全文获取类型
收费全文 | 740篇 |
免费 | 3篇 |
专业分类
化学工业 | 12篇 |
金属工艺 | 1篇 |
建筑科学 | 2篇 |
矿业工程 | 1篇 |
能源动力 | 1篇 |
轻工业 | 3篇 |
石油天然气 | 1篇 |
无线电 | 6篇 |
一般工业技术 | 7篇 |
冶金工业 | 707篇 |
自动化技术 | 2篇 |
出版年
2019年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 4篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 1篇 |
1999年 | 20篇 |
1998年 | 201篇 |
1997年 | 114篇 |
1996年 | 65篇 |
1995年 | 36篇 |
1994年 | 48篇 |
1993年 | 33篇 |
1992年 | 5篇 |
1991年 | 11篇 |
1990年 | 6篇 |
1989年 | 14篇 |
1988年 | 12篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 16篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1977年 | 28篇 |
1976年 | 66篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有743条查询结果,搜索用时 15 毫秒
91.
92.
93.
Differential influence of a selective melanocortin MC4 receptor antagonist (HS014) on melanocortin-induced behavioral effects in rats 总被引:1,自引:0,他引:1
AV Vergoni A Bertolini F Mutulis JE Wikberg HB Schi?th 《Canadian Metallurgical Quarterly》1998,362(2-3):95-101
We injected i.c.v. the natural agonist alpha-MSH (melanocyte-stimulating hormone) and the first selective melanocortin MC4 receptor antagonist HS014 (cyclic [AcCys11, D-Nal14, Cys18, Asp-NH(2)22]-beta-MSH(11-22) in rats and scored a number of behavioral effects which have been related to the melanocortic peptides. The results showed that HS014 (5 microg/rat) completely blocked alpha-MSH (3 and 5 microg/rat)-induced grooming, yawning and stretching. Penile erections induced by alpha-MSH were, however, only partially blocked by HS014. Injections of alpha-MSH decreased food intake in food-deprived rats, whereas HS014 increased food intake. When the peptides were given together, the food intake was similar to that of saline treated controls. Locomotion/exploration and resting were not influenced by either peptide. Our data show that exogenous beta-MSH decreases food intake, and that an endogenous central melanocortinergic inhibitory tone on feeding prevails which can be blocked with HS014, leading to an increase in food intake. Our data also provide evidence that grooming, stretching and yawning in rats may be mediated by the melanocortin MC4 receptor, whereas penile erections might perhaps be mediated by some other melanocortin receptor. 相似文献
94.
95.
96.
97.
Involvement of superoxide and nitric oxide on airway inflammation and hyperresponsiveness induced by diesel exhaust particles in mice 总被引:1,自引:0,他引:1
HB Lim T Ichinose Y Miyabara H Takano Y Kumagai N Shimojyo JL Devalia M Sagai 《Canadian Metallurgical Quarterly》1998,25(6):635-644
We previously demonstrated that chronic intratracheal instillation of diesel exhaust particles (DEP) induces airway inflammation and hyperresponsiveness in the mouse, and that these effects were partially reversed by the administration of superoxide dismutase (SOD). In the present study, we have investigated the involvement of superoxide in DEP-induced airway response by analyzing the localization and activity of two enzymes: (1) a superoxide producer, NADPH cytochrome P-450 reductase (P-450 reductase), and (2) a superoxide scavenger, SOD, in the lungs of the exposed mice and controls. P-450 reductase was detected mainly in ciliated cells and clara cells: its activity was increased by the repeated intratracheal instillation of DEP. While CuZn-SOD and Mn-SOD were also present in the airway epithelium, their activity was significantly decreased following DEP instillation. Exposure to DEP doubled the level of nitric oxide (NO) in the exhaled air. DEP exposure also increased the level of constitutive NO synthase (cNOS) in the airway epithelium and inducible NO synthase (iNOS) in the macrophages. Pretreatment with N-G-monomethyl L-arginine, a nonspecific inhibitor of NO synthase, significantly reduced the airway hyperresponsiveness induced by DEP. These results indicate that superoxide and NO may each contribute to the airway inflammation and hyperresponsiveness induced by the repeated intratracheal instillation of DEP in mice. 相似文献
98.
HB Gutstein A Mansour SJ Watson H Akil HL Fields 《Canadian Metallurgical Quarterly》1998,9(8):1777-1781
The periaqueductal gray (PAG) and rostral ventromedial medulla (RVM) are important brain stem pain modulating regions. Recent evidence suggests that kappa opioids antagonize the effects of mu opioids in the RVM. However, the anatomical relationship between mu and kappa opioid receptors in PAG and RVM is not well characterized. This study examined relationships between mu and kappa opioid receptor immunoreactivity (IR) and mRNA in PAG and RVM. Brain slices were processed for either immunocytochemistry or in situ hybridization. We found considerable anatomical overlap of mu and kappa opioid IR and mRNA in the RVM and PAG. These results provide an anatomical basis for recent behavioral and electrophysiological findings in RVM, and suggest modulatory interactions between mu and kappa opioids in PAG. 相似文献
99.
BE Roggo F Petersen R Delmendo HB Jenny HH Peter J Roesel 《Canadian Metallurgical Quarterly》1994,47(2):136-142
In the course of a screening program for HIV-1 protease inhibiting activity, six new homologues of 3-alkanoyl-5-hydroxymethyl tetronic acids (1 approximately 6) and the known natural product resistomycin (7) were isolated from cultures of the Actinomycete strain DSM 7357. The substituted tetronic acids belong to a recently described structural class of secondary metabolites. The HIV-1 activity of resistomycin (7) has not been reported before. 相似文献
100.