全文获取类型
收费全文 | 194篇 |
免费 | 17篇 |
专业分类
化学工业 | 58篇 |
金属工艺 | 1篇 |
建筑科学 | 6篇 |
矿业工程 | 1篇 |
能源动力 | 2篇 |
轻工业 | 19篇 |
水利工程 | 1篇 |
无线电 | 16篇 |
一般工业技术 | 19篇 |
冶金工业 | 79篇 |
原子能技术 | 1篇 |
自动化技术 | 8篇 |
出版年
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 14篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 7篇 |
2012年 | 8篇 |
2011年 | 9篇 |
2010年 | 2篇 |
2009年 | 6篇 |
2008年 | 3篇 |
2007年 | 7篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 22篇 |
1997年 | 13篇 |
1996年 | 9篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 12篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 5篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1969年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有211条查询结果,搜索用时 187 毫秒
151.
152.
Laser-induced fluorescence spectrometry is used to profile pH changes as droplets evaporate in an electrospray plume by measuring emission spectra of 2(or 4)-[10-(dimethylamino)-3-oxo-3H-benzo[c]xanthene-7-yl]-benzenedicarboxylic acid (carboxy SNARF-1), a pH-sensitive fluorescent dye. The observed pH changes depend on initial droplet pH and polarity. In some instances, small or negligible changes of pH are observed, consistent with expected buffering. The pH of initially acidic droplets decreases along the spray axis in both positive and negative ion modes, to an extent larger than expected from solvent evaporation. This phenomenon may be a manifestation of droplet cooling, droplet subdivision, or heterogeneous charge distribution within the spray plume or within individual ES droplets. 相似文献
153.
154.
Ornduff Sidney R.; Kelsey Robert M.; O'Leary K. Daniel 《Canadian Metallurgical Quarterly》1995,9(3):249
The authors address a typology of male batterers presented by J. M. Gottman et al. (1995) based on differences in heart rate reactivity during marital conflict. Limitations of the psychophysiological and marital affect data are discussed. The interpretations offered by Gottman et al. are challenged along conceptual and methodological grounds, and alternatives are offered. The importance and implications of these results for assessment and treatment await clarification of the mechanisms underlying the physiological differences that characterize Type 1 and Type 2 batterers. Until such clarification, it seems premature to render conclusions regarding the treatment of either type of male batterer. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
155.
Exact solutions for diffusion in single phase binary alloy systems with constant diffusion coefficient and zero-flux boundary
condition have been evaluated to establish the optimum zone size of applicability. Planar, cylindrical and spherical interface
geometry, and finite, singly infinite, and doubly infinite systems are treated Two solutions are presented for each geometry,
one well suited to short diffusion times, and one to long times. The effect of zone-size on the convergence of these solutions
is discussed. A generalized form of the diffusion solution for doubly infinite systems is proposed. 相似文献
156.
JF Baskar PP Smith G Nilaver RA Jupp S Hoffmann NJ Peffer DJ Tenney AM Colberg-Poley P Ghazal JA Nelson 《Canadian Metallurgical Quarterly》1996,70(5):3207-3214
The human cytomegalovirus (HCMV) major immediate-early promoter (MIEP) is one of the first promoters to activate upon infection. To examine HCMV MIEP tissue-specific expression, transgenic mice were established containing the lacZ gene regulated by the MIEP (nucleotides -670 to +54). In the transgenic mice, lacZ expression was demonstrated in 19 of 29 tissues tested by histochemical and immunochemical analyses. These tissues included brain, eye, spinal cord, esophagus, stomach, pancreas, kidney, bladder, testis, ovary, spleen, salivary gland, thymus, bone marrow, skin, cartilage, and cardiac, striated and smooth muscles. Although expression was observed in multiple organs, promoter activity was restricted to specific cell types. The cell types which demonstrated HCMV MIEP expression included retinal cells of the eye, ductile cells of the salivary gland, exocrine cells of the pancreas, mucosal cells of the stomach and intestine, neuronal cells of the brain, muscle fibers, thecal cells of the corpus luteum, and Leydig and sperm cells of the testis. These observations indicate that the HCMV MIEP is not a pan-specific promoter and that the majority of expressing tissues correlate with tissues naturally infected by the virus in the human host. 相似文献
157.
158.
DJ Mundt JL Kelsey AL Golden H Pastides AT Berg J Sklar T Hosea MM Panjabi 《Canadian Metallurgical Quarterly》1993,18(5):595-602
An epidemiologic case-control study of herniated lumbar intervertebral disc was conducted in Springfield, Massachusetts, New Brunswick, New Jersey, and New York, New York, to evaluate the role of several possible risk factors in the etiology of this disorder. Patients with signs and symptoms of herniated lumbar disc (N = 287) were matched to control subjects without back pain by age, sex, source of care, and geographic area. Of the total case-subject group, 177 were confirmed by surgery, computed tomographic scan, myelogram, or magnetic resonance imaging. This article focuses on non-occupational lifting, an activity not previously reported on. Frequent lifting of objects or children weighing 25 or more pounds with knees straight and back bent was associated with increased risk of herniated lumbar disc. This association was particularly strong among confirmed case subjects (relative risk = 3.95). Positive associations among confirmed case subjects were also seen for frequent lifting with arms extended (relative risk = 1.87) and twisting while lifting (relative risk = 1.90). No associations were found for frequent stretching or carrying. If confirmed in other investigations, these data suggest that instruction in lifting techniques should be extended into the home. 相似文献
159.
In Exp 1, rats with small medial septal lesions were less able than were control rats to remember the location of the arm of a Y maze they had been forced to enter on the preceding sample run. Moreover, as the retention interval between the sample and choice runs on this spatial delayed nonmatching-to-sample (DNMTS) task was increased to 1 and 2 min, the magnitude of the deficit increased. In contrast, these same lesioned rats were not deficient in Exp 2 in their ability to remember the object they had encountered in the straight alley on the sample run. In fact, when the retention interval was increased to 1 min on this nonspatial DNMTS task, the rats with medial septal lesions were more accurate than were the controls. This pattern of results did not appear to be due to task difficulty, recovery of function, or sequence of training. Rather, these results indicate that damage to the septohippocampal system disrupts spatial working memory more than it disrupts nonspatial working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
160.
Miczek Klaus A.; Kelsey John E.; Grossman Sebastian P. 《Canadian Metallurgical Quarterly》1972,79(2):318
Conducted 4 experiments with a total of 99 male albino Sprague-Dawley rats with septal lesions and 76 sham-operated controls. Ss tested 5 or 10 days, but not 2 days, after septal lesions acquired a 2-way conditioned avoidance response faster than controls. Punishment in a passive-avoidance test was least effective in suppressing milk-licking 2 days after septal lesions, and increased in effectiveness as a function of time after surgery. All experimental Ss were significantly more reactive to footshock than controls in a jump-flinch test. Results support the hypothesis that different aversively-controlled behaviors are mediated by different mechanisms within the septum. (31 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献