全文获取类型
收费全文 | 3895篇 |
免费 | 252篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 85篇 |
综合类 | 14篇 |
化学工业 | 1151篇 |
金属工艺 | 58篇 |
机械仪表 | 70篇 |
建筑科学 | 325篇 |
矿业工程 | 38篇 |
能源动力 | 76篇 |
轻工业 | 452篇 |
水利工程 | 24篇 |
石油天然气 | 2篇 |
无线电 | 261篇 |
一般工业技术 | 708篇 |
冶金工业 | 243篇 |
原子能技术 | 24篇 |
自动化技术 | 621篇 |
出版年
2023年 | 56篇 |
2022年 | 102篇 |
2021年 | 154篇 |
2020年 | 97篇 |
2019年 | 92篇 |
2018年 | 111篇 |
2017年 | 109篇 |
2016年 | 162篇 |
2015年 | 160篇 |
2014年 | 198篇 |
2013年 | 249篇 |
2012年 | 215篇 |
2011年 | 262篇 |
2010年 | 139篇 |
2009年 | 186篇 |
2008年 | 192篇 |
2007年 | 164篇 |
2006年 | 126篇 |
2005年 | 134篇 |
2004年 | 112篇 |
2003年 | 81篇 |
2002年 | 75篇 |
2001年 | 41篇 |
2000年 | 36篇 |
1999年 | 48篇 |
1998年 | 48篇 |
1997年 | 38篇 |
1996年 | 39篇 |
1995年 | 44篇 |
1994年 | 24篇 |
1993年 | 30篇 |
1992年 | 29篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 14篇 |
1988年 | 20篇 |
1987年 | 30篇 |
1986年 | 28篇 |
1985年 | 21篇 |
1984年 | 33篇 |
1983年 | 32篇 |
1982年 | 22篇 |
1981年 | 24篇 |
1980年 | 30篇 |
1979年 | 16篇 |
1976年 | 13篇 |
1975年 | 24篇 |
1974年 | 14篇 |
1973年 | 16篇 |
1970年 | 13篇 |
排序方式: 共有4152条查询结果,搜索用时 15 毫秒
91.
92.
Milo Hricovíni Raymond J. Owens Andrzej Bak Violetta Kozik Witold Musia Roberta Pierattelli Magdalna Mjekov Yoel Rodríguez Robert Musio Aneta Slodek Pavel tarha Karina Pitak Dagmara Sota Wioletta Florkiewicz Agnieszka Sobczak-Kupiec Josef Jampílek 《International journal of molecular sciences》2022,23(23)
The knowledge of interactions between different molecules is undoubtedly the driving force of all contemporary biomedical and biological sciences. Chemical biology/biological chemistry has become an important multidisciplinary bridge connecting the perspectives of chemistry and biology to the study of small molecules/peptidomimetics and their interactions in biological systems. Advances in structural biology research, in particular linking atomic structure to molecular properties and cellular context, are essential for the sophisticated design of new medicines that exhibit a high degree of druggability and very importantly, druglikeness. The authors of this contribution are outstanding scientists in the field who provided a brief overview of their work, which is arranged from in silico investigation through the characterization of interactions of compounds with biomolecules to bioactive materials. 相似文献
93.
Sandra Classen Elena Rahlf Johannes Jungwirth Nina Albers Luca Philipp Hebestreit Alexandra Zielinski Lena Poole Marco Groth Philipp Koch Thomas Liehr Stefanie Kankel Nils Cordes Cordula Petersen Kai Rothkamm Helmut Pospiech Kerstin Borgmann 《International journal of molecular sciences》2022,23(21)
BRCA1 is a well-known breast cancer risk gene, involved in DNA damage repair via homologous recombination (HR) and replication fork protection. Therapy resistance was linked to loss and amplification of the BRCA1 gene causing inferior survival of breast cancer patients. Most studies have focused on the analysis of complete loss or mutations in functional domains of BRCA1. How mutations in non-functional domains contribute to resistance mechanisms remains elusive and was the focus of this study. Therefore, clones of the breast cancer cell line MCF7 with indels in BRCA1 exon 9 and 14 were generated using CRISPR/Cas9. Clones with successful introduced BRCA1 mutations were evaluated regarding their capacity to perform HR, how they handle DNA replication stress (RS), and the consequences on the sensitivity to MMC, PARP1 inhibition, and ionizing radiation. Unexpectedly, BRCA1 mutations resulted in both increased sensitivity and resistance to exogenous DNA damage, despite a reduction of HR capacity in all clones. Resistance was associated with improved DNA double-strand break repair and reduction in replication stress (RS). Lower RS was accompanied by increased activation and interaction of proteins essential for the S phase-specific DNA damage response consisting of HR proteins, FANCD2, and CHK1. 相似文献
94.
Daniel Alexander Bizjak Lucas John Lynn Matits Alisa Uhl Sebastian Victor Waldemar Schulz Jana Schellenberg Johannes Peifer Wilhelm Bloch Manfred Weiß Beate Grüner Hendrik Bracht Jürgen Michael Steinacker Marijke Grau 《International journal of molecular sciences》2022,23(23)
Hematological and hemorheological parameters are known to be altered in COVID-19; however, the value of combined monitoring in order to deduce disease severity is only scarcely examined. A total of 44 acute SARS-CoV-2-infected patients (aCOV) and 44 age-matched healthy controls (Con) were included. Blood of aCOV was sampled at admission (T0), and at day 2 (T2), day 5 (T5), day 10 (T10), and day 30 (T30) while blood of Con was only sampled once. Inter- and intra-group differences were calculated for hematological and hemorheological parameters. Except for mean cellular volume and mean cellular hemoglobin, all blood cell parameters were significantly different between aCOV and Con. During the acute disease state (T0–T5), hematological and hemorheological parameters were highly altered in aCOV; in particular, anemic conditions and increased immune cell response/inflammation, oxidative/nitrosative stress, decreased deformability, as well as increased aggregation, were observed. During treatment and convalescence until T30, almost all abnormal values of aCOV improved towards Con values. During the acute state of the COVID-19 disease, the hematological, as well as the hemorheological system, show fast and potentially pathological changes that might contribute to the progression of the disease, but changes appear to be largely reversible after four weeks. Measuring RBC deformability and aggregation, as well as oxidative stress induction, may be helpful in monitoring critically ill COVID-19 patients. 相似文献
95.
