全文获取类型
收费全文 | 10412篇 |
免费 | 1233篇 |
国内免费 | 561篇 |
专业分类
电工技术 | 1217篇 |
综合类 | 1231篇 |
化学工业 | 827篇 |
金属工艺 | 314篇 |
机械仪表 | 575篇 |
建筑科学 | 2362篇 |
矿业工程 | 448篇 |
能源动力 | 332篇 |
轻工业 | 383篇 |
水利工程 | 762篇 |
石油天然气 | 276篇 |
武器工业 | 146篇 |
无线电 | 1038篇 |
一般工业技术 | 772篇 |
冶金工业 | 282篇 |
原子能技术 | 139篇 |
自动化技术 | 1102篇 |
出版年
2024年 | 59篇 |
2023年 | 176篇 |
2022年 | 338篇 |
2021年 | 440篇 |
2020年 | 352篇 |
2019年 | 292篇 |
2018年 | 268篇 |
2017年 | 301篇 |
2016年 | 394篇 |
2015年 | 419篇 |
2014年 | 865篇 |
2013年 | 585篇 |
2012年 | 788篇 |
2011年 | 803篇 |
2010年 | 620篇 |
2009年 | 707篇 |
2008年 | 603篇 |
2007年 | 744篇 |
2006年 | 650篇 |
2005年 | 516篇 |
2004年 | 398篇 |
2003年 | 380篇 |
2002年 | 312篇 |
2001年 | 286篇 |
2000年 | 197篇 |
1999年 | 144篇 |
1998年 | 110篇 |
1997年 | 85篇 |
1996年 | 68篇 |
1995年 | 57篇 |
1994年 | 54篇 |
1993年 | 40篇 |
1992年 | 23篇 |
1991年 | 24篇 |
1990年 | 24篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1959年 | 7篇 |
1958年 | 2篇 |
1956年 | 4篇 |
1955年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
61.
Federico Paolini Paoletti Simone Simoni Lucilla Parnetti Lorenzo Gaetani 《International journal of molecular sciences》2021,22(9)
Brain small vessel disease (SVD) refers to a variety of structural and functional changes affecting small arteries and micro vessels, and manifesting as white matter changes, microbleeds and lacunar infarcts. Growing evidence indicates that SVD might play a significant role in the neurobiology of central nervous system (CNS) neurodegenerative disorders, namely Alzheimer’s disease (AD) and Parkinson’s disease (PD), and neuroinflammatory diseases, such as multiple sclerosis (MS). These disorders share different pathophysiological pathways and molecular mechanisms (i.e., protein misfolding, derangement of cellular clearance systems, mitochondrial impairment and immune system activation) having neurodegeneration as biological outcome. In these diseases, the actual contribution of SVD to the clinical picture, and its impact on response to pharmacological treatments, is not known yet. Due to the high frequency of SVD in adult-aged patients, it is important to address this issue. In this review, we report preclinical and clinical data on the impact of SVD in AD, PD and MS, with the main aim of clarifying the predictability of SVD on clinical manifestations and treatment response. 相似文献
62.
Julian Zacharjasz Anna M. Mleczko Pawe Bkowski Tomasz Piontek Kamilla Bkowska-ywicka 《International journal of molecular sciences》2021,22(11)
Knee osteoarthritis (OA) is a degenerative knee joint disease that results from the breakdown of joint cartilage and underlying bone, affecting about 3.3% of the world’s population. As OA is a multifactorial disease, the underlying pathological process is closely associated with genetic changes in articular cartilage and bone. Many studies have focused on the role of small noncoding RNAs in OA and identified numbers of microRNAs that play important roles in regulating bone and cartilage homeostasis. The connection between other types of small noncoding RNAs, especially tRNA-derived fragments and knee osteoarthritis is still elusive. The observation that there is limited information about small RNAs different than miRNAs in knee OA was very surprising to us, especially given the fact that tRNA fragments are known to participate in a plethora of human diseases and a portion of them are even more abundant than miRNAs. Inspired by these findings, in this review we have summarized the possible involvement of microRNAs and tRNA-derived fragments in the pathology of knee osteoarthritis. 相似文献
63.
