全文获取类型
收费全文 | 7147篇 |
免费 | 395篇 |
国内免费 | 161篇 |
专业分类
电工技术 | 93篇 |
技术理论 | 6篇 |
综合类 | 368篇 |
化学工业 | 953篇 |
金属工艺 | 106篇 |
机械仪表 | 114篇 |
建筑科学 | 3681篇 |
矿业工程 | 128篇 |
能源动力 | 331篇 |
轻工业 | 372篇 |
水利工程 | 45篇 |
石油天然气 | 47篇 |
武器工业 | 7篇 |
无线电 | 229篇 |
一般工业技术 | 299篇 |
冶金工业 | 318篇 |
原子能技术 | 42篇 |
自动化技术 | 564篇 |
出版年
2024年 | 58篇 |
2023年 | 97篇 |
2022年 | 336篇 |
2021年 | 381篇 |
2020年 | 231篇 |
2019年 | 203篇 |
2018年 | 190篇 |
2017年 | 192篇 |
2016年 | 256篇 |
2015年 | 270篇 |
2014年 | 458篇 |
2013年 | 430篇 |
2012年 | 421篇 |
2011年 | 550篇 |
2010年 | 449篇 |
2009年 | 430篇 |
2008年 | 359篇 |
2007年 | 407篇 |
2006年 | 368篇 |
2005年 | 272篇 |
2004年 | 215篇 |
2003年 | 250篇 |
2002年 | 175篇 |
2001年 | 145篇 |
2000年 | 87篇 |
1999年 | 119篇 |
1998年 | 57篇 |
1997年 | 47篇 |
1996年 | 26篇 |
1995年 | 22篇 |
1994年 | 29篇 |
1993年 | 34篇 |
1992年 | 19篇 |
1991年 | 26篇 |
1990年 | 14篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 12篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1976年 | 2篇 |
1965年 | 3篇 |
1960年 | 2篇 |
1959年 | 1篇 |
1956年 | 3篇 |
1955年 | 1篇 |
排序方式: 共有7703条查询结果,搜索用时 15 毫秒
1.
论社区服务产业化 总被引:2,自引:0,他引:2
刘波 《重庆理工大学学报(自然科学版)》2003,17(1):127-131
社区经济作为一种优化的资源配置方式,利用社区服务为载体,将社区内互不相联的各种经济成份变为利益共同体,建立一种新的经济生产方式,从而带动社区乃至更广区域的经济发展。 相似文献
2.
3.
During the winter of 1988/1989, the relationships between the prevalence of work-related health and indoor climate complaints and a number of building, management, workplace and personal characteristics have been investigated in a study in more than 60 office buildings located throughout the Netherlands. To collect the information, a questionnaire was prepared on health and indoor climate complaints and personal and workplace characteristics. A checklist was used to obtain information on building characteristics More than 7000 questionnaires were completed by the regular users of the buildings investigated. The results showed that the prevalence of symptoms was higher in air-conditioned buildings than in naturally or mechanically ventilated buildings. some other variables were also related with most work-related complaints after adjustment for selected management, personal, workplace and job characteristics. These included gender, work satisfaction in general, presence of allergies and/or respiratory symptoms, and personal control over temperature at the workplace. No differences were found in symptom prevalences between buildings with spray and steam humidification. The combination of air-conditioning and humidification did not lead to further increases in the prevalence of complaints as compared to buildings with only airconditioning or only humidification. 相似文献
4.
5.
利用安徽省宿州市1999—2010年的统计数据,运用塞尔奎因-钱纳里标准法分析其城市化与工业化发展阶段,采用协整检验、Granger因果检验对其城市化与工业化的因果关系进行实证研究。结果表明:1)宿州工业化和城市化水平低于全国平均水平,均处于初期发展阶段;2)宿州城市化与工业化有高度相关关系,城市化滞后于工业化;3)宿州当前城市化发展是工业化发展的Granger原因,加快城市化发展有利于促进工业化水平提高;4)宿州城市化水平与第二产业增加值比重和第三产业增加值比重具有长期稳定的协整关系,但与非农就业人口比重不存在长期稳定的均衡关系;5)宿州城市化水平与第二产业增加值比重和第三产业增加值比重的弹性系数分别为0.21和0.86,说明其城市化水平对第三产业的拉动作用要比对第二产业的拉动作用更大一些。因此宿州市应促进人口向中心城区的集聚,发挥城市化对工业化的促进作用。 相似文献
6.
7.
