全文获取类型
收费全文 | 83187篇 |
免费 | 563篇 |
国内免费 | 402篇 |
专业分类
化学 | 27653篇 |
晶体学 | 852篇 |
力学 | 6868篇 |
数学 | 32313篇 |
物理学 | 16466篇 |
出版年
2022年 | 33篇 |
2021年 | 154篇 |
2020年 | 104篇 |
2019年 | 107篇 |
2018年 | 10485篇 |
2017年 | 10324篇 |
2016年 | 6186篇 |
2015年 | 1002篇 |
2014年 | 499篇 |
2013年 | 670篇 |
2012年 | 4162篇 |
2011年 | 10899篇 |
2010年 | 5896篇 |
2009年 | 6252篇 |
2008年 | 6968篇 |
2007年 | 9073篇 |
2006年 | 570篇 |
2005年 | 1587篇 |
2004年 | 1792篇 |
2003年 | 2184篇 |
2002年 | 1229篇 |
2001年 | 408篇 |
2000年 | 395篇 |
1999年 | 243篇 |
1998年 | 242篇 |
1997年 | 170篇 |
1996年 | 239篇 |
1995年 | 169篇 |
1994年 | 108篇 |
1993年 | 130篇 |
1992年 | 81篇 |
1991年 | 76篇 |
1990年 | 75篇 |
1989年 | 87篇 |
1988年 | 72篇 |
1987年 | 72篇 |
1986年 | 59篇 |
1985年 | 68篇 |
1984年 | 52篇 |
1983年 | 47篇 |
1982年 | 55篇 |
1981年 | 51篇 |
1980年 | 56篇 |
1979年 | 47篇 |
1978年 | 38篇 |
1914年 | 45篇 |
1913年 | 40篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
941.
Abachi S Abbott B Abolins M Acharya BS Adam I Adams DL Adams M Ahn S Aihara H Alitti J Álvarez G Alves GA Amidi E Amos N Anderson EW Aronson SH Astur R Avery RE Baarmand MM Baden A Balamurali V Balderston J Baldin B Banerjee S Bantly J Bartlett JF Bazizi K Bendich J Beri SB Bertram I Bezzubov VA Bhat PC Bhatnagar V Bhattacharjee M Bischoff A Biswas N Blazey G Blessing S Bloom P Boehnlein A Bojko NI Borcherding F Borders J Boswell C Brandt A Brock R Bross A Buchholz D Burtovoi VS Butler JM 《Physical review letters》1996,77(25):5011-5015
942.
Abachi S Abbott B Abolins M Acharya BS Adam I Adams DL Adams M Ahn S Aihara H Alitti J Álvarez G Alves GA Amidi E Amos N Anderson EW Aronson SH Astur R Avery RE Baarmand MM Baden A Balamurali V Balderston J Baldin B Banerjee S Bantly J Bartlett JF Bazizi K Bendich J Beri SB Bertram I Bezzubov VA Bhat PC Bhatnagar V Bhattacharjee M Bischoff A Biswas N Blazey G Blessing S Bloom P Boehnlein A Bojko NI Borcherding F Borders J Boswell C Brandt A Brock R Bross A Buchholz D Burtovoi VS Butler JM 《Physical review letters》1996,77(16):3303-3308
943.
944.
LetK be an algebraically closed field withp:=char (K)>0 andX a bielliptic curve over Spec(K) with genus≥6 and such that the canonical model ofX is ordinary. In this paper we determine all the possible gap sequences of Weierstrass points on such curves. 相似文献
945.
Gur Mosheiov 《The Journal of the Operational Research Society》1996,47(9):1184-1191
We study a problem of scheduling deteriorating jobs, i.e. jobs whose processing times are an increasing function of their starting times. We consider the case of a single machine and linear job-independent deterioration. The objective is to minimize the sum of weighted completion times, with weights proportional to the basic processing times. The optimal schedule is shown to be Λ-shaped, i.e. the sequence of the basic processing times has a single local maximum. Moreover, we show that the problem is solved in O(N log N) time. In the last section we test heuristics for the case of general weights. 相似文献
946.
The gas jet assisted glow discharge source has been employed for the RF-glow discharge atomic absorption spectrometry (RF-GDAAS). Data are described to illustrate the role of discharge power, pressure as well as gas flow rate on the sample loss rate, absorbance and self-bias potential. Results show that the optimum discharge conditions depend not only on the pressure and discharge power but also on the gas flow rate. The absorbance increases as much as 1 order of magnitude as the gas flow rate increases from 50 mL/min to 500 mL/min at a pressure of 3 mbar. The use of a gas-jet source allows the direct analysis of solids by RF-GDAAS. 相似文献
947.
Gerhard Hasslinger Erik S. Rieger 《The Journal of the Operational Research Society》1996,47(5):640-653
This paper deals with approximate analysis methods for open queueing networks. External and internal flows from and to the nodes are characterized by renewal processes with discrete time distributions of their interarrival times. Stationary distributions of the waiting time, the queue size and the interdeparture times are obtained using efficient discrete time algorithms for single server (GI/G/1) and multi-server (GI/D/c) nodes with deterministic service. The network analysis is extended to semi-Markovian representations of each flow among the nodes, which include parameters of the autocorrelation function. 相似文献
948.
Steve PhillipsJr. 《The Journal of the Operational Research Society》1996,47(5):697-701
The paper presents an application oriented procedure for solving the project management duration/resource tradeoff problem. A procedure is presented for reducing a project from a normal to a crash duration state at a minimum amount of additional resource expenditure assuming a linear utilization functions. The procedure is network based using a graphical Cut Search Approach to locate the minimal resource level at each reduction in total project duration. Activity-on-arc networks and flow networks are utilized. The paper is presented for practical application and for conceptual development as compared to a theoretical treatment. 相似文献
949.
950.