全文获取类型
收费全文 | 3792篇 |
免费 | 389篇 |
国内免费 | 189篇 |
专业分类
电工技术 | 163篇 |
综合类 | 179篇 |
化学工业 | 509篇 |
金属工艺 | 724篇 |
机械仪表 | 211篇 |
建筑科学 | 270篇 |
矿业工程 | 56篇 |
能源动力 | 101篇 |
轻工业 | 119篇 |
水利工程 | 59篇 |
石油天然气 | 47篇 |
武器工业 | 16篇 |
无线电 | 625篇 |
一般工业技术 | 800篇 |
冶金工业 | 218篇 |
原子能技术 | 61篇 |
自动化技术 | 212篇 |
出版年
2024年 | 33篇 |
2023年 | 149篇 |
2022年 | 137篇 |
2021年 | 151篇 |
2020年 | 187篇 |
2019年 | 117篇 |
2018年 | 127篇 |
2017年 | 176篇 |
2016年 | 161篇 |
2015年 | 128篇 |
2014年 | 241篇 |
2013年 | 248篇 |
2012年 | 222篇 |
2011年 | 260篇 |
2010年 | 191篇 |
2009年 | 193篇 |
2008年 | 136篇 |
2007年 | 161篇 |
2006年 | 179篇 |
2005年 | 131篇 |
2004年 | 113篇 |
2003年 | 114篇 |
2002年 | 95篇 |
2001年 | 99篇 |
2000年 | 93篇 |
1999年 | 70篇 |
1998年 | 74篇 |
1997年 | 56篇 |
1996年 | 39篇 |
1995年 | 28篇 |
1994年 | 35篇 |
1993年 | 26篇 |
1992年 | 25篇 |
1991年 | 24篇 |
1990年 | 38篇 |
1989年 | 29篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 9篇 |
1974年 | 1篇 |
排序方式: 共有4370条查询结果,搜索用时 15 毫秒
81.
S. L. Price H. L. Hettich S. Sen M. C. Currie D. R. Rhiger E. O. Mc Lean 《Journal of Electronic Materials》1998,27(6):564-572
With the goal of maximizing the yield of infrared focal plane arrays (IRFPAs), Santa Barbara Research Center’s (SBRC) Infrared
Materials Producibility Program (IRMP) has focused on assessing and improving the quality, yield, and throughput of CdZnTe
substrates. A baseline detector lot was fabricated to identify the critical drivers of IRFPA yield coming from the substrates
and to evaluate the quality and yield of the current vendor base for CdZnTe substrates. Substrate induced defects and impurities
that can potentially affect device performance and operability were carefully mapped out in detail on 44 × 67 mm2 size substrates, received from IRMP substrate vendors as well as SBRC. This paper will report on the correlations found between
this substrate characterization data base and the IRFPA level defect distributions. Key results from these correlation studies
are: (1) extended defects found on the substrates with the Nakagawa etch correlated well with responsivity reduction in the
final IRFPA; (2) cross-hatch patterns that were evident in the responsivity map correlated well with similar features seen
by x-ray topography on LPE double layers; and (3) a possible correlation of device performance (leakage current at 78K) with
copper and lithium impurities in the substrate. Recent initiatives toward improving the quality and yield of the substrate
growth process have focused on improving purity in the pre-growth charge preparation, modification of growth parameters to
reduce defects and scaling up of the vertical Bridgman growth process from its current 67 mm diameter boule size to 92 mm
diameter boules. Promising initial results from the large diameter boule growth process will be shown. The 92 mm diameter
CdZnTe boule (6 kg charge) shows two predominant single crystal grains encompassing 75% of boule volume. Defect characterization
of boules grown under baseline and modified conditions is discussed. 相似文献
82.
