全文获取类型
收费全文 | 19452篇 |
免费 | 1450篇 |
国内免费 | 1336篇 |
出版年
2024年 | 53篇 |
2023年 | 293篇 |
2022年 | 628篇 |
2021年 | 1069篇 |
2020年 | 712篇 |
2019年 | 893篇 |
2018年 | 804篇 |
2017年 | 616篇 |
2016年 | 885篇 |
2015年 | 1256篇 |
2014年 | 1476篇 |
2013年 | 1511篇 |
2012年 | 1760篇 |
2011年 | 1537篇 |
2010年 | 953篇 |
2009年 | 815篇 |
2008年 | 947篇 |
2007年 | 768篇 |
2006年 | 728篇 |
2005年 | 573篇 |
2004年 | 526篇 |
2003年 | 470篇 |
2002年 | 407篇 |
2001年 | 373篇 |
2000年 | 341篇 |
1999年 | 312篇 |
1998年 | 204篇 |
1997年 | 188篇 |
1996年 | 174篇 |
1995年 | 152篇 |
1994年 | 115篇 |
1993年 | 105篇 |
1992年 | 132篇 |
1991年 | 110篇 |
1990年 | 96篇 |
1989年 | 58篇 |
1988年 | 46篇 |
1987年 | 49篇 |
1986年 | 25篇 |
1985年 | 26篇 |
1984年 | 16篇 |
1983年 | 22篇 |
1982年 | 4篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
251.
Zhongkai Hao Qi Chen Wenrui Dai Yinjuan Ren Yin Zhou Jinlin Yang Sijie Xie Yanbin Shen Jihong Wu Wei Chen Guo Qin Xu 《Liver Transplantation》2020,10(10)
Developing a titanium dioxide (TiO2)‐based anode with superior high‐rate capability and long‐term cycling stability is important for efficient energy storage. Herein, a simple one‐step approach for fabricating blue TiO2 nanoparticles with oxygen vacancies is reported. Oxygen vacancies can enlarge lattice spaces, lower charge transfer resistance, and provide more active sites in TiO2 lattices. As a result, this blue TiO2 electrode exhibits a highly reversible capacity of 50 mAh g?1 at 100 C (16 800 mA g?1) even after 10 000 cycles, which is attributable to the combination of surface capacitive process and remarkable diffusion‐controlled insertion revealed by the kinetic analysis. The strategy of employing oxygen‐deficient nanoparticles may be extended to the design of other robust semiconductor materials as electrodes for energy storage. 相似文献
252.
Energy Harvesting from Breeze Wind (0.7–6 m s−1) Using Ultra‐Stretchable Triboelectric Nanogenerator
Zewei Ren Ziming Wang Zhirong Liu Longfei Wang Hengyu Guo Linlin Li Site Li Xiangyu Chen Wei Tang Zhong Lin Wang 《Liver Transplantation》2020,10(36)
Wind is one of the most important sources of green energy, but the current technology for harvesting wind energy is only effective when the wind speed is beyond 3.5–4.0 m s?1. This is mainly due to the limitation that the electromagnetic generator works best at high frequency. This means that light breezes cannot reach the wind velocity threshold of current wind turbines. Here, a high‐performance triboelectric nanogenerator (TENG) for efficiently harvesting energy from an ambient gentle wind, especially for speeds below 3 m s?1 is reported, by taking advantage of the relative high efficiency of TENGs at low‐frequency. Attributed to the multiplied‐frequency vibration of ultra‐stretchable and perforated electrodes, an average output of 20 mW m?3 can be achieved with inlet wind speed of 0.7 m s?1, while an average energy conversion efficiency of 7.8% at wind speed of 2.5 m s?1 is reached. A self‐charging power package is developed and the applicability of the TENG in various light breezes is demonstrated. This work demonstrates the advantages of TENG technology for breeze energy exploitation and proposes an effective supplementary approach for current employed wind turbines and micro energy structure. 相似文献
253.
