全文获取类型
收费全文 | 1273篇 |
免费 | 25篇 |
国内免费 | 2篇 |
专业分类
化学 | 985篇 |
晶体学 | 12篇 |
力学 | 9篇 |
数学 | 19篇 |
物理学 | 275篇 |
出版年
2023年 | 10篇 |
2021年 | 6篇 |
2020年 | 16篇 |
2019年 | 16篇 |
2018年 | 5篇 |
2016年 | 17篇 |
2015年 | 23篇 |
2014年 | 27篇 |
2013年 | 55篇 |
2012年 | 63篇 |
2011年 | 88篇 |
2010年 | 27篇 |
2009年 | 47篇 |
2008年 | 89篇 |
2007年 | 83篇 |
2006年 | 82篇 |
2005年 | 71篇 |
2004年 | 66篇 |
2003年 | 53篇 |
2002年 | 62篇 |
2001年 | 27篇 |
2000年 | 20篇 |
1999年 | 12篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 14篇 |
1992年 | 14篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 10篇 |
1988年 | 16篇 |
1987年 | 21篇 |
1986年 | 8篇 |
1985年 | 14篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 19篇 |
1980年 | 9篇 |
1979年 | 11篇 |
1978年 | 15篇 |
1977年 | 13篇 |
1976年 | 11篇 |
1974年 | 9篇 |
1973年 | 11篇 |
1970年 | 4篇 |
1966年 | 4篇 |
排序方式: 共有1300条查询结果,搜索用时 46 毫秒
81.
82.
Mitsuda A Goto T Yoshimura K Zhang W Sato N Kosuge K Wada H 《Physical review letters》2002,88(13):137204
We investigated the magnetization of Yb0.8Y0.2InCu4 as a function of temperature down to 0.6 K, pressure up to 1.2 GPa, and magnetic field up to 9 T. The valence transition temperature of Yb0.8Y0.2InCu4 is lowered with applying pressure. At 0.8 GPa, collapse of the valence transition and ferromagnetic ordering occur almost simultaneously. The ferromagnetic phase at 1.2 GPa is characterized by a low Curie temperature of 1.7 K and an extremely small ordered moment of 0.05 micro(B) per Yb. Some effect of screening the ordered moment may play a key role in the ferromagnetism and the valence transition. 相似文献
83.
Morita H Kawaguchi H Yoshimura T Tsukurimichi E Shimasaki C Horn E 《Chemistry (Weinheim an der Bergstrasse, Germany)》2000,6(21):3976-3983
5-(N-p)-Toluenesulfonyl)iminothianthrenes, whose sulfur atoms are oxidized to a sulfoxide or sulfone at the 10-position, were hydrolysed readily in high yield to N-unsubstituted-sulfilimines by using concentrated H2SO4. During hydrolysis, 10-monoxy-5-N-unsubstituted-sulfilimines were obtained as a separable mixture of the cis and trans isomers. The stereochemical interconversion of these compounds was studied under both hydrolytic and thermal conditions and their structures were elucidated by using X-ray crystallography. 相似文献
84.
Hiroshi Maejima Yuji Kanetada Hitoshi Sunahori Azusa Murase Takuya Otani Nozomi Sakamoto Osamu Yoshimura Yoshiko Tobimatsu 《Physical Therapy Research》2008,11(1):7-13
The objective of this study was to assess the effect of comprehensive exercise program widely accepted as a community-based physical intervention for the prevention of falling in the elderly persons on their controlling standing balance. Twenty-six community-dwelling elderly persons (13 males and females; 69.8 ± 2.8 years old) participated in this study. Daily exercise was comprised of walking for more than 30 min, stretching, muscle strengthening and balance exercise without exercise equipments. The intervention was continued for three months. Indicators of standing balance related to static balance, dynamic balance and postural response were measured before and after the intervention. As an effect of the intervention on static balance, the sway of center of pressure (COP) in the static stance significantly increased. In the dynamic balance, significant improvements were observed in one leg standing time, the 10-m gait time, functional reach. Additionally, the maximal movable length of COP which subjects can move voluntarily to right and left significantly increased. In the postural response, the integrated electromyography (IEMG) induced by postural response for sudden postural perturbation significantly decreased in the lower leg muscles. Since less muscular activities were sufficient to maintain posture, it was suggested that postural response was elicited more efficiently following the intervention. This study suggested that the comprehensive exercise program, which has been widely introduced as community-based interventions for the prevention of falling, have extensive effects on the control of standing balance covering static balance, dynamic balance and postural response in the elderly persons. 相似文献
85.
A nonlinear optical crystal YCa(4)O(BO(3))(3) (YCOB) is phase matchable for third-harmonic generation (THG) of a Nd:YAG laser by type I mixing between 1.064 and 0.532mum . By partial substitution of Gd for Y in YCOB, a solid solution Gd(x)Y(1-x)Ca(4)O(BO(3))(3) gradually changes the phase-matching angles of THG to (theta, ?)=(90( degrees ), 90 ( degrees )) . We present the properties of noncritically phase-matched THG in Gd(x) Y(1-x)Ca(4)O(BO(3))(3) (x=0.28) . 相似文献
86.
This paper is concerned with the analysis of dynamic deflection and acceleration of a concrete bridge which is subjected to a moving vehicle load. The bridge, to be constructed across the River Brahmaputra in India, consists of 20 main spans, and each main span is assumed to be double cantilever type with a small suspended span. The moving vehicle is modeled as one degree of freedom. The deflections and accelerations at specific locations on the bridge when the vehicle moves at constant speed are analyzed by using the finite element method. 相似文献
87.
88.
89.
90.
Tadayosi Yoshimura 《Fresenius' Journal of Analytical Chemistry》1981,308(5):445-447
Summary The electrode reaction of acetylacetone (AA) was investigated in unbuffered aqueous solutions by using 3 lead dioxide (PbO2) indicator electrode. A pH-range of about 2 to 12 was covered. At a pH higher than 3 and lower than 9, the height of the anodic and cathodic peaks is directly proportional to the AA concentration. The PbO2 electrode seems to be useful for determining a complexing agent such as AA.
Voltammetrische Untersuchung des pH-Verhaltens Acetylaceton in wäßriger Lösung an der Bleidioxid-Elektrode
Zusammenfassung Die Elektrodenreaktion von Acetylaceton wurde in ungepufferten wäßrigen Lösungen an der PbO2-Indicatorelektrode untersucht, wobei ein pH-Bereich von 2 bis 12 erfaßt wurde. Bei pH-Werten > 3 und < 9 ist die Höhe der anodischen und kathodischen Peaks direkt proportional der Acetylacetonkonzentration. Die PbO2-Elektrode scheint für die Bestimmung von Komplexbildnern (wie Acetylaceton) nützlich zu sein.相似文献