全文获取类型
收费全文 | 178篇 |
免费 | 4篇 |
专业分类
化学 | 113篇 |
力学 | 6篇 |
数学 | 21篇 |
物理学 | 42篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 7篇 |
2013年 | 11篇 |
2012年 | 5篇 |
2011年 | 10篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 10篇 |
2005年 | 5篇 |
2004年 | 11篇 |
2003年 | 12篇 |
2002年 | 14篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有182条查询结果,搜索用时 15 毫秒
61.
M. Tsuchiya K. Igarashi R. Yatsu K. Taira K.Y. Koay M. Kishi 《Optical and Quantum Electronics》2001,33(7-10):751-766
We report our studies on a fiber-optic soliton compressor for generation of sub-100 femtosecond (fs) optical pulses out of picosecond (ps) diode laser pulses. The soliton compressor is rather simple and composed of a 15 ~ 20 m-long step-like dispersion profiled fiber (SDPF) in conjunction with a single Er-doped fiber amplifier (EDFA). Careful design of such a SDPF compressor was performed, leading to demonstration of 20-fs class compression performance, and experimental investigation was carried out in detail on the optical pulse propagation in the compression processes. In addition, nonlinear fiber loops were applied to suppression of pulse pedestals, resulting successfully in high quality optical pulses of the 100-fs range. 相似文献
62.
V. Lupei A. Lupei N. Pavel T. Taira A. Ikesue 《Applied physics. B, Lasers and optics》2001,73(7):757-762
A high-resolution spectroscopic and emission-decay investigation of highly concentrated Nd:YAG single crystals and ceramics
shows that the state of the Nd3+ ions and their interaction in these materials are similar and can be used for construction of efficient solid-state lasers
directly pumped in the emitting level. This possibility is demonstrated by continuous-wave emission of concentrated Nd:YAG
crystals with up to 3.5 at. % Nd and ceramics with up to 6.8 at. % Nd under resonant 885-nm end pump.
Received: 28 May 2001 / Final version: 17 August 2001 / Published online: 10 October 2001 相似文献
63.
64.
The thermodynamic properties of the spinel ferromagnetic compounds CdCr2Se4 and CdCr2S4 have been investigated by making heat capacity and thermal expansion measurements on single crystals. For both compounds, the ferromagnetic transition is marked by λ-type thermal anomalies, and the results provide a pressure dependence of the transition temperatures that is in agreement with direct measurements. Below the transition, CdCr2S4 shows an anomalous heat-capacity contribution and negative thermal expansion, which are in contrast to the conventional behavior found in CdCr2Se4. 相似文献
65.
Aida Taira Toma Takahiro Kanada Satoshi 《Journal of Solid State Electrochemistry》2020,24(6):1415-1425
Journal of Solid State Electrochemistry - It is well known that reducing particle size and/or hollowing the particles improves the electrochemical performance, especially the rate capability, of... 相似文献
66.
67.
68.
Keisuke HIROTA Hiroo MATSUSE Shunji KOYA Ryuki HASHIDA Masafumi BEKKI Yoko YANAGA Kiyoko JOHZAKI Mami TOMINO Fumihiko MOURI Satoshi MORISHIGE Shuki OYA Yoshitaka YAMASAKI Koji NAGAFUJI Naoto SHIBA 《Physical Therapy Research》2021,24(1):69
Objective: Muscle atrophy is associated with autologous stem cell transplantation (ASCT)-related outcomes in patients with malignant lymphoma (ML). However, the impact of ASCT on muscle mass remains unclear in patients with ML. The aims of this study were to investigate changes in muscle mass and risk profiles for muscle atrophy after ASCT. Method: We enrolled 40 patients with refractory ML (age 58 [20-74] years, female/male 16/24, body mass index (BMI) 21.1 kg/m2 [17.1-29.6]). Psoas muscle mass was assessed using the psoas muscle index (PMI) before and after ASCT. Statistical analysis used: Independent factors associated with a severe decrease rate of change in PMI were evaluated by decision-tree analysis, respectively. Results: PMI was significantly decreased after ASCT (4.61 vs. 4.55 cm2/m2; P=0.0425). According to the decision-tree analysis, the regimen was selected as the initial split. The rates of change in PMI were −5.57% and −3.97% for patients administered MCEC and LEED, respectively. In patients who were administered LEED, the second branching factor was BMI. In patients with BMI < 20.3 kg/m2, the rate of change in PMI was −7.16%. On the other hand, the rate of change in PMI was 4.05% for patients with BMI ≥ 20.3 kg/m2. Conclusion: We demonstrated that muscle mass decreased after ASCT in patients with ML. Patients who received MCEC and patients with low BMI were at risk for a decrease in muscle mass. 相似文献
69.
Activation and Deactivation of Phillips Catalyst for Ethylene Polymerization Using Various Activators 下载免费PDF全文
The present article reveals important roles of metal alkyl activators in tuning the performance of the Phillips catalyst in ethylene polymerization. The addition of aluminum alkyl aids the activation of the catalyst, while excess addition leads to the loss of the activity. The balance between the activation and deactivation depends on the type of employed aluminum alkyl, and tri‐n‐octylaluminum offers the most efficient catalyst usage by preferentially suppressing the deactivation. The passivation of aluminum trialkyl with a hindered phenol mildens not only the deactivation but also chain transfer reactions, leading to an increment of high molecular weight fractions.
70.
The arylation of dihydrosilanes with aryl iodides or heteroaryl iodides in the presence of a palladium catalyst provides the corresponding monohydrosilanes in good to high yield. Moderate to good yields are obtained even in the presence of a variety of reactive functional groups, such as -NH2, -OH, or -CN, without their protection. 相似文献