全文获取类型
收费全文 | 14312篇 |
免费 | 2751篇 |
国内免费 | 1581篇 |
专业分类
化学 | 10158篇 |
晶体学 | 146篇 |
力学 | 673篇 |
综合类 | 118篇 |
数学 | 1577篇 |
物理学 | 5972篇 |
出版年
2024年 | 62篇 |
2023年 | 328篇 |
2022年 | 535篇 |
2021年 | 563篇 |
2020年 | 646篇 |
2019年 | 662篇 |
2018年 | 553篇 |
2017年 | 511篇 |
2016年 | 782篇 |
2015年 | 739篇 |
2014年 | 880篇 |
2013年 | 1074篇 |
2012年 | 1338篇 |
2011年 | 1355篇 |
2010年 | 922篇 |
2009年 | 819篇 |
2008年 | 923篇 |
2007年 | 863篇 |
2006年 | 742篇 |
2005年 | 594篇 |
2004年 | 433篇 |
2003年 | 390篇 |
2002年 | 458篇 |
2001年 | 399篇 |
2000年 | 261篇 |
1999年 | 335篇 |
1998年 | 247篇 |
1997年 | 185篇 |
1996年 | 179篇 |
1995年 | 124篇 |
1994年 | 110篇 |
1993年 | 107篇 |
1992年 | 95篇 |
1991年 | 106篇 |
1990年 | 71篇 |
1989年 | 60篇 |
1988年 | 44篇 |
1987年 | 34篇 |
1986年 | 34篇 |
1985年 | 25篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1959年 | 2篇 |
1957年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
Jia Yang Xingang Li Wenjun Li Xin Xi Qian Du Feng Pan Songqing Liu 《Biomedical chromatography : BMC》2020,34(8):e4857
Because of its unpredictable side effects and efficacy, the anticancer drug docetaxel (DTX) requires improved characterisation of its pharmacokinetic profiles through population pharmacokinetic studies. A sensitive and rugged LC–MS/MS method for the detection of DTX in human plasma was developed and optimised using paclitaxel as an internal standard (IS). The plasma samples underwent rapid extraction using hybrid solid-phase extraction-protein precipitation. The analyte and IS were separated with an isocratic system on a Zorbax Eclipse Plus C18 column using water containing 0.05% acetic acid along with 20 μM of sodium acetate and methanol (30/70, v/v) as the mobile phase. Quantification was performed using a triple quadrupole mass spectrometer through multiple reaction monitoring in positive mode, using the m/z 830.3 → 548.8 and m/z 876.3 → 307.7 transitions for DTX and paclitaxel, respectively. The range of the calibration curve was 1–500 ng/mL for DTX, and the linear correlation coefficient was >0.99. The accuracies ranged from −4.6 to 4.2%, and the precision was no higher than 7.0% for the analytes. No significant matrix effect was observed. Both DTX and the IS showed considerable recovery. This method was finally applied to the establishment of a population pharmacokinetic model to optimise the clinical use of DTX. 相似文献
13.
Jiatian Chen Le Yang Ying Li Qinghua Hou Lanlan Li Peng Jin 《International journal of quantum chemistry》2019,119(16):e25961
Inorganic planar ring-shape molecules with 4n + 2 π electrons are always the focus of experimental synthesis and theoretical research due to their potential aromaticity and stability. In this work, the whole series of five-membered heterocycle monoanions X nY5-n− (X, Y = group 15 elements; n = 1-4) were thoroughly investigated by means of density functional theory calculations. They all have large formation energies and HOMO-LUMO gap energies, suggesting the potential thermodynamic and kinetic stability. Their aromaticities are comparable to that of typical aromatic hydrocarbons. Their thermal stabilities were firmly established by the ab initio molecular dynamics simulations. As most of them are predicted for the first time, their various spectra were simulated for experimental characterization. Furthermore, we demonstrate that these five-membered cyclic anions can be employed as η5-ligand to construct novel all-inorganic metallocenes, which may serve as the building blocks of low-dimensional nanomaterials. 相似文献
14.
15.
16.
在氢化丁苯共聚物13C-NMR谱脂肪碳部分谱带归属的基础上,根据各谱带的主要来源,推导出六个二单元浓度的计算公式。计算出二单元、一单元的相对含量,各结构单元的数均序列长度、嵌段含量和其它结构参数。加氢前后的1H-和13C-NMR谱的组成计算结果基本一致。初步探讨了作为粘度指数改进剂的氢化丁苯共聚物微观结构与性能的关系,为合成提供了依据。 相似文献
17.
18.
19.
20.
In mononuclear HgI2[(C5H4N)3N], mercury is tetrahedrally coordinated by two nitrogen atoms of a tris(2‐pyridyl)amine ligand and two iodides. The coordination moieties are connected by weak intermolecular Hg(II)···I interactions to give a one‐dimensional structure. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献