全文获取类型
收费全文 | 4264篇 |
免费 | 49篇 |
专业分类
电工技术 | 14篇 |
化学工业 | 296篇 |
金属工艺 | 33篇 |
机械仪表 | 66篇 |
建筑科学 | 40篇 |
矿业工程 | 1篇 |
能源动力 | 36篇 |
轻工业 | 142篇 |
水利工程 | 20篇 |
石油天然气 | 4篇 |
无线电 | 173篇 |
一般工业技术 | 266篇 |
冶金工业 | 2977篇 |
原子能技术 | 23篇 |
自动化技术 | 222篇 |
出版年
2023年 | 17篇 |
2022年 | 37篇 |
2021年 | 46篇 |
2020年 | 18篇 |
2019年 | 25篇 |
2018年 | 30篇 |
2017年 | 37篇 |
2016年 | 47篇 |
2015年 | 23篇 |
2014年 | 42篇 |
2013年 | 97篇 |
2012年 | 70篇 |
2011年 | 94篇 |
2010年 | 68篇 |
2009年 | 82篇 |
2008年 | 68篇 |
2007年 | 65篇 |
2006年 | 45篇 |
2005年 | 48篇 |
2004年 | 36篇 |
2003年 | 44篇 |
2002年 | 30篇 |
2001年 | 23篇 |
2000年 | 26篇 |
1999年 | 92篇 |
1998年 | 954篇 |
1997年 | 566篇 |
1996年 | 360篇 |
1995年 | 222篇 |
1994年 | 147篇 |
1993年 | 192篇 |
1992年 | 33篇 |
1991年 | 38篇 |
1990年 | 29篇 |
1989年 | 38篇 |
1988年 | 34篇 |
1987年 | 35篇 |
1986年 | 27篇 |
1985年 | 28篇 |
1984年 | 5篇 |
1983年 | 13篇 |
1982年 | 18篇 |
1981年 | 39篇 |
1980年 | 22篇 |
1978年 | 7篇 |
1977年 | 89篇 |
1976年 | 168篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1967年 | 7篇 |
排序方式: 共有4313条查询结果,搜索用时 15 毫秒
81.
Damaceno Rafael J. P. Rossi Luciano Mugnaini Rogério Mena-Chalco Jesús P. 《Scientometrics》2019,119(1):303-333
Scientometrics - Science can be examined from several standpoints, such as through a bibliometric analysis of the scientific output of researchers, research groups or institutions. However, there... 相似文献
82.
EA Halm MJ Fine TJ Marrie CM Coley WN Kapoor DS Obrosky DE Singer 《Canadian Metallurgical Quarterly》1998,279(18):1452-1457
CONTEXT: Many groups have developed guidelines to shorten hospital length of stay in pneumonia in order to decrease costs, but the length of time until a patient hospitalized with pneumonia becomes clinically stable has not been established. OBJECTIVE: To describe the time to resolution of abnormalities in vital signs, ability to eat, and mental status in patients with community-acquired pneumonia and assess clinical outcomes after achieving stability. DESIGN: Prospective, multicenter, observational cohort study. SETTING: Three university and 1 community teaching hospital in Boston, Mass, Pittsburgh, Pa, and Halifax, Nova Scotia. PATIENTS: Six hundred eighty-six adults hospitalized with community-acquired pneumonia. MAIN OUTCOME MEASURES: Time to resolution of vital signs, ability to eat, mental status, hospital length of stay, and admission to an intensive care, coronary care, or telemetry unit. RESULTS: The median time to stability was 2 days for heart rate (< or =100 beats/min) and systolic blood pressure (> or =90 mm Hg), and 3 days for respiratory rate (< or =24 breaths/min), oxygen saturation (> or =90%), and temperature (< or =37.2 degrees C [99 degrees F]). The median time to overall clinical stability was 3 days for the most lenient definition of stability and 7 days for the most conservative definition. Patients with more severe cases of pneumonia at presentation took longer to reach stability. Once stability was achieved, clinical deterioration requiring intensive care, coronary care, or telemetry monitoring occurred in 1% of cases or fewer. Between 65% to 86% of patients stayed in the hospital more than 1 day after reaching stability, and fewer than 29% to 46% were converted to oral antibiotics within 1 day of stability, depending on the definition of stability. CONCLUSIONS: Our estimates of time to stability in pneumonia and explicit criteria for defining stability can provide an evidence-based estimate of optimal length of stay, and outline a clinically sensible approach to improving the efficiency of inpatient management. 相似文献
83.
84.
85.
86.
As the data collected in a survey we conducted show, a major part of the modern general practitioner's work continues to be in the field of family medicine. This fact is also confirmed by the results of other surveys of general practice today. Patients still appreciate their GPs as a source of good medical care and counseling for the whole family. Our own study has shown that most patients would even like to see an expansion of the GP's counseling activities. The duration of the doctor-family relationship extends over many years, and is frequently longer than a decade. 相似文献
87.
