全文获取类型
收费全文 | 5537篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
综合类 | 2篇 |
化学工业 | 20篇 |
机械仪表 | 1篇 |
建筑科学 | 5篇 |
能源动力 | 2篇 |
轻工业 | 17篇 |
水利工程 | 1篇 |
无线电 | 8篇 |
一般工业技术 | 34篇 |
冶金工业 | 5418篇 |
原子能技术 | 1篇 |
自动化技术 | 30篇 |
出版年
2022年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 7篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 10篇 |
2007年 | 11篇 |
2006年 | 8篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 8篇 |
1999年 | 168篇 |
1998年 | 1675篇 |
1997年 | 922篇 |
1996年 | 583篇 |
1995年 | 336篇 |
1994年 | 296篇 |
1993年 | 312篇 |
1992年 | 40篇 |
1991年 | 62篇 |
1990年 | 70篇 |
1989年 | 61篇 |
1988年 | 71篇 |
1987年 | 70篇 |
1986年 | 60篇 |
1985年 | 66篇 |
1984年 | 4篇 |
1983年 | 10篇 |
1982年 | 27篇 |
1981年 | 27篇 |
1980年 | 55篇 |
1979年 | 4篇 |
1978年 | 13篇 |
1977年 | 156篇 |
1976年 | 343篇 |
1975年 | 5篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1955年 | 4篇 |
排序方式: 共有5540条查询结果,搜索用时 46 毫秒
991.
RA Bruce T DeRouen DR Peterson JB Irving N Chinn B Blake V Hofer 《Canadian Metallurgical Quarterly》1977,39(6):833-840
In a follow-up study of 1,852 men with coronary heart disease, 195 deaths occurred within the first 3 years (33 +/- 13 months [mean +/- standard deviation]). Analysis of these cases indicated that the risk of sudden cardiac death in ambulatory men with clinical manifestations of coronary heart disease may be readily estimated from noninvasive clinical and exercise criteria. The important predictors are indexes of the severity of coronary heart disease and impairment of peak left ventricular function demonstrated with symptom-limited maximal exercise. The advantages of these predictors are that they may be elicited on the initial study as well as on follow-up noninvasive examinations of ambulatory patients. The appearance of nonelectrocardiographic predictors in serial examinations may provide an indication for invasive studies and be a more important finding than the ischemic S-T reponse to exertion. 相似文献
992.
993.
RS Sherwin W Tamborlane R Hendler L Saccá RA DeFronzo P Felig 《Canadian Metallurgical Quarterly》1977,45(5):1104-1107
Somatostatin was infused for 6 h into seven normal subjects with and without a replacement dose of glucagon. The addition of glucagon to somatostatin resulted in a 30-40% rise in plasma glucagon, whereas plasma insulin declined by 40-50% in both treatment groups. Plasma glucose and glucose production initially increased 2-fold with glucagon replacement, and subsequently declined by 2-3 h to levels comparable to those observed with somatostatin alone. After 6 h plasma glucose and glucose kinetics were no different whether or not glucagon was present. The rise in blood ketones after somatostatin was not exaggerated by glucagon replacement. We conclude that glucagon lack is not a modifying factor in the late hyperglycemic and hyperketonemic response to prolonged infusions of somatostatin. 相似文献
994.
This paper describes recent developments in the use of steel and concrete composite construction for offshore structures. The developments concern filling steel tubular members with cementitious materials to improve static and fatigue strength of memebers and joints. Applications are described for jacket to pile connections, nodal joints and repair situations. 相似文献
995.
The application of generalized fracture mechanics to ductile materials is considered. The deformations leading to crack propagation in SEN specimens of a copper-beryllium alloy in two conditions were established experimentally and can be described in terms of the generalized theory. In particular, it was possible to define and measure a surface work for fracture propagation in specimens subject to general yielding. The values of surface work obtained were 7.5×108 mJ m–2 for the alloy in a low yield stress (235 MPa) condition and 1.2×108 mJ m–2 for the high yield-stress (725 MPa) condition.On secondment from RARDE (Ministry of Defence) Fort Halstead, Sevenoakes, Kent. 相似文献
996.
997.
998.
999.
Basophilic stippling of the circulating erythrocytes is characteristic of the Mongolian gerbil. Its enzymatic digestion along with the concomitant removal of diffuse erythrocytic polychromasia by the action of ribonuclease demonstrates that it represents microscopically visible aggregates of cytoplasmic ribonucleoprotein, presumably of ribosomal origin. Up to 40% of the total circulating erythrocytes may be stippled in foetal and newborn animals. There is then a progressive decline in incidence until adult levels are attained at least by 20 weeks of age. The bone marrow of the adult gerbil contains a higher proportion of stippled red cells than the circulating blood. The stippling can be either coarse or fine and observable in both polychromatophilic and orthochromic cells. It is suggested that erythrocytes with basophilic stippling are relatively immature red cells still demonstrating remnants of cytoplasmic ribonucleoprotein. 相似文献
1000.
We have used dacryoscintigraphy to study the efficiency of the lacrimal system following the repair of a divided lower canaliculus in 4 children. This test has been reliable in evaluating lacrimal function and suggests that a canaliculus can be repaired and splinted satisfactorily. Our experience with dacryoscintigraphy confirms that it is a safe comfortable, and reliable method for studying the patency of the lacrimal drainage system. 相似文献