全文获取类型
收费全文 | 1371篇 |
免费 | 43篇 |
国内免费 | 5篇 |
专业分类
化学 | 962篇 |
晶体学 | 9篇 |
力学 | 34篇 |
数学 | 55篇 |
物理学 | 359篇 |
出版年
2021年 | 12篇 |
2020年 | 24篇 |
2019年 | 18篇 |
2018年 | 9篇 |
2017年 | 13篇 |
2016年 | 22篇 |
2015年 | 24篇 |
2014年 | 20篇 |
2013年 | 52篇 |
2012年 | 62篇 |
2011年 | 74篇 |
2010年 | 40篇 |
2009年 | 34篇 |
2008年 | 72篇 |
2007年 | 75篇 |
2006年 | 71篇 |
2005年 | 78篇 |
2004年 | 75篇 |
2003年 | 51篇 |
2002年 | 56篇 |
2001年 | 50篇 |
2000年 | 29篇 |
1999年 | 29篇 |
1998年 | 16篇 |
1997年 | 17篇 |
1996年 | 19篇 |
1995年 | 18篇 |
1994年 | 24篇 |
1993年 | 18篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 8篇 |
1985年 | 21篇 |
1984年 | 26篇 |
1983年 | 11篇 |
1982年 | 15篇 |
1981年 | 9篇 |
1980年 | 18篇 |
1979年 | 14篇 |
1978年 | 15篇 |
1976年 | 16篇 |
1975年 | 11篇 |
1974年 | 13篇 |
1973年 | 18篇 |
1969年 | 7篇 |
1967年 | 7篇 |
排序方式: 共有1419条查询结果,搜索用时 279 毫秒
1.
2.
Optical Review - This paper demonstrates a method to estimate the depth of a fluorescence object in turbid media using dual-wavelength excited photodynamic diagnosis, to aid in the invasion depth... 相似文献
3.
Hirokazu Nishimura 《International Journal of Theoretical Physics》1995,34(2):211-228
The notion of a manual, introduced and investigated in detail by Foulis, Randall, and their followers, has turned out to be further reaching than its originators had envisaged. Its omnipresence is comparable with the notion of a sheaf, whose significance is well recognized by every pure and applied mathematician. The principal concern of this paper is to give an appropriate vehicle, as general as possible, by which the theory of manuals can be developed. The vehicle is called an orthogonal category, which is akin to the notion of a category with coproducts. Orthogonal categories provide also a new perspective on the notion of a sheaf over a complete Boolean algebra, deepening our comprehension of Boolean mathematics and paving the way to quantum mathematics. 相似文献
4.
Masamichi Takase 《Topology》2004,43(6):1425-1447
Haefliger has shown that a smooth embedding of the (4k−1)-sphere in the 6k-sphere can be knotted in the smooth sense. In this paper, we give a formula with which we can detect the isotopy class of such a Haefliger knot. The formula is expressed in terms of the geometric characteristics of an extension, analogous to a Seifert surface, of the given embedding. In particular, the Hopf invariant associated to the extension plays a crucial role. This leads us to a new characterisation of Haefliger knots. 相似文献
5.
6.
S. Homma-Takeda Y. Nishimura Y. Watanabe H. Imaseki M. Yukawa 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(3):521-525
Stage-specific and age-dependent profiles of zinc, copper, manganese, and selenium in testis were examined in Wistar rats
by both inductively coupled argon plasma-mass spectrometry (ICP-MS) with a microdissection technique and in situ elemental
imaging of micro-PIXE analysis. The young adult animals (10 weeks old) contained higher levels of zinc and manganese in the
seminiferous tubules at stages VII-VIII than stages XI through VI and IX-X and the levels were higher than those of the immature
and old animals. Copper and selenium levels at stages VII-VIII of the young adult animals were also higher than those of the
immature and old animals. In stages VII and VIII, zinc was higher in the central area of the seminiferous epithelium, where
spermatozoa were localized, demonstrating a cell-specific property.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
8.
Yozo Miura Masamichi Dairoku 《Journal of polymer science. Part A, Polymer chemistry》2007,45(18):4364-4376
Dendritic multifunctional macroinitiators having six and 12 TIPNO‐based alkoxyamines, TIPNO‐6 and TIPNO‐12 , were synthesized and used in the living radical polymerization of styrene (St), methyl acrylate (MA), N,N‐dimethylacrylamide (DMAAm), and isoprene (IP). The polymerizations of St initiated with TIPNO‐6 gave 6‐arm star polymers with narrow polydispersities of 1.14–1.18. In the polymerizations of MA initiated with TIPNO‐6 and TIPNO‐12 , the influences of added TIPNO on the polydispersity indexes (PDIs) of the resulting star polymers were first investigated, and this led to the successful formation of poly(MA) star polymers with narrow polydispersities (1.10–1.18). Moreover, the polymerizations of DMAAm and IP from TIPNO‐6 in the presence or absence of TIPNO were briefly investigated. The benzyl ether bonds of the poly(St) and poly(MA) star polymers were cleaved by treating with Me3SiI or Pd/C, and the resulting arm's parts were analyzed with SEC. The PDIs of the resulting arm parts were low (1.19–1.23), and the Mns agreed with the Mn,theor, indicating that the poly(St) and poly(MA) star polymers had well‐controlled arms. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4364–4376, 2007 相似文献
9.
Katsunori Nishimura Rie Hidaka Fumitoshi Hirayama Hidetoshi Arima Kaneto Uekama 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):85-88
Geometries, electronic properties and NMR-shielding of cucurbit[5]uril, decamethylcucurbit[5]uril, cucurbit[6]uril, cucurbit[7]uril,
and cucurbit[8]uril are investigated with DFT calculations. All molecules are highly symmetrical with a distinct geometric
flexibility. In addition with a characteristic partial charge distribution these findings account for their chemical complex
building ability. 相似文献
10.
I Kitagawa A Matsuda T Nishimura S Hirai I Yoshioka 《Chemical & pharmaceutical bulletin》1967,15(9):1435-1437