全文获取类型
收费全文 | 740篇 |
免费 | 24篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 286篇 |
金属工艺 | 34篇 |
机械仪表 | 23篇 |
建筑科学 | 18篇 |
矿业工程 | 4篇 |
能源动力 | 19篇 |
轻工业 | 59篇 |
水利工程 | 1篇 |
石油天然气 | 8篇 |
无线电 | 18篇 |
一般工业技术 | 157篇 |
冶金工业 | 47篇 |
原子能技术 | 10篇 |
自动化技术 | 74篇 |
出版年
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 27篇 |
2020年 | 20篇 |
2019年 | 16篇 |
2018年 | 20篇 |
2017年 | 19篇 |
2016年 | 32篇 |
2015年 | 16篇 |
2014年 | 34篇 |
2013年 | 36篇 |
2012年 | 22篇 |
2011年 | 41篇 |
2010年 | 51篇 |
2009年 | 33篇 |
2008年 | 31篇 |
2007年 | 32篇 |
2006年 | 23篇 |
2005年 | 17篇 |
2004年 | 10篇 |
2003年 | 10篇 |
2002年 | 14篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 18篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1993年 | 9篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1986年 | 9篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1977年 | 11篇 |
1976年 | 7篇 |
1975年 | 8篇 |
1974年 | 9篇 |
1973年 | 12篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1936年 | 3篇 |
排序方式: 共有765条查询结果,搜索用时 0 毫秒
1.
2.
3.
D. L. Kuznetsov E. V. Kol’man Yu. S. Surkov V. V. Uvarin I. E. Filatov 《Technical Physics Letters》2007,33(7):604-606
The process of methane conversion in a mixture modeling the natural gas under the action of a periodic nanosecond pulsed electron beam and an electron-beam-induced non-self-sustained discharge has been numerically simulated and studied in experiment. The possibility of methane conversion under the action of electric pulses without significant heating of the processed gas mixture is demonstrated for the first time. The main conversion products in experiment were hydrogen, ethylene, and acetylene. 相似文献
4.
Jaroslav Mackerle 《International Journal of Pressure Vessels and Piping》1996,69(3):279-339
The paper gives a bibliographical review of the finite element methods (FEMs) applied for the analysis of pressure vessel structures/components and piping from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore the aim of this review is to give the reader an encyclopaedic view of the differnt possibilities that exist today for the finite element analysis in the fields of pressure vessels and piping. The bibliography at the end of the paper contains approximately 1900 references to papers, conference proceedings and theses/dissertations on the subject that were published in 1976–1996. These are classified in the following categories: linear and non-linear, static and dynamic, stress and deflection analysis; stability problems; thermal problems; fracture mechanics problems; contact problems; fluid-structure interaction problems; manufacturing of pipes and tubes; welded pipes and pressure vessel components; development of special finite elements for pressure vessels and pipes; finite element software; and other topics. Also finite element software, general purpose and special purpose codes, used for the analysis of pressure vessels and pipes are briefly discussed and presented. 相似文献
5.
Linear oligosiloxanes functionalized with bulky side chain tris(trimethylsilyl)hexyl (TTSH) substituents were transformed into cross-linked materials by UV 193 nm excimer pulsed laser ablation. The process occurred without any catalyst, by reactions of radicals formed in UV laser induced photolysis of side tris(trimethylsilyl)hexyl groups. Chemical changes were monitored by FTIR, LC/UV, GC/MS and solubility tests. 相似文献
6.
A. V. Koltygin Yu. P. Tsynovnikova O. A. Kol’ 《Russian Journal of Non-Ferrous Metals》2007,48(5):347-348
In the last years, there is carried out an intensive search for new molding mixtures capable of replacing sand-argillaceous mixtures whose properties have already been well studied. Unfortunately, the majority of them form a mold in the course of the hardening of a bonding agent, which requires creating a complex system for the regeneration of the used sand. In this connection, we investigated a waterless molding mixture with the use of organobentonite as the binder, which does not require any changes in the technological process of green-sand molding. The influence of the amount and composition of the solvent on the properties of waterless mixtures is estimated. 相似文献
7.
