全文获取类型
收费全文 | 1046篇 |
免费 | 21篇 |
专业分类
电工技术 | 17篇 |
化学工业 | 117篇 |
金属工艺 | 11篇 |
机械仪表 | 22篇 |
建筑科学 | 33篇 |
能源动力 | 10篇 |
轻工业 | 79篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 116篇 |
一般工业技术 | 176篇 |
冶金工业 | 365篇 |
原子能技术 | 6篇 |
自动化技术 | 112篇 |
出版年
2022年 | 12篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 15篇 |
2017年 | 12篇 |
2016年 | 21篇 |
2015年 | 5篇 |
2014年 | 17篇 |
2013年 | 33篇 |
2012年 | 20篇 |
2011年 | 41篇 |
2010年 | 30篇 |
2009年 | 24篇 |
2008年 | 28篇 |
2007年 | 26篇 |
2006年 | 38篇 |
2005年 | 31篇 |
2004年 | 28篇 |
2003年 | 23篇 |
2002年 | 31篇 |
2001年 | 30篇 |
2000年 | 16篇 |
1999年 | 32篇 |
1998年 | 115篇 |
1997年 | 48篇 |
1996年 | 48篇 |
1995年 | 38篇 |
1994年 | 23篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 6篇 |
1990年 | 13篇 |
1989年 | 12篇 |
1988年 | 18篇 |
1987年 | 24篇 |
1986年 | 14篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1978年 | 8篇 |
1977年 | 9篇 |
1976年 | 19篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1971年 | 7篇 |
排序方式: 共有1067条查询结果,搜索用时 28 毫秒
41.
42.
Jingwei Shi Xiao Shen Qi Kang Xing Yang Maximilian Denzinger Marko Kornmann Benno Traub 《International journal of molecular sciences》2022,23(7)
In search of new therapies for pancreatic cancer, cytokine pathways have attracted increasing interest in recent years. Cytokines play a vital role in the crosstalk between tumour cells and the tumour microenvironment. The related inflammatory cytokines IL-4 and IL-13 can regularly be detected at increased levels in the microenvironment of pancreatic cancer. They share a receptor heterodimer consisting of IL-4Rα and IL-13Rα1. While IL-4Rα induces a more oncogenic phenotype, the role of IL-13Rα1 was yet to be determined. ShRNA-based knockdown of IL-13Rα1 was performed in Capan-1 and MIA PaCa-2. We assessed cell growth and migratory capacities under the influence of IL-13Rα1. Pathway alterations were detected by immunoblot analysis. We now have demonstrated that the loss of IL-13Rα1 induces apoptosis in pancreatic cancer cells. This was associated with an epithelial-to-mesenchymal transition. Loss of IL-13Rα1 also abolished the effects of exogenous IL-4 and IL-13 stimulation. Interestingly, in wild type cells, cytokine stimulation caused a similar increase in migratory capacities as after IL-13Rα1 knockdown. Overall, our results indicate the vital role of IL-13Rα1 in the progression of pancreatic cancer. The differential expression of IL-4Rα and IL-13Rα1 has to be taken into account when considering a cytokine-targeted therapy in pancreatic cancer. 相似文献
43.
Electrolytic Adamantylation by Reductive Coupling of Quinolinylhalides in the Presence of 1-Bromoadamantane Electrochemically generated anion radicals of a number of halogen-substituted quinolines 1 a–g dehalogenate in N,N-dimethylformamide to halogen anions and radicals, which may stabilize by hydrogen abstraction from the solvent. In the presence of 1-bromoadamantane the fragments of reductive dehalogenation may be used synthetically for indirect generation of 1-bromoadamantane-radicals, which react predominantly to cross-coupled 2- and 7-monoadamantylated dihydroquinoline- and quinoline-structures, independent of the original halogen position. If C-2 is blocked, adamantylation takes place in the carbocyclic ring. Product distribution and cyclic-voltammetric results are discussed in terms of mechanism. 相似文献
44.
45.
