全文获取类型
收费全文 | 518篇 |
免费 | 11篇 |
专业分类
电工技术 | 10篇 |
综合类 | 1篇 |
化学工业 | 182篇 |
金属工艺 | 6篇 |
机械仪表 | 8篇 |
建筑科学 | 5篇 |
能源动力 | 10篇 |
轻工业 | 131篇 |
水利工程 | 1篇 |
无线电 | 38篇 |
一般工业技术 | 63篇 |
冶金工业 | 47篇 |
原子能技术 | 8篇 |
自动化技术 | 19篇 |
出版年
2023年 | 3篇 |
2022年 | 11篇 |
2021年 | 18篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 6篇 |
2014年 | 21篇 |
2013年 | 19篇 |
2012年 | 28篇 |
2011年 | 30篇 |
2010年 | 12篇 |
2009年 | 22篇 |
2008年 | 21篇 |
2007年 | 15篇 |
2006年 | 12篇 |
2005年 | 16篇 |
2004年 | 17篇 |
2003年 | 15篇 |
2002年 | 14篇 |
2001年 | 14篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 20篇 |
1997年 | 22篇 |
1996年 | 17篇 |
1995年 | 10篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1974年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有529条查询结果,搜索用时 15 毫秒
21.
Sasao T Itoh N Takano H Watanabe S Wei G Tsukamoto T Kuzumaki N Takimoto M 《Reproduction (Cambridge, England)》2004,128(6):709-716
We have previously identified and cloned a human gene, D40, that is preferentially expressed in testis among normal organs, while it is widely expressed in various human tumor cell lines and primary tumors derived from different organs. In this report, we have examined the expression and localization of this protein in human testis with an antibody specific to D40 protein. In Western analyses, the anti-D40 antibody recognized a major band with a molecular mass of 300 kDa and a minor band of 250 kDa. These bands were not observed in the testis lysates from patients with Sertoli-cell-only syndrome and with Kleinfelter syndrome, who lack germ cells of the testis, indicating that D40 protein is expressed in the germ cells of normal testis. Immunohistochemical studies have revealed that D40 protein is highly expressed in spermatocytes and in the pre-acrosome of round spermatids. In the acrosome, D40 protein expression is observed not inside but outside the acrosome membrane. This is consistent with the finding that the amino-acid sequence at the amino terminal of the D40 protein lacks a hydrophobic signal peptide that is required for proteins to translocate to the membrane. Expression of D40 protein is observed in the acrosome of ejaculated spermatozoa as well, although the level is low compared with that in the pre-acrosome of spermatids. These results suggest that D40 protein plays important roles in spermatogenesis, especially in the formation and maintenance of the acrosome. 相似文献
22.
As tongue cancer is one of the major malignant cancers in the world, understanding the mechanism of maintenance of lingual epithelial tissue, which is known to be the origin of tongue cancer, is unquestionably important. However, the actual stem cells that are responsible for the long-term maintenance of the lingual epithelium have not been identified. Moreover, a simple and convenient culture method for lingual epithelial stem cells has not yet been established. Recently, we have shown that Bmi1-positive cells, residing at the second or third layer of the epithelial cell layer at the base of the interpapillary pit (IPP), were slow-cycling and could supply keratinized epithelial cells for over one year, indicating that Bmi1-positive cells are long-term lingual epithelial stem cells. In addition, we have developed a novel lingual epithelium organoid culture system using a three-dimensional matrix and growth factors. Here, we discuss current progress in the identification of lingual stem cells and future applications of the lingual culture system for studying the regulatory mechanisms of the lingual epithelium and for regenerative medicine. 相似文献
23.
Noriaki Ozaki Hiroko Tokoro Yoshiho Hamada Asuka Namai Tomoyuki Matsuda Souhei Kaneko Shin‐ichi Ohkoshi 《Advanced functional materials》2012,22(10):2089-2093
The crystal structure, magnetic properties, and temperature‐ and photoinduced phase transition of [{CoII(4‐methylpyridine)(pyrimidine)}2{CoII(H2O)2}{WV(CN)8}2]·4H2O are described. In this compound, a temperature‐induced phase transition from the CoII (S = 3/2)‐NC‐WV(S = 1/2) [high‐temperature (HT)] phase to the CoIII(S = 0)‐NC‐WIV(S = 0) [low temperature (LT)] phase is observed due to a charge‐transfer‐induced spin transition. When the LT phase is irradiated with 785 nm light, ferromagnetism with a high Curie temperature (TC) of 48 K and a gigantic magnetic coercive field (Hc) of 27 000 Oe are observed. These TC and Hc values are the highest in photoinduced magnetization systems. The LT phase is optically converted to the photoinduced phase, which has a similar valence state as the HT phase due to the optically induced charge‐transfer‐induced spin transition. 相似文献
24.
EFFECT OF STEPWISE CHANGE OF DRYING RATE ON MICROSTRUCTURE EVOLUTION IN POLYMER FILMS 总被引:2,自引:0,他引:2
Masato Yamamura Takatoshi Nishio Toshihisa Kajiwara Kitaro Adachi 《Drying Technology》2001,19(7):1397-1410
The effect of the drying rate of the solvent on microstructure evolution in thin films of immiscible polystyrene/polycarbonate blends was investigated by applying a stepwise change in air velocity. The polymer blend was dissolved in tetrahydrofuran and cast on a glass substrate to form a thin liquid film. The drying rate of the solvent was measured by a gravimetric technique, and the phase-separated structure in the film was observed by optical microscopy. The results indicated that cellular structures of droplet arrays were formed in the phases evolved primarily during the early stage of drying, and the droplets then coalesced in the intermediate stage to form bigger droplets. The size of the first evolved phase decreased with increasing time at a high drying rate, whereas larger droplets were obtained with longer high drying rate regimes. These results suggested that the droplets were induced by secondary phase separation which was strongly affected by the drying rate of the solvent. 相似文献
25.
