全文获取类型
收费全文 | 2205篇 |
免费 | 197篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 25篇 |
综合类 | 2篇 |
化学工业 | 552篇 |
金属工艺 | 68篇 |
机械仪表 | 128篇 |
建筑科学 | 31篇 |
矿业工程 | 2篇 |
能源动力 | 97篇 |
轻工业 | 260篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
武器工业 | 1篇 |
无线电 | 387篇 |
一般工业技术 | 454篇 |
冶金工业 | 147篇 |
原子能技术 | 26篇 |
自动化技术 | 220篇 |
出版年
2024年 | 2篇 |
2023年 | 20篇 |
2022年 | 43篇 |
2021年 | 65篇 |
2020年 | 44篇 |
2019年 | 68篇 |
2018年 | 70篇 |
2017年 | 76篇 |
2016年 | 98篇 |
2015年 | 86篇 |
2014年 | 124篇 |
2013年 | 148篇 |
2012年 | 152篇 |
2011年 | 162篇 |
2010年 | 152篇 |
2009年 | 146篇 |
2008年 | 125篇 |
2007年 | 85篇 |
2006年 | 79篇 |
2005年 | 55篇 |
2004年 | 59篇 |
2003年 | 57篇 |
2002年 | 57篇 |
2001年 | 48篇 |
2000年 | 40篇 |
1999年 | 39篇 |
1998年 | 73篇 |
1997年 | 36篇 |
1996年 | 31篇 |
1995年 | 31篇 |
1994年 | 18篇 |
1993年 | 18篇 |
1992年 | 20篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有2404条查询结果,搜索用时 31 毫秒
1.
In vivo Kinetic Biodistribution of Nano‐Sized Outer Membrane Vesicles Derived from Bacteria
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Su Chul Jang Sae Rom Kim Yae Jin Yoon Kyong‐Su Park Ji Hyun Kim Jaewook Lee Oh Youn Kim Eun‐Jeong Choi Dae‐Kyum Kim Dong‐Sic Choi Yoon‐Keun Kim Jaesung Park Dolores Di Vizio Yong Song Gho 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(4):456-461
Evaluation of kinetic distribution and behaviors of nanoparticles in vivo provides crucial clues into their roles in living organisms. Extracellular vesicles are evolutionary conserved nanoparticles, known to play important biological functions in intercellular, inter‐species, and inter‐kingdom communication. In this study, the first kinetic analysis of the biodistribution of outer membrane vesicles (OMVs)—bacterial extracellular vesicles—with immune‐modulatory functions is performed. OMVs, injected intraperitoneally, spread to the whole mouse body and accumulate in the liver, lung, spleen, and kidney within 3 h of administration. As an early systemic inflammation response, increased levels of TNF‐α and IL‐6 are observed in serum and bronchoalveolar lavage fluid. In addition, the number of leukocytes and platelets in the blood is decreased. OMVs and cytokine concentrations, as well as body temperature are gradually decreased 6 h after OMV injection, in concomitance with the formation of eye exudates, and of an increase in ICAM‐1 levels in the lung. Following OMV elimination, most of the inflammatory signs are reverted, 12 h post‐injection. However, leukocytes in bronchoalveolar lavage fluid are increased as a late reaction. Taken together, these results suggest that OMVs are effective mediators of long distance communication in vivo. 相似文献
2.
To determine three‐dimensional fiber orientation states in injection‐molded short‐fiber composites, a confocal laser scanning microscope (CLSM) is used. Since the CLSM optically sections the specimen, more than two images of the cross sections on and below the surface of the composite can be obtained. Three‐dimensional fiber orientation states can be determined by using geometric parameters of fiber images obtained from two parallel cross sections. For experiments, carbon‐fiber‐reinforced polystyrene is examined by the CLSM and geometric parameters of fibers on each cross‐sectional plane are measured by an image analysis. In order to describe fiber orientation states compactly, orientation tensors are determined at different positions of the prepared specimen. Three‐dimensional orientation states are obtained without any difficulty by determining the out‐of‐plane angles utilizing fiber images on two parallel planes acquired by the CLSM. Orientation states are different at different positions and show the shell–core structure along the thickness of the specimen. Fiber orientation tensors are predicted by a numerical analysis and the numerically predicted orientation states show good agreement with measured ones. However, some differences are found at the end of cavity. They may result from the fountain flow effects, which are not considered in the numerical analysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 500–509, 2003 相似文献
3.
4.
