全文获取类型
收费全文 | 4133篇 |
免费 | 108篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 25篇 |
综合类 | 3篇 |
化学工业 | 633篇 |
金属工艺 | 18篇 |
机械仪表 | 32篇 |
建筑科学 | 203篇 |
矿业工程 | 85篇 |
能源动力 | 55篇 |
轻工业 | 433篇 |
水利工程 | 26篇 |
石油天然气 | 6篇 |
无线电 | 117篇 |
一般工业技术 | 428篇 |
冶金工业 | 1715篇 |
原子能技术 | 10篇 |
自动化技术 | 453篇 |
出版年
2022年 | 34篇 |
2021年 | 64篇 |
2020年 | 34篇 |
2019年 | 48篇 |
2018年 | 50篇 |
2017年 | 60篇 |
2016年 | 74篇 |
2015年 | 53篇 |
2014年 | 58篇 |
2013年 | 216篇 |
2012年 | 144篇 |
2011年 | 186篇 |
2010年 | 169篇 |
2009年 | 155篇 |
2008年 | 201篇 |
2007年 | 198篇 |
2006年 | 144篇 |
2005年 | 168篇 |
2004年 | 136篇 |
2003年 | 155篇 |
2002年 | 126篇 |
2001年 | 98篇 |
2000年 | 84篇 |
1999年 | 99篇 |
1998年 | 84篇 |
1997年 | 89篇 |
1996年 | 99篇 |
1995年 | 76篇 |
1994年 | 85篇 |
1993年 | 99篇 |
1992年 | 97篇 |
1991年 | 37篇 |
1990年 | 84篇 |
1989年 | 68篇 |
1988年 | 70篇 |
1987年 | 71篇 |
1986年 | 73篇 |
1985年 | 61篇 |
1984年 | 54篇 |
1983年 | 52篇 |
1982年 | 44篇 |
1981年 | 36篇 |
1980年 | 23篇 |
1979年 | 34篇 |
1978年 | 29篇 |
1977年 | 14篇 |
1976年 | 19篇 |
1975年 | 17篇 |
1974年 | 13篇 |
1973年 | 16篇 |
排序方式: 共有4242条查询结果,搜索用时 0 毫秒
231.
Howard George S.; Maxwell Scott E.; Berra Susan M.; Sternitzke Mary E. 《Canadian Metallurgical Quarterly》1985,70(1):233
Updated the report of W. M. Cox and V. Catt (see record 1978-21651-001) by determining the 40 top contributing institutions to the Journal of Applied Psychology, 1976–1982, and assessed the generalizability of productivity rankings based solely on contributions to this journal. A number of industrial and organizational psychologists were asked to indicate all the journals in which psychologists in the field were likely to publish. Five journals suggested by these nominators were used for comparison in the review. A list of the 40 most productive graduate programs based on these 5 journals is included. Results show the inadequacy of Cox and Catt's decision to base productivity ratings solely on contributions to 1 journal. Using 5 journals, 4 programs were catapulted into the top 10 rankings, while 7 programs dropped from top rankings in the Cox study (1970–1975) to below the 65th rank in the present study. Using only the Journal of Applied Psychology contributions, 2 of these programs ranked in the top 10, 1976–1982. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
232.
Investigated the hypothesis that in some contexts people may give more weight to their cognitive-affective reactions than to their behavioral reactions when making self-evaluative inferences. 69 university students who participated as Ss were administered the Coopersmith Self-Esteem Inventories and a self-concept inventory. In 1 of 2 contexts, Ss recalled either their positive cognitive-affective reactions, their positive behavioral reactions, or their unspecified positive reactions to several standard situations; these were reactions that had led them to feel a special appreciation for their own personal qualities. The experimental context of these recollections involved either private rehearsal, in which Ss simply thought about their past reactions, or public expression, in which they presented their reactions verbally while being tape-recorded. The impact of Ss' recollections on their subsequent self-esteem in each context was assessed. Results show that recalling positive cognitive-affective reactions had a significantly greater impact on self-esteem than did recalling positive behavioral or unspecified reactions when these recollections took place in a private, nonevaluative context, but not when they took place in the more public context in which the perspective of outside observers was likely to have been salient. Findings are discussed in terms of theories of self-inference processes and of actor–observer differences. Probable limitations of the findings are outlined. (73 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
233.
