全文获取类型
收费全文 | 811篇 |
免费 | 30篇 |
专业分类
电工技术 | 12篇 |
综合类 | 1篇 |
化学工业 | 74篇 |
金属工艺 | 3篇 |
机械仪表 | 8篇 |
建筑科学 | 22篇 |
矿业工程 | 3篇 |
能源动力 | 5篇 |
轻工业 | 111篇 |
水利工程 | 2篇 |
石油天然气 | 4篇 |
无线电 | 44篇 |
一般工业技术 | 89篇 |
冶金工业 | 388篇 |
原子能技术 | 5篇 |
自动化技术 | 70篇 |
出版年
2022年 | 8篇 |
2021年 | 14篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 8篇 |
2013年 | 29篇 |
2012年 | 25篇 |
2011年 | 27篇 |
2010年 | 19篇 |
2009年 | 19篇 |
2008年 | 38篇 |
2007年 | 37篇 |
2006年 | 36篇 |
2005年 | 28篇 |
2004年 | 16篇 |
2003年 | 22篇 |
2002年 | 28篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 22篇 |
1998年 | 64篇 |
1997年 | 52篇 |
1996年 | 32篇 |
1995年 | 32篇 |
1994年 | 22篇 |
1993年 | 34篇 |
1992年 | 12篇 |
1991年 | 5篇 |
1990年 | 11篇 |
1989年 | 15篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 15篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 13篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1966年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有841条查询结果,搜索用时 0 毫秒
1.
2.
3.
Managed care has become the dominant economic force in health care delivery and has challenged many of professional psychology's training concepts and cherished attitudes. Organized psychology has not kept pace with the rapid industrialization of health care during the past decade and has been overlooked as a participant in health economic decisions. A number of changes need to be made in professional education and training if psychology is to be a major player in the new health systems. Additionally, professional psychologists must reexamine some of their most generally accepted attitudes and beliefs if they are to survive. These are described with a number of recommendations for the survival of an embattled profession. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
JM Cummings RO Parra JA Boullier 《Canadian Metallurgical Quarterly》1995,45(3):414-8; discussion 418-20
OBJECTIVES: An evolving technology for the treatment of bladder outlet obstruction due to benign prostatic hyperplasia (BPH) is the use of the side-firing neodymium: yttrium-aluminum-garnet (Nd:YAG) laser to achieve prostatic tissue ablation. The purpose of this study was to determine the short-term efficacy of this procedure in both an objective and subjective manner. METHODS: We examined this technique by carefully evaluating our first 25 men undergoing the procedure. Each patient was subjected to careful symptom score analysis using the American Urological Association symptom index and multichannel urodynamics, including pressure-flow studies both preoperatively and at 3 months postoperatively. RESULTS: At the 3-month follow-up, symptom scores improved from a preoperative mean of 11.4 to 7.2 and the mean maximum flow rate improved from 6.1 to 14.5 cc/s. These are both significant at P < 0.001. Statistically similar improvement was seen in detrusor pressure at opening and at maximum flow. Eighty percent of the men studied had at least a 50% reduction in symptom score and a 50% improvement in flow rate. CONCLUSIONS: We conclude that laser prostatectomy is a promising minimally invasive treatment for bladder outlet obstruction secondary to BPH and deserves further evaluation at longer terms of follow-up. 相似文献
5.
Administering the Neuropsychiatric Inventory (NPI), we examined the behavioral symptoms of 22 patients with progressive supranuclear palsy (PSP), 50 patients with Alzheimer's disease, and 40 controls. PSP patients exhibited apathy (91%), disinhibition (36%), dysphoria (18%) and anxiety (18%), but rarely (< 9%) irritability, abnormal motor behaviors, or agitation. Apathy in PSP was significantly associated with executive dysfunction. The presence of high apathy and low agitation and anxiety scale scores correctly identified the PSP patients 85% of the time. Evaluating the behavioral abnormalities of patients with neurodegenerative disorders will aid diagnosis and facilitate management. 相似文献
6.
