全文获取类型
收费全文 | 1158篇 |
免费 | 39篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 23篇 |
综合类 | 1篇 |
化学工业 | 172篇 |
金属工艺 | 23篇 |
机械仪表 | 18篇 |
建筑科学 | 61篇 |
矿业工程 | 5篇 |
能源动力 | 20篇 |
轻工业 | 112篇 |
水利工程 | 15篇 |
石油天然气 | 2篇 |
无线电 | 49篇 |
一般工业技术 | 169篇 |
冶金工业 | 412篇 |
原子能技术 | 13篇 |
自动化技术 | 103篇 |
出版年
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 14篇 |
2018年 | 9篇 |
2017年 | 13篇 |
2016年 | 17篇 |
2015年 | 18篇 |
2014年 | 20篇 |
2013年 | 64篇 |
2012年 | 51篇 |
2011年 | 57篇 |
2010年 | 33篇 |
2009年 | 36篇 |
2008年 | 48篇 |
2007年 | 49篇 |
2006年 | 48篇 |
2005年 | 44篇 |
2004年 | 30篇 |
2003年 | 28篇 |
2002年 | 27篇 |
2001年 | 30篇 |
2000年 | 32篇 |
1999年 | 22篇 |
1998年 | 71篇 |
1997年 | 38篇 |
1996年 | 40篇 |
1995年 | 28篇 |
1994年 | 25篇 |
1993年 | 32篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 15篇 |
1988年 | 14篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 17篇 |
1984年 | 17篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 7篇 |
1978年 | 9篇 |
1977年 | 12篇 |
1976年 | 11篇 |
1975年 | 6篇 |
1973年 | 5篇 |
1972年 | 5篇 |
排序方式: 共有1198条查询结果,搜索用时 78 毫秒
1.
Manika Chaudhary Milan Singh Ashwani Kumar Yogendra K. Gautam Anil K. Malik Yogesh Kumar Beer Pal Singh 《Ceramics International》2021,47(2):2094-2106
The current research work presents a facile and cost–effective co-precipitation method to prepare doped (Co & Fe) CuO and undoped CuO nanostructures without usage of any type of surfactant or capping agents. The structural analysis reveals monoclinic crystal structure of synthesized pure CuO and doped-CuO nanostructures. The effect of different morphologies on the performance of supercapacitors has been found in CV (cyclic voltammetry) and GCD (galvanic charge discharge) investigations. The specific capacitances have been obtained 156 (±5) Fg?1, 168(±5) Fg?1 and 186 (±5) Fg?1 for CuO, Co-doped CuO and Fe-doped CuO electrodes, respectively at scan rate of 5 mVs?1, while it is found to be 114 (±5) Fg?1, 136 (±5) Fg?1 and 170 (±5) Fg?1 for CuO, Co–CuO and Fe–CuO, respectively at 0.5 Ag-1 as calculated from the GCD. The super capacitive performance of the Fe–CuO nanorods is mainly attributed to the synergism that evolves between CuO and Fe metal ion. The Fe-doped CuO with its nanorods like morphology provides superior specific capacitance value and excellent cyclic stability among all studied nanostructured electrodes. Consequently, it motivates to the use of Fe-doped CuO nanostructures as electrode material in the next generation energy storage devices. 相似文献
2.
Stolorow Robert D.; Atwood George E.; Orange Donna M. 《Canadian Metallurgical Quarterly》2006,23(1):184
In omitting crucial words and sentencees, neglecting relevant citations, and overlooking important distinctions, Jon Mills' (see record 2005-04819-001) critique of relational psychoanalysis significantly misrepresents the authors' viewpoint. This viewpoint seeks to contextualize, but not to nullify, individual worlds of experience and their limiting horizons. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Immunisation practices were examined at 6 hospitals in the western Cape during the latter half of 1992 to determine whether these practices had improved subsequent to the February 1991 resolution of the Health Matters Committee (HMC) on immunisation in hospitals, and since a similar study was undertaken in 1990. Exit interviews were conducted with the escorts of all children aged 3-59 months who attended the study hospitals on the days designated for the study. In the second study, 88 of the 311 children studied (28.3%) were in need of immunisation on arrival, but only 12 of the 88 (13.6%) were immunised during the hospital visit. There was no evidence of an increase in requests to see children's Road-to-Health cards (37.1% compared with 35.2% previously). The incidence of missed opportunities for measles immunisation in children aged 6-59 months remained unacceptably high (51.4% compared with 63.7% previously, when a strict definition was used; and 15.7% compared with 18.1% previously, when a lenient definition was used). Health authorities at all levels need to take urgent action to address the problem of missed opportunities for immunisation at hospitals. 相似文献
4.
