全文获取类型
| 收费全文 | 1349篇 |
| 免费 | 15篇 |
| 国内免费 | 3篇 |
专业分类
| 电工技术 | 98篇 |
| 化学工业 | 282篇 |
| 金属工艺 | 59篇 |
| 机械仪表 | 25篇 |
| 建筑科学 | 10篇 |
| 能源动力 | 40篇 |
| 轻工业 | 69篇 |
| 水利工程 | 2篇 |
| 石油天然气 | 2篇 |
| 无线电 | 157篇 |
| 一般工业技术 | 246篇 |
| 冶金工业 | 273篇 |
| 原子能技术 | 38篇 |
| 自动化技术 | 66篇 |
出版年
| 2024年 | 5篇 |
| 2023年 | 8篇 |
| 2022年 | 16篇 |
| 2021年 | 23篇 |
| 2020年 | 18篇 |
| 2019年 | 17篇 |
| 2018年 | 19篇 |
| 2017年 | 15篇 |
| 2016年 | 32篇 |
| 2015年 | 11篇 |
| 2014年 | 27篇 |
| 2013年 | 58篇 |
| 2012年 | 42篇 |
| 2011年 | 60篇 |
| 2010年 | 44篇 |
| 2009年 | 38篇 |
| 2008年 | 46篇 |
| 2007年 | 51篇 |
| 2006年 | 40篇 |
| 2005年 | 42篇 |
| 2004年 | 43篇 |
| 2003年 | 41篇 |
| 2002年 | 27篇 |
| 2001年 | 53篇 |
| 2000年 | 30篇 |
| 1999年 | 37篇 |
| 1998年 | 121篇 |
| 1997年 | 65篇 |
| 1996年 | 46篇 |
| 1995年 | 39篇 |
| 1994年 | 36篇 |
| 1993年 | 30篇 |
| 1992年 | 12篇 |
| 1991年 | 12篇 |
| 1990年 | 12篇 |
| 1989年 | 11篇 |
| 1988年 | 6篇 |
| 1987年 | 10篇 |
| 1986年 | 11篇 |
| 1985年 | 6篇 |
| 1984年 | 13篇 |
| 1983年 | 11篇 |
| 1982年 | 8篇 |
| 1979年 | 6篇 |
| 1978年 | 6篇 |
| 1977年 | 12篇 |
| 1976年 | 13篇 |
| 1975年 | 8篇 |
| 1974年 | 5篇 |
| 1973年 | 5篇 |
排序方式： 共有1367条查询结果，搜索用时 15 毫秒
991.
In Seob Park Sae Youn Lee Chihaya Adachi Takuma Yasuda 《Advanced functional materials》2016,26(11):1813-1821
Purely organic light‐emitting materials, which can harvest both singlet and triplet excited states to offer high electron‐to‐photon conversion efficiencies, are essential for the realization of high‐performance organic light‐emitting diodes (OLEDs) without using precious metal elements. Donor–acceptor architectures with an intramolecular charge‐transfer excited state have been proved to be a promising system for achieving these requirements through a mechanism of thermally activated delayed fluorescence (TADF). Here, luminescent wedge‐shaped molecules, which comprise a central phthalonitrile or 2,3‐dicyanopyrazine acceptor core coupled with various donor units, are reported as TADF emitters. This set of materials allows systematic fine‐tuning of the band gap and exhibits TADF emissions that cover the entire visible range from blue to red. Full‐color TADF‐OLEDs with high maximum external electroluminescence quantum efficiencies of up to 18.9% have been demonstrated by using these phthalonitrile and 2,3‐dicyanopyrazine‐based TADF emitters. 相似文献
992.
Koichiro Hayashi Takuma Maruhashi Michihiro Nakamura Wataru Sakamoto Toshinobu Yogo 《Advanced functional materials》2016,26(47):8613-8622
Exploiting exogenous and endogenous stimulus‐responsive degradable nanoparticles as drug carriers can improve drug delivery systems (DDSs). The use of hollow nanoparticles may facilitate degradation, and combination of DDS with photodynamic therapy (PDT) and photothermal therapy (PTT) may enhance the anticancer effects of treatments. Here, a one‐pot synthetic method is presented for an anticancer drug (doxorubicin [DOX]) and photosensitizer‐containing hollow hybrid nanoparticles (HNPs) with a disulfide and siloxane framework formed in response to exogenous (light) and endogenous (intracellular glutathione [GSH]) stimuli. The hollow HNPs emit fluorescence within the near‐infrared window and allow for the detection of tumors in vivo by fluorescence imaging. Furthermore, the disulfides within the HNP framework are cleaved by intracellular GSH, deforming the HNPs. Light irradiation facilitates penetration of GSH into the HNP framework and leads to the collapse of the HNPs. As a result, DOX is released from the hollow HNPs. Additionally, the hollow HNPs generate singlet oxygen (1O2) and heat in response to light; thus, fluorescence imaging of tumors combined with trimodal therapy consisting of DDS, PDT, and PTT is feasible, resulting in superior therapeutic efficacy. Thus, this method may have several applications in imaging and therapeutics in the future. 相似文献
993.