l‐Citrulline Supplementation‐Increased Skeletal Muscle PGC‐1α Expression Is Associated with Exercise Performance and Increased Skeletal Muscle Weight 下载免费PDF全文
Scope
l ‐citrulline has recently been reported as a more effective supplement for promoting intracellular nitric oxide (NO) production compared to l ‐arginine. Here, the effect of l ‐citrulline on skeletal muscle and its influence on exercise performance were investigated. The underlying mechanism of its effect, specifically on the expression of skeletal muscle peroxisome proliferator‐activated receptor‐gamma coactivator‐1α (PGC‐1α), was also elucidated.Methods and results
Six‐week‐old ICR mice were orally supplemented with l ‐citrulline (250 mg kg?1) daily, and their performance in weight‐loaded swimming exercise every other day for 15 days, was evaluated. In addition, mice muscles were weighed and evaluated for the expression of PGC‐1α and PGC‐1α‐regulated genes. Mice orally supplemented with l ‐citrulline had significantly higher gastrocnemius and biceps femoris muscle mass. Although not statistically significant, l ‐citrulline prolonged the swimming time to exhaustion. PGC‐1α upregulation was associated with vascular endothelial growth factor α (VEGFα) and insulin‐like growth factor 1 (IGF‐1) upregulation. VEGFα and IGF‐1 are important for angiogenesis and muscle growth, respectively, and are regulated by PGC‐1α. Treatment with NG‐nitro‐l ‐arginine methyl ester hydrochloride (l ‐NAME), a nitric oxide synthesis inhibitor, suppressed the l ‐citrulline‐induced PGC‐1α upregulation in vitro.Conclusion
Supplementation with l ‐citrulline upregulates skeletal muscle PGC‐1α levels resulting in higher skeletal muscle weight that improves time to exhaustion during exercise.26.
Arachidonic acid hydroperoxide (15-hydroperoxyeicosatetraenoic acid; 15-HPETE) was introduced into human parotid saliva and
incubated at 37°C. Straight phase high-performance liquid chromatography analysis of the reaction mixture showed that 15-HPETE
was detoxified to its reduced form, 15-hydroxyeicosatetraenoic acid, in the presence of glutathione. Therefore, it is concluded
that human parotid saliva possesses fatty acid hydroperoxide-reducing ability. However, its effectiveness was found to be
lower than that of blood plasma. 相似文献
27.
本文是在国际服饰文化与教育研讨会期间,本栏目主持人、我校服装艺术与工程学院讲师孙雪飞对日本著名时装设计师小筱弘子进行访谈的整理. 相似文献
28.
This paper proposes an engineering ethics education method for students on the basis of continuous education to improve communication ability. First, through the process of debate, the students acquire the fundamental skills necessary to marshal their arguments, to construct rebuttals, and to summarize debates. Second, the students study the fundamental techniques to make a presentation on technical subjects related to electrical engineering. Following these classes, in lectures on engineering ethics, the students probe the causes of various accidents and consider better approaches for avoiding such accidents with each other. In most cases, the students can express good and commonsensical opinions from an ethical standpoint. However, they can hardly make judgments when the situations, such as the human relations in the above accidents, are set up in concrete terms. During the engineering ethics class, the students come to know that the human relations behind the case make ethical matters more complicated. Furthermore, they come to understand that facilitating daily communications with co‐workers and/or supervisors is very important in order to avoid such accidents. The recognition of the students is primarily the result of the continuous education during 3 years. It can be said that the engineering ethics education thus constructed increases in the students this kind of spontaneous awareness as well as their ethical qualities as engineers. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(3): 1–8, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22283 相似文献
29.
Tomotake Morita Emi Ito Hiroko K. Kitamoto Kaoru Takegawa Tokuma Fukuoka Tomohiro Imura Dai Kitamoto 《Yeast (Chichester, England)》2010,27(11):905-917
The yeast Pseudozyma antarctica produces a large amount of glycolipid biosurfactants known as mannosylerythritol lipids (MELs), which show not only excellent surface‐active properties but also versatile biochemical actions. To investigate the biosynthesis of MELs in the yeast, we recently reported expressed sequence tag (EST) analysis and estimated genes expressing under MEL production conditions. Among the genes, a contiguous sequence of 938 bp, PA_004, showed high sequence identity to the gene emt1, encoding an erythritol/mannose transferase of Ustilago maydis, which is essential for MEL biosynthesis. The predicted translation product of the extended PA_004 containing the two introns and a stop codon was aligned with Emt1 of U. maydis. The predicted amino acid sequence shared high identity (72%) with Emt1 of U. maydis, although the amino‐terminal was incomplete. To identify the gene as PaEMT1 encoding an erythritol/mannose transferase of P. antarctica, the gene‐disrupted strain was developed by the method for targeted gene disruption, using hygromycin B resistance as the selection marker. The obtained ΔPaEMT1 strain failed to produce MELs, while its growth was the same as that of the parental strain. The additional mannosylerythritol into culture allowed ΔPaEMT1 strain to form MELs regardless of the carbon source supplied, indicating a defect of the erythritol/mannose transferase activity. Furthermore, we found that MEL formation is associated with the morphology and low‐temperature tolerance of the yeast. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
30.
Haining Liu Gregory J. Wilson Niranjan Balu Jeffrey H. Maki Daniel S. Hippe Wei Wu Hiroko Watase Jinnan Wang Martin L. Gunn Chun Yuan 《Magma (New York, N.Y.)》2018,31(1):87-99