全文获取类型
收费全文 | 35942篇 |
免费 | 1187篇 |
国内免费 | 183篇 |
专业分类
化学 | 24431篇 |
晶体学 | 301篇 |
力学 | 849篇 |
数学 | 4925篇 |
物理学 | 6806篇 |
出版年
2022年 | 351篇 |
2021年 | 473篇 |
2020年 | 608篇 |
2019年 | 591篇 |
2018年 | 432篇 |
2017年 | 375篇 |
2016年 | 905篇 |
2015年 | 776篇 |
2014年 | 911篇 |
2013年 | 1791篇 |
2012年 | 1964篇 |
2011年 | 2215篇 |
2010年 | 1348篇 |
2009年 | 1141篇 |
2008年 | 1881篇 |
2007年 | 1761篇 |
2006年 | 1736篇 |
2005年 | 1613篇 |
2004年 | 1475篇 |
2003年 | 1122篇 |
2002年 | 1178篇 |
2001年 | 638篇 |
2000年 | 587篇 |
1999年 | 522篇 |
1998年 | 478篇 |
1997年 | 471篇 |
1996年 | 517篇 |
1995年 | 418篇 |
1994年 | 444篇 |
1993年 | 451篇 |
1992年 | 414篇 |
1991年 | 350篇 |
1990年 | 335篇 |
1989年 | 308篇 |
1988年 | 328篇 |
1987年 | 352篇 |
1986年 | 308篇 |
1985年 | 471篇 |
1984年 | 443篇 |
1983年 | 331篇 |
1982年 | 370篇 |
1981年 | 363篇 |
1980年 | 354篇 |
1979年 | 338篇 |
1978年 | 362篇 |
1977年 | 345篇 |
1976年 | 281篇 |
1975年 | 293篇 |
1974年 | 286篇 |
1973年 | 250篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
102.
Van Kolpin 《International Journal of Game Theory》1993,22(1):43-50
The traditional design of cooperative games implicitly assumes that preferences are continuous. However, if agents implement tie breaking procedures, preferences are effectively lexicographic and thus discontinuous. This rouses concern over whether classic core nonemptiness theorems apply in such settings. We show that balanced NTU games may have empty cores when agents have discontinuous preferences. Moreover, exchange economies may lack coalitionally rational trades when consumers implement tie breaking rules, even if these rules are themselves continuous and convex as are all first order preferences. Results are more positive when “utility” is transferable. We prove that balancedness is necessary and sufficient to ensure a nonempty core in lexicographic TU games. 相似文献
103.
A combined-modality treatment program consisting of botulinum toxin injection (Botox) and voice therapy was used to treat 17 subjects diagnosed with adductor spasmodic dysphonia (ADD SD). Ten subjects with ADD SD served as the control and were given Botox only. Voice therapy after Botox injection was directed toward reducing the hyperfunctional vocal behaviors, primarily glottal overpressure at voice onset and anterior-posterior squeezing. The results indicated that subjects who underwent combined-modality treatment maintained significantly higher mean airflow rates for significantly longer periods. Moreover, there was a carryover effect in these patients when they received Botox only. Adductor spasmodic dysphonia is treated most effectively when intrinsic laryngeal muscle spasms are reduced or eliminated by Botox injection and extrinsic hyperfunctional vocal behaviors are treated with voice therapy 相似文献
104.
As pan of a biomimetic approach towards me marine triterpene teurilene (2), the synthesis of the chiral diepoxide 3 is described. Aiming at the synthesis of the squalene tetraepoxide 1, double Sharpless epoxidation led to the intermediate bisglycidic alcohol 7 being subject to a stereochemical analysis. 相似文献
105.
106.
107.
108.
109.
110.
Simon Thomas 《Archive for Mathematical Logic》1998,37(7):483-493
We study the relationship between the cofinality of the infinite symmetric group and the cardinal invariants and . In particular, we prove the following two results.
Theorem 0.1
It is consistent with
ZFC
that there exists a simple
$P_{\omega_{1}}$
-point and that
$c(Sym(\omega)) = \omega_{2} = 2^{\omega}$
.
Theorem 0.2
If there exist both a simple
$P_{\omega_{1}}$
-point and a
$P_{\omega_{2}}$
-point, then
$c(Sym(\omega)) = \omega_{1}$
.
Received: 7 March 1996 相似文献