Mobile robot used for planetary exploration performs several scientific missions over long distance travel and needs to have a high degree of autonomous mobility system because the communication delay from the Earth impedes its direct teleoperation. Localization of a mobile robot is of particular importance on the autonomous mobility. Classical localization methods such as wheel/visual odometry have been widely investigated and demonstrated, but they possess a well-known trade-off between computational cost and localization accuracy. This paper proposes an accurate gyro-based odometry method for a wheeled mobile robot in rough terrain. The robot in rough terrain is often subject to large wheel slip or vehicle sideslip related with its steering maneuver, and those slips degrade the localization accuracy. The basic approach of the proposed method is to exploit odometry data for the robot distance traveled as well as gyroscope data for the robot heading calculation; however each data-set is weighted in accordance with steering characteristics of a robot in rough terrain. The usefulness of the proposed method is examined through field experiments using a wheeled mobile robot testbed in Martian analog site. The experimental result confirms that the proposed method accurately estimates the robot trajectory. 相似文献
994.
995.
996.
997.
Kirill Bulgarevich Kenji Sakamoto Takeshi Yasuda Takeo Minari Masayuki Takeuchi 《Advanced Electronic Materials》2020,6(7)
Bias‐stress resistance of polymer‐based organic field‐effect transistors (OFETs) is considerably enhanced by coating the gate dielectric surface with an amorphous perfluoropolymer (CYTOP). In bottom‐gate (BG) OFETs offering a relatively simple fabrication process, the CYTOP coating causes a serious problem; that is, thin film formation of organic semiconducting polymers generally fails due to the lyophobic properties of CYTOP. This problem is solved by patterning the CYTOP coating layer with suitable designs. Here, a simple photo‐patterning method is established using CYTOP terminated with amidosilyl functional groups. This method is composed of self‐limited thinning process of CYTOP coating layers, exposure to vacuum ultraviolet light through a photomask, and development. BG/top‐contact OFET arrays are fabricated using poly(2,5‐bis(3‐hexadecylthiophene‐2‐yl)thieno[3,2‐b]thiophene) as the semiconducting polymer. The initial electrical properties and bias‐stress resistance are compared with those of OFETs with octadecyltrichlorosilane (ODTS)‐treated gate dielectrics. The CYTOP‐ and ODTS‐OFETs show approximately the same initial electrical properties with very small device‐to‐device variation, while the CYTOP‐OFETs exhibit much higher intrinsic bias‐stress resistance. Therefore, the spin‐coating combined with the simple photo‐patterning method is a promising technique that can form polymeric organic semiconductor layers on CYTOP layers and produce BG OFETs exhibiting very high operational stability. 相似文献
998.
1.IatroductionIntheprocessingofcarbonfiber/pitch-basedcar-bonmatriXcomposites(hereafterC/Ccomposites),manyporesareusuallyformedbyvolatilizationoforganiccompoundswithlowmolecularweightdux-ingcarbonizationprocessofaprecursorpitch,andthetotalporosityoftheC/Ccompositesbecomesaround25%.InordertoimprovemechanicalproP-ertiesoftheC/Ccompositesbydecreasingtheporos-ityaslowaspossible,someeffortshavebeenmadebyusingsuchaspressurecarbonization[1~5],ad-ditionofcarbonblackorthermosettingresininto.aprecurs… 相似文献
999.
Aqueous mixtures of montmorillonite and -naphthylamine with various mixing ratios were kept at 353 K for 3 days with stirring to convert them into the layer-type complex (MNC) consisting of both components, and then dried at 403 K. The resulting blocks, several centimetres in size, were heated below 1473 K under nitrogen. The addition of -naphthylamine (NA) in the equivalent amount to the cation exchange capacity of montmorillonite resulted in the most attractive porous material which includes homogeneous pores of 35nm radius and exhibits a maximum pore volume of 0.8 ml g–1 at 873 K. The samples containing greater and lesser amounts of NA gave a very brittle block and a less porous block after heating to high temperature, respectively. The materials obtained were also characterized by the waved card-house structure. The amount of NA added and the heat-treatment temperature did not vary the pore size so widely. 相似文献
1000.