全文获取类型
收费全文 | 1668篇 |
免费 | 99篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 25篇 |
综合类 | 3篇 |
化学工业 | 335篇 |
金属工艺 | 36篇 |
机械仪表 | 37篇 |
建筑科学 | 50篇 |
矿业工程 | 2篇 |
能源动力 | 62篇 |
轻工业 | 395篇 |
水利工程 | 25篇 |
石油天然气 | 14篇 |
无线电 | 95篇 |
一般工业技术 | 216篇 |
冶金工业 | 274篇 |
原子能技术 | 16篇 |
自动化技术 | 183篇 |
出版年
2024年 | 2篇 |
2023年 | 15篇 |
2022年 | 38篇 |
2021年 | 53篇 |
2020年 | 42篇 |
2019年 | 56篇 |
2018年 | 68篇 |
2017年 | 57篇 |
2016年 | 61篇 |
2015年 | 50篇 |
2014年 | 71篇 |
2013年 | 100篇 |
2012年 | 91篇 |
2011年 | 99篇 |
2010年 | 72篇 |
2009年 | 64篇 |
2008年 | 87篇 |
2007年 | 56篇 |
2006年 | 58篇 |
2005年 | 56篇 |
2004年 | 50篇 |
2003年 | 32篇 |
2002年 | 30篇 |
2001年 | 26篇 |
2000年 | 32篇 |
1999年 | 41篇 |
1998年 | 102篇 |
1997年 | 64篇 |
1996年 | 29篇 |
1995年 | 33篇 |
1994年 | 14篇 |
1993年 | 17篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 13篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 9篇 |
1975年 | 4篇 |
1974年 | 1篇 |
排序方式: 共有1768条查询结果,搜索用时 15 毫秒
181.
Anna Aiello Mattia Emanuela Ligotti Maider Garnica Giulia Accardi Anna Calabr Fanny Pojero Hugo Arasanz Ana Bocanegra Ester Blanco Luisa Chocarro Miriam Echaide Leticia Fernandez-Rubio Pablo Ramos Sergio Pieiro-Hermida Grazyna Kochan Nahid Zareian Farzin Farzaneh David Escors Calogero Caruso Giuseppina Candore 《International journal of molecular sciences》2022,23(17)
Vaccination, being able to prevent millions of cases of infectious diseases around the world every year, is the most effective medical intervention ever introduced. However, immunosenescence makes vaccines less effective in providing protection to older people. Although most studies explain that this is mainly due to the immunosenescence of T and B cells, the immunosenescence of innate immunity can also be a significant contributing factor. Alterations in function, number, subset, and distribution of blood neutrophils, monocytes, and natural killer and dendritic cells are detected in aging, thus potentially reducing the efficacy of vaccines in older individuals. In this paper, we focus on the immunosenescence of the innate blood immune cells. We discuss possible strategies to counteract the immunosenescence of innate immunity in order to improve the response to vaccination. In particular, we focus on advances in understanding the role and the development of new adjuvants, such as TLR agonists, considered a promising strategy to increase vaccination efficiency in older individuals. 相似文献
182.
D. Abriola N.P. BarradasI. Bogdanovi?-Radovi? M. ChiariA.F. Gurbich C. JeynesM. Kokkoris M. MayerA.R. Ramos L. ShiI. Vickridge 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(24):2972-2978
Ion Beam Analysis (IBA) is a set of material characterization techniques using energetic ion beams. IBA provides information about composition and the depth profile of elements in the near-surface layers of a sample, from the energy spectra of backscattered primary particles, recoils, nuclear reaction products or emitted γ-radiation. All IBA methods presuppose knowledge of the differential cross-section data however, only for strict Rutherford scattering is the cross-section known exactly. In order to address the data needs of the IBA community, the IAEA initiated the Coordinated Research Project (CRP) “Development of a Reference Database for Ion Beam Analysis” in 2005 which will conclude in 2010. The project focuses on the measurement, assessment, evaluation and benchmarking of elastic scattering and reaction cross sections. Data measured in this work have been incorporated in the IBANDL database (http://www-nds.iaea.org/ibandl/), whereas the evaluated cross-sections (calculated from the fit to the data of a nuclear model) are made available to the community through the on-line calculator SigmaCalc (http://www-nds.iaea.org/sigmacalc/).A summary of the results of the CRP activity is presented, and ways to further develop nuclear data for IBA are indicated. In particular, a newly proposed CRP devoted to particle induced gamma-ray emission is described. 相似文献
183.