J. Krinke G. Kuchler R. Brendel H. Artmann W. Frey S. Oelting M. Schulz H. P. Strunk 《Solar Energy Materials & Solar Cells》2001,65(1-4)
We demonstrate the epitaxial growth of silicon with ion assisted deposition on pyramidally structured porous silicon and investigate the microstructure of the epitaxial layer with transmission electron microscopy. The major defects in the grown pyramid structure are stacking faults on the {1 1 1} facets of the pyramids, whereas the epitaxial layers on the {0 0 1} facets are defect-free. The stacking fault density decreases by about three orders with increasing the deposition temperature from 600 to 850°C, but is constant when the ion energy changes. Depending on growth conditions Si-interstitials are built into the layers, which during electron microscopy form so called rod-like defects. 相似文献
83.
L. Jiao X. Niu Z. Lu C. R. Wronski A. Matsuda T. Kamei G. Ganguly 《Solar Energy Materials & Solar Cells》2001,66(1-4)
A study has been carried out on a-Si:H solar cell materials fabricated under a wide range of deposition conditions in different laboratories. The results on both thin films and corresponding Schottky barrier cell structures demonstrate that analysis and characterization based solely on the neutral dangling bonds are clearly inadequate. Contributions of charged defects to the properties of a-Si:H, their effect on light-induced changes are identified together with the limitations of methods commonly used to characterize the solar cell properties and stability of a-Si:H materials. Self-consistent fitting of a wide range of results on films and Schottky barrier cell structures is obtained with a gap state distribution in which charged defects are included. 相似文献
84.
85.
86.
87.
A thermodynamic modeling of GaN was carried out to describe the thermodynamic behavior of native defects, dopants, and carriers
(free electrons and holes) in GaN semiconductors. The compound energy model (CEM) was used. An unintentionally doped GaN was
taken as an example. Oxygen was introduced into the model as the unintentionally doped impurity, according to the practical
experimental phenomena. The energies of component compounds in the model were defined based on the results of the ab initio
calculations and adjusted to fit experimental data. The thermodynamic properties of the defects and the oxygen doped were
calculated to show the facility of the model. 相似文献
88.
研究了不同气氛下快速预热处理(RTA)后,硅片中的流动图形缺陷(FPDs)密度和随后两步热处理形成的魔幻清洁区(MDZ)之间的关系.硅片经过高温快速预热处理后,再经过800℃(4h)+1000℃(16h)常规退火,以形成MDZ.研究发现,当硅片在Ar气氛或N2/O2(9%)混合气氛下RTA预处理后,FPDs密度较低,随后热处理出现的氧沉淀诱生缺陷密度较高、清洁区较宽.对于N2/O2混和气氛,随着O2含量的增加,FPDs和氧沉淀诱生缺陷密度变小,纯O2气氛下预处理后硅片中FPDs和氧沉淀诱生缺陷密度最低.因此,可以通过调节N2/O2混合气氛中两种气氛的比例来控制空洞型微缺陷和硅片体内氧沉淀诱生缺陷的密度. 相似文献
89.
90.
Kierstin Torres Agnieszka Kuc Lorenzo Maschio Thang Pham Kate Reidy Lukas Dekanovsky Zdenek Sofer Frances M. Ross Julian Klein 《Advanced functional materials》2023,33(12):2211366
Understanding the stability limitations and defect formation mechanisms in 2D magnets is essential for their utilization in spintronic and memory technologies. Here, defects in mono- to multilayer CrSBr are correlated with structural, vibrational, and magnetic properties. Resonant Raman scattering is used to reveal distinct vibrational defect signatures. In pristine CrSBr, it is shown that bromine atoms mediate vibrational interlayer coupling, allowing for distinguishing between surface and bulk defect modes. Environmental exposure is shown to cause drastic degradation in monolayers, with the formation of intralayer defects. This is in contrast to multilayers that predominantly show bromine surface defects. Through deliberate ion irradiation, the formation of defect modes is tuned: these are strongly polarized and resonantly enhanced, reflecting the quasi--1D electronic character of CrSBr. Strikingly, pronounced signatures of spin-phonon coupling of the intrinsic phonon modes and the ion beam-induced defect modes are observed throughout the magnetic transition temperature. Overall, defect engineering of magnetic properties is possible, with resonant Raman spectroscopy serving as a direct fingerprint of magnetic phases and defects in CrSBr. 相似文献