全文获取类型
收费全文 | 178466篇 |
免费 | 3543篇 |
国内免费 | 1913篇 |
专业分类
化学 | 97839篇 |
晶体学 | 2550篇 |
力学 | 8104篇 |
综合类 | 111篇 |
数学 | 18691篇 |
物理学 | 56627篇 |
出版年
2021年 | 1279篇 |
2020年 | 1456篇 |
2019年 | 1452篇 |
2018年 | 1437篇 |
2017年 | 1432篇 |
2016年 | 2707篇 |
2015年 | 2256篇 |
2014年 | 2917篇 |
2013年 | 8271篇 |
2012年 | 6940篇 |
2011年 | 8673篇 |
2010年 | 5365篇 |
2009年 | 5523篇 |
2008年 | 7877篇 |
2007年 | 7763篇 |
2006年 | 7408篇 |
2005年 | 6903篇 |
2004年 | 6133篇 |
2003年 | 5280篇 |
2002年 | 5172篇 |
2001年 | 6219篇 |
2000年 | 4713篇 |
1999年 | 3629篇 |
1998年 | 2755篇 |
1997年 | 2743篇 |
1996年 | 2697篇 |
1995年 | 2394篇 |
1994年 | 2265篇 |
1993年 | 2102篇 |
1992年 | 2419篇 |
1991年 | 2371篇 |
1990年 | 2068篇 |
1989年 | 2041篇 |
1988年 | 2057篇 |
1987年 | 1990篇 |
1986年 | 1883篇 |
1985年 | 2796篇 |
1984年 | 2760篇 |
1983年 | 2213篇 |
1982年 | 2394篇 |
1981年 | 2277篇 |
1980年 | 2227篇 |
1979年 | 2173篇 |
1978年 | 2243篇 |
1977年 | 2199篇 |
1976年 | 2129篇 |
1975年 | 2119篇 |
1974年 | 2024篇 |
1973年 | 2105篇 |
1972年 | 1199篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
41.
42.
43.
Thalia Tsiaka Panagiotis Zoumpoulakis Vassilia J. Sinanoglou Constantinos Makris Georgios A. Heropoulos Antony C. Calokerinos 《Analytica chimica acta》2015
High-energy assisted extraction techniques, like ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE), are widely applied over the last years for the recovery of bioactive compounds such as carotenoids, antioxidants and phenols from foods, animals and herbal natural sources. Especially for the case of xanthophylls, the main carotenoid group of crustaceans, they can be extracted in a rapid and quantitative way with the use of UAE and MAE. 相似文献
44.
45.
Echabaane M. Hfaiedh S. Smiri B. Saidi F. Dridi C. 《Journal of Solid State Electrochemistry》2021,25(6):1797-1806
Journal of Solid State Electrochemistry - The fast and sensitive detection of copper ions would be essential for water monitoring. Herein, we report a novel development of an impedimetric sensor... 相似文献
46.
A model with 16 moments is here presented in the framework of RET of polyatomic gases. It furnishes as principal subsystem the relativistic counterpart of a work by Arima T., Ruggeri T., Sugiyama M.; this is present in literature and treats the non relativistic case which incorporates relaxation processes of molecular rotation and vibration. Another principal subsystem is the natural extension of the 14 moments model by Pennisi S. and Ruggeri T.; this is also present in literature in the relativistic framework but where the trace of the third balance equation is neglected. Its extension is found here for the case when this trace isn’t neglected.
相似文献47.
Sergio Ayala‐Mar Javier Donoso‐Quezada Roberto C. Gallo‐Villanueva Victor H. Perez‐Gonzalez Jos Gonzlez‐Valdez 《Electrophoresis》2019,40(23-24):3036-3049
Exosomes are nanovesicles secreted by most cellular types that carry important biochemical compounds throughout the body with different purposes, playing a preponderant role in cellular communication. Because of their structure, physicochemical properties and stability, recent studies are focusing in their use as nanocarriers for different therapeutic compounds for the treatment of different diseases ranging from cancer to Parkinson's disease. However, current bioseparation protocols and methodologies are selected based on the final exosome application or intended use and present both advantages and disadvantages when compared among them. In this context, this review aims to present the most important technologies available for exosome isolation while discussing their advantages and disadvantages and the possibilities of being combined with other strategies. This is critical since the development of novel exosome‐based therapeutic strategies will be constrained to the effectiveness and yield of the selected downstream purification methodologies for which a thorough understanding of the available technological resources is needed. 相似文献
48.
A protocol to correct for intra‐ and interspecific variation in tail hair growth to align isotope signatures of segmentally cut tail hair to a common time line
下载免费PDF全文
![点击此处可从《Rapid communications in mass spectrometry : RCM》网站下载免费的PDF全文](/ch/ext_images/free.gif)
49.
50.
Xiaoshuang Luo Xinxian Qin Zhengyi Liu Dan Chen Weiwei Yu Kankan Zhang Deyu Hu 《Biomedical chromatography : BMC》2020,34(1):e4694
A simple and rapid analytical method for the detection of trifloxystrobin, trifloxystrobin acid and tebuconazole in soil, brown rice, paddy plants and rice hulls was established and validated by liquid chromatography with tandem mass spectrometry. Acceptable linearity (R2 > 0.99), accuracy (average recoveries of 74.3–108.5%) and precision (intra- and inter-day relative standard deviations of 0.9–8.8%) were obtained using the developed determination approach. In the field trial, the half-lives of trifloxystrobin and tebuconazole in paddy plants were 5.7–8.3 days in three locations throughout China, and the terminal residue concentrations of trifloxystrobin and tebuconazole were <100 and 500 μg/kg (maximum residue limits set by China), respectively, at harvest, which indicated that, based on the recommended application procedure, trifloxystrobin and tebuconazole are safe for use on rice. The risk assessment results demonstrated that, owing to risk quotient values of both fungicides being <100%, the potential risk of trifloxystrobin and tebuconazole on rice was acceptable for Chinese consumers. These data could provide supporting information for the proper use and safety evaluation of trifloxystrobin and tebuconazole in rice. 相似文献