Tomoyuki Koga Shinya Kingetsu Nobuyuki Higashi 《International journal of molecular sciences》2021,22(9)
Self-assembly of artificial peptides has been widely studied for constructing nanostructured materials, with numerous potential applications in the nanobiotechnology field. Herein, we report the synthesis and hierarchical self-assembly of collagen-mimetic peptides (CMPs) bearing various aromatic groups at the N-termini, including 2-naphthyl, 1-naphtyl, anthracenyl, and pyrenyl groups, into nanofibers. The CMPs (R-(GPO)n: n > 4) formed a triple helix structure in water at 4 °C, as confirmed via CD analyses, and their conformations were more stable with increasing hydrophobicity of the terminal aromatic group and peptide chain length. The resulting pre-organized triple helical CMPs showed diverse self-assembly into highly ordered nanofibers, reflecting their slight differences in hydrophobic/hydrophilic balance and configuration of aromatic templates. TEM analysis demonstrated that 2Np-CMPn (n = 6 and 7) and Py-CMP6 provided well-developed natural collagen-like nanofibers and An-CMPn (n = 5–7) self-assembled into rod-like micelle fibers. On the other hand, 2Np-CMP5 and 1Np-CMP6 were unable to form nanofibers under the same conditions. Furthermore, the Py-CMP6 nanofiber was found to encapsulate a guest hydrophobic molecule, Nile red, and exhibited unique emission behavior based on the specific nanostructure. In addition to the ability of CMPs to bind small molecules, their controlled self-assembly enables their versatile utilization in drug delivery and wavelength-conversion nanomaterials. 相似文献
64.
Sang-Hyun Park Insu Shin Dr. Gun-Hee Kim Dr. Sung-Kyun Ko Prof. Dr. Injae Shin 《Chembiochem : a European journal of chemical biology》2021,22(24):3425-3430
A novel autophagy inhibitor, autophazole (Atz), which promoted cancer cell death via caspase activation, is described. This compound was identified from cell-based high-content screening of an imidazole library. The results showed that Atz was internalized into lysosomes of cells where it induced lysosomal membrane permeabilization (LMP). This process generated nonfunctional autolysosomes, thereby inhibiting autophagy. In addition, Atz was found to promote LMP-mediated apoptosis. Specifically, LMP induced by Atz caused release of cathepsins from lysosomes into the cytosol. Cathepsins in the cytosol cleaved Bid to generate tBid, which subsequently activated Bax to induce mitochondrial outer membrane permeabilization (MOMP). This event led to cancer cell death via caspase activation. Overall, the findings suggest that Atz will serve as a new chemical probe in efforts aimed at gaining a better understanding of the autophagic process. 相似文献
65.
66.
67.
68.
含Li的Al-Zn-Mg-Cu合金沉淀析出过程的定量分析 总被引:3,自引:0,他引:3
应用小角度X射线散射技术结合TEM分析定量的描述Al-Zn-Mg-Cu-Li合金时效过程中析出相尺寸分布和形貌等信息。通过分析确定合金在几种时效状态下析出相为轴比在0.2~0.4之间的扁回转椭球形。确定了析出相特征尺寸的对数正态分布和质量依回转半径的Maxwell分布。并分析分布曲线随动力强度Ks的变化特征,可以看出,析出相尺寸和质量分布曲线基本满足随动力强度增加,几何平均值增加,分布范围变宽。 相似文献
69.
介绍了目前我国铝型材的市场状况,指出中国铝型材企业未来的市场状况将与日本15年前的市场状况相似,也指出了我国型材企业目前与先进国家的差距及如何赶上的措施。 相似文献
70.