全文获取类型
收费全文 | 627篇 |
免费 | 29篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 27篇 |
化学工业 | 197篇 |
金属工艺 | 14篇 |
机械仪表 | 12篇 |
建筑科学 | 11篇 |
能源动力 | 39篇 |
轻工业 | 44篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 68篇 |
一般工业技术 | 96篇 |
冶金工业 | 75篇 |
原子能技术 | 14篇 |
自动化技术 | 57篇 |
出版年
2023年 | 11篇 |
2022年 | 5篇 |
2021年 | 38篇 |
2020年 | 21篇 |
2019年 | 16篇 |
2018年 | 25篇 |
2017年 | 18篇 |
2016年 | 28篇 |
2015年 | 18篇 |
2014年 | 32篇 |
2013年 | 37篇 |
2012年 | 33篇 |
2011年 | 47篇 |
2010年 | 32篇 |
2009年 | 26篇 |
2008年 | 28篇 |
2007年 | 13篇 |
2006年 | 7篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 11篇 |
2002年 | 17篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 25篇 |
1997年 | 18篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1970年 | 2篇 |
排序方式: 共有657条查询结果,搜索用时 828 毫秒
1.
Tomohiro Toigawa Yasuhiro Tsubata Takeshi Kai Takuya Furuta Yuta Kumagai Tatsuro Matsumura 《溶剂提取与离子交换》2021,39(1):74-89
ABSTRACT Absorbed-dose estimation is essential for evaluation of the radiation tolerance of minor-actinide-separation processes. We propose a dose-evaluation method based on radiation permeability, with comparisons of heterogeneous structures seen in the solvent-extraction process, such as emulsions forming in the mixture of the organic and aqueous phases. A demonstration of radiation-energy-transfer simulation is performed with a focus on the minor-actinide-recovery process from high-level liquid waste with the aid of the Monte Carlo radiation-transport code PHITS. The simulation results indicate that the dose absorbed by the extraction solvent from alpha radiation depends upon the emulsion structure, and that from beta and gamma radiation depends upon the mixer-settler-apparatus size. Non-negligible contributions of well-permeable gamma rays were indicated in terms of the plant operation of the minor-actinide-separation process. 相似文献
2.
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
3.
A method is proposed to generate categorical colour observer functions (individual colour matching functions) for any field size based on the CIE 2006 system of physiological observer functions. The method combines proposed categorical observer techniques of Sarkar et al with a physiologically-based individual observer model of Asano et al and a clustering technique to produce the optimal set of categorical observers. The number of required categorical observers varies depending on an application with as many as 50 required to predict individual observers' matches when a laser projector is viewed. However, 10 categorical observers are sufficient to represent colour-normal populations for personalized colour imaging. The proposed and recommended categorical observers represent a robust and inclusive technique to examine and quantify observer metamerism in any application of colorimetry. 相似文献
4.
The fracture behaviors of gellan hydrogels under compression remarkably depend on the strain rate as well as the boundary conditions for lateral expansion. In the geometry with no constraint for lateral expansion (conventional uniaxial compression), the gels rupture at relatively small strains independently of the compression rates. In contrast, when the gels are compressed extremely slowly (at a strain rate of ca. 10−5 s−1) in the geometry prohibiting the lateral expansion at their top and bottom surfaces, they are remarkably compressible down to 2% of the initial height without macroscopic fracture and they are accompanied by a large amount of water release. In such markedly compressed gels, many microscopic cracks are formed around the central layer, where strain concentration occurs due to the nonuniform deformation arising from the constrained geometry. In the highly compressible case, the formation of macroscopic cracks is prevented by the localization of microscopic cracks as well as the enhancement in mechanical toughness by a significant increase in polymer concentration due to water release. 相似文献
5.
6.
Thiamine pyrophosphatase activity in the Golgi apparatus of calcitonin-treated osteoclasts. 总被引:1,自引:0,他引:1
The thiamine pyrophosphatase (TPPase) activity described by Novikoff and Goldfisher was examined in osteoclasts affected by calcitonin in order to elucidate whether the morphological and functional changes of the osteoclasts have an influence over the secretion function of their Golgi apparatus. The Golgi apparatus of osteoclasts of which the ruffled border had disappeared and bone resorption discontinued as the result of treatment with calcitonin showed a slight TPPase activity. The reaction products of the enzyme in these inactive osteoclasts were distinctly fewer than that of control osteoclasts, which were not affected by calcitonin. From these results, it is suggested that there may be a connection between the morphological and functional changes of osteoclasts and the secretion function of the Golgi apparatus. 相似文献
7.
Increased sympathetic nervous activity has been proposed as one of the causes of left ventricular hypertrophy (LVH) associated with hypertension. However, the precise relationship is not fully understood. METHODS: To elucidate the relationship between myocardial sympathetic nervous activity and LVH in patients with essential hypertension EHT), we performed 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy in 49 patients with EHT and 17 normotensive control subjects. Sympathetic innervation of the left ventricle was evaluated using SPECT, and the whole heart uptake of the tracer was quantitatively assessed as the heart-to-mediastinum uptake ratio on both the early (15-min) and delayed (5-hr) images. Myocardial washout rate (MWR) of the tracer from 15 min to 5 hr after the isotope administration was also calculated. The left ventricular mass index (LVMI) was determined echocardiographically. RESULTS: In 49 hypertensive patients, there was a negative correlation between LVMI and heart-to-mediastinum uptake ratio on both the early and delayed images (r=-0.55, p < 0.0001; r=-0.63, p < 0.0001, respectively). In addition, there was a positive correlation between the LVMI and MWR of 123I-MIBG in these hypertensive patients (r=0.59, p < 0.0001). As for the regional uptake of the tracer, there was no significant difference between control subjects and hypertensive patients without cardiac hypertrophy, but a significant decrease of the uptake in the inferior and lateral regions was observed in hypertensive patients with cardiac hypertrophy. CONCLUSION: Patients with EHT had decreased accumulation and increased MWR of 123I-MIBG in proportion to the degree of LVH. Hypertensive patients with cardiac hypertrophy had impaired sympathetic innervation in the inferior and lateral regions of the left ventricle. 相似文献
8.
9.
10.
Microsystem Technologies - TEMPO-oxidized cellulose nanofiber (TOCN) has been drawing much attention as a useful material for preparation of transparent and stiff films or substrates. In this work,... 相似文献