全文获取类型
收费全文 | 6080篇 |
免费 | 53篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 21篇 |
综合类 | 6篇 |
化学工业 | 155篇 |
金属工艺 | 10篇 |
机械仪表 | 43篇 |
建筑科学 | 9篇 |
矿业工程 | 7篇 |
能源动力 | 20篇 |
轻工业 | 62篇 |
水利工程 | 4篇 |
石油天然气 | 5篇 |
无线电 | 112篇 |
一般工业技术 | 122篇 |
冶金工业 | 5472篇 |
原子能技术 | 4篇 |
自动化技术 | 83篇 |
出版年
2023年 | 4篇 |
2022年 | 14篇 |
2021年 | 11篇 |
2020年 | 13篇 |
2019年 | 15篇 |
2018年 | 19篇 |
2017年 | 28篇 |
2016年 | 31篇 |
2015年 | 16篇 |
2014年 | 29篇 |
2013年 | 42篇 |
2012年 | 35篇 |
2011年 | 64篇 |
2010年 | 41篇 |
2009年 | 32篇 |
2008年 | 42篇 |
2007年 | 38篇 |
2006年 | 26篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 22篇 |
2002年 | 15篇 |
2001年 | 14篇 |
2000年 | 14篇 |
1999年 | 177篇 |
1998年 | 1682篇 |
1997年 | 932篇 |
1996年 | 598篇 |
1995年 | 341篇 |
1994年 | 299篇 |
1993年 | 315篇 |
1992年 | 46篇 |
1991年 | 61篇 |
1990年 | 79篇 |
1989年 | 67篇 |
1988年 | 75篇 |
1987年 | 73篇 |
1986年 | 57篇 |
1985年 | 65篇 |
1984年 | 3篇 |
1983年 | 13篇 |
1982年 | 32篇 |
1981年 | 30篇 |
1980年 | 54篇 |
1979年 | 6篇 |
1978年 | 14篇 |
1977年 | 158篇 |
1976年 | 341篇 |
1975年 | 5篇 |
1955年 | 4篇 |
排序方式: 共有6135条查询结果,搜索用时 0 毫秒
21.
ES van Waalwijk van Doorn AH Meier AW Ambergen RA Janknegt 《Canadian Metallurgical Quarterly》1996,23(3):345-371
This article elucidates the clinical applicability and state of the art of ambulatory urodynamics. Ambulatory urodynamics have evolved into practical investigations like EAC, HFM, and EAC combined with renal pelvimetry. EAC has been shown to be the method of preference if detrusor overactivity is involved. Conventional filling cystometry has proved to be an unreliable way to exclude detrusor instability. De novo instability after suspension surgery often indicates that an existing detrusor overactivity was not identified preoperatively. EAC including flowmetry has shown considerable variance in obstructive and contractility parameters in males with LUTS indicative for BPH. This raises doubt whether the clinical flow analysis is the suitable "gold standard" as advocated by the ICS. For a real break through of EAC, less complex automatic analysis is necessary. HFM is a newer method within the range of ambulatory urodynamic tests. It has not yet been completely evaluated. But, because the technique is analogous to the office flowmetry, noninvasive and very well accepted by the patients, it is expected to be widely used. This expectation is strengthened by the fact that HFM seems to show individual therapeutic efficacy of drugs, such as alpha-blockers. As a research tool to evaluate efficacy, it is far more powerful than conventional methods because of the reduction of within-patient standard deviation to about 10%. Finally, EAC combined with pelvimetry offers a promising method for the clinical evaluation of a combined dysfunction of upper and lower urinary tract. 相似文献
22.
Chung JY Lee SJ Kris Y Braunschweig T Traicoff JL Hewitt SM 《Proteomics. Clinical applications》2008,2(10-11):1539-1547
Proteomic analysis of formalin-fixed paraffin-embedded (FFPE) tissue offers significant diagnostic utility but is complicated due to the high level of covalently crosslinked proteins arising from formalin fixation. To address these challenges, we developed a reliable protein extraction method for FFPE tissue, based on heat-induced antigen retrieval within a pressure cooker. The protein extraction yield from archival FFPE tissue section is approximately 90% of that recovered from frozen tissue. This method demonstrates preservation of immunoreactivity and recovery of full-length proteins by Western blotting. Additionally, we developed a well-based RP protein array platform utilizing an electrochemiluminescence detection system. Protein samples derived from FFPE tissue by means of laser capture dissection, with as few as 500 shots demonstrate measurable signal differences for different proteins. The lysates coated to the array plate, remain stable over 1?month at room temperature. Theses data suggest that this new protein-profiling platform coupled with the protein extraction method can be used for molecular profiling analysis in FFPE tissue, and contribute to the validation and development of biomarkers in clinical studies. 相似文献
23.
