全文获取类型
收费全文 | 298786篇 |
免费 | 1977篇 |
国内免费 | 524篇 |
专业分类
化学 | 142753篇 |
晶体学 | 5009篇 |
力学 | 14792篇 |
综合类 | 11篇 |
数学 | 43289篇 |
物理学 | 95433篇 |
出版年
2020年 | 1725篇 |
2019年 | 1921篇 |
2018年 | 10842篇 |
2017年 | 11726篇 |
2016年 | 7481篇 |
2015年 | 3045篇 |
2014年 | 3676篇 |
2013年 | 9206篇 |
2012年 | 10772篇 |
2011年 | 20332篇 |
2010年 | 12685篇 |
2009年 | 12770篇 |
2008年 | 17533篇 |
2007年 | 21029篇 |
2006年 | 6895篇 |
2005年 | 12786篇 |
2004年 | 8911篇 |
2003年 | 8448篇 |
2002年 | 6270篇 |
2001年 | 6305篇 |
2000年 | 4934篇 |
1999年 | 3561篇 |
1998年 | 2793篇 |
1997年 | 2721篇 |
1996年 | 2756篇 |
1995年 | 2535篇 |
1994年 | 2415篇 |
1993年 | 2243篇 |
1992年 | 2899篇 |
1991年 | 2800篇 |
1990年 | 2747篇 |
1989年 | 2773篇 |
1988年 | 2803篇 |
1987年 | 2803篇 |
1986年 | 2666篇 |
1985年 | 3390篇 |
1984年 | 3416篇 |
1983年 | 2696篇 |
1982年 | 2794篇 |
1981年 | 2852篇 |
1980年 | 2621篇 |
1979年 | 2978篇 |
1978年 | 2978篇 |
1977年 | 3009篇 |
1976年 | 2878篇 |
1975年 | 2605篇 |
1974年 | 2559篇 |
1973年 | 2553篇 |
1972年 | 1740篇 |
1968年 | 1802篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Summary. The reconstruction index of all semiregular permutation groups is determined. We show that this index satisfies 3 £ r(G, W) £ 5 3 \leq \rho(G, \Omega) \leq 5 and we classify the groups in each case. 相似文献
982.
A three-phase model of a hybrid chiral quark bag is proposed. In addition to the phases of asymptotically free current quarks
and of totally colorless mesons, the model contains the intermediate phase of massive constituent quarks. A self-consistent
solution with an account for the “Dirac sea” contribution is found in the (1+1)-dimensional case. The dependence of the bag
parameters on the parameters of the theory is investigated analytically and numerically.
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 117, No. 2, pp. 263–299, November, 1998. 相似文献
983.
Studies of breakdown threshold intensity for air at various pressures in the range of 24–760 torr using 0.355, 0.532 and 1.06
μm radiation are reported. We observep
−0.8 scaling ofI
th at 1.06 μm and a weak scaling ofp
−0.4 at 0.532 and 0.355 μm radiation. Strong dependence of breakdown spot size on laser power but weak dependence on air pressure
is observed. 相似文献
984.
Lorraine R. Gardiner Ralph E. Steuer 《The Journal of the Operational Research Society》1994,45(12):1456-1466
It has previously been shown that nine of the most prominent procedures of interactive multiple objective programming can be considered as special cases of a common procedure called the unified algorithm. In this paper, we show how four additional procedures can be similarly included in the unified approach. Also, the paper presents a procedure-switching matrix that depicts the possibilities for switching from one procedure to another, one iteration to the next, in the unified algorithm if so directed by a user. 相似文献
985.
The new olefinic substituted aminodisilanes, which are obtained from the reaction of organometallic reagents with aminochlorodisilanes, are converted into the chlorodisilanes by equilibration reactions or treatment with HCI. The resulting olefinic functionalized disilanes are identified by means of 29Si, 13C, 1H NMR and GC MS measurements. 相似文献
986.
L. A. Chetkina V. E. Zavodnik A. N. Sobolev V. K. Bel'skii B. P. Bespalov A. G. Abolin 《Journal of Structural Chemistry》1991,32(3):442-445
L. Ya. Karpov Physical Chemical Research Institute. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 3, pp. 141–144, May–June, 1991. 相似文献
987.
We show that if a polynomial filled Julia set has empty interior, then it is computable. 相似文献
988.
989.
A refined technique is presented to project rotational bands observed in the well studiedZ≧60 rare-earth region into the region of stable ground-state deformation atA ~-100 with corresponding neutron numbers ofN ≧60. With this procedure, estimates of properties of so far unknown nuclei in the A~-100 region can be obtained. As an illustration, isotopes aroundN=64 are discussed within this projection method and within the frame-work of the recent quartet model. 相似文献
990.
A. Kavokin 《Applied Physics A: Materials Science & Processing》2007,89(2):241-246
An overview is given of the current research trends in the physics of exciton-polaritons in microcavities. Potential applications
of the Bose–Einstein condensation and superfluidity of exciton-polaritons are discussed. The perspectives for the realization
of polariton lasers, polariton spin transistors and polarization modulators are presented.
PACS 78.67.-n; 71.36.+c; 42.55.Sa; 42.25.Kb 相似文献