全文获取类型
收费全文 | 219120篇 |
免费 | 17836篇 |
国内免费 | 8812篇 |
专业分类
电工技术 | 12429篇 |
技术理论 | 14篇 |
综合类 | 12836篇 |
化学工业 | 37451篇 |
金属工艺 | 11393篇 |
机械仪表 | 13078篇 |
建筑科学 | 17459篇 |
矿业工程 | 5432篇 |
能源动力 | 6213篇 |
轻工业 | 14293篇 |
水利工程 | 3678篇 |
石油天然气 | 11548篇 |
武器工业 | 1607篇 |
无线电 | 27087篇 |
一般工业技术 | 27876篇 |
冶金工业 | 11480篇 |
原子能技术 | 2278篇 |
自动化技术 | 29616篇 |
出版年
2024年 | 951篇 |
2023年 | 3500篇 |
2022年 | 6388篇 |
2021年 | 8543篇 |
2020年 | 6298篇 |
2019年 | 5306篇 |
2018年 | 5755篇 |
2017年 | 6653篇 |
2016年 | 6088篇 |
2015年 | 7929篇 |
2014年 | 10339篇 |
2013年 | 13198篇 |
2012年 | 13413篇 |
2011年 | 15110篇 |
2010年 | 12791篇 |
2009年 | 12633篇 |
2008年 | 12027篇 |
2007年 | 11722篇 |
2006年 | 11814篇 |
2005年 | 10414篇 |
2004年 | 7135篇 |
2003年 | 6141篇 |
2002年 | 5576篇 |
2001年 | 5030篇 |
2000年 | 5118篇 |
1999年 | 5729篇 |
1998年 | 5295篇 |
1997年 | 4371篇 |
1996年 | 3973篇 |
1995年 | 3325篇 |
1994年 | 2777篇 |
1993年 | 2197篇 |
1992年 | 1710篇 |
1991年 | 1282篇 |
1990年 | 1022篇 |
1989年 | 884篇 |
1988年 | 686篇 |
1987年 | 500篇 |
1986年 | 400篇 |
1985年 | 337篇 |
1984年 | 213篇 |
1983年 | 200篇 |
1982年 | 165篇 |
1981年 | 148篇 |
1980年 | 136篇 |
1979年 | 100篇 |
1978年 | 63篇 |
1977年 | 63篇 |
1976年 | 77篇 |
1975年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Myelodysplastic syndromes (MDS) are highly heterogeneous myeloid neoplasms, and a large number of
patients are difficult to diagnose and classify by blood and bone marrow examination. As a surface marker of
granulocyte, studies have shown CD10 can be used to define the degree of granulocyte maturation in MDS patients.
However, whether it can be used for differential diagnosis of MDS and other hematological diseases remains
inconclusive. To explore the value of CD10 for differential diagnosis of MDS, 60 newly diagnosed MDS, 20 aplastic
anemia (AA) patients, and 35 iron-deficient anemia (IDA) patients were selected for this study. Bone marrow (BM)
specimens were processed for surface marker analysis and labeled with pre-conjugated monoclonal antibodies. Stained
cells were detected by flow cytometry. Our results indicated that CD10-positive granulocytes were significantly
decreased in BM of MDS patients than AA and IDA patients, and the level of CD10-positive mature granulocytes was
not associated with the clinical stages of malignancy. Receiver operating characteristic (ROC) areas under the curve
(AUC) of CD10-positive granulocytes was 0.86 and 0.85, respectively, in MDS patients than the IDA group and AA
group with good specificity and sensitivity. Further, CD10-positive granulocytes were increased after effective
treatment. In conclusion, we found the decrease in CD10-positive granulocytes has a differential diagnostic value of MDS. 相似文献
62.
Amino acid modified polyaspartic acids were evaluated as calcium-scale inhibitors. Feasibility of scale inhibition experiments was analyzed by molecular dynamics simulation and Gaussian optimization, and the scale inhibition mechanism was theoretically analyzed. Scale inhibition performance was studied by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, static scale inhibition experiments, and electrochemical performance testing, which provided an experimental basis for the molecular dynamics simulation. The experimental results showed that Arg-SA-PASP has better scale inhibition and corrosion inhibition performance than His-SA-PASP. The scale inhibition effect increased with increasing concentration. Electrochemical tests indicated that Arg-SA-PASP is an excellent scale and corrosion inhibitor. 相似文献
63.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018)
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
64.
Xueye Chen Yue Tian 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2020,95(3):806-812
Since the beginning of the 21st Century, the development of microfluidic chip technology has been very rapid and has attracted the attention of more and more scholars. As an important part of the microfluidic chip, the performance of the micromixer is critical. The fractal structure in the microchannels helps to improve the mixing performance of the micromixer and improve the mixing efficiency of the micromixer. The research results of other scholars are of great significance to the research of the present paper, which mainly studies the effect of changing the baffle state on the mixing efficiency of the micromixer based on the Koch fractal principle. Through simulation analysis, it was found that the mixing efficiency of the baffles distributed on both sides of the microchannel was higher than the mixing efficiency of the baffles distributed on the microchannel side. When the distance between adjacent baffles was divided into 0.15, 0.25 and 0.35 mm, simulated data suggested that the baffle distance of 0.15 mm was best. Increasing the number of baffles from six to eight groups increased the mixing path of the fluid in the microchannel and improved mixing efficiency. A comparison of mixing efficiencies of the 0°, 15° and 30° baffle angles revealed that very significant improvement in mixing efficiency was obtained at 30°. © 2019 Society of Chemical Industry 相似文献
65.
基于C4AF可以提高水泥基材料的抗蚀性,以高铁低钙水泥熟料为研究对象,掺入不同含量的CuO,通过对熟料及其水化产物进行X射线衍射(XRD)、水化热、抗压强度、非蒸发水含量和固化氯离子能力等测试,探究Cu2+对高铁低钙水泥熟料水化性能与氯离子吸附固化能力的影响.结果发现,适量CuO的掺入促进了高铁低钙水泥熟料中C4AF的生成,降低了熟料液相的粘度,有利于C3S的晶粒生长,有利于提高高铁低钙水泥熟料的水化活性和固化氯离子能力,最佳掺量为0.2 wt%. 相似文献
66.
67.
68.
World Wide Web - Infectious diseases such as Influenza and Ebola pose a serious threat to everyone but certain demographics and cohorts face a higher risk of infection than others. This research... 相似文献
69.
Wesley P. Chan Hiroto Mizohana Xiangyu Chen Yasuto Shiigi Yoshiyuki Yamanoue Masaki Nagatsuka Masayuki Inaba 《野外机器人技术杂志》2019,36(1):17-33
The use of field robots can greatly decrease the amount of time, effort, and associated risk compared to if human workers were to carryout certain tasks such as disaster response. However, transportability and reliability remain two main issues for most current robot systems. To address the issue of transportability, we have developed a lightweight modularizable platform named AeroArm. To address the issue of reliability, we utilize a multimodal sensing approach, combining the use of multiple sensors and sensor types, and the use of different detection algorithms, as well as active continuous closed‐loop feedback to accurately estimate the state of the robot with respect to the environment. We used Challenge 2 of the 2017 Mohammed Bin Zayed International Robotics Competition as an example outdoor manipulation task, demonstrating the capabilities of our robot system and approach in achieving reliable performance in the fields, and ranked fifth place internationally in the competition. 相似文献
70.
World Wide Web - The wide spread use of positioning and photographing devices gives rise to a deluge of traffic trajectory data (e.g., vehicle passage records and taxi trajectory data), with each... 相似文献