全文获取类型
收费全文 | 2159篇 |
免费 | 81篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 98篇 |
综合类 | 3篇 |
化学工业 | 577篇 |
金属工艺 | 50篇 |
机械仪表 | 44篇 |
建筑科学 | 42篇 |
矿业工程 | 4篇 |
能源动力 | 98篇 |
轻工业 | 230篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
武器工业 | 1篇 |
无线电 | 211篇 |
一般工业技术 | 436篇 |
冶金工业 | 228篇 |
原子能技术 | 63篇 |
自动化技术 | 155篇 |
出版年
2023年 | 15篇 |
2022年 | 6篇 |
2021年 | 47篇 |
2020年 | 20篇 |
2019年 | 37篇 |
2018年 | 39篇 |
2017年 | 28篇 |
2016年 | 47篇 |
2015年 | 32篇 |
2014年 | 41篇 |
2013年 | 106篇 |
2012年 | 76篇 |
2011年 | 126篇 |
2010年 | 90篇 |
2009年 | 100篇 |
2008年 | 111篇 |
2007年 | 101篇 |
2006年 | 93篇 |
2005年 | 108篇 |
2004年 | 81篇 |
2003年 | 89篇 |
2002年 | 85篇 |
2001年 | 54篇 |
2000年 | 57篇 |
1999年 | 59篇 |
1998年 | 88篇 |
1997年 | 63篇 |
1996年 | 52篇 |
1995年 | 41篇 |
1994年 | 48篇 |
1993年 | 44篇 |
1992年 | 35篇 |
1991年 | 36篇 |
1990年 | 18篇 |
1989年 | 18篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 16篇 |
1985年 | 20篇 |
1984年 | 10篇 |
1983年 | 19篇 |
1982年 | 15篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1973年 | 3篇 |
1971年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有2247条查询结果,搜索用时 765 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.
Polarity Effect and Electromagnetic Radiation of Partial Discharge Accompanying Growth of Electrical Tree 下载免费PDF全文
Tatsuya Mutakamihigashi Yoshito Kuroishi Hideki Ueno 《Electrical Engineering in Japan》2015,192(3):19-26
We have investigated the characteristics of radiated electromagnetic (EM) waves from positive and negative partial discharges (PD) in epoxy resin and cross‐linked polyethylene. We found that there is a correlation among the EM level from PD, the positive PD current, and electrical trees. Therefore, the growth of an electrical tree produces a lot of positive PD. We have also investigated the characteristics of the frequency region of EM waves from PD in air, insulating oil, and liquid epoxy in addition to the above insulators. EM waves were detected in the frequency region of 40 MHz to 300 MHz from positive and negative PD in epoxy resin and cross‐linked polyethylene. EM waves were also detected in the frequency region of 40 MHz to 150 MHz from positive and negative PD in air. In the case of insulating oil and liquid epoxy, EM waves were detected in the frequency regions of 40 MHz to 150 MHz from positive PD, and 40 MHz to 250 MHz from negative PD. The frequency region differed depending on the material and the discharge polarity. Our investigation indicates that the cause is differences in electric field strength at the time of PD occurrence. 相似文献
4.
Mitsuo Miyazawa Hideki Kawazoe Mitsuro Hyakumachi 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2003,78(6):620-625
The microbial transformation of l‐menthol ( 1 ) was investigated by using 12 isolates of soil‐borne plant pathogenic fungi, Rhizoctonia solani (AG‐1‐IA Rs24, Joichi‐2, RRG97‐1; AG‐1‐IB TR22, R147, 110.4; AG‐1‐IC F‐1, F‐4, P‐1; AG‐1‐ID RCP‐1, RCP‐3, and RCP‐7) as a biocatalyst. Rhizoctonia solani F‐1, F‐4 and P‐1 showed 89.7–99.9% yields of converted product from 1 , RCP‐1, RCP‐3, and RCP‐7 26.0–26.9% and the other isolates 0.1–12.0%. In the cases of F‐1, F‐4 and P‐1, substrate 1 was converted to (?)‐(1S,3R,4S,6S)‐6‐hydroxymenthol ( 2 ), (?)‐(1S,3R,4S)‐1‐hydroxymenthol ( 3 ) and (+)‐(1S,3R,4R,6S)‐6,8‐dihydroxymenthol ( 4 ), which was a new compound. Substrate 1 was converted to 2 and/or 3 by RRG97‐1, 110.4, RCP‐1, RCP‐3 and RCP‐7. The structures of the metabolic products were elucidated on the basis of their spectral data. In addition, metabolic pathways of the biotransformation of 1 by Rhizoctonia solani are discussed. Finally, from the main component analysis and the differences in the yields of converted product from 1 , the 12 isolates of Rhizoctonia solani were divided into three groups based on an analysis of the metabolites. Copyright © 2003 Society of Chemical Industry 相似文献
5.
