全文获取类型
收费全文 | 80648篇 |
免费 | 448篇 |
国内免费 | 374篇 |
专业分类
化学 | 25525篇 |
晶体学 | 802篇 |
力学 | 6777篇 |
数学 | 32307篇 |
物理学 | 16059篇 |
出版年
2018年 | 10452篇 |
2017年 | 10287篇 |
2016年 | 6167篇 |
2015年 | 952篇 |
2014年 | 435篇 |
2013年 | 587篇 |
2012年 | 3860篇 |
2011年 | 10545篇 |
2010年 | 5696篇 |
2009年 | 6088篇 |
2008年 | 6630篇 |
2007年 | 8769篇 |
2006年 | 285篇 |
2005年 | 1312篇 |
2004年 | 1542篇 |
2003年 | 1988篇 |
2002年 | 1048篇 |
2001年 | 276篇 |
2000年 | 344篇 |
1999年 | 186篇 |
1998年 | 235篇 |
1997年 | 181篇 |
1996年 | 236篇 |
1995年 | 156篇 |
1994年 | 112篇 |
1993年 | 132篇 |
1992年 | 84篇 |
1991年 | 96篇 |
1990年 | 84篇 |
1989年 | 85篇 |
1988年 | 108篇 |
1987年 | 97篇 |
1986年 | 96篇 |
1985年 | 103篇 |
1984年 | 98篇 |
1983年 | 74篇 |
1982年 | 73篇 |
1981年 | 70篇 |
1980年 | 88篇 |
1979年 | 84篇 |
1978年 | 76篇 |
1977年 | 67篇 |
1976年 | 64篇 |
1975年 | 59篇 |
1974年 | 67篇 |
1973年 | 62篇 |
1972年 | 46篇 |
1914年 | 45篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Tomáš Hložek Martin Štícha Miroslava Bursová Ivan Jelínek Petr Tůma Radomír Čabala 《Electrophoresis》2020,41(18-19):1564-1567
Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10–1000 ng/mL), with adequate accuracy (90.1–114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR. 相似文献
2.
In the paper, the authors establish several integral representations for the generating functions of the large and little Schröder numbers and for the large and little Schröder numbers. 相似文献
3.
Mesoscopic modeling at the pore scale offers great promise in exploring the underlying structure transport performance of flow through porous media. The present work studies the fluid flow subjected to capillarity-induced resonance in porous media characterized by different porous structure and wettability. The effects of porosity and wettability on the displacement behavior of the fluid flow through porous media are discussed. The results are presented in the form of temporal evolution of percentage saturation and displacement of the fluid front through porous media. The present study reveals that the vibration in the form of acoustic excitation could be significant in the mobilization of fluid through the porous media. The dependence of displacement of the fluid on physicochemical parameters like wettability of the surface, frequency along with the porosity is analyzed. It was observed that the mean displacement of the fluid is more in the case of invading fluid with wetting phase where the driving force strength is not so dominant. 相似文献
4.
5.
Sarah Peluse 《Israel Journal of Mathematics》2018,227(1):379-396
We prove that the group of diffeomorphisms of the interval [0, 1] contains surface groups whose action on (0, 1) has no global fix point and such that only countably many points of the interval (0, 1) have non-trivial stabiliser. 相似文献
6.
7.
8.
9.
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
10.
Dr. Liat Avram Dr. Václav Havel Ronit Shusterman-Krush Dr. Mark A. Iron Dr. Moritz Zaiss Prof. Vladimír Šindelář Dr. Amnon Bar-Shir 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(7):1687-1690
The accumulated knowledge regarding molecular architectures is based on established, reliable, and accessible analytical tools that provide robust structural and functional information on assemblies. However, both the dynamicity and low population of noncovalently interacting moieties within studied molecular systems limit the efficiency and accuracy of traditional methods. Herein, the use of a saturation transfer-based NMR approach to study the dynamic binding characteristics of an anion to a series of synthetic receptors derived from bambusuril macrocycles is demonstrated. The exchange rates of BF4− are mediated by the side chains on the receptor (100 s−1<kex<5000 s−1), which play a critical role in receptor-anion binding dynamics. The signal amplification obtained with this approach allows for the identification of different types of intermolecular interactions between the receptor and the anion, something that could not have been detected by techniques hitherto used to study molecular assemblies. These findings, which are supported by a computational molecular dynamic study, demonstrate the uniqueness and added value of this NMR method. 相似文献