Helms-Erikson Heather; Tanner Jennifer L.; Crouter Ann C.; McHale Susan M. 《Canadian Metallurgical Quarterly》2000,14(4):658
The authors examined the links between mothers' work qualities and their individual well-being and marital quality, as well as adolescent daughters' and sons' gender-role attitudes, as a function of mothers' provider-role attitudes, in 134 dual-earner families. In home interviews, mothers described their work, provider-role attitudes, family relationships, and mental health; their offspring reported gender-role attitudes. Women's attitudes about breadwinning were coded into main-secondary, coprovider, and ambivalent coprovider groups. Mothers' provider-role attitudes moderated the links between status indicators and mothers' depression, marital conflict, and daughters' gender-role attitudes. For example, depression and marital conflict were negatively related to coprovider mothers' earnings and occupational prestige. The same was not true for main-secondary and ambivalent coprovider mothers. These findings underscore the importance of considering employed women's interpretation of their work roles when exploring work-family links. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
234.
Larsen SW Jessen MN Ostergaard J Larsen C 《Drug development and industrial pharmacy》2008,34(3):297-304
In vitro drug release and transport rates from oil depot formulations under nonsink conditions have been investigated in the rotating dialysis cell model. Eight model drug compounds and eight oil vehicle compositions were used for the releaseexperiments. The experimentally obtained apparent first-order rate constants related to the drug appearance in the acceptor phase after initial instillation of a drug-containing oil solution were found to be in excellent agreement with the rate constants obtained from a theoretically derived expression. It was observed that the drug oil-water distribution coefficient was the key parameter influencing the release characteristics. As compared with ketoprofen, flurbiprofen exhibited a higher affinity for the oil, resulting in a significantly lower and more slowly decreasing drug concentrations in the aqueous donor compartment. Release profiles for prilocaine and the more lipophilic agent bupivacaine after incorporation of both drugs in fractionated coconut oil were characterized by a fast release of prilocaine, whereas bupivacaine was liberated much slower to the acceptor phase. The high oil-buffer interfacial area generated in vitro by rotation of the donor cell tends to overestimate release rates in comparison to those expected in vivo, for example, after intra-articular administration of oil solutions. The present in vitro method may constitute a valuable tool in accelerated in vitro release testing of parenteral oil depot formulations in areas comprising formulation design and product quality control. 相似文献
235.
236.
Eighteen sessions of cognitive–behavioral (CB) and 13 sessions of psychodynamic–interpersonal therapy obtained from experienced clinicians in a naturalistic setting were investigated to determine the various therapeutic interventions associated with high and low emotional experiencing (EXP). Clients receiving reflections and acknowledgments, affiliative and noncontrolling interventions, or interventions highlighting nonspecific client content were associated with maintained high EXP. Lengthier interventions and interventions rated as affiliative but moderately controlling were associated with shifts to low EXP. For clients of CB therapists, questions, interventions rated affiliative but controlling, and highlighting minimal emotional content were also associated with shifts to low EXP. Male therapists were associated with clients who maintained high EXP and female therapists were associated with clients who shifted to low EXP. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
237.
Viswanath Venkatesh James Y. L. Thong Frank K. Y. Chan Paul Jen‐Hwa Hu Susan A. Brown 《Information Systems Journal》2011,21(6):527-555
This study presents two extensions to the two‐stage expectation‐confirmation theory of information systems (IS) continuance. First, we expand the belief set from perceived usefulness in the original IS continuance model to include three additional predictors identified in the unified theory of acceptance and use of technology, namely effort expectancy, social influence and facilitating conditions. Second, we ground the IS continuance model in the context of transactional systems that involve transmission of personal and sensitive information and include trust as a key contextual belief in the model. To test the expanded IS continuance model, we conducted a longitudinal field study of 3159 Hong Kong citizens across two electronic government (e‐government) technologies that enable citizens' access to government services. In general, the results support the expanded model that provides a rich understanding of the changes in the pre‐usage beliefs and attitudes through the emergent constructs of disconfirmation and satisfaction, ultimately influencing IS continuance intention. Finally, we discuss the theoretical and practical implications of the expanded model. 相似文献
238.
