全文获取类型
收费全文 | 3035篇 |
免费 | 139篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 103篇 |
综合类 | 3篇 |
化学工业 | 723篇 |
金属工艺 | 110篇 |
机械仪表 | 105篇 |
建筑科学 | 82篇 |
矿业工程 | 2篇 |
能源动力 | 253篇 |
轻工业 | 279篇 |
水利工程 | 35篇 |
石油天然气 | 34篇 |
无线电 | 329篇 |
一般工业技术 | 577篇 |
冶金工业 | 230篇 |
原子能技术 | 19篇 |
自动化技术 | 308篇 |
出版年
2024年 | 6篇 |
2023年 | 45篇 |
2022年 | 63篇 |
2021年 | 162篇 |
2020年 | 112篇 |
2019年 | 101篇 |
2018年 | 147篇 |
2017年 | 126篇 |
2016年 | 133篇 |
2015年 | 88篇 |
2014年 | 119篇 |
2013年 | 294篇 |
2012年 | 205篇 |
2011年 | 202篇 |
2010年 | 140篇 |
2009年 | 124篇 |
2008年 | 109篇 |
2007年 | 94篇 |
2006年 | 88篇 |
2005年 | 63篇 |
2004年 | 52篇 |
2003年 | 62篇 |
2002年 | 49篇 |
2001年 | 50篇 |
2000年 | 55篇 |
1999年 | 35篇 |
1998年 | 74篇 |
1997年 | 50篇 |
1996年 | 40篇 |
1995年 | 42篇 |
1994年 | 25篇 |
1993年 | 33篇 |
1992年 | 7篇 |
1991年 | 15篇 |
1990年 | 15篇 |
1989年 | 12篇 |
1988年 | 24篇 |
1987年 | 22篇 |
1986年 | 15篇 |
1985年 | 13篇 |
1984年 | 16篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1970年 | 3篇 |
排序方式: 共有3192条查询结果,搜索用时 31 毫秒
1.
Abidur Rahman Makoto Kobayashi Kotaro Sugimoto Yuta Endo Manabu Kojima Shigenori Furukawa Takafumi Watanabe Shu Soeda Yuko Hashimoto Keiya Fujimori Hideki Chiba 《International journal of molecular sciences》2021,22(7)
Background: Within the claudin (CLDN) family, CLDN12 mRNA expression is altered in various types of cancer, but its clinicopathological relevance has yet to be established due to the absence of specific antibodies (Abs) with broad applications. Methods: We generated a monoclonal Ab (mAb) against human/mouse CLDN12 and verified its specificity. By performing immunohistochemical staining and semiquantification, we evaluated the relationship between CLDN12 expression and clinicopathological parameters in tissues from 138 cases of cervical cancer. Results: Western blot and immunohistochemical analyses revealed that the established mAb selectively recognized the CLDN12 protein. Twenty six of the 138 cases (18.8%) showed low CLDN12 expression, and the disease-specific survival (DSS) and recurrence-free survival rates were significantly decreased compared with those in the high CLDN12 expression group. We also demonstrated, via univariable and multivariable analyses, that the low CLDN12 expression represents a significant prognostic factor for the DSS of cervical cancer patients (HR 3.412, p = 0.002 and HR 2.615, p = 0.029, respectively). Conclusions: It can be concluded that a reduced CLDN12 expression predicts a poor outcome for cervical cancer. The novel anti-CLDN12 mAb could be a valuable tool to evaluate the biological relevance of the CLDN12 expression in diverse cancer types and other diseases. 相似文献
2.
3.
4.
5.
