyperglycemic rats, and the effect was comparable to that of 1,1-dimethylbiguanide (metformin).  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