全文获取类型
收费全文 | 1189篇 |
免费 | 8篇 |
国内免费 | 3篇 |
专业分类
化学 | 904篇 |
晶体学 | 13篇 |
力学 | 8篇 |
数学 | 107篇 |
物理学 | 168篇 |
出版年
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 15篇 |
2014年 | 10篇 |
2013年 | 68篇 |
2012年 | 31篇 |
2011年 | 61篇 |
2010年 | 29篇 |
2009年 | 38篇 |
2008年 | 54篇 |
2007年 | 64篇 |
2006年 | 61篇 |
2005年 | 64篇 |
2004年 | 56篇 |
2003年 | 67篇 |
2002年 | 54篇 |
2001年 | 27篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 12篇 |
1996年 | 11篇 |
1995年 | 13篇 |
1994年 | 14篇 |
1993年 | 10篇 |
1992年 | 19篇 |
1991年 | 19篇 |
1990年 | 12篇 |
1989年 | 15篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 19篇 |
1985年 | 20篇 |
1984年 | 31篇 |
1983年 | 9篇 |
1982年 | 18篇 |
1981年 | 16篇 |
1980年 | 23篇 |
1979年 | 29篇 |
1978年 | 21篇 |
1977年 | 10篇 |
1976年 | 14篇 |
1975年 | 18篇 |
1974年 | 10篇 |
1972年 | 9篇 |
1967年 | 4篇 |
排序方式: 共有1200条查询结果,搜索用时 15 毫秒
1.
Supramolecular Polyelectrolyte Complexes of Bone Morphogenetic Protein‐2 with Sulfonated Polyrotaxanes to Induce Enhanced Osteogenic Differentiation 下载免费PDF全文
2.
E. Marin F. Boschetto M. Zanocco W. Zhu T. Adachi N. Kanamura T. Yamamoto B.J. McEntire E.N. Jones C. Powell J. Hendry R.M. Bock B.S. Bal G. Pezzotti 《Materials Today Chemistry》2021
Most structural bioceramics are comprised of metallic oxides such as alumina and zirconia. They are generally considered to be completely bioinert, but a non-oxide ceramic, silicon nitride, achieves equivalent levels of mechanical reliability while being bioactive. Silicon nitride can not only stimulate cellular proliferation but it is also antipathogenic with demonstrated efficacy against Gram-positive and Gram-negative bacteria, fungi, and viruses. In this work, three physical vapor deposition coatings with different Si:N ratios (silicon-rich, stoichiometric, and nitrogen-rich) were deposited on mirror-polished silica glass substrates. The coatings were characterized by spectroscopic and microscopic techniques and tested in vitro against E. coli and KUSA-A1 mesenchymal cells. Results showed that nitrogen-enriched SixNy has a strong antibacterial effect against E. coli and contributes to cellular proliferation while silicon-enriched SixNy stimulates the production of bone tissue, with higher indexes for mineralization and quality. These results suggest that SixNy's biological properties can be optimized for specific applications by carefully tuning its surface chemistry. 相似文献
3.
Polystyrene sulfonic acid resin (Amberlyst 15) was found to initiate the cationic polymerization of 1,3-dioxolane easily in bulk at 0 to 50° C, and polymers with a reduced viscosity of 0.1 were obtained. However, this resin showed only low initiator activity for the polymerizations of 2-methyl-1, 3-dioxolane and trioxane. 相似文献
4.
Kiyoshi Igusa 《中国科学 数学(英文版)》2019,(7)
We introduce diagrams for m-cluster categories which we call "horizontal" and "vertical" mutation fans. These are analogous to the mutation fans(also known as "semi-invariant pictures" or "scattering diagrams") for the standard(m = 1) cluster case, which are dual to the poset of finitely generated torsion classes. The purpose of these diagrams is to visualize mutations and analogues of maximal green sequences in the m-cluster category with special emphasis on the c-vectors(the "brick" labels). 相似文献
5.
Triangulated categories coming from cyclic posets were originally introduced by the authors in a previous paper as a generalization of the constructions of various triangulated categories with cluster structures.We give an overview, and then analyze "triangulation clusters" which are those corresponding to topological triangulations of the 2-disk. Locally finite nontriangulation clusters give topological triangulations of the "cactus space" associated to the "cactus cyclic poset". 相似文献
6.
Fujisawa Kiyoshi Okano Mitsuki Martín-Pastor Manuel López-Sánchez Rubén Elguero José Alkorta Ibon 《Structural chemistry》2021,32(1):215-224
Structural Chemistry - Experimental multinuclear determination of the chemical shifts, especially 15N and 109Ag, of five silver(I) trinuclear pyrazolate complexes, (PzAg)3, coupled with ZORA... 相似文献
7.
Koichiro Shirota Ichirou Yamaguchi Kiyoshi Kanie Tomiki Ikeda Tamejiro Hiyama Ichiro Kobayashi 《Liquid crystals》2013,40(5):555-558
The optical properties of two kinds of photochromic antiferroelectric liquid crystal (AFLC) containing an azo group have been examined. Depending on the substituting group at the chiral centre, these AFLCs showed different photoinduced phase transitions by Ar+ laser light irradiation. This phase transition has led to a new form of optical switching controlled by a bias voltage. In addition, it was found that these AFLCs caused an azimuthal photoalignment effect regulated by linearly polarized Ar+ laser light irradiation. These phenomena were applied to image storage. 相似文献
8.
9.
Kiyoshi Tanemura 《Tetrahedron letters》2018,59(49):4293-4298
Silica gel-mediated hydrochlorination of unactivated alkenes using 35% hydrochloric acid under organic solvent-free conditions proceeded to give the corresponding chlorides in good yields. Hydrobromination or hydriodination using 47% hydrobromic acid or 55% hydriodic acid afforded the corresponding halides, respectively. Silica gel could be recycled five times without any significant loss of activities. 相似文献
10.