184.
Since 1977, at the “Solar Energy Thermal Applications Laboratory of M.T.A.” in Marmaris, Turkey, an experimental study of a “Trombe Thermal Storage Wall” passive system continues in operation; two analogous houses have been built, one of which is serving as a reference system. The incident solar radiation on a vertical surface, the temperature changes of the internal and external surfaces of the wall, at interval of thirty minutes, and the convective flow through the “Trombe-Wall” have been measured in order to determine the solar fractions transmitted by the processes of radiation, convection and thermocirculation. In the present study, the variation of the “Trombe-Wall” efficiency has been calculated during the period of a year using a computer evaluation model in which the half hour measurement data have been introduced. The experimental results show that, according to the months, 15–35 per cent of the incident solar radiation over the south facade is transmitted to the interior through the “Trombe-Wall”, while the reference house transmits from the south facade 8–19 per cent of solar radiation received. Finally, it can now be confirmed that the results of the “Trombe-Wall” system without any special type insulation, contributes to practically the total heating load of the village houses under the sunny Aegean Sea Climatic conditions. 相似文献
185.
Antonio Carlos A. Ramos O. G. Balev Nelson Studart 《Journal of Low Temperature Physics》2005,138(1-2):403-408
No Heading The profile of a suspended helium film over a narrow channel is calculated self-consistently for several values of the bulk liquid helium level. We also determine the electron distribution in the channel when surface electrons are deposited on the film. It is shown that a thin van der Waals film with spatially dependent thickness is formed in a wide region at the channel center where a large fraction of electrons are confined. We obtain that the effective lateral confining potential can be described by a parabolic one is experimental conditions reported in the literature.PACS numbers: 73.20.Dx, 67.70.+n 相似文献
186.
Moliner Carolina; Martínez-Tur Vicente; Peiró José M.; Ramos José; Cropanzano Russell 《Canadian Metallurgical Quarterly》2005,12(2):99
Relationships between organizational justice and well-being are traditionally investigated at the individual level. This article extends previous efforts by testing such relationships at the work-unit level. Three corridors of influence were examined. First, the level (work units' average scores) of justice is related to the level of burnout. Second, justice climate strength (level of agreement among work-unit members) moderates the predictability of the level of burnout. Third, justice strength is related to burnout strength. The authors interviewed 324 contact employees from 108 work units in 59 service organizations. Findings showed the predominance of interactional justice over distributive and procedural justice in all 3 corridors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
187.
F Ramos Fuentes 《Canadian Metallurgical Quarterly》1998,49(5):540-542
Calcifying tendinitis is a relatively common disorder of the rotator cuff. For symptomatic patients, excision of the calcium deposits offers reliable pain relief. The arthroscopic technique is demanding. Arthroscopic localization of the deposit is frequently demanding. The technique described in this article facilitates the localization of calcium deposits based on preoperative ultrasonography. Knowing the exact topography of the deposit relative to the visible landmarks allows the surgeon to localize the site of the deposit from the intra-articular view. Probing the rotator cuff with a spinal needle and looking for calcific material at the tip of the needle is an important step in verifying the location of the deposit. 相似文献
188.
A retrospective review of 247 clinical files of patient that have responded to the office allergy and immunology since 1990 to 1993 in Monclova, Coah., for allergy illness. This study was to determine the frequency of Aeroalergens and foods sensitization in Monclova, Coahuila, mediated Allergy Test Skin (intradermo reactions, and Prick) and MAST immuno Systems (Multiple Allergy System Test). The patients were highly sensitive to house dust (13.5%) others aeroalergen pollen grains, were; rusian thistle (7.1%), Pigweed (5.4%), Cynodon Dactylon (4.9%), Pecan (4.8%), Ragweed Mix (4.8%), Rye grass (4.8%) other polen (32.4%). The molds: Candida (3.2%), Alternaria (2.7%), Rhizopus (3.6%), Penicillium (2.1%), Fusarium (2.1%), other molds (8.7%). The foods more important were: Wheat (21.3%), Cheese (10.0%), Shellfish Mix (10.0%), Pork (8.8%), Egg Yolk (7.5%). 相似文献
189.