Muhammad Sheeraz Mamoon Ur Rashid Asad Ali Fazli Akram Ho Jeong Lee Jin San Choi Jong-Seong Bae Yong Soo Kim Young-Han Shin Chang Won Ahn Tae Heon Kim 《Journal of the European Ceramic Society》2021,41(10):5155-5162
We demonstrate the structural evolution of polymorphic phases in Al2O3-inserted SrMnO3 ceramics synthesized by solid state reaction. While the 4H-hexagonal phase is predominant in pure SrMnO3 ceramics, a small amount of 6H-hexagonal polymorph is identified in addition to the primary 4H-hexagonal SrMnO3 and the secondary hexagonal SrAl2O4 phases in the as-sintered ceramics, evidenced by x-ray diffraction and subsequent Rietveld refinement analyses. The existence of the 6H-hexagonal SrMnO3 phase is corroborated using Raman spectroscopy. The chemical compositions and electronic structures of the Al2O3-inserted SrMnO3 compounds are also examined using energy dispersive spectroscopy and x-ray photoelectron spectroscopy, respectively. The first-principles calculations reveal that there is no clear difference between the total energies of 4H- and 6H-hexagonal polymorphs regardless of the presence/absence of Sr and oxygen vacancies. Possible origins are discussed with the estimation of actual strain based on the refined lattice parameter of 6H SrMnO3. 相似文献
6.
Maqbool Ali Jamil Hussain Sungyoung Lee Byeong Ho Kang Kashif Sattar 《Expert Systems》2020,37(1):e12401
The case-based learning (CBL) approach has gained attention in medical education as an alternative to traditional learning methodology. However, current CBL systems do not facilitate and provide computer-based domain knowledge to medical students for solving real-world clinical cases during CBL practice. To automate CBL, clinical documents are beneficial for constructing domain knowledge. In the literature, most systems and methodologies require a knowledge engineer to construct machine-readable knowledge. Keeping in view these facts, we present a knowledge construction methodology (KCM-CD) to construct domain knowledge ontology (i.e., structured declarative knowledge) from unstructured text in a systematic way using artificial intelligence techniques, with minimum intervention from a knowledge engineer. To utilize the strength of humans and computers, and to realize the KCM-CD methodology, an interactive case-based learning system(iCBLS) was developed. Finally, the developed ontological model was evaluated to evaluate the quality of domain knowledge in terms of coherence measure. The results showed that the overall domain model has positive coherence values, indicating that all words in each branch of the domain ontology are correlated with each other and the quality of the developed model is acceptable. 相似文献
7.
Abdul Rahman Mohtasebzadeh Longfei Ye Thomas M. Crawford 《International journal of molecular sciences》2015,16(8):19769-19779
We study magnetic-field directed self-assembly of magnetic nanoparticles onto templates recorded on perpendicular magnetic recording media, and quantify feature width and height as a function of assembly time. Feature widths are determined from Scanning Electron Microscope (SEM) images, while heights are obtained with Atomic Force Microscopy (AFM). For short assembly times, widths were ~150 nm, while heights were ~14 nm, a single nanoparticle on average with a 10:1 aspect ratio. For long assembly times, widths approach 550 nm, while the average height grows to 3 nanoparticles, ~35 nm; a 16:1 aspect ratio. We perform magnetometry on these self-assembled structures and observe the slope of the magnetic moment vs. field curve increases with time. This increase suggests magnetic nanoparticle interactions evolve from nanoparticle–nanoparticle interactions to cluster–cluster interactions as opposed to feature–feature interactions. We suggest the aspect ratio increase occurs because the magnetic field gradients are strongest near the transitions between recorded regions in perpendicular media. If these gradients can be optimized for assembly, strong potential exists for using perpendicular recording templates to assemble complex heterogeneous materials. 相似文献
8.
9.
Syafikah Huda Paiman Mukhlis A Rahman Khairul Hamimah Abas Azian Abd Aziz Ahmad Fauzi Ismail Mohd Hafiz Dzarfan Othman Juhana Jaafar Mohammad Noorul Anam Mohd Norddin 《化学工程与技术》2019,42(6):1321-1329
Removal by absorptive ceramic membranes can simultaneously absorb and separate metal ions from water. Alumina/yttria‐stabilized zirconia (Al2O3/YSZ) hollow‐fiber membranes, fabricated using phase inversion and sintering process, were deposited with iron oxide by an in‐situ hydrothermal process. The results showed that α‐Fe2O3 was produced and incorporated across the membranes. A reduction in flux was recorded with the deposition of α‐Fe2O3. However, it improved the adsorption capacity for heavy metal adsorption. The adsorption‐separation test demonstrated that the optimized membrane is able to completely remove Pb(II) ions after two hours. 相似文献
10.
Clean Technologies and Environmental Policy - The concentration of any disinfectant is a major parameter which is used to evaluate the quality of water. Chlorine is the most common disinfecting... 相似文献