全文获取类型
收费全文 | 674篇 |
免费 | 23篇 |
专业分类
电工技术 | 8篇 |
综合类 | 1篇 |
化学工业 | 141篇 |
金属工艺 | 6篇 |
机械仪表 | 16篇 |
建筑科学 | 11篇 |
矿业工程 | 1篇 |
能源动力 | 11篇 |
轻工业 | 51篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
无线电 | 69篇 |
一般工业技术 | 122篇 |
冶金工业 | 178篇 |
原子能技术 | 3篇 |
自动化技术 | 74篇 |
出版年
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 15篇 |
2017年 | 15篇 |
2016年 | 10篇 |
2015年 | 4篇 |
2014年 | 17篇 |
2013年 | 29篇 |
2012年 | 22篇 |
2011年 | 32篇 |
2010年 | 21篇 |
2009年 | 21篇 |
2008年 | 25篇 |
2007年 | 27篇 |
2006年 | 20篇 |
2005年 | 19篇 |
2004年 | 21篇 |
2003年 | 15篇 |
2002年 | 13篇 |
2001年 | 14篇 |
2000年 | 15篇 |
1999年 | 15篇 |
1998年 | 52篇 |
1997年 | 36篇 |
1996年 | 21篇 |
1995年 | 18篇 |
1994年 | 13篇 |
1993年 | 17篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1970年 | 4篇 |
1961年 | 2篇 |
排序方式: 共有697条查询结果,搜索用时 0 毫秒
1.
Ian G. Richardson Adrian R. Brough Rik Brydson Geoffrey W. Groves Christopher M. Dobson 《Journal of the American Ceramic Society》1993,76(9):2285-2288
Solid-state 27 Al and 29 Si magic angle spinning NMR spectroscopy has been combined with electron energy loss spectroscopy carried out in the transmission electron microscope to determine the location of Al substituting in a semicrystalline C-S-H gel present in a hydrated synthetic slag glass. The gel is found to contain mainly pentameric silicate chains in which the central silicon is substituted by aluminum. 相似文献
2.
H Rodgers M Sudlow R Dobson RA Kenny RG Thomson 《Canadian Metallurgical Quarterly》1997,47(418):309-310
The demand for anticoagulation services is rising. Warfarin anticoagulation has been shown to reduce the risk of stroke in patients with non-valvular atrial fibrillation by 68%. This raises issues about how services are best organized to initiate and monitor anticoagulation in this potentially large group of patients. We report the results of a regional postal survey undertaken to describe the views of general practitioners and consultants regarding warfarin anticoagulation in light of this potentially high increase in demand. 相似文献
3.
4.
We examine the production and ordering fulfillment system of a firm offering a large variety of products to time-sensitive customers. The firm wants to combine a finish-to-order strategy with an existing customer ordering system. The finish-to-order policy guarantees significant inventory savings due to the large number of end-product offerings, but it may also increase setup costs due to a short delivery commitment. The ordering system assigns periodic ordering dates to customers, encourages them to place their orders only on these dates, and promises them the same short delivery time irrespective of their geographic locations. The ordering system facilitates a smooth capacity load as well as transportation economies by allowing shipments to each location once during each ordering cycle. We propose a formulation for the combinatorial problem of choosing an ordering-day assignment and a finish-to-order production schedule that minimizes setup costs and maintains a balanced capacity load. We examine a Lagrangian relaxation of this formulation and heuristic solutions based on our relaxation. Our numerical work demonstrates that our best heuristic differs from the optimal solution by 5% on average for small problems (with up to 10 products and 10 customers). Moreover, we show that the difference between the objective value of the relaxation and that of the best heuristic decreases significantly as the problem size increases, being as low as 4% on average for problems with 30 products and 30 customers. 相似文献
5.
M. Dobson R. Rada C. Chen A. Michailidis A. Ulloa 《Journal of Computer Assisted Learning》1993,9(1):34-50
Abstract In an effort to reduce the expensive resource requirements in courseware production and to allow effective management of, and communication and collaboration between authors, a model is needed to harmonize the diverse theoretical backgrounds such a process requires. To this end we look at five abstract models which where chosen for their apparent appropriateness within the general area of collaborative authoring and reuse of multimedia courseware. These models consist of a functional model of hypertext, an infrastructure model for an open collaborative authoring system, two object-oriented communication models, and a courseware production model. We attempt a consolidation of these models and ultimately make several conclusions, which are exposed during a conceptual harmonisation. The principal conclusion is that a hypermedia logical model is not by itself adequate to support collaboration and reuse. Our modeling conclusions have driven the design of a system which will be implemented and tested. 相似文献
6.