Haley William E.; Larson Dale G.; Kasl-Godley Julia; Neimeyer Robert A.; Kwilosz Donna M. 《Canadian Metallurgical Quarterly》2003,34(6):626
Professional psychologists are increasingly likely to encounter opportunities to work with patients and families facing end-of-life issues. Psychologists can provide psychological assessment, intervention for patients and families, consultation with and support of health care team members, grief therapy, and program development and evaluation. Psychological services are useful for healthy individuals who wish to make thoughtful plans about their own future care, patients with life-limiting illnesses, families stressed by providing end-of-life care, bereaved individuals, and health care providers who face issues of burnout and strain. Several challenges for psychologists working in end-of-life care are noted, including training, development of clear roles, and reimbursement. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Mobile gene elements associated with integrons, including as gene cassettes, have been proposed to play an important role in bacterial evolution by providing an extensive genetic resource. This study hypothesized that critical genes for enzymes involved in EBPR systems, including those involved in polyphosphate, PHA and glycogen synthesis, may be present in mobile gene cassettes. Although no such genes were identified in any of the functional and deteriorated enhanced biological phosphorus removal (EBPR) laboratory-scale SBR systems examined here, many of the open reading frames (ORFs) remained unidentified because of the incompleteness of publicly available databases. An ORF of unknown function (SBR6-2) was encountered in deteriorated EBPR system with an unexpectedly high frequency, comprising 35% of the gene cassette-associated sequences for that system. 相似文献
6.
M. J. Vissenberg P. W. de Bont E. M. van Oers R. A. de Haan E. Boellaard A. M. van der Kraan V. H. J. de Beer R. A. van Santen 《Catalysis Letters》1996,40(1-2):25-29
Ion exchanged CoNaY was sulfided at 473 and 673 K and subsequently heated in He at 673 and 773 K. The resulting samples were characterized by means of overall sulfur analysis, temperature programmed Ar treatment and Fourier transform infrared spectroscopy. It was shown that during He flushing at sufficiently high temperature a protolysis reaction occurs resulting in the decomposition of Co sulfide into Co2+ ions and H2S. 相似文献
7.
Introduces this special issue of Psychoanalytic Psychology. This special issue on Women, Psychoanalysis, and Gender is a commemoration of the capability, influence, acceptance, and authority of women in the community of psychoanalysis. In this issue, we turn to both new and more established voices in an expanded arena of gender, culture, and psychoanalysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Results from laboratory experiments and a 500 tonnes per month pilot plant have been used to draw up criteria for designing the crystallization of an organic salt from its aqueous solution. The crystallization kinetics were determined in a continuous forced circulation crystallizer. The experiments in the forced circulation evaporative crystallizer were carried out and evaluated in accordance with the MSMPR (mixed suspension mixed product removal) concept.The residence time was varied between 0.8 and 10 hours, and the density of the suspension between 180 and 870 kg m?3. It was found that, within the residence time and suspension density ranges studied, growth and nucleation rates have the same dependence on the supersaturation. On the other hand, the nucleation rate decreases with increasing suspension density. If the crystallization kinetics and other design criteria, such as vapour velocity, i.e. supersaturation ratio in the vicinity of the evaporative surface, or height of liquid above the heat exchangers, are taken into account, it is possible to obtain a space—time yield which is five times higher than in the pilot plant, so that the plant to be built can be designed to be correspondingly smaller. 相似文献
9.
Lord Charles G.; Desforges Donna M.; Fein Steven; Pugh Marilyn A.; Lepper Mark R. 《Canadian Metallurgical Quarterly》1994,66(4):658
Social typicality effects occur when people apply their attitudes more consistently toward typical than toward atypical category members presumably because attitudes are directed toward the prototypic category member. Four studies tested whether individuals also apply social policy attitudes more consistently toward typical than toward atypical persons affected by the policy. Study 1 used attitude concept maps to assess how extensively individuals spontaneously reference the typical person affected by a social policy. Death penalty proponents did so more than did opponents; welfare proponents and opponents did so equally. In 3 other studies, death penalty proponents displayed greater typicality effects in sentencing "convicted murderers" than did opponents, welfare proponents and opponents displayed equal typicality effects in evaluating cases of suspected welfare fraud, and individuals whose attitude concept maps about welfare referred more to persons displayed greater typicality effects than did individuals whose maps referred more to principles. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
We investigated how prior knowledge influences the amount of short-term nonverbal and verbal memory and long-term retention in students of high and low ability in reading comprehension. Sixty-four junior high students were divided into four equal-sized groups on the basis of preassessed reading ability (high and low) and preassessed amount of existing prior knowledge about baseball (high and low). Each subject silently read an account of a half inning of a baseball game. After reading, each subject recalled the account nonverbally by moving figures and verbally by retelling the story. After an interpolated task, they summarized the game and sorted passage sentences for idea importance. There was a significant main effect for prior knowledge on all measures. No interactions between prior knowledge and ability were found. These results delineate the powerful effect of prior knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献