Xiaohui Zeng Jiatu Liu Jianfeng Mao Junnan Hao Zhijie Wang Si Zhou Chris D. Ling Zaiping Guo 《Liver Transplantation》2020,10(32)
Rechargeable aqueous Zn/MnO2 batteries are very attractive large‐scale energy storage technologies, but still suffer from limited cycle life and low capacity. Here the novel adoption of a near‐neutral acetate‐based electrolyte (pH ≈ 6) is presented to promote the two‐electron Mn4+/Mn2+ redox reaction and simultaneously enable a stable Zn anode. The acetate anion triggers a highly reversible MnO2/Mn2+ reaction, which ensures high capacity and avoids the issue of structural collapse of MnO2. Meanwhile, the anode‐friendly electrolyte enables a dendrite‐free Zn anode with outstanding stability and high plating/stripping Coulombic efficiency (99.8%). Hence, a high capacity of 556 mA h g?1, a lifetime of 4000 cycles without decay, and excellent rate capability up to 70 mA cm?2 are demonstated in this new near‐neutral aqueous Zn/MnO2 battery by simply manipulating the salt anion in the electrolyte. The acetate anion not only modifies the surface properties of MnO2 cathode but also creates a highly compatible environment for the Zn anode. This work provides a new opportunity for developing high‐performance Zn/MnO2 and other aqueous batteries based on the salt anion chemistry. 相似文献
254.
Qiangjian Ju Ruguang Ma Yu Pei Beibei Guo Zichuang Li Qian Liu Tiju Thomas Minghui Yang Graham J. Hutchings Jiacheng Wang 《Liver Transplantation》2020,10(21)
The development of Pt‐free catalysts for the alkaline hydrogen evolution reaction (HER), which is widely used in industrial scale water‐alkali electrolyzers, remains a contemporary and pressing challenge. Ruthenium (Ru) has excellent water‐dissociation abilities and could be an alternative water splitting catalyst. However, its large hydrogen binding energy limits HER activity. Here, a new approach is proposed to boost the HER activity of Ru through uniform loading of Ru nanoparticles on triazine‐ring (C3N3)‐doped carbon (triNC). The composite (Ru/triNC) exhibits outstanding HER activity with an ultralow overpotential of ≈2 mV at 10 mA cm?2; thereby making it the best performing electrocatalyst hitherto reported for alkaline HER. The calculated metal mass activity of Ru/triNC is >10 and 15 times higher than that of Pt/C and Pt/triNC. Both theoretical and experimental studies reveal that the triazine‐ring is a good match for Ru to weaken the hydrogen binding on Ru through interfacial charge transfer via increased contact electrification. Therefore, Ru/triNC can provide the optimal hydrogen adsorption free energy (approaching zero), while maintaining the strong water‐dissociation activity. This study provides a new avenue for designing highly efficient and stable electrocatalysts for water splitting. 相似文献
255.
Bioprocess and Biosystems Engineering - The properties of the anode material and structure are critical to the microbial growth and interfacial electron transfer between the biofilm and the anode.... 相似文献
256.