One month following the Great Hanshin Earthquake of January 17, 1995, we conducted a survey of 173 hospitals in Aichi Prefecture to pinpoint problems related to their actual disaster-readiness and the medical backup systems in place to deal with such disasters. This study revealed that staff at 50% of the surveyed hospitals could reach the hospital within an hour, but that communication is almost entirely dependent on phone lines, suggesting that cordless/portable/mobile phones, radio systems, Internet, communications satellites and the like should be studied in the days to come for possible use as effective communication alternatives in times of disaster. Whereas 92% of the surveyed hospitals had manuals dealing with fire outbreaks, other areas were less well represented. For example, only 36.9% of surveyed hospitals had manuals for earthquakes, 31.7% had manuals for power outages and 14.2% had manuals to deal with flooding and water disasters. New manuals must be developed incorporating the key points garnered from experience (especially Hanshin) and be ready for use immediately. It is the time for each hospital to seriously rethink the measures it should take to deal with disasters. 相似文献
6.
Hideki Taguchi Yuzuru Takahashi Hiroki Miyamoto 《Journal of the American Ceramic Society》1985,68(10):264-C
Specimens of partially stabilized zirconia were slip cast from aqueous suspensions and sintered at 1500°C for 3 h. The relative density of the cast specimens and the firing shrinkage of the sintered specimens depend on the milling time for the suspension. Vickers hardness and KIC values of 11.46±s0.07 GN/m2 and 6.10 ±0.04 MN.m3/2 , respectively, were obtained for all sintered specimens. The dispersion of the suspension is important in increasing the relative density of the cast specimens. 相似文献
7.
Iida M. Kuroda N. Otsuka H. Hirose M. Yamasaki Y. Ohta K. Shimakawa K. Nakabayashi T. Yamauchi H. Sano T. Gyohten T. Maruta M. Yamazaki A. Morishita F. Dosaka K. Takeuchi M. Arimoto K. 《Solid-State Circuits, IEEE Journal of》2005,40(11):2296-2304
A 16 Mb embedded DRAM macro in a fully CMOS logic compatible 90 nm process with a low noise core architecture and a high-accuracy post-fabrication tuning scheme has been developed. Based on the proposed techniques, 61% improvement of the sensing accuracy is realized. Even with the smallest 5 fF/cell capacitance, a 322 MHz random-cycle access while 32 ms data retention time which contributes to save the data retention power down to 60 /spl mu/W are achieved. 相似文献
8.
9.
10.
The catalytic activity of KGa-priderite, K1.6Ga1.6Ti6.4O16, and its related compound KGa8Ga9Ti15O56 was investigated for the selective reduction of nitrogen monoxide (NO) with propylene (C3H6) in the presence of high oxygen concentrations. The KGa-priderite showed significant activity during this reaction, but the related compound showed only a little activity. These compounds are quite different from the conventional catalysts for NOx selective reduction and are characterized by the fact that their properties are free from the effects of solid acidity and support metals. This difference was attributable to the NO desorption rate at the surface of these compounds. It has become clear that the KGa-priderite catalyst remarkably adsorbed NO, and it is suggested that the amount of NO adsorbed and the amount of catalytic activity are able to be increased by the design of priderite structure. 相似文献