Gianmaria Salvio Alessandro Ciarloni Melissa Cutini Nicola delli Muti Federica Finocchi Michele Perrone Silvia Rossi Giancarlo Balercia 《International journal of molecular sciences》2022,23(10)
Metabolic syndrome (MetS) is a highly prevalent condition among adult males, affecting up to 41% of men in Europe. It is characterized by the association of obesity, hypertension, and atherogenic dyslipidemia, which lead to premature morbidity and mortality due to cardiovascular disease (CVD). Male infertility is another common condition which accounts for about 50% of cases of couple infertility worldwide. Interestingly, male infertility and MetS shares several risk factors (e.g., smoking, ageing, physical inactivity, and excessive alcohol consumption), leading to reactive oxygen species (ROS) production and increased oxidative stress (OS), and resulting in endothelial dysfunction and altered semen quality. Thus, the present narrative review aims to discuss the pathophysiological mechanisms which link male infertility and MetS and to investigate the latest available evidence on the reproductive consequences of MetS. 相似文献
88.
Molecular Framework of Mouse Endothelial Cell Dysfunction during Inflammation: A Proteomics Approach
Michael T. Rossi Jordan C. Langston Narender Singh Carmen Merali Qingliang Yang Salim Merali Balabhaskar Prabhakarpandian Laurie E. Kilpatrick Mohammad F. Kiani 《International journal of molecular sciences》2022,23(15)
A key aspect of cytokine-induced changes as observed in sepsis is the dysregulated activation of endothelial cells (ECs), initiating a cascade of inflammatory signaling leading to leukocyte adhesion/migration and organ damage. The therapeutic targeting of ECs has been hampered by concerns regarding organ-specific EC heterogeneity and their response to inflammation. Using in vitro and in silico analysis, we present a comprehensive analysis of the proteomic changes in mouse lung, liver and kidney ECs following exposure to a clinically relevant cocktail of proinflammatory cytokines. Mouse lung, liver and kidney ECs were incubated with TNF-α/IL-1β/IFN-γ for 4 or 24 h to model the cytokine-induced changes. Quantitative label-free global proteomics and bioinformatic analysis performed on the ECs provide a molecular framework for the EC response to inflammatory stimuli over time and organ-specific differences. Gene Ontology and PANTHER analysis suggest why some organs are more susceptible to inflammation early on, and show that, as inflammation progresses, some protein expression patterns become more uniform while additional organ-specific proteins are expressed. These findings provide an in-depth understanding of the molecular changes involved in the EC response to inflammation and can support the development of drugs targeting ECs within different organs. Data are available via ProteomeXchange (identifier PXD031804). 相似文献
89.
Effect of a novel soy fermented product enriched with isoflavones and calcium on bone tissue of rats
Bedani R Rossi EA Lepera JS Wang CC de Valdez GF 《Archivos latinoamericanos de nutrición》2006,56(2):146-152
The objective was to evaluate the effect of soy fermented product intake on the corporal weight and bone tissue of ovariectomized mature rats. This product was fermented with Enterococcus faecium and Lactobacillus jugurti and enriched with isoflavones and calcium. The animals were divided in 5 groups: sham-ovariectomized; ovariectomized; ovariectomized treated with soy fermented product enriched with isoflavones and calcium; ovariectomized treated with soy fermented product enriched with calcium and ovariectomized treated with non-fermented product enriched only with calcium. In order to evaluate the effect of the tested product on bone tissue (femur and tibia), the following parameters were analyzed: length; mechanical assay of three points; density (Archimedes principle); mineral content; calcium content; measure of the trabecular widths. The corporal weight of group treated with soy fermented product containing isoflavones and calcium showed no statistical difference from sham-ovariectomized group and trabecular widths tended to have larger than ovariectomized group. However, there was no significant difference to the other evaluated parameters in result of the diverse treatments. Thus, soy fermented product enriched with isoflavones and calcium inhibited the increasing of corporal weight caused by ovariectomy and revealed a tendency to trabecular protection after castration. 相似文献
90.
The plating of brass on steel from a tartrate based alloy bath has been studied using electrochemical methods and surface analysis techniques. The coating composition obtained using both direct current (d.c.) and pulsed current (p.c.) electrolysis was examined for a variety of temperatures, current densities and bath compositions. The dissolution process of a suitable composition of brass anodes was studied using small amounts of nitrate as depolarizing agent. Tests in a pilot plant showed that when electrolysis is carried outin continuo the coating composition remains constant with time (±1%). Tests were performed at cathode current densities of industrial interest (20–30 A dm–2). The Auger and XPS analyses combined with Ar+ etching indicated a homogeneous composition throughout the coating. 相似文献