Luo Dan Xia Zhi Li Heng Tu Danna Wang Ting Zhang Wei Peng Lu Yi Wenfu Zhang Sai Shu Junhua Xu Hui Li Yong Shi Buyun Huang Chengjiao Tang Wen Xiao Shuna Shu Xiaolan Liu Yan Zhang Yuan Guo Shan Yu Zhi Wang Baoxiang Gao Yuan Hu Qinxue Wang Hanzhong Song Xiaohui Mei Hong Zhou Xiaoqin Zheng Zhenhua 《中国病毒学》2020,35(6):861-867
In December 2019, SARS-CoV-2 was first detected in the samples obtained from three adult patients who suffered from an unknown viral pneumonia in Wuhan (Li et al. 2020). This unknown viral pneumonia is further named as coronavirus disease 2019 (COVID-19) by the World Health Organization. To date, the number of new COVID-19 cases has continued to skyrocket and the impact of SARS-CoV-2 on humans is far greater than any pathogen of this century in both breadth and depth. Previous studies have shown that adults with COVID-19 have symptoms of fever, dry cough, dyspnea, fatigue and lymphocytopenia. Moreover, COVID-19 is more likely to cause death in the elderly, especially those with chronic comorbidities (Huang et al. 2020). In Wuhan, more than 50, 000 COVID-19 cases have been confirmed, including over 780 pediatric patients, and only one child death case (Lu et al. 2020). Although the number of children cases was far fewer than that of adults, COVID-19 might endanger children's health and the information on children remains limited, especially in serological study. In the retrospective study, the investigators analyzed the epidemiological, clinical and serological characteristics of children with COVID-19 in Wuhan in the early stages of the outbreak, which might provide theoretical and practical help in controlling COVID-19 and similar emerging infectious diseases in the future. 相似文献
257.
258.
Hao Yu Zong Wubei Zeng Dongchang Han Jingluan Chen Shuifu Tang Jianian Zhao Zhe Li Xiaojuan Ma Kun Xie Xianrong Zhu Qinlong Chen Yuanling Zhao Xiucai Guo Jingxin Liu Yao-Guang 《中国科学:生命科学英文版》2020,63(6):933-935
正Dear Editor,CRISPR (clustered regularly interspaced short palindromic repeats)/Cas genome editing is a powerful tool for introducing specific mutations in organisms including plants. The system is composed of a nuclease such as Cas9 or Cas12a and an engineered single-guide RNA (sgRNA) incorporating a target sequence (Li et al., 2019). A Cas9/sgRNA complex re- 相似文献
259.
Niu Lili Guo Yanchen Lin Zhengrong Shi Zhe Bian Tianyuan Qi Lin Meng Long Grace Anthony A. Zheng Hairong Yuan Ti-Fei 《中国科学:生命科学英文版》2020,63(9):1328-1336
Ultrasound stimulation is an emerging noninvasive option in treating neuropsychiatric disorders. The present study investigates the behavioral alterations resulting from ultrasound stimulation on the nucleus accumbens(NAc) in freely moving mice. Our results show that an acute ultrasound stimulation on the NAc, rather than the visual cortex or auditory cortex, led to a pronounced avoidance behavior, while repeated NAc ultrasound stimulation resulted in an obvious conditioned place aversion with changes in synaptic protein(Glu A1/2 subunit) expression. Notably, NAc ultrasound stimulation suppressed the morphine-induced conditioned place preference. The results provide evidence that NAc ultrasound stimulation can be applied as a potential noninvasive therapeutic option in treating psychiatric disorders. 相似文献
260.
为了解二毛期时滩羊串子花型裘皮与其它类型裘皮中蛋白质的差异,本试验采用iTRAQ技术及LC-MS/MS蛋白质组学研究方法,对串子花型、软大花型、绿豆丝型及其它不规则型花穗裘皮蛋白质进行鉴定和筛选,并运用Proteome Discoverer l.4软件进行定量分析,结合数据库搜索,鉴定出具有显著表达差异的蛋白,同时应用生物学技术对其进行GO和Pathway分析。结果显示4类花穗型裘皮共检测出2 886个蛋白,其中有135个、142个、113个差异蛋白分别存在于软大花型与串子花型、绿豆丝型与串子花型、其它不规则型与串子花型3个对比组中。对有表达差异的蛋白进行分析,发现膜联蛋白与血管内皮生长因子可能与软大花型毛股形成相关,KAP3和KAP6可能与滩羊串子花型毛股结构相关。研究发现滩羊不同二毛裘皮蛋白水平上的差异,可为选育优良的滩羊串子花型二毛裘皮提供理论基础。 相似文献