全文获取类型
收费全文 | 428篇 |
免费 | 6篇 |
国内免费 | 2篇 |
专业分类
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 |
出版年
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.
SR McColl MA Staykova A Wozniak S Fordham J Bruce DO Willenborg 《Canadian Metallurgical Quarterly》1998,161(11):6421-6426
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.
Amino acid sequence of a four-iron-four-sulphur ferredoxin isolated from Bacillus stearothermophilus
T Hase N Ohmiya H Matsubara RN Mullinger KK Rao DO Hall 《Canadian Metallurgical Quarterly》1976,159(1):55-63
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.