GM Gazzaniga G Angelini G Pastorino E Santoro M Lucchini ML Dal Prà 《Canadian Metallurgical Quarterly》1993,78(3):271-275
Four hundred forty-six patients with Tourette Syndrome (TS) and/or their parents completed a 52-item self-report survey about vocal and motor tics, and the frequency of associated co-morbid conditions of aggression, obsessions and compulsions, attentional problems, sleep disturbance, mood disturbance, anxiety, and self-mutilative behaviours which have been frequently reported in the literature on TS. Respondents also responded to an open-ended question regarding the most disabling aspects of TS. Results were analyzed within two age groups; under 18 years of age (N = 245) and 18 years of age or older (N = 177). Tics and associated conditions were the most frequently reported disabling aspect by both age groups. Subjects under age 18, however, reported significantly more frequent problems with hyperactivity, temper control, aggressive behaviours and sleepwalking than adults with TS. 相似文献
5.
A new discontinuous modulation method based on space-vector control is proposed and analyzed. The proposed technique employs a pulse-dropping method and is designed in the time domain. It features a very wide modulation range while maintaining the required waveform qualities and switching numbers in the overmodulation region. Since the modulation method and modulation index equation are simple, the proposed technique can be easily implemented by software and is applicable to the overmodulation region in ac motor drives. The performance indexes are discussed and experiments have been performed. 相似文献
6.
N. Realdon M. Dal Zotto E. Ragazzi G. Dalla Fini 《Drug development and industrial pharmacy》1996,22(2):125-134
The release rate of a drug dissolved in the liquid phase of lipogels may be greatly affected by the type and concentration of gelling agent and by processing conditions and mechanical treatment of the ointment. These differences in release rate are reduced after application of mechanical stress comparable with the strain exerted on the ointment during application to the skin. Therefore, changes in the concentration of gelling agents used to achieve suitable consistency and manufacturing and packing processes that meet industrial and marketing requirements do not appear to exert a practical influence on drug availability after application to the skin. 相似文献
7.
Vendrame L. Zabotto E. Dal Fabbro A. Zanini A. Verzellesi G. Zanoni E. Chantre A. Pavan P. 《Electron Devices, IEEE Transactions on》1995,42(9):1636-1646
In this paper we describe a set of measurements representing a complete characterization of impact-ionization effects in bipolar transistors. We demonstrate that impact-ionization significantly influences the dependence of base resistance on current and voltages applied to the device. A dc method for the simultaneous extraction of all parasitic resistances in bipolar transistors is presented. The method can separate the influence of current-crowding on the base resistance from that of base width and conductivity modulation; the collector parasitic resistance is measured in the active region. Starting from the parameters extracted by means of these techniques, a complete and accurate circuit-model of impact-ionization effects can be defined 相似文献
8.
Park Y.C. Lee K.Y. Youn D.H. Kim N.H. Kim W.K. Park S.H. 《IEEE transactions on bio-medical engineering》1992,39(8):868-871
An efficient algorithm detecting the presence of a fetal QRS complex is presented. The proposed fetal QRS detection method computes the averaged magnitude of the difference between the fetal ECG signal and the reference signal to detect the fetal QRS event. The detected fetal QRS complexes are exponentially averaged to generate the template signal which can track the slowly varying shape of the fetal ECG signal. As an effort to obtain improved detection performances, two approaches of normalizing the fetal ECG signal and the template are considered. 相似文献
9.
On-line dead-time compensation method using disturbance observer 总被引:7,自引:0,他引:7
Hyun-Soo Kim Hyung-Tae Moon Myung-Joong Youn 《Power Electronics, IEEE Transactions on》2003,18(6):1336-1345
A new on-line dead-time compensation method for a permanent magnet (PM) synchronous motor drive is proposed. Using a simple disturbance observer without any additional circuit and off-line experimental measurement, disturbance voltages in the rotor reference dq frame caused by the dead time and nonideal switching characteristics of power devices are estimated in an on-line manner and fed to voltage references in order to compensate the dead-time effects. The proposed method is applied to a PM synchronous motor drive system and implemented by using software of a digital signal processor (DSP) TMS320C31. Simulations and experiments are carried out for this system and the results well demonstrate the effectiveness of the proposed method. 相似文献
10.
Silvano Dal Zilio Denis Lugiez 《Applicable Algebra in Engineering, Communication and Computing》2006,17(5):337-377
XML documents may be roughly described as unranked, ordered trees and it is therefore natural to use tree automata to process or validate them. This idea has already been successfully applied in the context of Document Type Definition (DTD), the simplest standard for defining document validity, but additional work is needed to take into account XML Schema, a more advanced standard, for which regular tree automata are not satisfactory. In this paper, we introduce Sheaves Logic (SL), a new tree logic that extends the syntax of the – recursion-free fragment of – W3C XML Schema Definition Language (WXS). Then, we define a new class of automata for unranked trees that provides decision procedures for the basic questions about SL: model-checking; satisfiability; entailment. The same class of automata is also used to answer basic questions about WXS, including recursive schemas: decidability of type-checking documents; testing the emptiness of schemas; testing that a schema subsumes another one.This work was partially supported by the French government research grant ACI TRALALA and by IST Global Computing Profundis. 相似文献