全文获取类型
收费全文 | 145898篇 |
免费 | 22445篇 |
国内免费 | 6301篇 |
专业分类
电工技术 | 8312篇 |
技术理论 | 9篇 |
综合类 | 9029篇 |
化学工业 | 32769篇 |
金属工艺 | 6511篇 |
机械仪表 | 7432篇 |
建筑科学 | 10168篇 |
矿业工程 | 2930篇 |
能源动力 | 3695篇 |
轻工业 | 18871篇 |
水利工程 | 2783篇 |
石油天然气 | 4880篇 |
武器工业 | 1174篇 |
无线电 | 18676篇 |
一般工业技术 | 21745篇 |
冶金工业 | 4884篇 |
原子能技术 | 1263篇 |
自动化技术 | 19513篇 |
出版年
2024年 | 533篇 |
2023年 | 1732篇 |
2022年 | 3471篇 |
2021年 | 4705篇 |
2020年 | 4788篇 |
2019年 | 5660篇 |
2018年 | 6060篇 |
2017年 | 6741篇 |
2016年 | 6899篇 |
2015年 | 8464篇 |
2014年 | 9463篇 |
2013年 | 11721篇 |
2012年 | 10744篇 |
2011年 | 11067篇 |
2010年 | 10468篇 |
2009年 | 10047篇 |
2008年 | 9735篇 |
2007年 | 8922篇 |
2006年 | 8018篇 |
2005年 | 6625篇 |
2004年 | 5075篇 |
2003年 | 4308篇 |
2002年 | 4147篇 |
2001年 | 3525篇 |
2000年 | 2989篇 |
1999年 | 2107篇 |
1998年 | 1318篇 |
1997年 | 1097篇 |
1996年 | 867篇 |
1995年 | 756篇 |
1994年 | 556篇 |
1993年 | 422篇 |
1992年 | 347篇 |
1991年 | 297篇 |
1990年 | 204篇 |
1989年 | 150篇 |
1988年 | 123篇 |
1987年 | 77篇 |
1986年 | 90篇 |
1985年 | 44篇 |
1984年 | 47篇 |
1983年 | 24篇 |
1982年 | 24篇 |
1981年 | 36篇 |
1980年 | 45篇 |
1979年 | 17篇 |
1977年 | 11篇 |
1976年 | 19篇 |
1975年 | 11篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
Mónica Giménez‐Marqués Elena Bellido Thomas Berthelot Teresa Simón‐Yarza Tania Hidalgo Rosana Simón‐Vázquez África González‐Fernández José Avila Maria Carmen Asensio Ruxandra Gref Patrick Couvreur Christian Serre Patricia Horcajada 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(40)
Controlling the outer surface of nanometric metal–organic frameworks (nanoMOFs) and further understanding the in vivo effect of the coated material are crucial for the convenient biomedical applications of MOFs. However, in most studies, the surface modification protocol is often associated with significant toxicity and/or lack of selectivity. As an alternative, how the highly selective and general grafting GraftFast method leads, through a green and simple process, to the successful attachment of multifunctional biopolymers (polyethylene glycol (PEG) and hyaluronic acid) on the external surface of nanoMOFs is reported. In particular, effectively PEGylated iron trimesate MIL‐100(Fe) nanoparticles (NPs) exhibit suitable grafting stability and superior chemical and colloidal stability in different biofluids, while conserving full porosity and allowing the adsorption of bioactive molecules (cosmetic and antitumor agents). Furthermore, the nature of the MOF–PEG interaction is deeply investigated using high‐resolution soft X‐ray spectroscopy. Finally, a cell penetration study using the radio‐labeled antitumor agent gemcitabine monophosphate (3H‐GMP)‐loaded MIL‐100(Fe)@PEG NPs shows reduced macrophage phagocytosis, confirming a significant in vitro PEG furtiveness. 相似文献
972.
Étude O'Neel‐Judy Dylan Nicholls John Castañeda John G. Gibbs 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(32)
Using a dynamic fabrication process, hybrid, photoactivated microswimmers made from two different semiconductors, titanium dioxide (TiO2) and cuprous oxide (Cu2O) are developed, where each material occupies a distinct portion of the multiconstituent particles. Structured light‐activated microswimmers made from only TiO2 or Cu2O are observed to be driven in hydrogen peroxide and water most vigorously under UV or blue light, respectively, whereas hybrid structures made from both of these materials exhibit wavelength‐dependent modes of motion due to the disparate responses of each photocatalyst. It is also found that the hybrid particles are activated in water alone, a behavior which is not observed in those made from a single semiconductor, and thus, the system may open up a new class of fuel‐free photoactive colloids that take advantage of semiconductor heterojunctions. The TiO2/Cu2O hybrid microswimmer presented here is but an example of a broader method for inducing different modes of motion in a single light‐activated particle, which is not limited to the specific geometries and materials presented in this study. 相似文献
973.