We have developed a three-dimensional toroidal gyrokinetic particle simulation to study tokamak turbulence. The gyrokinetic equations are a reduced set derived from the Vlasov-Maxwell equations by phase averaging over the ion gyromotion and keeping only the time and space scales relevant for describing tokamak plasmas. These large-scale simulations in complex geometry can produce gigabytes of data consisting of large 3D arrays evolving in time. Visualization plays a critical role in going from the raw nonlinear solution of these complex equations to a simplified theoretical model explaining the essential underlying physics 相似文献
7.
Hamed Rezaishiraz Andrew Hyland Martin C Mahoney Richard J O'Connor K Michael Cummings 《Nicotine & tobacco research》2007,9(11):1139-1146
The present study investigated whether treatment with the combination of denicotinized cigarettes and 21-mg nicotine patch for 2 weeks before a designated quit date could lessen cravings for smoking, thereby helping smokers abstain from smoking. The study was a randomized controlled clinical trial conducted at Roswell Park Cancer Institute, Buffalo, New York, in 2004 and 2005. Patients included 98 adult heavy smokers (using 20 or more cigarettes/day). Half of the subjects received 2 weeks of combination of denicotinized cigarettes (Quest 3) and 21-mg nicotine patch for 2 weeks before the quit date. The remaining smokers were switched to light cigarettes (Quest 1) during the 2 weeks before the quit date. After the quit date, all subjects received counseling for smoking cessation and were provided nicotine patches for up to 8 weeks after the quit date. Self-reported cravings for smoking, withdrawal symptoms, and smoking abstinence were measured at predetermined intervals using phone-based surveys and in clinical visits. The group that used denicotinized cigarettes and nicotine patch before quitting reported less frequent and less intense cravings for cigarettes in the 2 weeks before and after the designated quit date. Self-reported withdrawal symptoms and quit rates did not differ significantly between the groups. The use of a denicotinized cigarette combined with the nicotine patch appears to lessen cravings to smoke in the immediate postcessation period. A larger, better-powered study is needed to test if this treatment combination has merit for increasing quit rates. 相似文献
8.
R Wong G Thomas B Cummings P Froud W Shelley R Withers J Williams 《Canadian Metallurgical Quarterly》1998,40(2):437-446
BACKGROUND: Research on the subject of insight has been hampered by difficulties in definition and reliable measurement. METHODS: We compared several rating scales to measure insight on a group of 33 psychotic patients as well as assessing patients' psychopathology, clinical characteristics and cognitive functioning. RESULTS: Most currently used scales showed a high degree of inter-correlation. Measures of insight related strongly to the presence of delusions; grandiosity (inversely), and depression (positively). Higher insight scores correlated with indices of treatment compliance and inversely with substance abuse. Measures of pre-morbid IQ and impaired executive functioning, including the Wisconsin Card Sorting Test were not associated with poor insight. CONCLUSIONS: The study highlights aspects of psychopathology and clinical variables particularly related to insight and supports the continued use of standardized scales in further research in this area. 相似文献
9.
1H dipolar decoupled 13C n.m.r. experiments with the aid of the magic angle spinning technique have been used to determine the graft content and the isomer content of the polybutadiene grafts in a graft copolymer with isotactic polypropylene. 相似文献
10.
The study of numerical abilities, and how they are acquired, is being used to explore the continuity between ontogenesis and environmental learning. One technique that proves useful in this exploration is the artificial simulation of numerical abilities with neural networks, using different learning paradigms to explore development. A neural network simulation of subitization, sometimes referred to as visual enumeration, and of counting, a recurrent operation, has been developed using the so-called multi-net architecture. Our numerical ability simulations use two or more neural networks combining supervised and unsupervised learning techniques to model subitization and counting. Subitization has been simulated using networks employing unsupervised self-organizing learning, the results of which agree with infant subitization experiments and are comparable with supervised neural network simulations of subitization reported in the literature. Counting has been simulated using a multi-net system of supervised static and recurrent backpropagation networks that learn their individual tasks within an unsupervised, competitive framework. The developmental profile of the counting simulation shows similarities to that of children learning to count and demonstrates how neural networks can learn how to be combined together in a process modelling development. 相似文献