全文获取类型
收费全文 | 5452篇 |
免费 | 372篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 112篇 |
综合类 | 4篇 |
化学工业 | 1158篇 |
金属工艺 | 176篇 |
机械仪表 | 343篇 |
建筑科学 | 90篇 |
矿业工程 | 4篇 |
能源动力 | 229篇 |
轻工业 | 574篇 |
水利工程 | 46篇 |
石油天然气 | 7篇 |
无线电 | 961篇 |
一般工业技术 | 1169篇 |
冶金工业 | 337篇 |
原子能技术 | 63篇 |
自动化技术 | 569篇 |
出版年
2024年 | 9篇 |
2023年 | 73篇 |
2022年 | 107篇 |
2021年 | 182篇 |
2020年 | 96篇 |
2019年 | 129篇 |
2018年 | 161篇 |
2017年 | 150篇 |
2016年 | 189篇 |
2015年 | 155篇 |
2014年 | 231篇 |
2013年 | 325篇 |
2012年 | 384篇 |
2011年 | 431篇 |
2010年 | 307篇 |
2009年 | 305篇 |
2008年 | 322篇 |
2007年 | 238篇 |
2006年 | 233篇 |
2005年 | 164篇 |
2004年 | 194篇 |
2003年 | 152篇 |
2002年 | 180篇 |
2001年 | 149篇 |
2000年 | 104篇 |
1999年 | 110篇 |
1998年 | 196篇 |
1997年 | 103篇 |
1996年 | 79篇 |
1995年 | 50篇 |
1994年 | 46篇 |
1993年 | 47篇 |
1992年 | 46篇 |
1991年 | 28篇 |
1990年 | 20篇 |
1989年 | 18篇 |
1988年 | 14篇 |
1987年 | 17篇 |
1986年 | 17篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1972年 | 3篇 |
1969年 | 3篇 |
1962年 | 3篇 |
排序方式: 共有5842条查询结果,搜索用时 15 毫秒
51.
Durai Mani Kumaravel Sakthivel Mukannan Arivanandhan Krishnakumar Balu Thiripuranthagan Sivakumar Ahn Young-Ho 《Journal of Porous Materials》2021,28(6):1907-1917
Journal of Porous Materials - Valeric acid can be produced by selective hydrogenation of biomass-derived levulinic acid. The present work aims to synthesize ethyl valerate (EV), a fuel, fuel... 相似文献
52.
Nguyen Khanh Toan Nguyen Chi Tai Soo-A Kim Sang-Gun Ahn 《International journal of molecular sciences》2021,22(1)
Salivary gland dysfunction induces salivary flow reduction and a dry mouth, and commonly involves oral dysfunction, tooth structure deterioration, and infection through reduced salivation. This study aimed to investigate the impact of aging on the salivary gland by a metabolomics approach in an extensive aging mouse model, SAMP1/Klotho -/- mice. We found that the salivary secretion of SAMP1/Klotho -/- mice was dramatically decreased compared with that of SAMP1/Klotho WT (+/+) mice. Metabolomics profiling analysis showed that the level of acetylcholine was significantly decreased in SAMP1/Klotho -/- mice, although the corresponding levels of acetylcholine precursors, acetyl-CoA and choline, increased. Interestingly, the mRNA and protein expression of choline acetyltransferase (ChAT), which is responsible for catalyzing acetylcholine synthesis, was significantly decreased in SAMP1/Klotho -/- mice. The overexpression of ChAT induced the expression of salivary gland functional markers (α–amylase, ZO-1, and Aqua5) in primary cultured salivary gland cells from SAMP1/Klotho +/+ and -/- mice. In an in vivo study, adeno-associated virus (AAV)-ChAT transduction significantly increased saliva secretion compared with the control in SAMP1/Klotho -/- mice. These results suggest that the dysfunction in acetylcholine biosynthesis induced by ChAT reduction may cause impaired salivary gland function 相似文献
53.
54.