In an effort to streamline the personal interview and to reduce the influence of subjectivity inpreparation of ranking lists for postgraduate year-one applicants, a standardized interview was constructed for use in evaluating condidates for admission to a training program in internal medicine. The interview was conducted in a uniformly structured manner by 14 interviewers of 260 applicants. Each applicant received an interview score which correlated well with the final decision of the Intern Selection Committee. For each interviewer various measures of performance were obtained which allowed a classification into "hard" versus "easy" interviewer and indicated the comparability of each interview's evaluations with the final decisions. Thus, the standardized interview resulted in quantifiable data in the form of uniform evaluations of applicants and interviewers. 相似文献
24.
Jihoon Park Hyun-Woo Shin Joona Bang June Huh 《International journal of molecular sciences》2022,23(10)
The order-disorder transitions (ODT) of core-shell bottle brush copolymer and its structural isomers were investigated by dissipative particle dynamics simulations and theoretically by random phase approximation. Introducing a chain topology parameter which parametrizes linking points between M diblock chains each with N monomers, the degree of incompatibility at ODT (; being the Flory–Huggins interaction parameter between constituent monomers) was predicted as a function of chain topology parameter () and the number of linked diblock chains per bottle brush copolymer (M). It was found that there exists an optimal chain topology about at which gets a minimum while the domain spacing remains nearly unchanged. The prediction provides a theoretical guideline for designing an optimal copolymer architecture capable of forming sub-10 nm periodic structures even with non-high components. 相似文献
25.
A modular upgrade design for packet transport switch nodes is presented where packet loss is dramatically reduced by intra‐module and inter‐module buffer sharing. This modular design offers significant cost and power reduction in a high‐data‐rate system where buffers are highly costly and power‐greedy. 相似文献
26.
Hongkyu Eoh Youngdoo Jung Chanho Park Chang Eun Lee Tae Hyun Park Han Sol Kang Seungbae Jeon Du Yeol Ryu June Huh Cheolmin Park 《Advanced functional materials》2022,32(1):2103697
Structural color (SC) arising from a periodically ordered self-assembled block copolymer (BCP) photonic crystal (PC) is useful for reflective-mode sensing displays owing to its capability of stimuli-responsive structure alteration. However, a set of PC inks, each providing a precisely addressable SC in the full visible range, has rarely been demonstrated. Here, a strategy for developing BCP PC inks with tunable structures is presented. This involves solution-blending of two lamellar-forming BCPs with different molecular weights. By controlling the mixing ratio of the two BCPs, a thin 1D BCP PC film is developed with alternating in-plane lamellae whose periodicity varies linearly from ≈46 to ≈91 nm. Subsequent preferential swelling of one-type lamellae with either solvent or non-volatile ionic liquid causes the photonic band gap of the films to red-shift, giving rise to full-visible-range SC correlated with the pristine nanostructures of the blended films in both liquid and solid states. The BCP PC palette of solution-blended binary solutions is conveniently employed in various coating processes, allowing facile development of BCP SC on the targeted surface. Furthermore, full-color SC paintings are realized with their transparent PC inks, facilitating low-power pattern encryption. 相似文献
27.
Parametric GLRT for Multichannel Adaptive Signal Detection 总被引:1,自引:0,他引:1
This paper considers the problem of detecting a multichannel signal in the presence of spatially and temporally colored disturbance. A parametric generalized likelihood ratio test (GLRT) is developed by modeling the disturbance as a multichannel autoregressive (AR) process. Maximum likelihood (ML) parameter estimation underlying the parametric GLRT is examined. It is shown that the ML estimator for the alternative hypothesis is nonlinear and there exists no closed-form expression. To address this issue, an asymptotic ML (AML) estimator is presented, which yields asymptotically optimum parameter estimates at reduced complexity. The performance of the parametric GLRT is studied by considering challenging cases with limited or no training signals for parameter estimation. Such cases (especially when training is unavailable) are of great interest in detecting signals in heterogeneous, fast changing, or dense-target environments, but generally cannot be handled by most existing multichannel detectors which rely more heavily on training at an adequate level. Compared with the recently introduced parametric adaptive matched filter (PAMF) and parametric Rao detectors, the parametric GLRT achieves higher data efficiency, offering improved detection performance in general. 相似文献
28.
We consider a cellular CDMA system in which blocking is enforced when the relative interference exceeds a certain threshold
level. This paper addresses a radio network design problem in such a CDMA system. Given the data of call‐traffic distributed
over the service area and potential sites of base stations, the objective of the problem is to locate base stations so as
to minimize the associated cost for establishing base stations while keeping the probability of blocking under control. We
develop an efficient algorithm for solving the design problem. Computational experiments with real‐world data are conducted
to show both the efficiency and the practicality of the proposed design method.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
29.
We developed a pipelined scheduling technique of functional hardware and software modules for platform‐based system‐on‐a‐chip (SoC) designs. It is based on a modified list scheduling algorithm. We used the pipelined scheduling technique for a performance analysis of an MPEG4 video encoder application. Then, we applied it for architecture exploration to achieve a better performance. In our experiments, the modified SoC platform with 6 pipelines for the 32‐bit dual layer architecture shows a 118% improvement in performance compared to the given basic SoC platform with 4 pipelines for the 16‐bit single‐layer architecture. 相似文献
30.