全文获取类型
收费全文 | 1255篇 |
免费 | 78篇 |
专业分类
电工技术 | 21篇 |
综合类 | 1篇 |
化学工业 | 306篇 |
金属工艺 | 12篇 |
机械仪表 | 16篇 |
建筑科学 | 27篇 |
矿业工程 | 2篇 |
能源动力 | 40篇 |
轻工业 | 272篇 |
水利工程 | 16篇 |
石油天然气 | 10篇 |
无线电 | 80篇 |
一般工业技术 | 159篇 |
冶金工业 | 207篇 |
原子能技术 | 7篇 |
自动化技术 | 157篇 |
出版年
2024年 | 5篇 |
2023年 | 12篇 |
2022年 | 25篇 |
2021年 | 46篇 |
2020年 | 31篇 |
2019年 | 34篇 |
2018年 | 38篇 |
2017年 | 44篇 |
2016年 | 32篇 |
2015年 | 35篇 |
2014年 | 50篇 |
2013年 | 82篇 |
2012年 | 71篇 |
2011年 | 80篇 |
2010年 | 61篇 |
2009年 | 61篇 |
2008年 | 58篇 |
2007年 | 52篇 |
2006年 | 47篇 |
2005年 | 35篇 |
2004年 | 35篇 |
2003年 | 25篇 |
2002年 | 31篇 |
2001年 | 21篇 |
2000年 | 12篇 |
1999年 | 24篇 |
1998年 | 85篇 |
1997年 | 45篇 |
1996年 | 31篇 |
1995年 | 27篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 4篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1973年 | 2篇 |
排序方式: 共有1333条查询结果,搜索用时 3 毫秒
971.
972.
J Pérez Obón R Fernández Liesa J Marín García J Rivares Esteban J Fraile Rodrigo R Martínez-Berganza y Asensio A Ortiz García 《Canadian Metallurgical Quarterly》1994,45(2):107-110
We constructed previously the expressing library of Leishmania donovani genomic DNA with lambda gt11 as vector. In this paper, 2 x 10(4) phages were plated on E. coli Y1090r-, and screened with a rabbit antiserum prepared by immunization with Leishmania donovani promastigotes. Bound antibodies were detected using alkaline phosphatase labeled anti-rabbit antibodies. A positive expressing clone was detected and transferred into E. coli Y1098r- to prepare lysate, a 39 kDa polypeptide in E. coli Y1089r-lysate was recognized by anti-Leishmania donovani serum. The result indicated that the 39 kDa polypeptide which was not fused with the major portion of beta-galactosidase existed disconnectedly. This finding remained to be further studied. 相似文献
973.
The applicability of accepted engineering procedures to predict the amplitude of singular crack tip fields during the transitional regime prior to steady state has been investigated. Estimates of both transient and steady state values of the C(t)-integral for simplified geometries are compared with results obtained from detailed finite element analyses. Different creep exponents and both primary (mechanical) and secondary (displacement-controlled) loadings are considered.Estimates of the steady state value C* were obtained from Nuclear Electric's high termperature assessment procedure, R5, which is based on reference stress concepts, and from the EPRI's fully plastic solutions for J-integrals. The transient behaviour of C(t) was estimated using approximations given by Ehlers and Riedel (Advances in Fracture Research, Proc. Fifth Int. Conf. on Fracture, Vol. 2, Pergamon, New York, 1981, pp. 691–698), Saxena (Fracture Mechanics: Seventeenth Volume, ASTM STP 905, ASTM, Philadelphia, 1986, pp. 185–201), and the R5 procedure (Ainsworth et al., Fatigue Fract. Eng. Struct. 10 (1987) 115–127). In most cases, the transient estimates given by the latter two were found to conservatively predict the finite element results, although some underpredictions were encountered in the planar geometries shortly after loading. The recommended use of plane stress reference stresses with the R5 procedure, however, provides overall conservatism in the values of C(t). Ehlers and Riedel estimates, though, are generally non-conservative, except for the lowest crack-tip constraint configuration analysed (i.e. centre cracked plate). 相似文献
974.
975.
JA Pérez Arbej M López Carreira F Arnaiz Esteban E Martínez Pérez MA Nogueras Gimeno R Espuela Orgaz V Crespo Mayor 《Canadian Metallurgical Quarterly》1996,20(10):892-894
Presentation of one case-report of leukaemic infiltration of the prostate. Interestingly, the biopsy was only performed after finding distinctly elevated PSA levels and not because of the clinical findings, whether exploratory or echographic. 相似文献
976.
Characterization of corrugated waveguides by modal analysis 总被引:1,自引:0,他引:1
A general formulation for the characterization of corrugated waveguides is presented. The formulation is based on modal expansion in the different smooth-walled waveguides which constitute the corrugated structure and on the use of mode matching at discontinuities. The use of an admittance matrix formulation and a suitable root-finding algorithm leads to a rigorous and efficient technique. Dispersion curves are presented for corrugated waveguides of circular and rectangular cross-sections. Complex modes are obtained for deep corrugations. The effect of the finite thickness and width of teeth and slots on the dispersion behavior is shown 相似文献
977.
There has recently been a growing interest in using new packaging materials-dielectric and/or magnetic-in a wide variety of applications for controlling the microwave heating of food. The study of the thermal behavior of these products requires the accurate determination of the complex permittivity and permeability when the temperature varies, and when the materials are irradiated in specific conditions. One of the main challenges is to distinguish the dielectric losses from the magnetic ones. In this paper, a practical measurement method is proposed, which consists of irradiating a rod sample successively with a homogeneous electric-field distribution with a low magnetic field and with a homogeneous magnetic-field distribution with low electric field. An accurate and efficient electromagnetic analysis tool is used to generate a set of points, which allow the construction of several bilinear functions that relate the scattering parameters of the circuit to the complex values of /spl epsiv/ and /spl mu/ so that /spl epsiv/ and /spl mu/ can then be easily determined from experimental measurements in accordance to whatever the special irradiation conditions. Some results for test materials are presented and discussed. 相似文献
978.
R Hernández J A Esteban M García F Morán 《Computer applications in the biosciences》1991,7(2):169-174
In this paper we describe PASHEMOS, a user-friendly program written in Pascal to solve the Meinhardt-Klingler model numerically. This model studies the shell pattern pigmentation of molluscs. Moreover, PASHEMOS enables theoretical analysis to be performed on the different steady states. The program takes into account the four differential equation systems established in the model. It numerically solves these systems. This program is developed in such a way that both the equation system type and the parameter values can be chosen. The pattern is displayed in each case, and other output possibilities are available (i.e. three-dimensional concentration plotting, phase plane, phase space, stability analysis). The implementation of the program for the case of a three-variable system is shown as an example of PASHEMOS handling. Program applications for other models are also discussed. 相似文献
979.
980.
EM Rodriguez EA de Moya E Guerrero ER Monterroso TC Quinn E Puello MR de Qui?ones B Thorington PD Glasner F Zacarias 《Canadian Metallurgical Quarterly》1993,6(3):313-318
Emergency air medical transport has become an integral part of the practice of medicine. In 1990, there were more than 170 air medical programs in operation in the United States. The proper and safe use of air medical transport requires a basic understanding of the medical implications of flight and the capabilities and constraints involved in transporting patients by air. The purpose of this paper is to review this information and provide guidelines for the use of air medical transport. 相似文献