The Influence of Carbon Nitride Nanosheets Doping on the Crystalline Formation of MIL‐88B(Fe) and the Photocatalytic Activities 下载免费PDF全文
Zhen‐Dong Lei Yuan‐Cheng Xue Wen‐Qian Chen Lin Li Wen‐Hui Qiu Yong Zhang Liang Tang 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(35)
In this research, bulk graphitic carbon nitride (g‐C3N4) is exfoliated and transferred to the carbon nitride nanosheets (CNNSs), which are then coupled with MIL‐88B(Fe) to form the hybrid. From the results of the powder X‐ray diffraction, scanning electronic microscopy and thermogravimetric analysis, it is found that the doping of CNNSs on the surface of MIL‐88(Fe) could maintain the basic structure of MIL‐88B(Fe), and the smaller dimension of CNNSs might influence the crystallization process of metal‐organic frameworks (MOFs) compared to bulk g‐C3N4. Besides, the effects of the CNNSs incorporation on photocatalysis are also investigated. Through the photoluminescence spectra, electrochemical measurements, and photocatalytic experiments, the hybrid containing 6% CNNSs is certified to possess the highest catalytic activity to degrade methylene blue and reduce Cr(VI) under visible light. The improvement of the photocatalytic performance can be attributed to the matched energy level which favors the formation of the heterojunctions. Besides, it promotes the charge migration such that the contact between MOFs and CNNSs is more intimate, which can be inferred from the electronic microscopy images. Finally, a possible photocatalytic mechanism is put forward by the relative calculation and the employment of the scavengers to trap the active species. 相似文献
974.
975.
MXene Yarn Supercapacitors: High‐Performance Biscrolled MXene/Carbon Nanotube Yarn Supercapacitors (Small 37/2018) 下载免费PDF全文
976.
Highly Uniform Resistive Switching Properties of Solution‐Processed Silver‐Embedded Gelatin Thin Film 下载免费PDF全文
Yu‐Chi Chang Cheng‐Jung Lee Li‐Wen Wang Yeong‐Her Wang 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(13)
The silver‐embedded gelatin (AgG) thin film produced by the solution method of metal salts dissolved in gelatin is presented. Its simple fabrication method ensures the uniform distribution of Ag dots. Memory devices based on AgG exhibit good device performance, such as the ON/OFF ratio in excess of 105 and the coefficient of variation in less of 50%. To further investigate the position of filament formation and the role of each element, current sensing atomic force microscopy (CSAFM) analysis as well as elemental line profiles across the two different conditions in the LRS and HRS are analyzed. The conductive and nonconductive regions in the current map of the CSAFM image show that the conductive filaments occur in the AgG layer around Ag dots. The migration of oxygen ions and the redox reaction of carbon are demonstrated to be the driving mechanism for the resistive switching of AgG memory devices. The results show that dissolving metal salts in gelatin is an effective way to achieve high‐performance organic–electronic applications. 相似文献
977.
Green Synthesis of Hierarchically Porous Carbon Nanotubes as Advanced Materials for High‐Efficient Energy Storage 下载免费PDF全文
Jian‐Gan Wang Hongzhen Liu Xingyuan Zhang Xu Li Xingrui Liu Feiyu Kang 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(13)
Hierarchically porous carbon nanomaterials with well‐defined architecture can afford a promising platform for effectively addressing energy and environmental concerns. Herein, a totally green and straightforward synthesis strategy for the fabrication of hierarchically porous carbon nanotubes (HPCNTs) by a simple carbonization treatment without any assistance of soft/hard templates and activation procedures is demonstrated. A high specific surface area of 1419 m2 g?1 and hierarchical micro‐/meso‐/macroporosity can be achieved for the HPCNTs. The unique porous architecture enables the HPCNTs serving as excellent electrode/host materials for high‐performance supercapacitors and Li–sulfur batteries. The design strategy may pave a new avenue for the rational synthesis of hierarchically porous carbon nanostructures for high‐efficient energy storage applications. 相似文献
978.
UV Photodetectors Based on BiOCl Nanosheet Arrays: The Effects of Morphologies and Electrode Configurations 下载免费PDF全文
A facile chemical bath method is adopted to grow bismuth oxychloride (BiOCl) nanosheet arrays on a piece of Cu foil (denoted as BiOCl‐Cu) and isolated BiOCl nanosheets are collected by ultrasonication. A self‐supporting BiOCl film is obtained by the removal of Cu foil. Photodetectors (PDs) based on these BiOCl materials are assembled and the effects of morphologies and electrode configurations on the photoelectric performance of these PDs are examined. The BiOCl nanosheet PD achieves high responsivities in the spectral range from 250 to 350 nm, while it presents quite a small photocurrent and slow response speed. The BiOCl film PD yields low photocurrents and near‐unity on–off ratios, demonstrating poor photoelectric performance. The photocurrent of the BiOCl‐Cu PD with both electrodes on the BiOCl film is much higher than those of these above‐mentioned PDs, and the response times are fast. Meanwhile, the BiOCl‐Cu PD with separate electrodes on the BiOCl film and Cu foil achieves even higher photocurrents and presents a self‐powering characteristic, depicting the improved photodetecting performances induced by the specific morphology and distinct electrode configuration. These results would promote the applications of BiOCl nanostructures in the photoelectric devices. 相似文献
979.
Fabricating Ir/C Nanofiber Networks as Free‐Standing Air Cathodes for Rechargeable Li‐CO2 Batteries 下载免费PDF全文
Chengyi Wang Qinming Zhang Xin Zhang Xin‐Gai Wang Zhaojun Xie Zhen Zhou 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(28)
Li‐CO2 batteries are promising energy storage systems by utilizing CO2 at the same time, though there are still some critical barriers before its practical applications such as high charging overpotential and poor cycling stability. In this work, iridium/carbon nanofibers (Ir/CNFs) are prepared via electrospinning and subsequent heat treatment, and are used as cathode catalysts for rechargeable Li‐CO2 batteries. Benefitting from the unique porous network structure and the high activity of ultrasmall Ir nanoparticles, Ir/CNFs exhibit excellent CO2 reduction and evolution activities. The Li‐CO2 batteries present extremely large discharge capacity, high coulombic efficiency, and long cycling life. Moreover, free‐standing Ir/CNF films are used directly as air cathodes to assemble Li‐CO2 batteries, which show high energy density and ultralong operation time, demonstrating great potential for practical applications. 相似文献
980.