全文获取类型
收费全文 | 7487篇 |
免费 | 217篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 94篇 |
综合类 | 1篇 |
化学工业 | 1238篇 |
金属工艺 | 123篇 |
机械仪表 | 217篇 |
建筑科学 | 289篇 |
矿业工程 | 21篇 |
能源动力 | 291篇 |
轻工业 | 615篇 |
水利工程 | 96篇 |
石油天然气 | 30篇 |
武器工业 | 2篇 |
无线电 | 581篇 |
一般工业技术 | 1250篇 |
冶金工业 | 1887篇 |
原子能技术 | 45篇 |
自动化技术 | 930篇 |
出版年
2022年 | 59篇 |
2021年 | 94篇 |
2020年 | 80篇 |
2019年 | 95篇 |
2018年 | 102篇 |
2017年 | 102篇 |
2016年 | 125篇 |
2015年 | 106篇 |
2014年 | 141篇 |
2013年 | 347篇 |
2012年 | 288篇 |
2011年 | 479篇 |
2010年 | 367篇 |
2009年 | 283篇 |
2008年 | 394篇 |
2007年 | 387篇 |
2006年 | 325篇 |
2005年 | 304篇 |
2004年 | 249篇 |
2003年 | 244篇 |
2002年 | 256篇 |
2001年 | 141篇 |
2000年 | 132篇 |
1999年 | 137篇 |
1998年 | 321篇 |
1997年 | 228篇 |
1996年 | 186篇 |
1995年 | 154篇 |
1994年 | 139篇 |
1993年 | 133篇 |
1992年 | 92篇 |
1991年 | 59篇 |
1990年 | 78篇 |
1989年 | 71篇 |
1988年 | 65篇 |
1987年 | 56篇 |
1986年 | 88篇 |
1985年 | 68篇 |
1984年 | 58篇 |
1983年 | 54篇 |
1982年 | 49篇 |
1981年 | 45篇 |
1980年 | 45篇 |
1979年 | 37篇 |
1978年 | 44篇 |
1977年 | 66篇 |
1976年 | 70篇 |
1975年 | 40篇 |
1974年 | 32篇 |
1972年 | 31篇 |
排序方式: 共有7710条查询结果,搜索用时 15 毫秒
1.
Hammons Joshua A. Tumey Scott J. Idell Yaakov Jeffries Jason R. 《JOM Journal of the Minerals, Metals and Materials Society》2020,72(1):176-186
JOM - Alpha-radiation damage in metals is a concern for long-term radioactive storage and systems that produce nuclear energy. Accurate prediction of irradiated material properties and failure... 相似文献
2.
Differences between oculomotor and perceptual artifacts for temporally limited head mounted displays
Alexander Goettker Kevin J. MacKenzie T. Scott Murdison 《Journal of the Society for Information Display》2020,28(6):509-519
We used perceptual and oculomotor measures to understand the negative impacts of low (phantom array) and high (motion blur) duty cycles with a high‐speed, AR‐likehead‐mounted display prototype. We observed large intersubject variability for the detection of phantom array artifacts but a highly consistent and systematic effect on saccadic eye movement targeting during low duty cycle presentations. This adverse effect on saccade endpoints was also related to an increased error rate in a perceptual discrimination task, showing a direct effect of display duty cycle on the perceptual quality. For high duty cycles, the probability of detecting motion blur increased during head movements, and this effect was elevated at lower refresh rates. We did not find an impact of the temporal display characteristics on compensatory eye movements during head motion (e.g., VOR). Together, our results allow us to quantify the tradeoff of different negative spatiotemporal impacts of user movements and make subsequent recommendations for optimized temporal HMD parameters. 相似文献
3.
Co-browsing is an activity in which a group of users navigate their way through of a set of Web pages together for a shared
purpose. Effective co-browsing among users with different device capabilities requires a shared understanding of those Web
pages. This paper demonstrates the concept of shared viewpoints (SVPs), and personal viewpoints (PVPs), for co-browsing, before
detailing a framework for implementing these concepts. Finally, the effectiveness of the framework is presented through a
perceptual experiment. 相似文献
4.
