全文获取类型
收费全文 | 4094篇 |
免费 | 75篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 38篇 |
综合类 | 1篇 |
化学工业 | 388篇 |
金属工艺 | 54篇 |
机械仪表 | 47篇 |
建筑科学 | 89篇 |
矿业工程 | 7篇 |
能源动力 | 39篇 |
轻工业 | 323篇 |
水利工程 | 16篇 |
石油天然气 | 6篇 |
无线电 | 201篇 |
一般工业技术 | 360篇 |
冶金工业 | 2185篇 |
原子能技术 | 17篇 |
自动化技术 | 401篇 |
出版年
2022年 | 13篇 |
2021年 | 31篇 |
2020年 | 32篇 |
2019年 | 35篇 |
2018年 | 37篇 |
2017年 | 36篇 |
2016年 | 34篇 |
2015年 | 33篇 |
2014年 | 48篇 |
2013年 | 123篇 |
2012年 | 80篇 |
2011年 | 112篇 |
2010年 | 88篇 |
2009年 | 78篇 |
2008年 | 102篇 |
2007年 | 110篇 |
2006年 | 94篇 |
2005年 | 67篇 |
2004年 | 67篇 |
2003年 | 70篇 |
2002年 | 69篇 |
2001年 | 45篇 |
2000年 | 54篇 |
1999年 | 107篇 |
1998年 | 592篇 |
1997年 | 353篇 |
1996年 | 248篇 |
1995年 | 156篇 |
1994年 | 116篇 |
1993年 | 152篇 |
1992年 | 47篇 |
1991年 | 53篇 |
1990年 | 43篇 |
1989年 | 62篇 |
1988年 | 40篇 |
1987年 | 39篇 |
1986年 | 48篇 |
1985年 | 58篇 |
1984年 | 26篇 |
1983年 | 33篇 |
1982年 | 41篇 |
1981年 | 34篇 |
1980年 | 51篇 |
1979年 | 25篇 |
1978年 | 23篇 |
1977年 | 46篇 |
1976年 | 86篇 |
1975年 | 26篇 |
1972年 | 12篇 |
1963年 | 13篇 |
排序方式: 共有4172条查询结果,搜索用时 15 毫秒
31.
Examines, in the context of cancer illness, S. E. Taylor and J. D. Brown's (see record 1988-16903-001) claim that mental health is to a degree predicated on illusory beliefs about the self, one's control, and the future. The Heroic Model (HM), a stance toward cancer characterized by belief that positive thoughts and feelings, a fighting spirit, and an optimistic outlook will promote cancer remission, is presented as paradigmatic of Taylor and Brown's thesis. Strong and weak formulations of the HM (the former affirming a direct influence of mental states over physical processes, and the latter affirming indirect effects only) are examined with respect to their potential adaptive value as true or false beliefs, with different consequences for well-being. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
32.
33.
34.
Comments on an article by T. R. Elliott and E. K. Byrd (see record 1987-23075-001), in which the authors conducted a citation analysis of articles in Rehabilitation Psychology, Volumes 27-29. They claimed to identify influential authors and publications useful for training and research in rehabilitation psychology. Their method of citation analysis, however, appears to have distorted their results. Crisp discusses the problems with their methodology, and makes suggestions for using a different citation method, using more than three volumes of the journal, and including other journals in the analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
35.
W Astfalk FM H?cker HJ Kirschner G Stuhldreier P Schweizer 《Canadian Metallurgical Quarterly》1997,122(10):898-900
Since 1990, we have been conducting ambulatory pediatric surgery in an unit established solely for this purpose, supported by a team of kindergarten teachers, pediatric nurses, anesthesiologists and pediatric surgeons. This prospective investigation includes all ambulatory pediatric operations performed in our department from 1990 to 1995. In this time 3665 infants and children between the ages of 6 weeks and 18 years underwent an ambulatory operation. The ratio male to female was 4.1 to 1. The series consists of 1400 inguinal hernias, 722 inguinal testes, 191 hydroceles/funiculoceles, 75 umbilical hernias, 667 phimoses, 70 meatotomies, 59 hemangiomas, 217 endoscopies and 264 other surgical procedures. Postoperative complications defined as secondary hemorrhage, fever, obvious vomiting, urine retention and laryngospasm upon terminating anesthesia accompanied by subsequent vomiting occurred in 59 (1.6%) of all infants and children. Wound infections were seen in 0.48% (17/3517) of all patients. The recurrence rate for inguinal hernias were 0.79% and 1.12% for inguinal testes. Our experience enables us to summarize that a variety of pediatric operations can be performed today as ambulatory procedures. Nevertheless one must be prepared for the occurrence of complications and always have capacities free for inpatient care where adequate observation and treatment are available. Further improvement is necessary in quality management. In the last 20 years only a few data have been published about recurrence rates after pediatric ambulatory operations for inguinal hernias and inguinal testes. Therefore we started a prospective long- term study. 相似文献
36.
37.
Several samples of exhaust diesel soot are investigated by inverse gas chromatography and linear solvation energy relationship (LSER) modelling according to their soluble organic fraction content and their time of exposure in oxidative conditions. The results demonstrate the evolution of the adsorptive properties of the studied materials towards volatile compounds during the oxidation under NO2. 相似文献
38.
There is often a need to approximate integrals of highly oscillatory functions when studying scattering and diffraction of electromagnetic waves. This paper presents a method of estimating certain types of these integrals by evaluating one interpolating function and performing one or two relatively easy numerical integrations. The method is demonstrated for the case of a Fresnel integral 相似文献
39.
Insulin-like growth factor I activates the invasion suppressor function of E-cadherin in MCF-7 human mammary carcinoma cells in vitro 总被引:1,自引:0,他引:1
ME Bracke BM Vyncke EA Bruyneel SJ Vermeulen GK De Bruyne NA Van Larebeke K Vleminckx FM Van Roy MM Mareel 《Canadian Metallurgical Quarterly》1993,68(2):282-289
The calcium-dependent cell-cell adhesion molecule E-cadherin has been shown to counteract invasion of epithelial neoplastic cells. Using three monoclonal antibodies, we have demonstrated the presence of E-cadherin at the surface of human MCF-7/6 mammary carcinoma cells by indirect immunofluorescence coupled to flow cytometry and by immunocytochemistry. Nevertheless, MCF-7/6 cells failed to aggregate in a medium containing 1.25 mM CaCl2, and they were invasive after confrontation with embryonic chick heart fragments in organ culture. Treatment of MCF-7/6 cells with 0.5 microgram ml-1 insulin-like growth factor I (IGF-I) led to homotypic aggregation within 5 to 10 min and inhibited invasion in vitro during at least 8 days. The effect of IGF-I on cellular aggregation was insensitive to cycloheximide. However, monoclonal antibodies that interfered with the function of either the IGF-I receptor (alpha IR3) or E-cadherin (HECD-1, MB2) blocked the effect of IGF-I on aggregation. The effects of IGF-I on aggregation and on invasion could be mimicked by 1 microgram ml-1 insulin, but not by 0.5 microgram ml-1 IGF-II. The insulin effects were presumably not mediated by the IGF-I receptor, since they could not be blocked by an antibody against this receptor (alpha IR3). Our results indicate that IGF-I activates the invasion suppressor role of E-cadherin in MCF-7/6 cells. 相似文献
40.