全文获取类型
收费全文 | 518篇 |
免费 | 13篇 |
国内免费 | 5篇 |
专业分类
化学 | 249篇 |
晶体学 | 1篇 |
力学 | 22篇 |
数学 | 78篇 |
物理学 | 186篇 |
出版年
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2016年 | 8篇 |
2015年 | 5篇 |
2014年 | 21篇 |
2013年 | 13篇 |
2012年 | 20篇 |
2011年 | 37篇 |
2010年 | 8篇 |
2009年 | 14篇 |
2008年 | 30篇 |
2007年 | 25篇 |
2006年 | 26篇 |
2005年 | 18篇 |
2004年 | 23篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 6篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 9篇 |
1993年 | 13篇 |
1992年 | 12篇 |
1991年 | 7篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1978年 | 3篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1929年 | 5篇 |
1928年 | 3篇 |
1927年 | 4篇 |
1925年 | 6篇 |
1924年 | 4篇 |
1923年 | 3篇 |
1879年 | 3篇 |
排序方式: 共有536条查询结果,搜索用时 31 毫秒
51.
52.
53.
54.
Harald Müller Michael Eggert Jürgen Czarske Lars Büttner Andreas Fischer 《Experiments in fluids》2007,43(2-3):223-232
The main advantage of the described Doppler global velocimeter (DGV) systems based on frequency modulation (FM) or frequency
shift keying (FSK) is that no reference detector is required. The frequency variation of the laser light during one modulation
period additionally allows an on-line calibration of the complete DGV system. Thus, the new method has the potential to reduce
the uncertainty of conventional DGV velocity measurements since time resolved velocity field measurements on a spinning disc
have shown standard deviations down to 0.02 m/s. On investigating flow fields, velocity components notably less than 0.5 m/s
were resolved. 相似文献
55.
56.
High-frequency excitation may affect the slow behavior of a dynamical system. For example, equilibria may move, disappear, or gain or loose stability. We consider such slow effects of fast excitation for a simple mechanical system that incorporates features of many engineering structures. The study is intended to contribute to the general understanding of periodically excited linear and nonlinear systems, as well as to the current attempts to utilize high-frequency excitation for altering the low-frequency properties of structures. 相似文献
57.
Lange H Maultzsch J Meng W Mollenhauer D Paulus B Peica N Schlecht S Thomsen C 《Langmuir : the ACS journal of surfaces and colloids》2011,27(11):7258-7264
We demonstrate a phase transfer method to create stable colloidal solutions of Au nanoparticles with 4-methoxypyridine ligands. We then investigate the adsorption behavior of 4-methoxypyridine onto gold surfaces by Raman spectroscopy, DFT calculations, and (1)H NMR. In contrast to unsubstituted pyridine and the frequently used (N,N-dimethylamino)pyridine (DMAP), a flat adsorption of 4-methoxypyridine on gold was found. 相似文献
58.
Atilla-Gokcumen GE Bedigian AV Sasse S Eggert US 《Journal of the American Chemical Society》2011,133(26):10010-10013
Although cells undergo dramatic shape changes during cytokinesis, the role of the plasma membrane and lipids is poorly understood. We report that inactivation of glucosyl ceramide synthase (GCS), either by RNAi or with the small molecule PPMP, causes failure of cleavage furrow ingression. Using mass-spectrometry-based global lipid profiling, we identify individual lipids that are enhanced or depleted due to GCS inhibition. We show that GCS inhibition results in the mislocalization of actin and the ERM proteins, key cytoskeletal proteins that connect the plasma membrane to the actin cortex. Our data suggest that ceramides participate in mediating the interactions between the membrane and the cortex. 相似文献
59.
In continuation of our recent paper on vibrational quadratic response functions for vibrational configuration interaction wave functions, we present in this paper a derivation and implementation of the pure vibrational cubic response function for vibrational configuration interaction wave functions. In addition, we present combined electronic and vibrational cubic response functions derived from sum-over-states expressions in the Born-Oppenheimer framework and a discussion of complicating issues. The implementation enables analytic calculation of the pure vibrational cubic response function via response theory, which constitutes a part of the vibronic cubic response function. 相似文献
60.
Gloriam DE Wellendorph P Johansen LD Thomsen AR Phonekeo K Pedersen DS Bräuner-Osborne H 《Chemistry & biology》2011,18(11):1489-1498
GPRC6A is a Family C G protein-coupled receptor recently discovered and deorphanized by our group. This study integrates chemogenomic ligand inference, homology modeling, compound synthesis, and pharmacological mechanism-of-action studies to disclose two noticeable results of methodological and pharmacological character: (1) chemogenomic lead identification through the first, to our knowledge, ligand inference between two different GPCR families, Families A and C; and (2) the discovery of the most selective GPRC6A allosteric antagonists discovered to date. The unprecedented inference of?pharmacological activity across GPCR families provides proof-of-concept for in?silico approaches against Family C targets based on Family A templates, greatly expanding the prospects of successful drug design and discovery. The antagonists were tested against a panel of seven Family A and C G protein-coupled receptors containing the chemogenomic binding sequence motif where some of the identified GPRC6A antagonists showed some activity. However, three compounds with at least ~3-fold selectivity for GPRC6A were discovered, which present a significant step forward compared with the previously published GPRC6A antagonists, calindol and NPS 2143, which both display ~30-fold selectivity for the calcium-sensing receptor compared to GPRC6A. The antagonists constitute novel research tools toward investigating the signaling mechanism of the GPRC6A receptor at the cellular level and serve as initial ligands for further optimization of potency and selectivity enabling future ex?vivo/in?vivo pharmacological studies. 相似文献