全文获取类型
收费全文 | 1347篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 16篇 |
综合类 | 1篇 |
化学工业 | 192篇 |
金属工艺 | 20篇 |
机械仪表 | 21篇 |
建筑科学 | 53篇 |
矿业工程 | 5篇 |
能源动力 | 32篇 |
轻工业 | 163篇 |
水利工程 | 8篇 |
石油天然气 | 40篇 |
无线电 | 90篇 |
一般工业技术 | 143篇 |
冶金工业 | 401篇 |
原子能技术 | 12篇 |
自动化技术 | 191篇 |
出版年
2022年 | 5篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 23篇 |
2017年 | 19篇 |
2016年 | 23篇 |
2015年 | 15篇 |
2014年 | 22篇 |
2013年 | 85篇 |
2012年 | 49篇 |
2011年 | 61篇 |
2010年 | 27篇 |
2009年 | 33篇 |
2008年 | 43篇 |
2007年 | 46篇 |
2006年 | 40篇 |
2005年 | 32篇 |
2004年 | 22篇 |
2003年 | 20篇 |
2002年 | 31篇 |
2001年 | 23篇 |
2000年 | 36篇 |
1999年 | 34篇 |
1998年 | 142篇 |
1997年 | 77篇 |
1996年 | 55篇 |
1995年 | 43篇 |
1994年 | 36篇 |
1993年 | 26篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 22篇 |
1987年 | 18篇 |
1986年 | 17篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 13篇 |
1981年 | 15篇 |
1980年 | 15篇 |
1979年 | 17篇 |
1978年 | 9篇 |
1977年 | 16篇 |
1976年 | 21篇 |
1974年 | 8篇 |
1973年 | 8篇 |
1972年 | 7篇 |
排序方式: 共有1388条查询结果,搜索用时 15 毫秒
101.
Wie müsste ein ideales und globales Internet-Frühwarnsystem aussehen? Der Beitrag stellt ein Modell für ein Frühwarnsystem
vor und führt aus, welche Komponenten dafür ben?tigt werden und warum eine Frühwarnung nur durch kollaborative Ans?tze und
eine Vielzahl von Systemen funktionieren kann. Anschlie?end werden einige aktuelle Forschungsvorarbeiten im Bereich Internet-Frühwarnung
skizziert. 相似文献
102.
Mark Scott Cooper William Robert Hardin Timothy Wayne Petersen Rose Ann Cattolico 《Journal of Bioscience and Bioengineering》2010,109(2):198-201
We report here that BODIPY 505/515, a green lipophilic fluorescent dye, serves as an excellent vital stain for the oil-containing lipid bodies of live algal cells. BODIPY 505/515 vital staining can be used in combination with fluorescent activated cell sorting to detect and isolate algal cells possessing high lipid content. 相似文献
103.
K G Petersen A Khalaf P J?gle L Kerp 《Computer methods and programs in biomedicine》1990,32(3-4):325-331
Two computer programs were developed, program I to optimise insulin treatment using six injections per day, and program II to convert these insulin profiles into less frequent injections of mixtures of regular and NPH insulin. The first software in an HP 41 CV pocket computer uses iterative adjustments during the day and on subsequent days to determine the optimal timing and dosage of insulin. Six self-monitored glucose values at 3 h intervals, insulin doses, and the effects of insulin on plasma glucose are memorised for calculations. The calculated insulin doses were applied by Optipen as five s.c. injections of regular insulin and one bedside injection of NPH insulin. After 5 days the optimised individual insulin profiles with six daily injections were processed by program II. It applies the pharmacokinetics of regular and NPH insulin to make suggestions for a more conventional insulin therapy with one, two, three or four daily injections of regular insulin, NPH insulin, or varying mixtures of both insulins. The procedure was well tolerated in eight insulin-dependent diabetes mellitus out-patients. Insulin therapy with two or three injections, fitted by the second program and selected according to the quality score, produced plasma glucose profiles as satisfactory as those obtained with six injections. The system allows the fine tuning of insulin therapy to out-patients with their individual diets and physical activities. 相似文献
104.
