全文获取类型
收费全文 | 13593篇 |
免费 | 1489篇 |
国内免费 | 1042篇 |
专业分类
电工技术 | 933篇 |
综合类 | 1676篇 |
化学工业 | 562篇 |
金属工艺 | 243篇 |
机械仪表 | 1639篇 |
建筑科学 | 345篇 |
矿业工程 | 115篇 |
能源动力 | 294篇 |
轻工业 | 250篇 |
水利工程 | 391篇 |
石油天然气 | 391篇 |
武器工业 | 191篇 |
无线电 | 1952篇 |
一般工业技术 | 2400篇 |
冶金工业 | 221篇 |
原子能技术 | 358篇 |
自动化技术 | 4163篇 |
出版年
2024年 | 20篇 |
2023年 | 129篇 |
2022年 | 287篇 |
2021年 | 313篇 |
2020年 | 372篇 |
2019年 | 336篇 |
2018年 | 411篇 |
2017年 | 492篇 |
2016年 | 566篇 |
2015年 | 561篇 |
2014年 | 824篇 |
2013年 | 917篇 |
2012年 | 1204篇 |
2011年 | 1189篇 |
2010年 | 768篇 |
2009年 | 827篇 |
2008年 | 803篇 |
2007年 | 892篇 |
2006年 | 806篇 |
2005年 | 651篇 |
2004年 | 487篇 |
2003年 | 506篇 |
2002年 | 391篇 |
2001年 | 318篇 |
2000年 | 280篇 |
1999年 | 233篇 |
1998年 | 240篇 |
1997年 | 187篇 |
1996年 | 180篇 |
1995年 | 152篇 |
1994年 | 133篇 |
1993年 | 113篇 |
1992年 | 83篇 |
1991年 | 65篇 |
1990年 | 90篇 |
1989年 | 55篇 |
1988年 | 49篇 |
1987年 | 30篇 |
1986年 | 32篇 |
1985年 | 16篇 |
1984年 | 31篇 |
1983年 | 9篇 |
1982年 | 15篇 |
1981年 | 12篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 12篇 |
1976年 | 4篇 |
1959年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Felipe A. Perdomo Siti H. Khalit Claire S. Adjiman Amparo Galindo George Jackson 《American Institute of Chemical Engineers》2021,67(3):e17194
The SAFT-γ Mie group-contribution equation of state is used to represent the fluid-phase behavior of aqueous solutions of a variety of linear, branched, and cyclic amines. New group interactions are developed in order to model the mixtures of interest, including the like and unlike interactions between alkyl primary, secondary, and tertiary amine groups (NH2, NH, N), cyclic secondary and tertiary amine groups (cNH, cN), and cyclic methine-amine groups (cCHNH, cCHN) with water (H2O). The group-interaction parameters are estimated from appropriate experimental thermodynamic data for pure amines and selected mixtures. By taking advantage of the group-contribution nature of the method, one can describe the fluid-phase behavior of mixtures of molecules comprising those groups over broad ranges of temperature, pressure, and composition. A number of aqueous solutions of amines are studied including linear, branched aliphatic, and cyclic amines. Liquid–liquid equilibria (LLE) bounded by lower critical solution temperatures (LCSTs) have been reported experimentally and are reproduced here with the SAFT-γ Mie approach. The main feature of the approach is the ability not only to represent accurately the experimental data employed in the parameter estimation, but also to predict the vapor–liquid, liquid–liquid, and vapor–liquid–liquid equilibria, and LCSTs with the same set of parameters. Pure compound and binary phase diagrams of diverse types of amines and their aqueous solutions are assessed in order to demonstrate the main features of the thermodynamic and fluid-phase behavior. 相似文献
2.
This calibration device of radio comprehensive tester is studied and established in this paper. It solves the verification and
calibration of a large number of general-purpose radio comprehensive testers. The calibration device consists of four calibration sub-
systems and calibration software system, including RF generator, audio generator, audio analyzer and RF analyzer. It also researches
on the configuration of standard equipment and analyzes the uncertainty of the calibration devices, ensuring accurate and reliable val-
ue transfer. 相似文献
3.
Hashim A.
