全文获取类型
收费全文 | 62294篇 |
免费 | 3968篇 |
国内免费 | 2861篇 |
专业分类
电工技术 | 2662篇 |
技术理论 | 19篇 |
综合类 | 5796篇 |
化学工业 | 7246篇 |
金属工艺 | 2382篇 |
机械仪表 | 3053篇 |
建筑科学 | 11635篇 |
矿业工程 | 3159篇 |
能源动力 | 1932篇 |
轻工业 | 3917篇 |
水利工程 | 2214篇 |
石油天然气 | 4143篇 |
武器工业 | 371篇 |
无线电 | 3155篇 |
一般工业技术 | 3641篇 |
冶金工业 | 4545篇 |
原子能技术 | 189篇 |
自动化技术 | 9064篇 |
出版年
2024年 | 103篇 |
2023年 | 411篇 |
2022年 | 893篇 |
2021年 | 1278篇 |
2020年 | 1336篇 |
2019年 | 1156篇 |
2018年 | 1060篇 |
2017年 | 1351篇 |
2016年 | 1740篇 |
2015年 | 1828篇 |
2014年 | 3632篇 |
2013年 | 3243篇 |
2012年 | 3923篇 |
2011年 | 4525篇 |
2010年 | 3864篇 |
2009年 | 3714篇 |
2008年 | 3353篇 |
2007年 | 4436篇 |
2006年 | 4450篇 |
2005年 | 4063篇 |
2004年 | 3473篇 |
2003年 | 3229篇 |
2002年 | 2586篇 |
2001年 | 2350篇 |
2000年 | 1907篇 |
1999年 | 1356篇 |
1998年 | 961篇 |
1997年 | 686篇 |
1996年 | 512篇 |
1995年 | 357篇 |
1994年 | 270篇 |
1993年 | 184篇 |
1992年 | 165篇 |
1991年 | 93篇 |
1990年 | 88篇 |
1989年 | 76篇 |
1988年 | 53篇 |
1987年 | 33篇 |
1986年 | 43篇 |
1985年 | 48篇 |
1984年 | 29篇 |
1983年 | 20篇 |
1982年 | 20篇 |
1981年 | 23篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1965年 | 11篇 |
1963年 | 10篇 |
1959年 | 11篇 |
1955年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
文章首先对智能化电子信息技术进行了深入的研究,而后分析了该技术在应用过程中出现的问题,最后结合该技术的相关特点给出了相应的问题解决措施,希望能够对智能化电子信息技术的发展提供帮助。 相似文献
3.
《International Journal of Hydrogen Energy》2022,47(93):39338-39363
In the last few decades, global warming, environmental pollution, and an energy shortage of fossil fuel may cause a severe economic crisis and health threats. Storage, conversion, and application of regenerable and dispersive energy would be a promising solution to release this crisis. The development of porous carbon materials from regenerated biomass are competent methods to store energy with high performance and limited environmental damages. In this regard, bio-carbon with abundant surface functional groups and an easily tunable three-dimensional porous structure may be a potential candidate as a sustainable and green carbon material. Up to now, although some literature has screened the biomass source, reaction temperature, and activator dosage during thermochemical synthesis, a comprehensive evaluation and a detailed discussion of the relationship between raw materials, preparation methods, and the structural and chemical properties of carbon materials are still lacking. Hence, in this review, we first assess the recent advancements in carbonization and activation process of biomass with different compositions and the activity performance in various energy storage applications including supercapacitors, lithium-ion batteries, and hydrogen storage, highlighting the mechanisms and open questions in current energy society. After that, the connections between preparation methods and porous carbon properties including specific surface area, pore volume, and surface chemistry are reviewed in detail. Importantly, we discuss the relationship between the pore structure of prepared porous carbon with surface functional groups, and the energy storage performance in various energy storage fields for different biomass sources and thermal conversion methods. Finally, the conclusion and prospective are concluded to give an outlook for the development of biomass carbon materials, and energy storage applications technologies. This review demonstrates significant potentials for energy applications of biomass materials, and it is expected to inspire new discoveries to promote practical applications of biomass materials in more energy storage and conversion fields. 相似文献
4.