Robert Lemanis Kian Tadayon Elke Reich Gargi Joshi Richard Johannes Best Kevin Stevens Igor Zlotnikov 《Journal of the Royal Society Interface》2022,19(191)
The ability of evolution to shape organic form involves the interactions of multiple systems of constraints, including fabrication, phylogeny and function. The tendency to place function above everything else has characterized some of the historical biological literature as a series of ‘Just-So’ stories that provided untested explanations for individual features of an organism. A similar tendency occurs in biomaterials research, where features for which a mechanical function can be postulated are treated as an adaptation. Moreover, functional adaptation of an entire structure is often discussed based on the local characterization of specimens kept in conditions that are far from those in which they evolved. In this work, environmental- and frequency-dependent mechanical characterization of the shells of two cephalopods, Nautilus pompilius and Argonauta argo, is used to demonstrate the importance of multi-scale environmentally controlled characterization of biogenic materials. We uncover two mechanistically independent strategies to achieve deformable, stiff, strong and tough highly mineralized structures. These results are then used to critique interpretations of adaptation in the literature. By integrating the hierarchical nature of biological structures and the environment in which they exist, biomaterials testing can be a powerful tool for generating functional hypotheses that should be informed by how these structures are fabricated and their evolutionary history. 相似文献
96.
97.
Maciej Dulewicz Agnieszka Kulczyska-Przybik Piotr Mroczko Johannes Kornhuber Piotr Lewczuk Barbara Mroczko 《International journal of molecular sciences》2022,23(15)
Alzheimer’s disease (AD) is a progressive condition and the most common cause of dementia worldwide. The neuropathological changes characteristic of the disorder can be successfully detected before the development of full-blown AD. Early diagnosis of the disease constitutes a formidable challenge for clinicians. CSF biomarkers are the in vivo evidence of neuropathological changes developing in the brain of dementia patients. Therefore, measurement of their concentrations allows for improved accuracy of clinical diagnosis. Moreover, AD biomarkers may provide an indication of disease stage. Importantly, the CSF biomarkers of AD play a pivotal role in the new diagnostic criteria for the disease, and in the recent biological definition of AD by the National Institute on Aging, NIH and Alzheimer’s Association. Due to the necessity of collecting CSF by lumbar puncture, the procedure seems to be an important issue not only from a medical, but also a legal, viewpoint. Furthermore, recent technological advances may contribute to the automation of AD biomarkers measurement and may result in the establishment of unified cut-off values and reference limits. Moreover, a group of international experts in the field of AD biomarkers have developed a consensus and guidelines on the interpretation of CSF biomarkers in the context of AD diagnosis. Thus, technological advancement and expert recommendations may contribute to a more widespread use of these diagnostic tests in clinical practice to support a diagnosis of mild cognitive impairment (MCI) or dementia due to AD. This review article presents up-to-date data regarding the usefulness of CSF biomarkers in routine clinical practice and in biomarkers research. 相似文献
98.
交叉层积木作为一种新型木建筑材料已经在北美地区推广开来,然而在我国还没有得到引进和推广.本文介绍了这种新型材料的性能特点,总结其生产工艺、设计方法和研究进展,重点对交叉层积木七种半刚性连接的抗震性能进行试验研究.研究表明:紧固件全部被拔出的失效模式为理想的延性破坏模式,滞回曲线表现出高度非线性、刚度退化、强度退化以及捏拢现象.通过试验数据分析,给出了在延性和承载能力两方面最佳的连接. 相似文献
99.
A comparative study of the purification of betanin 总被引:3,自引:0,他引:3
Letícia Christina Pires GonçalvesMarco Aurélio de Souza Trassi Nathana Barbosa LopesFelipe Augusto Dörr Monica Teixeira dos SantosWilhelm Josef Baader Vani Xavier Oliveira Jr.Erick Leite Bastos 《Food chemistry》2012,131(1):231-238
Betanin is a natural pigment with antioxidant properties used as a food colourant. This work describes the spectrophotometric and chromatographic quantification of betanin (2S/15S) and its epimer isobetanin (2S/15R) in fresh beetroot juice, food-grade beetroot powder and betanin standard diluted in dextrin. Absorption spectra of all three samples were deconvoluted using a mixed three-function model. Food-grade beetroot powder has the largest amount of violet-red impurities, probably formed during processing. The purification of betanin from these complex matrices was carried out by seven different methods. Ion exchange chromatography was the most efficient method for the purification of betanin from all samples; however, fractions contain high amounts of salt. Reversed-phase HPLC as well as reversed-phase column chromatography also produced good results at a much faster rate. The longer retention time of isobetanin when compared to betanin in reversed-phase conditions has been investigated by means of quantum-mechanical methods. 相似文献
100.
目的:探究人乳N-链寡糖组(human milk N-glycome,HMN)与牛乳N-链寡糖组(bovine milk N-glycome,BMN)对小鼠肠道菌群的影响.方法:以C57BL/6J雄性小鼠为对象,首先在体外测定粪便菌群中与N-链寡糖相关的糖苷酶活性,并模拟粪便菌群对HMN与BMN的利用;然后将小鼠随机分... 相似文献