全文获取类型
收费全文 | 8923篇 |
免费 | 746篇 |
国内免费 | 16篇 |
专业分类
电工技术 | 121篇 |
综合类 | 15篇 |
化学工业 | 2148篇 |
金属工艺 | 350篇 |
机械仪表 | 431篇 |
建筑科学 | 135篇 |
矿业工程 | 3篇 |
能源动力 | 348篇 |
轻工业 | 915篇 |
水利工程 | 35篇 |
石油天然气 | 7篇 |
武器工业 | 1篇 |
无线电 | 1522篇 |
一般工业技术 | 2105篇 |
冶金工业 | 594篇 |
原子能技术 | 83篇 |
自动化技术 | 872篇 |
出版年
2024年 | 11篇 |
2023年 | 134篇 |
2022年 | 196篇 |
2021年 | 330篇 |
2020年 | 231篇 |
2019年 | 232篇 |
2018年 | 315篇 |
2017年 | 337篇 |
2016年 | 406篇 |
2015年 | 354篇 |
2014年 | 462篇 |
2013年 | 639篇 |
2012年 | 649篇 |
2011年 | 841篇 |
2010年 | 587篇 |
2009年 | 550篇 |
2008年 | 448篇 |
2007年 | 390篇 |
2006年 | 323篇 |
2005年 | 259篇 |
2004年 | 263篇 |
2003年 | 220篇 |
2002年 | 165篇 |
2001年 | 153篇 |
2000年 | 157篇 |
1999年 | 137篇 |
1998年 | 230篇 |
1997年 | 127篇 |
1996年 | 105篇 |
1995年 | 57篇 |
1994年 | 64篇 |
1993年 | 46篇 |
1992年 | 36篇 |
1991年 | 23篇 |
1990年 | 23篇 |
1989年 | 24篇 |
1988年 | 16篇 |
1987年 | 10篇 |
1986年 | 15篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1974年 | 7篇 |
1971年 | 7篇 |
1970年 | 6篇 |
排序方式: 共有9685条查询结果,搜索用时 15 毫秒
991.
The wetting balance test was used to study the wettability of Sn-1.0Ag-Ce (Ce content = 0, 0.1, 0.3, and 0.5 wt%) solder alloys on electroless nickel/electroless palladium/immersion gold (ENEPIG) surface finishes with Pd thicknesses of 0, 0.05, 0.1, and 0.15 μm. Scanning electron microscopy was used to evaluate the interfacial reaction between the molten solders and surface finish materials during the wetting test. The Ni3Sn4 intermetallic compound (IMC) plays an important role in promoting wetting properties. The Pd layer retards formation of the Ni3Sn4 IMC and changes its morphology, thereby affecting the wettability of the surface finish/solder systems. ENEPIG surface finishes seem to be suitable for use with cerium-containing solders. 相似文献
992.
A vertically aligned anatase TiO2 (A-TiO2) nanotube array has been fabricated by coating a ZnO nanorod (NR) template with a TiO2 precursor solution. After coating, the ZnO NR cores were selectively etched in an acidic environment to form TiO2 nanotubes (NTs). More specifically, after growing the ZnO NRs via a hydrothermal method, one drop of the TiO2 precursor solution was cast to coat the ZnO NRs, the tops of which were previously covered with chemical capping materials by electrostatic interaction, and then the sample was sintered. Finally, the sample was immersed in an acidic solution resulting in selective etching of the ZnO NR cores. Thus, only TiO2 NTs remained on the substrate. The capping material is effectively used to create a perfect, hexagonal open-ended TiO2 NT array, which interestingly extends onset absorption towards the visible region. 相似文献
993.
Jem‐Kun Chen Gang‐Yan Zhou Chi‐Jung Chang Ai‐Wei Lee Feng‐Chih Chang 《Advanced Materials Interfaces》2014,1(2)
In this study, nanopillar arrays of silicon oxide are fabricated through a process involving very‐large‐scale integration, for use as two‐dimensional periodic relief gratings (2DPRGs) on silicon surfaces. Oligonucleotides are successively immobilized on the pillar surface, allowing the system to be used as an optical detector specific for the targeted single‐stranded DNAs (ssDNAs). The surfaces of the oligonucleotides‐modified 2DPRGs undergo insignificant structural changes, but upon hybridizing with target ssDNA, the 2DPRGs undergo dramatic changes in terms of their pillar scale. Binding of the oligonucleotides to the 2DPRG occurs in a way that allows them to retain their function and selectively bind the target ssDNA. The performance of the sensor is evaluated by capturing the target ssDNA on the 2DPRGs and measuring the effective refractive index (neff). The binding of the target ssDNA species to the 2DPRGs results in a color change from pure blue to red, observable by the naked eye along an angle of 15–20°. Moreover, effective medium theory is used to calculate the filling factors inside the 2DPRGs and, thereby, examine the values of neff during the structural changes of the 2DPRGs. Accordingly, these new films have potential applications as label‐free optical biosensors. 相似文献
994.