Karen L. Klomparens Maureen A. Petersen Donald C. Ramsdell William G. Chaney 《Microscopy research and technique》1986,4(1):47-54
Scanning electron microscopy autoradiography (SEM-AR) in conjunction with light microscope autoradiography (LM-AR) was used to follow the movement of 125I-labeled blueberry shoestring virus (BBSSV) through its aphid vector Illinoia pepperi with varying acquisition access periods (AAP). At 6 hr AAP, the virus had reached the stomach; at 12 hr AAP, it had reached the anterior of the intestines, and after 48 hr, AAP was present throughout the aphid. SEM-AR using backscatter electron detection proved very useful because the sample bulk resulted in a shortened exposure time compared to LM sections, correlation of the autoradiograms could be made with fine structure, preparing large numbers of samples was easy, and examining whole longitudinal sections of aphids at low magnification with a clearly visible marker was possible. Limitations were mostly attributed to sample preparation and, in some cases, were easily remedied. 相似文献
105.
Time-of-flight MR-angiography of large volumes is limited by the occurrence of saturation effects, which lead to low signal in both veins and arteries. Alternatively to a number of other MRA-techniques, intravenous application of paramagnetic contrast media in combination with 3D-pulse sequences with or without flow refocussing allows the depiction of slow vessels in large volumes without technical extra expenses. The main intracranial indication is anatomical 3D-imaging of normal and dysplastic cerebral veins with high spatial resolution, and the additional depiction of the venous drainage in AVMs, when unenhanced MRA shows only the arteriel supply and the nidus. In large cerebral aneurysms, bridging veins and venous sinuses, partial thromboses can easily be differentiated from slow flow. Contrast-enhancing tumors can be depicted together with normal or displaced vessels. Improvements of arterial signal due to contrast media with currently used routine MRA techniques are clinically not significant. Signal loss due to spin dephasing in vessels with complex flow is not influences by contrast media. Results of contrast-enhanced MRA are determined by the timing of injection. Since arteries and veins are both imaged with high signal intensity, improvements of postprocessing procedures for secondary vessel segmentation are necessary. 相似文献
106.
JJ Kehayias RD Bent MC Green M Hugi H Nann TE Ward 《Canadian Metallurgical Quarterly》1986,33(4):1388-1392
107.
This paper investigates the problem of designing a state feedback control to stabilize an uncertain nonlinear system. We focus attention on the amplitude (norm) of the controller which is used to achieve this end. The uncertain system is described by a state equation which contains uncertain parameters which are unknown but bounded. A Lyapunov function is used to establish the stability of the closed loop system. The paper gives necessary and sufficient concitions for the uncertain system to be stabilizable with a given Lyapunov function. Furthermore, a procedure is indicated for the construction of the desired feedback control law. 相似文献
108.
Ohne Zusammenfassung 相似文献
109.
Four antimony cover-coat enamels, four fluoride cover-coat enamels, and four ground-coat enamels were formulated to give varying coefficients of expansion. The calculated values were 250, 275, 300, and 325 × 10–7. The observed coefficients of expansion are included in the paper. The enamels were applied to standard 2-quart pudding pans and were tested for thermal shock and impact resistance using the standard methods of the Enameled Utensil Manufacturers’Council. The results show that thermal-shock resistance is controlled chiefly by the coefficient of expansion of the ground-coat and cover-coat enamels. The best results were obtained by using a cover-coat enamel with a low coefficient of expansion and a ground coat with a high coefficient of expansion. No conclusive evidence was found to indicate any effect of the coefficient of expansion of the ground- and cover-coat enamels on impact resistance. The solubility resistance and reflectance curves for the enamels are also included. 相似文献
110.
K. Pond BSc PhD T. Petersen BSc PhD G. Rees BSc PhD R. Perry BSc 《Water and Environment Journal》2000,14(1):22-26
The quality of recreational waters has become of increasing importance and, where water-based activities are permitted, such waters should be required to comply with minimum standards to protect public health. At present, there are no freshwater sites in the UK which are identified as official bathing areas, despite a significant proportion being identified in other EU Member States and the increasing use of such waters for bathing. This paper presents a case for the official identification of three freshwater bathing sites which, traditionally, have been used for bathing for more than ninety years. 相似文献