An efficient algorithm is presented for numerically evaluating a self-consistent field theoretic (SCFT) model of block copolymer structure. This algorithm is implemented on a distributed memory parallel cluster in order to solve the SCFT equations on large computational grids. Simulation results are presented for a two-component molten mixture of a symmetric ABA triblock copolymer with an A homopolymer. These results illustrate a case in which simulating a large system is required to resolve features with a wide range of length scales. 相似文献
5.
Halliday-Boykins Colleen A.; Henggeler Scott W.; Rowland Melisa D.; DeLucia Christian 《Canadian Metallurgical Quarterly》2004,72(6):993
The authors examined heterogeneity in symptom trajectories among youths following psychiatric crises as well as the psychosocial correlates and placement outcomes associated with identified trajectories. Using semiparametric mixture modeling with 156 youths approved for psychiatric hospitalization, the authors identified 5 trajectories based on symptoms over the 16 months following crisis: high improved, high unimproved, borderline improved, borderline unimproved, and subclinical. Membership in unimproved symptom groups was associated with less suicidality, younger age, more youth hopelessness, and more caregiver empowerment. Improved symptom group membership predicted long-term decreases in days in out-of-home placements. More important, and in contrast with general impressions from the existing literature, findings suggest that a substantive proportion of youths with serious emotional disturbance sustain high levels of symptomatology following intensive mental health services. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Stewart C. Kai Shen Dwarkadas S. Scott M.L. Jian Yin 《Distributed Systems Online, IEEE》2004,5(10):1-1
The growth of the Internet and of various intranets has spawned a wealth of online services, most of which are implemented on local-area clusters using remote invocation (for example, remote procedure call/remote method invocation) among manually placed application components. Component placement can be a significant challenge for large-scale services, particularly when application resource needs are workload dependent. Automatic component placement has the potential to maximize overall system throughput. The key idea is to construct (offline) a mapping between input workload and individual-component resource consumption. Such mappings, called component profiles, then support high-performance placement. Preliminary results on an online auction benchmark based on J2EE (Java 2 Platform, Enterprise Edition) suggest that profile-driven tools can identify placements that achieve near-optimal overall throughput. 相似文献
7.
DL Scott 《Canadian Metallurgical Quarterly》1993,20(3):582-584
Changes in clinical and laboratory measures of disease activity were studied prospectively in 12 European centers. Altogether 282 rheumatoid patients were evaluated during 6 months of therapy with slow-acting drugs. Patients' global assessment was taken to indicate overall response. The number of swollen joints and number of tender joints correlated highly with this. The erythrocyte sedimentation rate (ESR) correlated less well but was more uniform across centers. Grip strength, C-reactive protein and hemoglobin performed poorly between centers. There were cultural and linguistic difficulties using the Health Assessment Questionnaire in a European setting. Physician's global assessments were similar to the patient's global assessments and provided redundant information. The best measures are: the number of swollen joints, the number of tender joints, the ESR, and the patient's global assessment. It may also help to measure articular pain. 相似文献
8.
The current, most frequently employed, commercial route to produce hydroxyapatite prosthetic coatings is plasma spraying. However, this has several important limitations especially for textured surfaces. Low temperature methods of coating fabrication such as cathodic electrodeposition are attractive alternatives. However, quantitative characterisation of the phase composition of thin electrodeposited coatings can be problematic. An X-ray diffraction method, which provides quantitative compositional information without reference to external or internal standards, is introduced and validated. The method can also be applied when Bragg peaks from the supporting substrate are apparent within the data and preferred orientation can be tolerated. This method has been used to examine in detail the microstructure of electrodeposited coatings which are compared directly with those formed by a commercial plasma spraying process.We show that, unlike the plasma sprayed coatings, the electrodeposited material consists of a single crystalline phase (hydroxyapatite) and a significantly reduced amorphous phase. The electrodeposited coatings also possess significantly more microstrain and a smaller crystallite size than the corresponding plasma sprayed material. 相似文献
9.
10.