全文获取类型
收费全文 | 3067篇 |
免费 | 2篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 17篇 |
综合类 | 3篇 |
化学工业 | 251篇 |
金属工艺 | 7篇 |
机械仪表 | 191篇 |
建筑科学 | 208篇 |
矿业工程 | 16篇 |
能源动力 | 1篇 |
轻工业 | 680篇 |
水利工程 | 22篇 |
石油天然气 | 39篇 |
武器工业 | 4篇 |
无线电 | 140篇 |
一般工业技术 | 1328篇 |
冶金工业 | 19篇 |
原子能技术 | 10篇 |
自动化技术 | 140篇 |
出版年
2012年 | 310篇 |
2011年 | 383篇 |
2010年 | 69篇 |
2009年 | 29篇 |
2008年 | 288篇 |
2007年 | 288篇 |
2006年 | 209篇 |
2005年 | 197篇 |
2004年 | 174篇 |
2003年 | 158篇 |
2002年 | 158篇 |
2001年 | 122篇 |
2000年 | 140篇 |
1999年 | 59篇 |
1998年 | 47篇 |
1997年 | 45篇 |
1996年 | 30篇 |
1995年 | 54篇 |
1994年 | 49篇 |
1993年 | 18篇 |
1992年 | 16篇 |
1991年 | 28篇 |
1990年 | 28篇 |
1989年 | 22篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 17篇 |
1985年 | 29篇 |
1984年 | 22篇 |
1983年 | 20篇 |
1982年 | 8篇 |
1981年 | 1篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1956年 | 3篇 |
1955年 | 2篇 |
1954年 | 2篇 |
1948年 | 2篇 |
1947年 | 1篇 |
排序方式: 共有3076条查询结果,搜索用时 0 毫秒
41.
Gosink LJ Anderson JC Bethel EW Joy KI 《IEEE transactions on visualization and computer graphics》2008,14(6):1715-1722
The visualization and analysis of AMR-based simulations is integral to the process of obtaining new insight in scientific research. We present a new method for performing query-driven visualization and analysis on AMR data, with specific emphasis on time-varying AMR data. Our work introduces a new method that directly addresses the dynamic spatial and temporal properties of AMR grids that challenge many existing visualization techniques. Further, we present the first implementation of query-driven visualization on the GPU that uses a GPU-based indexing structure to both answer queries and efficiently utilize GPU memory. We apply our method to two different science domains to demonstrate its broad applicability. 相似文献
42.
43.
Glycoproteinoses, Pompe disease, and sialic acid storage diseases are characterized by a massive accumulation of unprocessed oligosaccharides and/or glycoconjugates in urine. The identification of these glycocompounds is essential for a proper diagnosis. In this study, we investigated the potential of MALDI‐TOF‐MS to identify glycocompounds present in urine from patients with different inborn errors of glycan metabolism. Urinary glycocompounds were permethylated, and analyzed using GC‐MS and MALDI‐TOF‐MS. In order to confirm tentative assignments, a second aliquot of urine was purified on a C18 Sep‐Pak cartridge and glycocompounds were desalted on a column of nonporous graphitized carbon. The glycocompounds were then sequentially on‐plate digested using an array of exoglycosidases. A range of disease‐specific oligosaccharides as well as glycopeptides was identified for all oligosacchariduria models. In addition, free sialic acid accumulated in urine from a patient suffering from French‐type sialuria, has been detected by a GC‐MS approach, which could be applied to other sialic acid storage diseases. This procedure is simple, and can be performed in few simple steps in less than 24 h. This current method can be applied for newborn screening for other inherited metabolic diseases as well as for assessing treatments in clinical trials. 相似文献
44.
45.
Details are given for the design, calibration, and operation of an apparatus for measuring the finite load-deformation behavior of a sheet of living epithelial cells cultured on a mesoscopic freestanding elastomer membrane, 10 microm thick and 5 mm in diameter. Although similar in concept to bulge tests used to investigate the mechanical properties of micromachined thin films, cell-elastomer composite diaphragm inflation tests pose a unique set of experimental challenges. Composite diaphragm (CD) specimens are extremely compliant (E<50 kPa), experience large displacements when subject to small inflation pressures (approximately 100 Pa), and must be continuously immersed in a bath of liquid culture medium during the acquisition of load-deformation measurements. Given these considerations, we have constructed an inflation apparatus consisting of an air-piston-cylinder pump integrated with a modular specimen mounting fixture that constitutes a horizontally semi-infinite reservoir of liquid culture medium. In a deformation-controlled inflation test, pressurized air is used to inflate a CD specimen into the liquid reservoir with minimum disturbance of the liquid-air interface. Piston displacements and absolute pump chamber air pressures are utilized as feedback to cycle the displaced (or inflated) CD volume V in a 0.05 Hz triangular or sinusoidal wave form (V(MIN)=0 microl, V(MAX)相似文献
46.
We describe a new segmentation method of dynamic nuclear medicine images based on the cross-Psi(B)-energy operator. Psi(B) is a nonlinear measure which quantifies the interaction between two time-signals including their first and second derivatives. Similarity measure, noted SimilB, between the time activity curve (TAC) of each pixel and the mean value of the TACs of a reference region of the scintigraphic image series is calculated. The resulting SimilB map is a functional image representing regions with different temporal dynamics. Some new properties of Psi(B) are presented. Particularly, we show that Psi(B) as a similarity measure is robust to both scale and time shift. The proposed method is applied to nuclear cardiac sequences for visualization and analysis of the ventricular emptying pattern, which may be useful in studying motion or conduction abnormalities. Results of a normal subject and four patients with abnormal ventricular contraction patterns are presented to highlight the suitability of this operator for studying non-stationary TAC series. 相似文献
47.
48.
49.
50.