Diti Chatterjee Bhowmick Miwon Ahn Eunjin Oh Rajakrishnan Veluthakal Debbie C. Thurmond 《International journal of molecular sciences》2021,22(4)
Type 2 diabetes (T2D) is one of the prominent causes of morbidity and mortality in the United States and beyond, reaching global pandemic proportions. One hallmark of T2D is dysfunctional glucose-stimulated insulin secretion from the pancreatic β-cell. Insulin is secreted via the recruitment of insulin secretory granules to the plasma membrane, where the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) and SNARE regulators work together to dock the secretory granules and release insulin into the circulation. SNARE proteins and their regulators include the Syntaxins, SNAPs, Sec1/Munc18, VAMPs, and double C2-domain proteins. Recent studies using genomics, proteomics, and biochemical approaches have linked deficiencies of exocytosis proteins with the onset and progression of T2D. Promising results are also emerging wherein restoration or enhancement of certain exocytosis proteins to β-cells improves whole-body glucose homeostasis, enhances β-cell function, and surprisingly, protection of β-cell mass. Intriguingly, overexpression and knockout studies have revealed novel functions of certain exocytosis proteins, like Syntaxin 4, suggesting that exocytosis proteins can impact a variety of pathways, including inflammatory signaling and aging. In this review, we present the conventional and unconventional functions of β-cell exocytosis proteins in normal physiology and T2D and describe how these insights might improve clinical care for T2D. 相似文献
55.
56.
Jaewan Jeon Sungmin Lee Hyunwoo Kim Hyunkoo Kang HyeSook Youn Sunmi Jo BuHyun Youn Hae Yu Kim 《International journal of molecular sciences》2021,22(10)
Although there are many patients with brain tumors worldwide, there are numerous difficulties in overcoming brain tumors. Among brain tumors, glioblastoma, with a 5-year survival rate of 5.1%, is the most malignant. In addition to surgical operations, chemotherapy and radiotherapy are generally performed, but the patients have very limited options. Temozolomide is the most commonly prescribed drug for patients with glioblastoma. However, it is difficult to completely remove the tumor with this drug alone. Therefore, it is necessary to discuss the potential of anticancer drugs, other than temozolomide, against glioblastomas. Since the discovery of cisplatin, platinum-based drugs have become one of the leading chemotherapeutic drugs. Although many studies have reported the efficacy of platinum-based anticancer drugs against various carcinomas, studies on their effectiveness against brain tumors are insufficient. In this review, we elucidated the anticancer effects and advantages of platinum-based drugs used in brain tumors. In addition, the cases and limitations of the clinical application of platinum-based drugs are summarized. As a solution to overcome these obstacles, we emphasized the potential of a novel approach to increase the effectiveness of platinum-based drugs. 相似文献
57.
Soo-In Sohn Jae-Hyung Ahn Subramani Pandian Young-Ju Oh Eun-Kyoung Shin Hyeon-Jung Kang Woo-Suk Cho Youn-Sung Cho Kong-Sik Shin 《International journal of molecular sciences》2021,22(11)
Bacterial communities in rhizosphere and root nodules have significant contributions to the growth and productivity of the soybean (Glycine max (L.) Merr.). In this report, we analyzed the physiological properties and dynamics of bacterial community structure in rhizosphere and root nodules at different growth stages using BioLog EcoPlate and high-throughput sequencing technology, respectively. The BioLog assay found that the metabolic capability of rhizosphere is in increasing trend in the growth of soybeans as compared to the bulk soil. As a result of the Illumina sequencing analysis, the microbial community structure of rhizosphere and root nodules was found to be influenced by the variety and growth stage of the soybean. At the phylum level, Actinobacteria were the most abundant in rhizosphere at all growth stages, followed by Alphaproteobacteria and Acidobacteria, and the phylum Bacteroidetes showed the greatest change. But, in the root nodules Alphaproteobacteria were dominant. The results of the OTU analysis exhibited the dominance of Bradyrhizobium during the entire stage of growth, but the ratio of non-rhizobial bacteria showed an increasing trend as the soybean growth progressed. These findings revealed that bacterial community in the rhizosphere and root nodules changed according to both the variety and growth stages of soybean in the field. 相似文献
58.
59.
Seungmin Ahn Hoyoung Jung Prof. Dr. Jung-Min Kee 《Chembiochem : a European journal of chemical biology》2021,22(2):319-325
Protein phosphorylation is one of the most studied post-translational modifications (PTMs). Despite the remarkable advances in phosphoproteomics, a chemically less-stable subset of the phosphosites, which we call the crypto-phosphoproteome, has remained underexplored due to technological challenges. In this Viewpoint, we briefly summarize the current understanding of these elusive protein phosphorylations and identify the missing pieces for future studies. 相似文献
60.