A Multifunctional Nanoplatform for Imaging,Radiotherapy, and the Prediction of Therapeutic Response 下载免费PDF全文
Casey McQuade Ajlan Al Zaki Yaanik Desai Michael Vido Timothy Sakhuja Zhiliang Cheng Robert J. Hickey Daniel Joh So‐Jung Park Gary Kao Jay F. Dorsey Andrew Tsourkas 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(7):834-843
Gold nanoparticles have garnered interest as both radiosensitzers and computed tomography (CT) contrast agents. However, the extremely high concentrations of gold required to generate CT contrast is far beyond that needed for meaningful radiosensitization, which limits their use as combined therapeutic–diagnostic (theranostic) agents. To establish a theranostic nanoplatform with well‐aligned radiotherapeutic and diagnostic properties for better integration into standard radiation therapy practice, a gold‐ and superparamagnetic iron oxide nanoparticle (SPION)‐loaded micelle (GSM) is developed. Intravenous injection of GSMs into tumor‐bearing mice led to selective tumoral accumulation, enabling magnetic resonance (MR) imaging of tumor margins. Subsequent irradiation leads to a 90‐day survival of 71% in GSM‐treated mice, compared with 25% for irradiation‐only mice. Furthermore, measurements of the GSM‐enhanced MR contrast are highly predictive of tumor response. Therefore, GSMs may not only guide and enhance the efficacy of radiation therapy, but may allow patients to be managed more effectively. 相似文献
995.
Metal‐Etching‐Free Direct Delamination and Transfer of Single‐Layer Graphene with a High Degree of Freedom 下载免费PDF全文
996.
A smartphone‐based U‐Healthcare system for real‐time monitoring of acute myocardial infarction 下载免费PDF全文
Jaehyo Jung Jihoon Lee Jihwan Lee Youn Tae Kim 《International Journal of Communication Systems》2015,28(18):2311-2325
In recent years, medical service has been evolving from systems designed around centralized hospitals to Ubiquitous Healthcare (U‐Healthcare). U‐Healthcare system can facilitate real‐time monitoring of patient states, and can provide medical checkups and management whenever and wherever the medical staff deems necessary. U‐Healthcare services can provide chronic condition monitoring in the early stages of diseases and help execute decisive medical action in emergencies. However, thus far, the application of U‐Healthcare systems has been limited to diseases such as obesity, diabetes, etc. Acute myocardial infarction (AMI) is among the most critical chronic diseases and requires early detection and treatment. In this paper, we propose an AMI diagnostic software technique and protocol that can support real‐time communication between the patient and medical personnel. Our monitoring and diagnostic system has been developed using a protocol based on ISO/IEEE 11073. When data is transferred from the patient's smartphone to a server in hospital, the medical personnel consult the patient's biosensor data to determine the status of the relevant disease and provide appropriate medical service. The relevant information is sent back to the patient's smartphone through a wireless network, and patients can view their data in graphical format through their smartphone. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
997.
Surface Chemistry of Vitamin: Pyridoxal 5′‐Phosphate (Vitamin B6) as a Multifunctional Compound for Surface Functionalization 下载免费PDF全文
Jung Seung Lee Kyuri Kim Kihong Lee Joseph P. Park Kisuk Yang Seung‐Woo Cho Haeshin Lee 《Advanced functional materials》2015,25(30):4754-4760
Vitamins are non‐toxic compounds that perform a variety of biological functions and also available in a large quantity. Other than the usage as food supplements, few attempts have been made to use them as functional materials. In this study, we report that vitamin B6, pyridoxal 5′‐phosphate (PLP), is a multi‐functional molecule for oxide surface chemistry. PLP‐immobilized surfaces exhibit superhydrophilicity and even hemophilicity, enhancing proliferation, migration, and differentiation of mammalian cells. Unlike existing molecules used so far in surface modification, PLP has an intrinsic chemical reactivity toward biomacromolecules due to the presence of the aldehyde group. In fact, RGD peptide is covalently tethered onto PLP surfaces directly in one step without any chemical activation. Furthermore, PLP‐functionalized implant device showed rapid bone healing. As vitamin B6 is a FDA approved molecule for human usage, the surface chemistry of vitamin B6 potentially allows a fast route for surface functionalized medical devices into clinic. 相似文献
998.
Seung‐Kyun Kang Suk‐Won Hwang Sooyoun Yu Jung‐Hun Seo Elise A. Corbin Jiho Shin Dae Seung Wie Rashid Bashir Zhenqiang Ma John A. Rogers 《Advanced functional materials》2015,25(12):1789-1797
Biodegradable substrates and encapsulating materials play critical roles in the development of an emerging class of semiconductor technology, generally referred as “transient electronics”, whose key characteristic is an ability to dissolve completely, in a controlled manner, upon immersion in ground water or biofluids. The results presented here introduce the use of thin foils of Mo, Fe, W, or Zn as biodegradable substrates and silicate spin‐on‐glass (SOG) materials as insulating and encapsulating layers, with demonstrations of transient active (diode and transistor) and passive (capacitor and inductor) electronic components. Complete measurements of electrical characteristics demonstrate that the device performance can reach levels comparable to those possible with conventional, nontransient materials. Dissolution kinetics of the foils and cytotoxicity tests of the SOG yield information relevant to use in transient electronics for temporary biomedical implants, resorbable environmental monitors, and reduced waste consumer electronics. 相似文献
999.
Vitamins: Surface Chemistry of Vitamin: Pyridoxal 5′‐Phosphate (Vitamin B6) as a Multifunctional Compound for Surface Functionalization (Adv. Funct. Mater. 30/2015) 下载免费PDF全文
Jung Seung Lee Kyuri Kim Kihong Lee Joseph P. Park Kisuk Yang Seung‐Woo Cho Haeshin Lee 《Advanced functional materials》2015,25(30):4745-4745
1000.
Organic Electronics: Self‐Assembled,Millimeter‐Sized TIPS‐Pentacene Spherulites Grown on Partially Crosslinked Polymer Gate Dielectric (Adv. Funct. Mater. 24/2015) 下载免费PDF全文
Hocheon Yoo Hyun Ho Choi Tae Joo Shin Taiuk Rim Kilwon Cho Sungjune Jung Jae‐Joon Kim 《Advanced functional materials》2015,25(24):3795-3795