全文获取类型
收费全文 | 118篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
化学 | 53篇 |
数学 | 35篇 |
物理学 | 31篇 |
出版年
2021年 | 3篇 |
2020年 | 3篇 |
2014年 | 2篇 |
2012年 | 3篇 |
2011年 | 10篇 |
2010年 | 2篇 |
2008年 | 2篇 |
2007年 | 9篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 6篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 9篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 3篇 |
1965年 | 1篇 |
排序方式: 共有119条查询结果,搜索用时 31 毫秒
51.
52.
We consider some sufficient conditions for the pro-p completion of an orientable Poincaré duality group of dimension n ≥ 3 to be a virtually pro-p Poincaré duality group of dimension at most n ? 2. 相似文献
53.
Jonathan A. Hillman 《Geometriae Dedicata》2007,129(1):57-72
We show that every torsion-free virtually poly-Z group of Hirsch length 4 is the fundamental group of a closed 4-manifold with a geometry of solvable Lie type, by realizing
each such group as a lattice subgroup of one of the corresponding isometry groups.
相似文献
54.
Hillman R 《Physical chemistry chemical physics : PCCP》2011,13(12):5204-5205
55.
Mehta DD Zaéartu M Quatieri TF Deliyski DD Hillman RE 《The Journal of the Acoustical Society of America》2011,130(6):3999-4009
Vocal fold vibratory asymmetry is often associated with inefficient sound production through its impact on source spectral tilt. This association is investigated in both a computational voice production model and a group of 47 human subjects. The model provides indirect control over the degree of left-right phase asymmetry within a nonlinear source-filter framework, and high-speed videoendoscopy provides in vivo measures of vocal fold vibratory asymmetry. Source spectral tilt measures are estimated from the inverse-filtered spectrum of the simulated and recorded radiated acoustic pressure. As expected, model simulations indicate that increasing left-right phase asymmetry induces steeper spectral tilt. Subject data, however, reveal that none of the vibratory asymmetry measures correlates with spectral tilt measures. Probing further into physiological correlates of spectral tilt that might be affected by asymmetry, the glottal area waveform is parameterized to obtain measures of the open phase (open/plateau quotient) and closing phase (speed/closing quotient). Subjects' left-right phase asymmetry exhibits low, but statistically significant, correlations with speed quotient (r=0.45) and closing quotient (r=-0.39). Results call for future studies into the effect of asymmetric vocal fold vibration on glottal airflow and the associated impact on voice source spectral properties and vocal efficiency. 相似文献
56.
Dr. Haidong Li Qichao Yao Feng Xu Prof. Dr. Yueqing Li Dayeh Kim Jeewon Chung Gain Baek Dr. Xiaofeng Wu Prima Fitria Hillman Eun Young Lee Haoying Ge Prof. Dr. Jiangli Fan Prof. Jingyun Wang Prof. Dr. Sang-Jip Nam Prof. Dr. Xiaojun Peng Prof. Dr. Juyoung Yoon 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):10272-10281
Monitoring fluctuations in enzyme overexpression facilitates early tumor detection and excision. An AIEgen probe (DQM-ALP) for the imaging of alkaline phosphatase (ALP) activity was synthesized. The probe consists of a quinoline-malononitrile (QM) core decorated with hydrophilic phosphate groups as ALP-recognition units. The rapid liberation of DQM-OH aggregates in the presence of ALP resulted in aggregation-induced fluorescence. The up-regulation of ALP expression in tumor cells was imaged using DQM-ALP. The probe permeated into 3D cervical and liver tumor spheroids for imaging spatially heterogeneous ALP activity with high spatial resolution on a two-photon microscopy platform, providing the fluorescence-guided recognition of sub-millimeter tumorigenesis. DQM-ALP enabled differentiation between tumor and normal tissue ex vivo and in vivo, suggesting that the probe may serve as a powerful tool to assist surgeons during tumor resection. 相似文献
57.
58.
Jonathan A. Hillman 《Commentarii Mathematici Helvetici》1988,63(1):664-671
We show that a torsion free abelian normal subgroup of rank two of a two-knot group which is contained in the commutator subgroup
must be free abelian, the centralizer of the abelian subgroup is not contained in the commutator subgroup, and neither of
the latter two groups is finitely generated. Furthermore, we characterize algebraically the groups of 2-knots which are cyclic
branched covers of twist spun torus knots. 相似文献
59.
All-optical anatomical co-registration for molecular imaging of small animals using dynamic contrast
Optical molecular imaging in small animals harnesses the power of highly specific and biocompatible contrast agents for drug development and disease research1-7. However, the widespread adoption of in vivo optical imaging has been inhibited by its inability to clearly resolve and identify targeted internal organs. Optical tomography8-11 and combined X-ray and micro-computed tomography (micro-CT)12 approaches developed to address this problem are generally expensive, complex or incapable of true anatomical co-registration. Here, we present a remarkably simple all-optical method that can generate co-registered anatomical maps of a mouse's internal organs, while also acquiring in vivo molecular imaging data. The technique uses a time series of images acquired after injection of an inert dye. Differences in the dye's in vivo biodistribution dynamics allow precise delineation and identification of major organs. Such co-registered anatomical maps permit longitudinal organ identification irrespective of repositioning or weight gain, thereby promising greatly improved accuracy and versatility for studies of orthotopic disease, diagnostics and therapies. 相似文献
60.