Amir Mohammadzadeh Pter P. Lakatos Mihly Balogh Ferenc Zdor Dvid rpd Kardi Zoltn S. Zdori Kornl Kirly Anna Rita Galambos Szilvia Barsi Pl Riba Sndor Benyhe Lszl Kles Tams Tbi va Szk Laszlo G. Harsing Jr. Mahmoud Al-Khrasani 《International journal of molecular sciences》2021,22(5)
The limited effect of current medications on neuropathic pain (NP) has initiated large efforts to develop effective treatments. Animal studies showed that glycine transporter (GlyT) inhibitors are promising analgesics in NP, though concerns regarding adverse effects were raised. We aimed to study NFPS and Org-25543, GlyT-1 and GlyT-2 inhibitors, respectively and their combination in rat mononeuropathic pain evoked by partial sciatic nerve ligation. Cerebrospinal fluid (CSF) glycine content was also determined by capillary electrophoresis. Subcutaneous (s.c.) 4 mg/kg NFPS or Org-25543 showed analgesia following acute administration (30–60 min). Small doses of each compound failed to produce antiallodynia up to 180 min after the acute administration. However, NFPS (1 mg/kg) produced antiallodynia after four days of treatment. Co-treatment with subanalgesic doses of NFPS (1 mg/kg) and Org-25543 (2 mg/kg) produced analgesia at 60 min and thereafter meanwhile increased significantly the CSF glycine content. This combination alleviated NP without affecting motor function. Test compounds failed to activate G-proteins in spinal cord. To the best of our knowledge for the first time we demonstrated augmented analgesia by combining GlyT-1 and 2 inhibitors. Increased CSF glycine content supports involvement of glycinergic system. Combining selective GlyT inhibitors or developing non-selective GlyT inhibitors might have therapeutic value in NP. 相似文献
7.
Penel Simon; Morrison R.Gwilym; Dobson Paul D.; Mortishire-Smith Russell J.; Doig Andrew J. 《Protein engineering, design & selection : PEDS》2003,16(12):957-961
We analysed the length distributions of different types of ß-strandin a high resolution, non-homologous set of 500 protein structures,finding differences in their mean lengths. Antiparallel edgestrands in strandturnstrand motifs show a preferencefor an even number of residues. This propensity is enhancedif the length is corrected for ß-bulges, which insertan extra residue into the strand. Residues in antiparallel edgeß-strands alternate between being in hydrogen bondedand non-hydrogen bonded rings. Antiparallel edges with an evennumber of residues are more likely to have their final ßresidue in a non-hydrogen bonded ring. This suggests that non-hydrogenbonded rings are intrinsically more stable than hydrogen bondedrings, perhaps because its side chain packing is closer. Therefore,we suggest that a simple way to increase ß-hairpinstability, or the stability of an antiparallel edge strand,is to have a non-hydrogen bonded ring at the end of the strand. Received June 19, 2003; revised October 25, 2003; accepted November 7, 2003 相似文献
8.
K.?WarnerEmail author J.?A.?Laszlo 《Journal of the American Oil Chemists' Society》2005,82(9):647-652
To determine antioxidative effects of ferulic acid and esterified ferulic acids, these compounds were added to soybean oils
(SBO), which were evaluated for oxidative stability and frying stability. Additives included feruloylated MAG and DAG (FMG/FDG),
ferulic acid, ethyl ferulate, and TBHQ. After frying tests with potato chips, oils were analyzed for retention of additives
and polar compounds. Chips were evaluated for hexanal and rancid odor. After 15 h frying, 71% of FMG/FDG was retained, whereas
55% of ethyl ferulate was retained. TBHQ and ferulic acid levels were 6% and <1%, respectively. Frying oils with ethyl ferulate
or TBHQ produced significantly less polar compounds than SBO with no additives. Chips fried in SBO with TBHQ or ferulic acid
had significantly lower amounts of hexanal and significantly less rancid odor after 8 d at 60°C than other samples. Oils were
also aged at 60°C, and stability was analyzed by PV, hexanal, and rancid odor. Oils with TBHQ or FMG/FDG had significantly
less peroxides and hexanal, and a lower rancid odor intensity than the control. FMG/FDG inhibited deterioration at 60°C, whereas
ethyl ferulate inhibited the formation of polar compounds in frying oil. Ferulic acid acted as an antioxidant in aged fried
food. TBHQ inhibited oil degradation at both temperatures.
Presented at the 94th AOCS Meeting & Expo, Kansas City, MO, May 4–7, 2003. 相似文献
9.
Watson PJ O'Higgins P Fagan MJ Dobson CA 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2011,225(1):48-57
Three-dimensional reconstructions of bone geometry from microCT (computed tomography) data are frequently used in biomechanical and finite element analyses. Digitization of bone models is usually a simple process for specimens with a complete geometry, but in instances of damage or disarticulation it can be very challenging. Subsequent to digitization, further imaging techniques are often required to estimate the geometry of missing bone or connecting cartilage. This paper presents an innovative approach to the reconstruction of incomplete scan data, to reproduce proper anatomical arrangements of bones, including absent connecting cartilaginous elements. Utilizing geometric morphometric tools, the reconstruction technique is validated through comparison of a reconstructed 9 year old pelvis, to the original CT data. A principal component analysis and an overlay of the two pelves provide a measure of the accuracy of the reconstructed model. Future work aims to investigate the biomechanical effects of any minor positional error on the bone's predicted structural properties through the use of finite element analysis. 相似文献
10.
The NP-hard microaggregation problem seeks a partition of data points into groups of minimum specified size k, so as to minimize the sum of the squared euclidean distances of every point to its group's centroid. One recent heuristic provides an O(k3) guarantee for this objective function and an O(k2) guarantee for a version of the problem that seeks to minimize the sum of the distances of the points to its group's centroid. This paper establishes approximation bounds for another microaggregation heuristic, providing better approximation guarantees of O(k2) for the squared distance measure and O(k) for the distance measure. 相似文献