J Figueras L Lladó-Garriga C Lama J Pujol-Ràfols M Navarro M Martínez-Villacampa J Domínguez C Sancho A Rafecas J Fabregat J Torras E Ramos X Xiol C Baliellas T Casanovas E Jaurrieta 《Canadian Metallurgical Quarterly》1998,21(5):218-223
A retrospective analysis of our experience in the treatment of hiliary cholangiocarcinoma or Klatskin tumor was performed with the aim of evaluating the morbi-mortality and prognosis of its treatment to thereby determine the usefulness of the different therapeutic options. From 1989 to 1997, 51 patients diagnosed with hiliary cholangiocarcinoma were treated in our hospital. Surgery was indicated in 16 with curative aims (group I) while palliative treatment with percutaneous biliary drainage was indicated in 35 (group II). Biliary resection was carried out in 8 patients being associated with hepatic resection in 4 (group IA) and in 8 patients undergoing liver transplantation (group IB). Clinico-epidemiologic data and hospital stay were similar in all the groups. The frequency of complications was similar in groups I and II although the frequency of cholangitis (49%) in group II was noticeable. The percentage of readmissions was also greater in group II (12 vs 46%, respectively; p = 0.03) with prosthesis obstruction being the most frequent cause. Accumulated survival at 1, 2, and 3 years in group I was 84, 64 and 48% with a median survival of 33 months, while in group II the median survival was of 6 months with no patient surviving more than 2 years (p = 0.0001). When groups IA and IB were compared, greater frequency of complications in groups IA (100 vs 37%; p = 0.002), similar frequency of readmissions (87 vs 75%; p = NS), median survival greater in group IB (12.5 months vs 48 months) and significantly higher actuarial survival in group IB (48% in 2 years vs 83% to 2 years; p = 0.02) was observed. In conclusion, surgery is the treatment of choice in hiliary cholangiocarcinoma whenever possible, given the greater survival without a significant increase in morbimortality. Likewise, we consider that liver transplantation is a useful option in the treatment of patients with cholangiocarcinoma type IV of Bismuth. 相似文献
190.
T Alonso Ortiz E Mariscal Ramos M Armadá Maresca J Arizcun Pineda P Zuluaga Arias 《Canadian Metallurgical Quarterly》1998,49(4):388-392
OBJECTIVE: Three-dimensional models created by milling machines and stereolithography on the basis of 3-dimensional computed tomography scans have become essential in the diagnosis and therapy planning of oral and maxillofacial disorders. The purpose of this study, based on 3 clinical cases, was to examine the advantages of using 3-dimensional computed tomography scans and 3-dimensional milling models of the maxillary sinus before operative sinus elevation and of developing an operative layout with the aid of 3-dimensional models. REPORT DESIGN: Three patients with atrophy of the maxillary alveolar ridge received computed tomography scans before operative sinus elevation with iliac bone transplants and simultaneous dental implantation. These computed tomography data were used to create 3-dimensional graphic and plastic reconstructions of the maxillary sinuses. RESULTS: The 3-dimensional milling models enabled the development of an exact preoperative layout that took into consideration the exact shape of the iliac bone and the selection of dental screw implants. Furthermore, the models offered the possibility of producing an acrylic device for precise implant insertion. Precise planning resulted in good success with implantation 2 years after surgery. CONCLUSION: Three-dimensional diagnosis and treatment layout have become an acknowledge method of operative maxillary sinus floor augmentation combined with simultaneous dental implantation in the upper jaw in difficult cases of sinus lift operations. As far as transplant shape and sinus anatomy are concerned, this has resulted in greater intraoperative precision. A 1-step procedure can thus be performed for augmentation and implantation through use of a well-adapted block transplant and dental screw implants in patients with extensive alveolar ridge atrophy. 相似文献