Dulce María Delgadillo Adriana Ivonne Cspedes-Cruz Emmanuel Ríos-Castro María Guadalupe Rodríguez Maldonado Mariel Lpez-Nogueda Miguel Mrquez-Gutirrez Rocío Villalobos-Manzo Lorena Ramírez-Reyes Misael Domínguez-Fuentes Jos Tapia-Ramírez 《International journal of molecular sciences》2022,23(10)
Autoimmune lymphoproliferative syndrome (ALPS) is a rare disease defined as a defect in the lymphocyte apoptotic pathway. Currently, the diagnosis of ALPS is based on clinical aspects, defective lymphocyte apoptosis and mutations in Fas, FasL and Casp 10 genes. Despite this, ALPS has been misdiagnosed. The aim of this work was to go one step further in the knowledge of the disease, through a molecular and proteomic analysis of peripheral blood mononuclear cells (PBMCs) from two children, a 13-year-old girl and a 6-year-old boy, called patient 1 and patient 2, respectively, with clinical data supporting the diagnosis of ALPS. Fas, FasL and Casp10 genes from both patients were sequenced, and a sample of the total proteins from patient 1 was analyzed by label-free proteomics. Pathway analysis of deregulated proteins from PBMCs was performed on the STRING and PANTHER bioinformatics databases. A mutation resulting in an in-frame premature stop codon and protein truncation was detected in the Fas gene from patient 2. From patient 1, the proteomic analysis showed differences in the level of expression of proteins involved in, among other processes, cell cycle, regulation of cell cycle arrest and immune response. Noticeably, the most down-regulated protein is an important regulator of the cell cycle process. This could be an explanation of the disease in patient 1. 相似文献
8.
为提高传统不确定性推理在中医辨证中的准确率和灵活性,提出了基于D-S证据理论的中医辨证模型。模型采用群决策理论,以证素为识别框架,以不同专家的诊断结果为基本可信度分配,对专家的诊断结果进行证据融合,模型能够降低系统的不确定性,提高证素诊断的准确率和可信度。以冠心病的中医诊断为例,验证了模型的有效性。 相似文献
9.
Charlotte Szewczykowski Christian Mardin Marianna Lucio Gerd Wallukat Jakob Hoffmanns Thora Schrder Franziska Raith Lennart Rogge Felix Heltmann Michael Moritz Lorenz Beitlich Julia Schottenhamml Martin Herrmann Thomas Harrer Marion Ganslmayer Friedrich E. Kruse Martin Krter Jochen Guck Robert Lmmer Matthias Zenkel Andreas Gießl Bettina Hohberger 《International journal of molecular sciences》2022,23(13)
Long COVID (LC) describes the clinical phenotype of symptoms after infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Diagnostic and therapeutic options are limited, as the pathomechanism of LC is elusive. As the number of acute SARS-CoV-2 infections was and is large, LC will be a challenge for the healthcare system. Previous studies revealed an impaired blood flow, the formation of microclots, and autoimmune mechanisms as potential factors in this complex interplay. Since functionally active autoantibodies against G-protein-coupled receptors (GPCR-AAbs) were observed in patients after SARS-CoV-2 infection, this study aimed to correlate the appearance of GPCR-AAbs with capillary microcirculation. The seropositivity of GPCR-AAbs was measured by an established cardiomyocyte bioassay in 42 patients with LC and 6 controls. Retinal microcirculation was measured by OCT–angiography and quantified as macula and peripapillary vessel density (VD) by the Erlangen-Angio Tool. A statistical analysis yielded impaired VD in patients with LC compared to the controls, which was accentuated in female persons. A significant decrease in macula and peripapillary VD for AAbs targeting adrenergic β2-receptor, MAS-receptor angiotensin-II-type-1 receptor, and adrenergic α1-receptor were observed. The present study might suggest that a seropositivity of GPCR-AAbs can be linked to an impaired retinal capillary microcirculation, potentially mirroring the systemic microcirculation with consecutive clinical symptoms. 相似文献
10.
Vitaly Shubin Yury Shelygin Sergey Achkasov Oleg Sushkov Ilya Nazarov Alexey Ponomarenko Iuliia Alimova Anna Loginova Aleksey Tsukanov 《International journal of molecular sciences》2022,23(13)
The aim of this study was to determine the characteristics of Russian patients with microsatellite instability (MSI) tumors. MSI in the tumor was determined in 514 patients with colon cancer using PCR and subsequent fragment analysis for five markers (NR21, NR24, BAT25, BAT26, and NR27). In the presence of microsatellite instability, the mismatch repair (MMR) system genes were examined using the NGS and MLPA methods to establish the diagnosis of Lynch syndrome. The overall frequency of MSI tumors was 15%: at stage I—19% (9/48), at stage II—21% (44/213), at stage III—16% (26/160), and at stage IV—2% (2/93). Patients with MSI tumors differed in the age of diagnosis, tumor localization, time of cancer recurrence, and stage of the disease. The overall and disease-free survival of patients whose tumors had MSI status was higher than that of patients with microsatellite-stable status, p = 0.04 and p = 0.02, respectively. Analysis of overall and disease-free survival of patients with Lynch syndrome and patients with sporadic colon cancer, but with MSI status, did not reveal significant differences, p = 0.52 and p = 0.24, respectively. The age of patients with Lynch syndrome was significantly younger than that of patients with sporadic colon cancer whose tumors had MSI status (p < 0.001). 相似文献