White Kamila S.; Raffa Susan D.; Jakle Katherine R.; Stoddard Jill A.; Barlow David H.; Brown Timothy A.; Covino Nicholas A.; Ullman Edward; Gervino Eernest V. 《Canadian Metallurgical Quarterly》2008,76(3):422
The present study examined current and lifetime psychiatric morbidity, chest pain, and health care utilization in 229 patients with noncardiac chest pain (NCCP), angina-like pain in the absence of cardiac etiology. Diagnostic interview findings based on the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) revealed a psychiatrically heterogeneous sample of whom 44% had a current Axis I psychiatric disorder. A total of 41% were diagnosed with a current anxiety disorder, and 13% were diagnosed with a mood disorder. Overall, 75% of patients had an Axis I clinical or subclinical disorder. Lifetime diagnoses of anxiety (55%) and mood disorders (44%) were also prevalent, including major depressive disorder (41%), social phobia (25%), and panic disorder (22%). Patients with an Axis I disorder reported more frequent and more painful chest pain compared with those without an Axis I disorder. Presence of an Axis I disorder was associated with increased life interference and health care utilization. Findings reveal that varied DSM-IV Axis I psychiatric disorders are prevalent among patients with NCCP, and this psychiatric morbidity is associated with a less favorable NCCP presentation. Implications for early identification of psychiatric disorders are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
239.
Altman SJ Rivers ML Reno MD Cygan RT McLain AA 《Environmental science & technology》2005,39(8):2679-2685
Synchrotron-source X-ray computerized microtomography (CMT) was used to evaluate the adsorptive properties of aggregate soil samples. A linear relationship between measured mean mass attenuation coefficient (sigma) and mass fraction iron was generated by imaging mineral standards with known iron contents. On the basis of reported stoichiometries of the clay minerals and identifications of iron oxyhydroxides (1), we calculated the mass fraction iron and iron oxyhydroxide in the intergranular material. The mass fractions of iron were estimated to range from 0.17 to 0.22 for measurements made at 18 keV and from 0.18 to 0.21 for measurements made at 26 keV. One aggregate sample also contained regions within the intergranular material with mass fraction iron ranging from 0.29 to 0.31 and from 0.33 to 0.36 for the 18 and 26 keV measurements, respectively. The mass fraction iron oxyhydroxide ranged from 0.18 to 0.35 for the low-iron intergranular material and from 0.40 to 0.59 for the high-iron intergranular material. Using absorption edge difference imaging with CMT, we visualized cesium on the intergranular material, presumably because of adsorption and possible exchange reactions. By characterizing the mass fraction iron, the mass fraction iron oxyhydroxide, and the adsorptive capacity of these soil mineral aggregates, we provide information useful for conceptualization, development, and parametrization of transport models. 相似文献
240.
Kendall Richard Carver Jeffrey C. Fisher David Henderson Dale Mark Andrew Post Douglass Rhoades Jr. Clifford E. Squires Susan 《Software, IEEE》2008,25(4):59-65
Computational science is increasingly supporting advances in scientific and engineering knowledge. The unique constraints of these types of projects result in a development process that differs from the process more traditional information technology projects use. This article reports the results of the sixth case study conducted under the support of the Darpa High Productivity Computing Systems Program. The case study aimed to investigate the technical challenges of code development in this environment, understand the use of development tools, and document the findings as concrete lessons learned for other developers' benefit. The project studied here is a major component of a weather forecasting system of systems. It includes complex behavior and interaction of several individual physical systems (such as the atmosphere and the ocean). This article describes the development of the code and presents important lessons learned. 相似文献