全文获取类型
收费全文 | 9011篇 |
免费 | 373篇 |
国内免费 | 23篇 |
专业分类
电工技术 | 89篇 |
综合类 | 37篇 |
化学工业 | 2190篇 |
金属工艺 | 151篇 |
机械仪表 | 164篇 |
建筑科学 | 483篇 |
矿业工程 | 14篇 |
能源动力 | 281篇 |
轻工业 | 676篇 |
水利工程 | 59篇 |
石油天然气 | 33篇 |
无线电 | 688篇 |
一般工业技术 | 1811篇 |
冶金工业 | 1150篇 |
原子能技术 | 71篇 |
自动化技术 | 1510篇 |
出版年
2023年 | 95篇 |
2022年 | 170篇 |
2021年 | 253篇 |
2020年 | 172篇 |
2019年 | 234篇 |
2018年 | 261篇 |
2017年 | 186篇 |
2016年 | 246篇 |
2015年 | 219篇 |
2014年 | 292篇 |
2013年 | 509篇 |
2012年 | 477篇 |
2011年 | 546篇 |
2010年 | 404篇 |
2009年 | 421篇 |
2008年 | 437篇 |
2007年 | 423篇 |
2006年 | 335篇 |
2005年 | 322篇 |
2004年 | 269篇 |
2003年 | 243篇 |
2002年 | 214篇 |
2001年 | 146篇 |
2000年 | 157篇 |
1999年 | 144篇 |
1998年 | 312篇 |
1997年 | 220篇 |
1996年 | 139篇 |
1995年 | 161篇 |
1994年 | 128篇 |
1993年 | 105篇 |
1992年 | 100篇 |
1991年 | 91篇 |
1990年 | 58篇 |
1989年 | 63篇 |
1988年 | 71篇 |
1987年 | 67篇 |
1986年 | 44篇 |
1985年 | 54篇 |
1984年 | 52篇 |
1983年 | 32篇 |
1982年 | 37篇 |
1981年 | 53篇 |
1980年 | 40篇 |
1979年 | 41篇 |
1978年 | 34篇 |
1977年 | 42篇 |
1976年 | 73篇 |
1975年 | 32篇 |
1974年 | 24篇 |
排序方式: 共有9407条查询结果,搜索用时 0 毫秒
41.
I. G. Voigt-Martin E. Zhou P. Simon R. W. Garbella D. Yan W. Paulus H. Ringsdorf 《Advanced functional materials》1993,2(5):245-268
The experiments described in this paper were undertaken in order to obtain information about the relationship between the structure and non-linear optical properties (second-harmonic generation) of organic thin films. For this purpose, two closely related dyes, diones and tetrones, were compared, both of which are shown to have large hyperpolarisabilities. Their microscopic properties are investigated by conformational analysis and electron diffraction. It could be shown that detailed knowledge about the structure and the adjacent neighbour packing can be obtained from conformational analysis and electron diffraction in order to understand the non-linear optical properties of the two dyes. 相似文献
42.
Marleen Julia Meyer Simon Falk Sarah Rmer Clarissa Prinzinger Sabine Tacke Joachim Geyer Stefan Simm Mladen Vassilev Tzvetkov 《International journal of molecular sciences》2022,23(9)
OCT1 and OCT2 are polyspecific membrane transporters that are involved in hepatic and renal drug clearance in humans and mice. In this study, we cloned dog OCT1 and OCT2 and compared their function to the human and mouse orthologs. We used liver and kidney RNA to clone dog OCT1 and OCT2. The cloned and the publicly available RNA-Seq sequences differed from the annotated exon-intron structure of OCT1 in the dog genome CanFam3.1. An additional exon between exons 2 and 3 was identified and confirmed by sequencing in six additional dog breeds. Next, dog OCT1 and OCT2 were stably overexpressed in HEK293 cells and the transport kinetics of five drugs were analyzed. We observed strong differences in the transport kinetics between dog and human orthologs. Dog OCT1 transported fenoterol with 12.9-fold higher capacity but 14.3-fold lower affinity (higher KM) than human OCT1. Human OCT1 transported ipratropium with 5.2-fold higher capacity but 8.4-fold lower affinity than dog OCT1. Compared to human OCT2, dog OCT2 showed 10-fold lower transport of fenoterol and butylscopolamine. In conclusion, the functional characterization of dog OCT1 and OCT2 reported here may have implications when using dogs as pre-clinical models as well as for drug therapy in dogs. 相似文献
43.
Decarbonylation of formic acid in 46.6–80.2% (6.5–14.1 m) sulphuric acid was studied by driving CO out of the reaction medium by an air current followed by its photometrical determination with Ag-Na-sulphamoyl-benzoate. The logarithm of the reaction rate constant increases straight with the acidity of the medium in the 6.5–12.6 M H2SO4 range. The data obtained argue in favour of a possible implication of a sulphuric acid molecule respectively hydrogensulphate ion in a rate controlling step. 相似文献
44.
45.
Kiswendsida Abel Ouedraogo Simon Enjalbert Frédéric Vanderhaegen 《Engineering Applications of Artificial Intelligence》2013,26(1):24-34
This paper proposes a functional architecture to learn from resilience. First, it defines the concept of resilience applied to Human–Machine System (HMS) in terms of safety management for perturbations and proposes some indicators to assess this resilience. Local and global indicators for evaluating human–machine resilience are used for several criteria. A multi-criteria resilience approach is then developed in order to monitor the evolution of local and global resilience. The resilience indicators are the possible inputs of a learning system that is capable of producing several outputs, such as predictions of the possible evolutions of the system's resilience and possible alternatives for human operators to control resilience. Our system has a feedback–feedforward architecture and is capable of learning from the resilience indicators. A practical example is explained in detail to illustrate the feasibility of such prediction. 相似文献
46.
47.
Two qubit quantum computations are viewed as two player, strictly competitive games and a game-theoretic measure of optimality of these computations is developed. To this end, the geometry of Hilbert space of quantum computations is used to establish the equivalence of game-theoretic solution concepts of Nash equilibrium and mini-max outcomes in games of this type, and quantum mechanisms are designed for realizing these mini-max outcomes. 相似文献
48.
49.
Ulrich Atz 《Personal and Ubiquitous Computing》2013,17(4):639-652
How can we measure subjective experiences or internal states? The rise of happiness as a variable of interest in policy decisions, for instance, necessitates appropriate methods for valid and practical measurements. This self-experimental work contributes to scientific development by analysing and evaluating three methods for recording stress: the experience sampling method with a smartphone, an adapted version of the day reconstruction method (DRM, a diary method) and an ubiquitous biophysical measure of the heart rate. All three methods yield significant treatment effects for eight “natural experiments” as stressors. Surprisingly, the DRM outperforms the other two methods in a simple factor analysis and appears to have no recall bias. Also reactivity has no substantial impact, and an applied researcher should minimise the complexity of the input (amount and type of questions, interface and integration) rather than reduce the number of prompts. Some evidence suggests a Likert-type scale should be preferred over a continuous one. This work also reflects upon the nature of single-subject research and the role of the experimenter. 相似文献
50.