全文获取类型
收费全文 | 225186篇 |
免费 | 18964篇 |
国内免费 | 12375篇 |
专业分类
电工技术 | 34453篇 |
技术理论 | 22篇 |
综合类 | 25484篇 |
化学工业 | 11454篇 |
金属工艺 | 7554篇 |
机械仪表 | 18724篇 |
建筑科学 | 18754篇 |
矿业工程 | 8914篇 |
能源动力 | 8245篇 |
轻工业 | 10249篇 |
水利工程 | 6596篇 |
石油天然气 | 6640篇 |
武器工业 | 3813篇 |
无线电 | 21655篇 |
一般工业技术 | 11451篇 |
冶金工业 | 6673篇 |
原子能技术 | 2327篇 |
自动化技术 | 53517篇 |
出版年
2024年 | 334篇 |
2023年 | 2004篇 |
2022年 | 3837篇 |
2021年 | 5200篇 |
2020年 | 5556篇 |
2019年 | 4099篇 |
2018年 | 3749篇 |
2017年 | 5260篇 |
2016年 | 6333篇 |
2015年 | 7441篇 |
2014年 | 14041篇 |
2013年 | 12015篇 |
2012年 | 16799篇 |
2011年 | 17735篇 |
2010年 | 13391篇 |
2009年 | 13376篇 |
2008年 | 13676篇 |
2007年 | 17596篇 |
2006年 | 15834篇 |
2005年 | 14191篇 |
2004年 | 11597篇 |
2003年 | 10514篇 |
2002年 | 7957篇 |
2001年 | 6652篇 |
2000年 | 5471篇 |
1999年 | 4402篇 |
1998年 | 3285篇 |
1997年 | 2659篇 |
1996年 | 2381篇 |
1995年 | 2062篇 |
1994年 | 1694篇 |
1993年 | 1161篇 |
1992年 | 995篇 |
1991年 | 706篇 |
1990年 | 579篇 |
1989年 | 482篇 |
1988年 | 351篇 |
1987年 | 206篇 |
1986年 | 122篇 |
1985年 | 129篇 |
1984年 | 109篇 |
1983年 | 92篇 |
1982年 | 75篇 |
1981年 | 71篇 |
1980年 | 55篇 |
1979年 | 46篇 |
1978年 | 34篇 |
1977年 | 29篇 |
1976年 | 24篇 |
1959年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Ilaria Fraudentali Renato A. Rodrigues-Pousada Riccardo Angelini Sandip A. Ghuge Alessandra Cona 《International journal of molecular sciences》2021,22(10)
Polyamines are ubiquitous, low-molecular-weight aliphatic compounds, present in living organisms and essential for cell growth and differentiation. Copper amine oxidases (CuAOs) oxidize polyamines to aminoaldehydes releasing ammonium and hydrogen peroxide, which participates in the complex network of reactive oxygen species acting as signaling molecules involved in responses to biotic and abiotic stresses. CuAOs have been identified and characterized in different plant species, but the most extensive study on a CuAO gene family has been carried out in Arabidopsis thaliana. Growing attention has been devoted in the last years to the investigation of the CuAO expression pattern during development and in response to an array of stress and stress-related hormones, events in which recent studies have highlighted CuAOs to play a key role by modulation of a multilevel phenotypic plasticity expression. In this review, the attention will be focused on the involvement of different AtCuAOs in the IAA/JA/ABA signal transduction pathways which mediate stress-induced phenotypic plasticity events. 相似文献
2.
Xiao-Lei Qiu Zi-Rui Fan Yang-Yang Liu Ding-Fu Wang Shi-Xin Wang Chun-Xia Li 《International journal of molecular sciences》2021,22(8)
A self-nanoemulsifying drug delivery system (SNEDDS) was developed to enhance the absorption of heparin after oral administration, in which heparin was compounded with phospholipids to achieve better fat solubility in the form of heparin-phospholipid (HEP-Pc) complex. HEP-Pc complex was prepared using the solvent evaporation method, which increased the solubility of heparin in n-octanol. The successful preparation of HEP-Pc complex was confirmed by differential scanning calorimetry (DSC), Fourier-transform infrared (FT-IR) spectroscopy, NMR, and SEM. A heparin lipid microemulsion (HEP-LM) was prepared by high-pressure homogenization and characterized. HEP-LM can enhance the absorption of heparin after oral administration, significantly prolong activated partial thromboplastin time (APTT) and thrombin time (TT) in mice, and reduce fibrinogen (FIB) content. All these outcomes indicate that HEP-LM has great potential as an oral heparin formulation. 相似文献
3.
4.
邓乐善 《中国水能及电气化》2021,(1):56-58
针对民乐县农村人饮机井水位自动供水系统控制中存在的可靠性低、成本高等问题,文章结合深井泵提取地下水进行供水的实际情况,提出了软启动控制柜+浮球开关+微电脑时间控制器改进的思路和方法,运用效果良好。 相似文献
5.
谭金军 《自动化技术与应用》2021,40(1):181-183
为进一步提升企业思想政治教育工作的信息化水平,本文详细介绍了企业思想政治教育系统的数据库设计方案,以便更加充分地发挥各种多媒体教学设备在企业思想政治教育工作方面的优势。 相似文献
6.
Ruirui Lu Katharina Metzner Fangyuan Zhou Cathrin Flauaus Annika Balzulat Patrick Engel Jonas Petersen Rebekka Ehinger Anne Bausch Peter Ruth Robert Lukowski Achim Schmidtko 《International journal of molecular sciences》2021,22(1)
The sodium-activated potassium channel Slack (KNa1.1, Slo2.2, or Kcnt1) is highly expressed in populations of sensory neurons, where it mediates the sodium-activated potassium current (IKNa) and modulates neuronal activity. Previous studies suggest that Slack is involved in the processing of neuropathic pain. However, mechanisms underlying the regulation of Slack activity in this context are poorly understood. Using whole-cell patch-clamp recordings we found that Slack-mediated IKNa in sensory neurons of mice is reduced after peripheral nerve injury, thereby contributing to neuropathic pain hypersensitivity. Interestingly, Slack is closely associated with ATP-sensitive P2X3 receptors in a population of sensory neurons. In vitro experiments revealed that Slack-mediated IKNa may be bidirectionally modulated in response to P2X3 activation. Moreover, mice lacking Slack show altered nocifensive responses to P2X3 stimulation. Our study identifies P2X3/Slack signaling as a mechanism contributing to hypersensitivity after peripheral nerve injury and proposes a potential novel strategy for treatment of neuropathic pain. 相似文献
7.
8.
9.
In this paper, a novel method is proposed for increasing the performance through coupling of top-down models adjusting the object detector based on a new loss function. Generally, object detectors and keypoint estimators are sequentially used in real-time multi-person pose estimations; however, these two models are separately trained. Therefore, the results of the object detector are not optimized for the keypoint estimator. To solve this problem, we analyze the relationship between the two models and propose a feedback-based loss optimization in the object detector, based on the estimation results of the keypoint estimator. In addition, the resulting bounding box of the object detector is readjusted to improve the accuracy of the keypoint estimation model. The experimental results demonstrate that the proposed approach can perform real-time operations with a high frame rate similar to that of the baseline model. Moreover, it achieved an accuracy of 74.2 average precision (AP), which is higher than the state-of-the-arts model including the human detector used in the experiment. 相似文献
10.