M. Koláč B. S. Neganov A. Sahling S. Sahling 《Journal of Low Temperature Physics》1986,63(5-6):459-477
The low-temperature heat release in copper due to ortho-para conversion in hydrogen bubbles is investigated. Deviations from a model of free solid hydrogen are observed: a more intense heat release atT10 K and a rapid (10 h) heat release after cooling to 1.3 K. The experimental results can be explained by the assumption of autocatalytic conversion in the bulk and the catalytic influence of the bubble surface. 相似文献
8.
Radovan Novotný Radek Vlach Jaroslav Kadlec Radek Kuchta 《Microsystem Technologies》2014,20(4-5):719-728
Ceramics joints are applied for producing products that should be made in a general shapes and dimensions for more advantageous usage. The article presents the research work related to ceramic joint quality evaluation, the thermal-structural analysis of ceramic joining and ceramic bond design and implementation. The role of ceramic material in the electronics industry and motivation for joining ceramics is described in the introduction. The requirements and methods for improving the quality of joints are summarized. Also, the results of simulations of pressure sensor cooling after removal from the oven during joining are discussed. The experimental results are evaluated by using a t-test before and after process cooling modification. Important directions for future research are summarized, with emphasis on the statistical determination of poor connection, and how the interface of modification of joint technology and process setting affects results and parameters that have been achieved. 相似文献
9.
Summary The dynamic mechanical behaviour of 4% aqueous solutions and networks of poly (N, N-diethylacrylamide) and copolymers of diethylacrylamide
with sodium methacrylate (MNa) (molar ratio xMNA=0–0.05) swollen in water was measured in the temperature range 20–80 °C. With increasing temperature, at Tc polymer chains collapse from random coil to more compact globular conformations. While in the region of coil conformations
(T > Tc) the mechanical behaviour of solutions has a liquid-like character (the loss modulus G″ is higher than the storage modulus
G′ for a constant frequency ω=1 Hz), in the region of globular conformations (T > Tc) a heterogeneous physical network is built in solutions, and the mechanical behaviour has a solid-like character (G′ > G″).
In networks the collapse is reflected in an increase of storage modulus G′; the magnitude of this increase decreases with
ionization. The dependence of the loss modulus G″ on the temperature of solutions and networks allows us to conclude that
the magnitude of losses in the collapsed state is affected rather by xMNa (the modulus G″ increases with increasing ionization) than by the heterogeneous structure of the samples. 相似文献
10.
The genesis of polyaniline nanotubes 总被引:1,自引:0,他引:1
Aniline has been oxidized with ammonium peroxydisulfate in 0.4 M acetic acid. Protons are produced in the course of oxidation and the pH decreases as the reaction proceeds. The oxidation had two subsequent phases: (1) the oxidation of the neutral aniline molecules and the initially produced low-molecular weight aniline oligomers at low acidity, followed by (2) the oxidation of the anilinium cation after the acidity became higher. The two phases of oxidation gave different products, aniline oligomers with mixed ortho- and para-coupling of aniline molecules, and polyaniline nanotubes, respectively.The aniline oligomers are produced at first at low acidity, pH > 4, some of them as rod-like crystals. The molecular weight of the oligomers has been assessed by gel-permeation chromatography to be of several thousands. The 2-3 wt.% content of sulfur in deprotonated samples suggests that the oxidation products are partly sulfonated. The oxidation of ortho-coupled anilines combined with intramolecular cyclization produces phenazine units or their blocks, as indicated by FTIR spectra. A high-molecular weight polyaniline is produced at pH < 2. The protonation of the intermediate pernigraniline form of polyaniline is a prerequisite for the polymerization.The nano-sized oligomer crystallites serve as starting templates for the nucleation of PANI nanotubes. Further growth of nanotubes proceeds by the self-organization of the phenazine units or their blocks located at the ends of the PANI chains. Polyaniline nanotubes have a typical outer diameter of 100-200 nm, with a wall thickness of 50-100 nm, an inner diameter of 0-100 nm, and a length extending to several micrometres. 相似文献