全文获取类型
收费全文 | 2064篇 |
免费 | 12篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 40篇 |
金属工艺 | 4篇 |
机械仪表 | 2篇 |
建筑科学 | 9篇 |
能源动力 | 5篇 |
轻工业 | 75篇 |
水利工程 | 11篇 |
石油天然气 | 1篇 |
无线电 | 15篇 |
一般工业技术 | 34篇 |
冶金工业 | 1828篇 |
原子能技术 | 5篇 |
自动化技术 | 46篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2019年 | 6篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 2篇 |
2013年 | 13篇 |
2012年 | 18篇 |
2011年 | 18篇 |
2010年 | 10篇 |
2009年 | 17篇 |
2008年 | 19篇 |
2007年 | 14篇 |
2006年 | 13篇 |
2005年 | 11篇 |
2004年 | 12篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 61篇 |
1998年 | 553篇 |
1997年 | 338篇 |
1996年 | 224篇 |
1995年 | 113篇 |
1994年 | 105篇 |
1993年 | 110篇 |
1992年 | 16篇 |
1991年 | 27篇 |
1990年 | 23篇 |
1989年 | 29篇 |
1988年 | 27篇 |
1987年 | 23篇 |
1986年 | 20篇 |
1985年 | 30篇 |
1983年 | 1篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 33篇 |
1976年 | 92篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有2076条查询结果,搜索用时 8 毫秒
101.
102.
A new technique is described for evaluating trauma to the elbow. The modified radial head--capitellum view is an alternative radiological projection to that described by Greenspan and Norman (the radial head--capitellum view). This new projection is useful in demonstrating minimally displaced or non-displaced fractures of the radial head, capitellum and coronoid process. 相似文献
103.
We studied 13 consecutive infants admitted to our Neonatal Intensive Care Unit over 37 months from 1 June 1994 to 30 June 1997, who were diagnosed with severe persistent pulmonary hypertension (PPHN) meeting extracorporeal membrane oxygenation (ECMO) criteria as defined by Bartlett and/or Short. They were managed with conservative ventilation strategy, with emphasis on the use of moderate ventilatory pressures whilst avoiding paralysis. Peak inspiratory pressure (PIP) on intermittent mandatory ventilation was adjusted according to adequate chest excursion. High PIP was avoided. Two main ventilatory techniques were used: 1) low ventilatory rate < or = 40/min, PIP 20 to 30 cmH2O, inspiratory time (IT) 0.5 seconds, positive end-expiratory pressure (PEEP) 5 cmH2O, and 2) high ventilatory rate 100/min, PEEP 0 cmH2O, IT 0.3 seconds. The aim was to keep preductal PaO2 > or = 50 mmHg. We did not sought to achieve alkalotic pH or low PaCO2. When PIP requirements exceeded 30 to 35 cmH2O, the use of an alternative rescue therapy such as pulmonary vasodilator, high frequency ventilation and/or surfactant were considered. Only 1 infant died of PPHN. Low mortality due to PPHN can be achieved using this strategy. There is a need for a randomised controlled trial to compare this strategy with other alternative treatment strategies. 相似文献
104.
STUDY DESIGN: The biomechanical influence of in situ setting hydroxyapatite cement was examined for use in pedicle screw revision surgery. Pull-out testing of control and pedicle screws augmented with hydroxyapatite cement was performed in human cadaver vertebrae. OBJECTIVES: To determine the immediate effect of using hydroxyapatite cement to augment revision pedicle screws after failure of the primary pedicle screw fixation. SUMMARY OF BACKGROUND DATA: The potential problems associated with using polymethylmethacrylate to augment revision pedicular instrumentation have prompted the search for other solutions. The introduction of resorbable hydroxyapatite pastes may have provided new biocompatible solutions for pedicle screw revision. METHODS: Ten human cadaver vertebrae were instrumented with 6.0-mm pedicle screws in each pedicle. The screws were loaded to failure in axial tension (pull-out). The failed pedicles then were instrumented with 7.0-mm pedicle screws, either augmented with hydroxyapatite cement or nonaugmented, which also were loaded to failure. Finally, the nonaugmented 7.0-mm screw hole was reinstrumented with a hydroxyapatite cement-augmented, 7.0-mm pedicle screw and loaded to failure. RESULTS: The pull-out strength of the 7.0-mm, hydroxyapatite cement-augmented screws was 325% (P = 2.9 x 10(-5)) of that of the 6.0-mm control screws, whereas the strength of the 7.0-mm nonaugmented screws was only 73% (P = 2.0 x 10(-2)) of that of the 6.0-mm control screws. The 7.0-mm screws augmented with hydroxyapatite cement also were able to salvage 7.0-mm pull-out sites to 384% (P = 6.9E-5) of the pull-out strength of the 7.0-mm nonaugmented screws. CONCLUSIONS: Hydroxyapatite cement may be a mechanically viable alternative to polymethyl methacrylate for augmenting revision pedicular instrumentation and should be considered for future experimental, animal, and clinical testing. 相似文献
105.
106.
107.
Notes that documentation of the reversibility of posthypnotic amnesia has been hampered by the correlation of hypnotizability with the initial level of response to amnesia suggestions. 691 college students were placed in groups differing in hypnotic susceptibility that could be matched for initial amnesia recall, thereby eliminating the ceiling effect. At virtually every point along the distribution of initial amnesia response, hypnotizable Ss were significantly better able than insusceptible Ss to recapture the previously blocked memories after the amnesia suggestion was lifted. Conversely, those Ss who showed reversibility of amnesia were more responsive overall to hypnosis than those who did not. It is concluded that reversibility is of value in distinguishing between amnesia and pseudoamnesia and between partial amnesia and nonamnesia. Furthermore, reversibility helps define posthypnotic amnesia as a process involving the disruption of retrieval processes in memory. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
109.
110.