全文获取类型
收费全文 | 61755篇 |
免费 | 1210篇 |
国内免费 | 1524篇 |
专业分类
教育 | 34413篇 |
科学研究 | 12150篇 |
各国文化 | 300篇 |
体育 | 4332篇 |
综合类 | 3585篇 |
文化理论 | 214篇 |
信息传播 | 9495篇 |
出版年
2024年 | 16篇 |
2023年 | 67篇 |
2022年 | 706篇 |
2021年 | 1649篇 |
2020年 | 1220篇 |
2019年 | 679篇 |
2018年 | 723篇 |
2017年 | 816篇 |
2016年 | 767篇 |
2015年 | 2081篇 |
2014年 | 3237篇 |
2013年 | 4244篇 |
2012年 | 4646篇 |
2011年 | 5170篇 |
2010年 | 4855篇 |
2009年 | 4217篇 |
2008年 | 4199篇 |
2007年 | 4696篇 |
2006年 | 4641篇 |
2005年 | 3660篇 |
2004年 | 2037篇 |
2003年 | 1794篇 |
2002年 | 1748篇 |
2001年 | 1609篇 |
2000年 | 1038篇 |
1999年 | 973篇 |
1998年 | 705篇 |
1997年 | 490篇 |
1996年 | 408篇 |
1995年 | 262篇 |
1994年 | 246篇 |
1993年 | 197篇 |
1992年 | 180篇 |
1991年 | 115篇 |
1990年 | 57篇 |
1989年 | 81篇 |
1988年 | 39篇 |
1987年 | 17篇 |
1986年 | 37篇 |
1985年 | 23篇 |
1984年 | 36篇 |
1983年 | 27篇 |
1982年 | 11篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1977年 | 3篇 |
1974年 | 3篇 |
1957年 | 23篇 |
1951年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptually by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling. Based on this novel floating foundation, the hydrodynamic performance was investigated in the frequency domain and time domain by using the wave analysis software HydroD and DeepC from Det Norske Veritas. The frequency domain analysis was conducted to investigate the effects of the incident wave angle and water depth. The time-domain analysis was carried out to evaluate the response of the floating foundation under a selected operational condition. The hydrodynamic performances of this floating foundation with respect to time series and response spectra were also investigated in this study. 相似文献
962.
Chang Xin Zhang Chengyu Gao Lan Liu Xiao You Shengping Qi Wei Wang Kang Guo Xin Su Rongxin Lu Han He Zhimin 《天津大学学报(英文版)》2019,25(5):488-496
2,5-Furandicarboxylic acid(FDCA) is a potential biorenewable chemical for applications including plastics, polyamides, drugs, etc. The selective biosynthesis of FDCA from 5-hydroxymethylfurfural(HMF) by a specific enzyme poses a great challenge. In this study, we reported an efficient strategy to produce FDCA from HMF by the tandem biocatalysis of laccase(Cot A-TJ102@UIO-66-NH_2) and Novozym 435. For the first step, a nanoparticle metal–organic framework was synthesized as a carrier to immobilize Cot A-TJ102@UIO-66-NH_2, which was assigned for the production of 5-formyl-2-furancarboxylic acid(FFCA) and featured an enzyme loading of 255.54 mg/g, specific activity of 135.90 U/mg, and solid loading ratio of 99.65%. Under optimal conditions, an ideal FFCA yield of 98.5% was achieved, and the Cot A-TJ102@UIO-66-NH_2 presented a high recycling capacity after 10 cycles. For the second step, Novozym 435 was applied for the further conversion of FFCA into FDCA, presenting a high FDCA yield of 95.5% under the optimized conditions. Novozym 435 also exhibited a high recyclability after eight cycles. As a result, the tandem biocatalysis strategy provided a 94.2% FDCA yield from HMF, indicating its excellence as a method for FDCA production. 相似文献
963.
中国共产党作为我国的执政党,其执政方式的确立及演变有一个历史过程,取决于各方面的因素。在新的历史条件下,也要适应国情和社会环境的变化而不断的改进,从而使党的领导效能趋向优化,更快的把我们国家带入现代化社会。本文就试图从法律角度来研究我党执政方式的演变与改进,更好的推进依法治国方略的贯彻实施。 相似文献
964.