Hashim 《国际强度与非线性控制杂志
》2020,30(10):3848-3870
》2020,30(10):3848-3870
This paper introduces two novel nonlinear stochastic attitude estimators developed on the Special Orthogonal Group with the tracking error of the normalized Euclidean distance meeting predefined transient and steady‐state characteristics. The tracking error is confined to initially start within a predetermined large set such that the transient performance is guaranteed to obey dynamically reducing boundaries and decrease smoothly and asymptotically to the origin in probability from almost any initial condition. The proposed estimators produce accurate attitude estimates with remarkable convergence properties using measurements obtained from low‐cost inertial measurement units. The estimators proposed in continuous form are complemented by their discrete versions for the implementation purposes. The simulation results illustrate the effectiveness and robustness of the proposed estimators against uncertain measurements and large initialization error, whether in continuous or discrete form. 相似文献
4.
针对以英飞凌TC275单片机为平台的整车控制器,进行控制器局域网络标定协议(controller area network calibration protocol,CCP)底层驱动程序的开发。依据CCP的需求开发了英飞凌TC275的控制器局域网络(controller area network,CAN)模块、系统定时器(system timer,STM)模块和FLASH模块的底层驱动程序,实现CCP标定系统的通信连接、数据上传、数据下载、数据存储等功能。为验证系统的性能,进行整车控制器的实际测试,测试结果表明:所开发的基于TC275单片机的CCP底层驱动程序能够实现CCP的功能要求。 相似文献
5.
在双离心机的线加速度计动态校准中,三参数余弦算法贯穿在幅频特性、相频特性以及幅值线性度的整个测试中。本文详细描述了三参数余弦算法的概念和推导过程,以及在双离心机线加速度计动态校准数据处理过程中三参数余弦算法的程序实现;介绍了在幅频特性和相频特性中关于采集点的选取方式,降低由于采集点选择方式不同对数据拟合精度造成的影响。选取某型线加速度计为例,利用双离心机进行动态校准,对采集得到的数据点进行曲线拟合并得到测试结果,验证了所编写的三参数余弦算法程序的可行性。 相似文献
6.
7.
ABSTRACTThis study investigates the use of numerical simulations to describe the solid-state diffusion of a sintering stage during a metal injection moulding process for micro-fluidic components with 316L stainless steel powders. Finite element (FE) analysis based on a thermo-elasto-viscoplastic model was conducted to describe the densification process of a stainless steel porous component during solid-state sintering. The numerical analyses, which were performed on a 3D micro-structured component with various powder volume loadings to take into account the thermal debinding effect to propose a full debinding sintering simulation, demonstrated that the FE simulation results are in agreement with the experimental ones. 相似文献
8.
提出了一种小型轻便的流速仪检定系统的设计方案,并运用改进的多学科协同优化方法求解各学科设计变量的最优解。首先介绍了算法思想及改进措施,并根据系统设计要求建立了各学科的设计变量、目标函数和约束条件;其次,运用遗传算法求解各学科设计变量的最优解,并根据优化结果完善了系统的设计方案,同时运用计算机仿真等方法验证了优化结果的可行性。结果表明,优化后的检定系统满足流体力学效应、匀速运动时间、系统重量等设计要求,同时证明了协同优化算法解决多学科设计优化问题的有效性。 相似文献
9.
Chahid Ayouch El-Hassan Essoufi Mouhcine Tilioua 《Computers & Mathematics with Applications》2019,77(5):1347-1357
The present paper deals with global existence of weak solutions of a time-space fractional Landau–Lifshitz–Bloch equation involving the weak Caputo derivative and a fractional Laplacian. We use Faedo–Galerkin method with some commutator estimates in order to prove global existence of weak solutions for the model. The uniqueness is also discussed in a special one dimensional case. 相似文献
10.
In this paper, a nonconforming finite element method (NFEM) is proposed for the constrained optimal control problems (OCPs) governed by a bilinear state equation. The state and adjoint state are approximated by the nonconforming element, and the control is approximated by the orthogonal projection through the state and adjoint state. Some superclose and superconvergence properties are obtained by full use of the distinguish characters of this element, such as the interpolation operator equals the Ritz projection, and the consistency error is one order higher than its interpolation error in the broken energy norm. Finally, some numerical results are provided to verify the theoretical analysis. 相似文献