New concepts for the utilisation of residual products from food industry - Prospects for the potato starch industry. In disposed waste are quite a lot of reusable substances of high value. These residual products can be transferred into commercial products in dependency to the adequate technology either as raw material for secondary processes, as operating supplies or as ingredients of novel products. Numerous valuable substances in food production are suitable for separation and recycling at the end of their life cycle even though present separation and recycling processes are not absolutely cost saving. Based on a concept of food production in its entirely the actual state is exemplary demonstrated at the potato starch industry in its occurrence, quantity and utilisation of the residual products. The target state of a clean production process will be realised by the development of multifunctional food ingredients. The outlined concept can be naturally transferred to several areas of industrial food production. The intentions of this research area are located at the development of techniques, which fulfil the conditions of environmental protection with costs to a minimum. 相似文献
46.
47.
Zimmerman Jeffrey; Hess Allen K.; McGarrah Nancy A.; Benjamin G. Andrew H.; Ally Glenn A.; Gollan Jackie K.; Kaser-Boyd Nancy 《Canadian Metallurgical Quarterly》2009,40(6):539
The provision of psychological (e.g., psychotherapy, coparenting, mediation, collaborative divorce, child custody evaluation) services for families of divorce are growing specialties for many clinical and forensic psychologists. However, practice in domestic relations psychology, such as divorce and custody assessment and testimony, is a high-risk venture for incurring ethics complaints and law suits. The lead article and the three commentaries that follow enumerate the various roles practitioners might play, clarify how each role requires specific skill sets that may be outside one’s particular competence and necessitate additional training, describe how countertransferential issues arise, urge meticulous record keeping, discuss some of the subtleties of confidentiality and the releasing of information, describe how transparency in clarifying expectations leads to a lowering of contentiousness, and provide tips for divorce and forensic practice. The special challenges associated with psychologists being tempted to move beyond their role on a case and those of particularly high-risk situations (e.g., complaints of child abuse or domestic violence) are also discussed. Suggestions are offered to help psychologists better serve the public while taking steps to better inoculate themselves from complaints. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
48.
G. Xiong R. Shao S. J. Peppernick A. G. Joly K. M. Beck W. P. Hess M. Cai J. Duchene J. Y. Wang W. D. Wei 《JOM Journal of the Minerals, Metals and Materials Society》2010,62(12):90-93
Photoelectron emission microscopy (PEEM) is a versatile technique that can image a variety of materials including metals, semiconductors and even insulators. Under favorable conditions the most advanced aberration corrected instruments have a spatial resolution approaching 2 nm. Although PEEM cannot compete with transmission or scanning electron microscopies for ultimate resolution, the technique is much gentler and has the unique advantage of imaging structure as well as electronic and magnetic states on the nanoscale. Since the image contrast is derived from spatial variations in electron photoemission intensity, PEEM is ideal for interrogating both static and dynamic electronic properties of complex nanostructured materials. Here, we review the key principles and contrast mechanisms of PEEM and briefly summarize materials applications of PEEM. 相似文献
49.
In this article we introduce the term “energy polarization” to explain the politics of energy market reform in the Russian Duma. Our model tests the impact of regional energy production, party cohesion and ideology, and electoral mandate on the energy policy decisions of the Duma deputies (oil, gas, and electricity bills and resolution proposals) between 1994 and 2003. We find a strong divide between Single-Member District (SMD) and Proportional Representation (PR) deputies High statistical significance of gas production is demonstrated throughout the three Duma terms and shows Gazprom's key position in the post-Soviet Russian economy. Oil production is variably significant in the two first Dumas, when the main legislative debates on oil privatization occur. There is no constant left–right continuum, which is consistent with the deputies' proclaimed party ideology. The pro- and anti-reform poles observed in our Poole-based single dimensional scale are not necessarily connected with liberal and state-oriented regulatory policies, respectively. Party switching is a solid indicator of Russia's polarized legislative dynamics when it comes to energy sector reform. 相似文献
50.
Maike Gleichenhagen Benno F. Zimmermann Birgit Herzig Ingar Janzik Siegfried Jahnke Markus Boner Peter Stehle Rudolf Galensa 《Food chemistry》2013
The intrinsic isotopic labelling of plants with 13CO2 is an effective method to generate highly labelled compounds using photosynthesis and avoiding labour-intensive complex organic syntheses. In this study, the intrinsic isotopic labelling of polyphenols in parsley, spinach and peppermint is shown for the first time. The plants were grown in an atmosphere where 12CO2 was replaced by 13CO2, in order to generate highly labelled compounds. The total content of 13C as well as the individual polyphenols were analysed by Isotopic Ratio-MS and HPLC–Iontrap-MSn. 相似文献