全文获取类型
收费全文 | 14371篇 |
免费 | 42篇 |
国内免费 | 46篇 |
专业分类
系统科学 | 81篇 |
丛书文集 | 80篇 |
教育与普及 | 30篇 |
理论与方法论 | 92篇 |
现状及发展 | 6651篇 |
研究方法 | 735篇 |
综合类 | 6576篇 |
自然研究 | 214篇 |
出版年
2016年 | 84篇 |
2013年 | 132篇 |
2012年 | 287篇 |
2011年 | 472篇 |
2010年 | 138篇 |
2008年 | 271篇 |
2007年 | 298篇 |
2006年 | 293篇 |
2005年 | 307篇 |
2004年 | 290篇 |
2003年 | 276篇 |
2002年 | 260篇 |
2001年 | 416篇 |
2000年 | 386篇 |
1999年 | 286篇 |
1992年 | 250篇 |
1991年 | 194篇 |
1990年 | 225篇 |
1989年 | 204篇 |
1988年 | 215篇 |
1987年 | 229篇 |
1986年 | 178篇 |
1985年 | 269篇 |
1984年 | 194篇 |
1983年 | 160篇 |
1982年 | 189篇 |
1981年 | 150篇 |
1980年 | 196篇 |
1979年 | 450篇 |
1978年 | 348篇 |
1977年 | 366篇 |
1976年 | 270篇 |
1975年 | 315篇 |
1974年 | 392篇 |
1973年 | 383篇 |
1972年 | 435篇 |
1971年 | 408篇 |
1970年 | 502篇 |
1969年 | 446篇 |
1968年 | 440篇 |
1967年 | 429篇 |
1966年 | 389篇 |
1965年 | 256篇 |
1959年 | 113篇 |
1958年 | 213篇 |
1957年 | 142篇 |
1956年 | 122篇 |
1955年 | 109篇 |
1954年 | 87篇 |
1948年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Aspirin-like drugs may block pain independently of prostaglandin synthesis inhibition 总被引:2,自引:0,他引:2
K. Brune W. S. Beck G. Geisslinger S. Menzel-Soglowek B. M. Peskar B. A. Peskar 《Cellular and molecular life sciences : CMLS》1991,47(3):257-261
Summary Using flurbiprofen, a chiral anti-inflammatory and analgesic 2-arylpropionic acid derivative, the enantiomers of which are not converted to each other (less than 5%) in rats or man, we obtained evidence that prostaglandin synthesis inhibition is primarily mediating the anti-inflammatory activity but prostaglandin synthesis independent mechanisms contribute to the analgesic effects. Thus, the S-form inhibited prostaglandin synthesis, inflammation and nociception in rats. The R-form had much less effect on prostaglandin synthesis and did not affect inflammation. It did, however, block nociception in rats almost as potently as the S-form. S-flurbiprofen, in contrast to the R-form, was clearly ulcerogenic in the gastrointestinal mucosa. These results indicate additional molecular mechanisms of analgesia and suggest the use of R-arylpropionic acids as analgesics. 相似文献
23.
24.
FROM MANUFACTURING SCHEDULING TO SUPPLY CHAIN COORDINATION:THE CONTROL OF COMPLEXITY AND UNCERTAINTY
Peter B.LUH 《系统科学与系统工程学报(英文版)》2003,12(3):279-297
With time-based competition and rapid technology advancements, effective manufacturingscheduling and supply chain coordination are critical to quickly respond to changing marketconditions. These problems, however, are difficult in view of inherent complexity and variousuncertainties involved. Based on a series of results by the authors, decomposition and coordination byusing Lagrangian relaxation is identified in this paper as an effective way to control complexity anduncertainty.A manufacturing scheduling problem is first formulated within the job shop context withuncertain order arrivals, processing times, due dates, and part priorities as a separable optimizationproblem. A solution methodology that combines Lagrangian relaxation, stochastic dynamicprogramming, and heuristics is developed. Method improvements to effectively solve large problemsare also highlighted. To extend manufacturing scheduling within a factory to coordinate autonomicmembers across chains of suppliers, a decentralized supply chai 相似文献
25.
M E MacDonald A Novelletto C Lin D Tagle G Barnes G Bates S Taylor B Allitto M Altherr R Myers 《Nature genetics》1992,1(2):99-103
Analysis of 78 Huntington's disease (HD) chromosomes with multi-allele markers revealed 26 different haplotypes, suggesting a variety of independent HD mutations. The most frequent haplotype, accounting for about one third of disease chromosomes, suggests that the disease gene is between D4S182 and D4S180. However, the paucity of an expected class of chromosomes that can be related to this major haplotype by assuming single crossovers may reflect the operation of other mechanisms in creating haplotype diversity. Some of these mechanisms sustain alternative scenarios that do not require a multiple mutational origin for HD and/or its positioning between D4S182 and D4S180. 相似文献
26.
Ramsés Fuenmayor 《Systemic Practice and Action Research》1991,4(5):473-490
Both an ontoepistemology for reductionist modern science (counter-ontoepistemology) and an ontology for interpretive Systemology have been outlined in the two preceding papers in this special issue ofSystems Practice. In the present article, the notion of “truth” is interpreted in terms of both the ontoepistemology of “reductionism” and the ontology of interpretive systemology. Both interpretations are discussed. Such a discussion represents the objective of this paper, that is, to outline the epistemological “face” of the ontoepistemology of interpretive systemology. In order to design that “epistemological face,” the relation between ontology and epistemology must be clarified. Such a relation is seen from the standpoint already provided by the ontology. After the discussion on the notion of truth, the general shape of a systemic-interpretive inquiring process is outlined. 相似文献
27.
28.
Edwin Y.B.Pun 《复旦学报(自然科学版)》2007,(5)
1 Results Rare earth doped waveguide amplifiers and devices have been demonstrated in silica, crystal and other glass hosts. These rare earth doped optical waveguide devices are based on inorganic materials. Many processing steps are required and can lead to long fabrication time and low yield.Polymer materials offer many distinct properties compared to inorganic materials, such as ease of fabrication, low production costs, simple processing steps, and compatibility with micro-fabrication technologies. ... 相似文献
29.
30.