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   428篇
  免费   6篇
  国内免费   2篇
电工技术   5篇
综合类   6篇
化学工业   27篇
金属工艺   2篇
机械仪表   6篇
建筑科学   5篇
能源动力   2篇
轻工业   21篇
石油天然气   1篇
无线电   12篇
一般工业技术   20篇
冶金工业   324篇
自动化技术   5篇
  2021年   1篇
  2020年   2篇
  2016年   2篇
  2015年   1篇
  2014年   4篇
  2013年   15篇
  2012年   8篇
  2011年   9篇
  2010年   7篇
  2009年   8篇
  2008年   8篇
  2007年   3篇
  2006年   3篇
  2005年   3篇
  2004年   6篇
  2003年   6篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1999年   9篇
  1998年   115篇
  1997年   49篇
  1996年   27篇
  1995年   23篇
  1994年   13篇
  1993年   25篇
  1992年   4篇
  1991年   4篇
  1990年   3篇
  1989年   9篇
  1988年   3篇
  1987年   6篇
  1986年   1篇
  1985年   4篇
  1984年   2篇
  1983年   1篇
  1982年   3篇
  1981年   3篇
  1979年   2篇
  1977年   9篇
  1976年   23篇
  1975年   3篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1962年   1篇
  1956年   1篇
排序方式: 共有436条查询结果,搜索用时 15 毫秒
61.
Emerging data suggest that polymorphonuclear leukocytes (PMNLs) can play an important role in Ag-dependent immune responses. Therefore, we have assessed the involvement of these cells in the development of an organ-specific autoimmune disease, experimental autoimmune encephalomyelitis (EAE), in the mouse. Depletion of peripheral blood PMNLs beginning day 8 after immunization significantly delayed and in some cases totally prevented the development of clinical EAE in mice. Depletion of PMNLs beginning 1 day before sensitization and continuing until day 7 postimmunization had no effect on the subsequent development of EAE, suggesting that depletion alters the efferent but not the afferent arm of the immune response. In vitro studies showed that lymphoid cells from mice protected from EAE by PMNL depletion beginning on day 8 postsensitization proliferated in response to specific Ag to a level equal to cells from sensitized animals treated with control serum, again indicating that treatment was not affecting the afferent limb of the immune response. Further evidence that PMNL may be necessary in initiating the pathology of EAE was seen in passive transfer experiments where PMNL-depleted recipients of MBP-specific lymphoid effector cells developed EAE much less effectively than did animals treated with control Ab. Taken together, these data indicate that PMNLs play a critical role in the effector phase of the development of the clinicopathologic expression of EAE in mice.  相似文献   
62.
63.
64.
PGM3 activity was investigated by means of horizontal starch gel electrophoresis. In the pig of the German Landrace three different phenotypes have been recognized: F, S and FS. Family studies suggest the occurrence of at least two alleles--PGM3F and the PGM3S at an autosomal locus.  相似文献   
65.
Myopathy resembling nutritional muscular dystrophy occurred in a colony of 150 guinea pigs. Of 54 animals affected, 27 died. Major clinical signs were depression, conjunctivitis, and reluctance to move. Lesions were widespread throughout skeletal and cardiac musculature. Clinical signs and deaths ceased when the diet was changed to a different commercial ration. A single intramuscular injection of sodium selenite and alphatocopherol brought prompt remission of clinical signs in one group of 20 so treated.  相似文献   
66.
A novel method of RNA fractionation based on a gradual release of the RNA molecules from ribonucleoprotein complexes has been used for the analysis of ribosomal and non-ribosomal complexes of rat liver cytoplasm. Adsorption of native ribonucleoproteins on a Celite column (occuring through only the protein moiety) followed by a consequent dissociation of RNP complexes brought about by various agents results in RNA fractionation in accordance with the tightness of the RNA-protein bonds. The cytoplasmic ribosomal and rapidly labelled non-ribosomal RNA species are separated into several fractions identified as 18S and 28S rRNA's, mRNA and messenger-like RNA. A relatively small fraction (about 10% of the total) of rRNA tenaciously bound to protein has been also revealed.  相似文献   
67.
681 usable questionnaire returns were received from PhD psychologist respondents. Since completing the language requirements 65% or almost ? of the cases had not read a single item (article or book). "The median number of items read in French, German, Spanish, and Russian was 0." 70% made no oral use of the languages. There is an "extreme incongruity between input and output" in the study of foreign languages at the PhD level. Alternative solutions are proposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
68.
An analysis is made of 24 cases of primitive lithiasis of the biliary tracts, viz; 10 of diffuse intrahepatic lithiasis, 9 of intrahepatic lithiasis localized in one of the ducts; and 5 of extrahepatic lithiasis. The most common cause were stenosis (14 cases) generally of idiopathic or congenital nature, followed by those of iatrogenic or tumoral origin. There were also cases of isolated or diffuse anomalus dilatation of the biliary ducts. A lithogenetic bile as well as infectious processes are rather considered secondary factors. The diagnosis of the real nature of the condiction was usually established in the postoperative period, this being an explanation why repeated surgery was so common (75%). There was a high postoperative mortality in the diffuse forms owing to severe manifestations of biliary sepsis perpetuated by the stones. Depending upon the individual cases the following procedures are proposed: 1) Biliodigestive anastomosis 2) Sphinteropapilloplasty 3) Dilatation and calibration of the stenosis 4) Postoperative instrumental extraction of calculi. The last-named procedure was carried out in 58% of the cases and result in an improvement in the serious prognosis. Primitive lithiasis should always be borne in mind when undertaking surgery of the biliary tracts in order to avoid additional surgery.  相似文献   
69.
The management of simple snoring in adults is reviewed. Snoring is associated with oscillations of the soft palate and adjacent structures, as a consequence of a critically reduced pharyngeal cross-sectional area under conditions of sleep-induced flow limitation. Anatomical and physiological factors resulting in upper airway collapse and snoring are reviewed. The conservative treatment of snoring encompasses weight loss, alcohol and sedatives avoidance, as well as smoking cessation. Nasal obstruction should be relieved, either medically or surgically. If these measures fail, polysomnography should be performed. Patients with obstructive sleep apnoea should be offered nasal continuous positive airway pressure therapy. Uvulopalatopharyngoplasty can be proposed to nonapnoeic snorers, with a good chance of success, as far as reported snoring is concerned. Unfortunately, this has not been confirmed by objective recordings, and long-term results have not been adequately studied.  相似文献   
70.
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