Ya Gu Quanmin Zhu Hassan Nouri 《International Journal of Adaptive Control and Signal Processing》2022,36(1):138-154
This article presents a state-space model with time-delay to map the relationship between known input-output data for discrete systems. For the given input-output data, a model identification algorithm combining parameter estimation and state estimation is proposed in line with the causality constraints. Consequently, this article proposes a least squares parameter estimation algorithm, and analyzes its convergence for the studied systems to prove that the parameter estimation errors converge to zero under the persistent excitation conditions. In control system design, the U-model based control is introduced to provide a unilateral platform to improve the design efficiency and generality. A simulation portfolio from modeling to control is provided with computational experiments to validate the derived results. 相似文献
5.
以“创新、协调、绿色、开放、共享”为内核的新发展理念,是对马克思主义发展理念的继承和发扬,极具时代精神,富含问题意识,为高校思想政治教育发展、教育教学改革实践提供了强大的理论支撑。本文以“通信原理”为例,阐述了新发展理念在课程改革中的思路和方法,实现了思想政治教育与专业基础课程有机融合,为深化高校教学改革、创新人才培养模式提供了思路。 相似文献
6.
围绕人工智能与智慧海洋建设这条主线,论述人工智能、智慧海洋的概念,列举当前较为成熟的人工智能与海洋科技在海洋观测方面融合的切入点,初步展现一种海洋技术与装备智能化的发展路径,提出加快人工智能技术向智慧海洋建设赋能的几点建议。 相似文献
7.
A. Nakano T. Shimazaki M. Sekiya H. Shiozawa K. Ohtsuka A. Aoyagi T. Iwakiri Z. Mikami M. Sato Y. Sugino K. Kinoshita T. Matsuoka T. Imamura Y. Takayama K. Yamamoto 《International Journal of Hydrogen Energy》2021,46(29):15649-15659
Monitoring the temperature in liquid hydrogen (LH2) storage tanks on ships is important for the safety of maritime navigation. In addition, accurate temperature measurement is also required for commercial transactions. Temperature and pressure define the density of liquid hydrogen, which is directly linked to trading interests. In this study, we developed and tested a liquid hydrogen temperature monitoring system that uses platinum resistance sensors with a nominal electrical resistance of approximately 1000 Ω at room temperature, PT-1000, for marine applications. The temperature measurements were carried out using a newly developed temperature monitoring system under different pressure conditions. The measured values are compared with a calibrated reference PT-1000 resistance thermometer. We confirm a measurement accuracy of ±50 mK in a pressure range of 0.1 MPa–0.5 MPa. 相似文献
8.
药物相互作用改变了剂量效应关系,可能会降低疗效或增加毒性,是临床应用中合并用药治疗时重要的考虑因素。预测具有临床意义的药物相互作用是药物研发过程中获益风险评估的重要环节。本文概述了药物研发过程中药物相互作用研究的目的和意义,体内和体外研究的主要内容;梳理分析了2020年国家药品监督管理局(National Medical Products Administration, NMPA)和美国食品药品监督管理局(Food and Drug Administration, FDA)批准上市的新药药物相互作用研究情况,旨在为我国药物研发过程中药物相互作用研究及其监管审评提供参考。 相似文献
9.
The Canadian landscape has typically captured a global imaginary of a pristine wild, but how might its urban designed landscapes be distinctly understood? Foregrounded by the landscape transformations accelerated by climate change, the book Innate Terrain: Canadian Landscape Architecture, edited by Professor Alissa North from the University of Toronto, highlights landscape architecture projects situated on the unique Canadian terrain. Providing further provocation on Canadian landscape architecture, Innate Terrain seeks to fill the literary gap on contemporary landscape perspectives, distinguishing Canadian landscape architecture from global practice, and particularly, its well-documented American counterpart. Landscape architecture in the Canadian context has evolved and established its own distinct identity, one imbued with national and local sensitivities. Informed by diverse environmental and cultural contexts, Canadian-designed landscapes reflect and refer to the prevailing ecosystems of Canada’s innate terrain. Contrary to the preceding International Style, landscape architecture projects in Canada have adopted the ethos of Critical Regionalism in the second half of the 20th century. Contemporary Canadian practitioners are designing landscapes that are deeply informed by their surrounding geographical context while emphasizing cultural specificity. Central to this cultural specificity, addressed by a new generation of landscape architects, is the increasing recognition of Indigenous Traditional Knowledge within the discipline. Canadian landscape architects have collaborated with First Nations, Inuit, and Métis communities, including the keepers of this knowledge, to develop land management strategies and design landscape interventions. 相似文献
10.
本文以肇庆市固体废物产业发展为实例,阐明全市固体废物产业发展现状以及发展方向,并提出了相应的策略。 相似文献