LI Ya-juan WANG Guo-zhao 《浙江大学学报(A卷英文版)》2006,7(6):1084-1087
INTRODUCTION Modification of knots of a B-spline curve changes the shape of the curve. In some recent pub-lications (Juhász and Hoffmann, 2001; 2003; Hoff-mann and Juhász, 2004; Li and Wang, 2005), the authors studied the effect of the alteration of a single knot on the shape of the curve. Hoffmann (2004) and Li & Wang (2006) applied these theories into the constrained shape modification of B-spline and NURBS curves. Juhász (2001) and Hoffmann & Ju-hász (2005) studied the effe… 相似文献
965.
王小妍 《宁波广播电视大学学报》2007,5(1):95-96,118
没有感情的设计是空洞的,没有理智的设计是无用的,有情感有理智的设计才是完整的设计。金属材质的手机以理性、功能化为前提,适应了现在追求是科技的理念,又不失给人情感内在、广义的想象空间,顺应了时尚的潮流。将金属作为其材质的手机述说了引起世人共鸣的语言,它是属于一种内在的、广义的语言。情感品质所追求表达的是与人的经验类似的东西,手机的金属材质看似理智的一种设计,但给人一种想象的空间,有着情感化的语言,看似理智与情感的矛盾,却又那么协调的共融。 相似文献
966.
对高职高专经贸类专业课程整合的思考 总被引:2,自引:0,他引:2
王金台 《中国职业技术教育》2005,(19):28-30
高职经贸类专业必须按照培养目标要求,坚持以就业为导向、以能力为本位的原则进行课程整合,从而使经贸人才的培养与市场需求相吻合. 相似文献
967.
王少杰 《新疆教育学院学报》2003,19(4):59-63
政论学以日本留学生的创作为世纪先锋,奠定了中国人社科的激进传统。留学生政论学试图构思爱国主义的正面理论,并且释放新民政治的强烈变革感情.提倡积极参与政治管理的人精神,是中国集权体制和官本位化社会所欠缺的。 相似文献
968.
按常规方法制备抗鸡传染性法氏囊炎卵黄抗体(yolkantibody,YA),经冻融、温度、机械振荡、光照和防后剂(0.01%流柳汞、0.01%叠氮钠和0.5%苯酚)等处理后测定其琼脂扩散试验(Agargelnredritation,AGP)效价的变化.实验结果表明,冻融毛次后卵黄抗体的AGP效价自1:64降至1:32,冻融6次降至1:16,0.5%苯酚的存在使YA的AGP效价自1:64降至1:16;其它物理因素对YA的AGP效价影响不明显. 相似文献
969.
Objective: We aim to describe the environment iodine concentration in salt, water and soil along Zhejiang Province coast in the China foreland. It will be helpful for us to judge whether this area is insufficient in iodine and universal iodized salt is necessary or not. Methods: We collected iodized salt samples, drinking water samples (tap water in the towns, and well water or spring water in the villages), water samples from different sources (ditches, lakes, rivers) and soil samples through random sampling in June, 2005. Salt, water and soil iodine was detected by arsenic-cerium redox method. Statistical analysis was expressed as mean±SEMby Windows SPSS 13.0. Results: (1) The iodine concentration in salt was 27.9±4.33 mg/kg (n=108). (2) Seventy-five water samples were collected. The water iodine value was 0.6~84.8 μg/L (mean of 11.66 μg/L). The watershed along the Qiantang River has significantly higher iodine content than the water in Lin'an in mountain area (P<0.01). The iodine content and mean iodine content of tap water, well or spring water and natural water sources were 4.30±2.43 μg/L (n=34), 23.59±27.74 μg/L (n=19)and 12.72±10.72 μg/L (n=22) respectively. This indicated that among environmental water sources, the ditch iodine content was the highest with river water iodine being the lowest (P<0.01). (3) Soil iodine value was 0.11~2.93 mg/kg (mean of 1.32 mg/kg).Though there was no statistical difference of soil iodine in different districts (P=0.131), soil iodine content correlated positively with water iodine content. Conclusion: Iodine concentration in salt accords with national policy of adding iodine in salt. Foreland has more iodine in water than mountain area. The data reflected that water and soil iodine in foreland area was not high, which suggests universal iodized salt should be necessary. Environment iodine has relatively close association with pollution. 相似文献
970.
思想政治教育传统的主客二分思维方式把人抽象化、实体化,导致对受教育者真实需求的忽略和教育内容、教育方式的呆板滞后,不能实现个人与社会、政治教育和全面发展教育的协调,从而使思想政治教育改革不能取得令人满意的效果。马克思“现实的个人”思想是对传统实体化抽象人性观的变革,有利于消解与变革思想政治教育旧的思维方式,真正体现出教育的以人为本,确保思想政治教育改革取得更大的实效。 相似文献