全文获取类型
收费全文 | 4698篇 |
免费 | 189篇 |
国内免费 | 21篇 |
专业分类
化学 | 3099篇 |
晶体学 | 36篇 |
力学 | 210篇 |
数学 | 407篇 |
物理学 | 1156篇 |
出版年
2023年 | 18篇 |
2022年 | 44篇 |
2021年 | 109篇 |
2020年 | 74篇 |
2019年 | 89篇 |
2018年 | 48篇 |
2017年 | 48篇 |
2016年 | 119篇 |
2015年 | 134篇 |
2014年 | 176篇 |
2013年 | 284篇 |
2012年 | 329篇 |
2011年 | 379篇 |
2010年 | 230篇 |
2009年 | 207篇 |
2008年 | 327篇 |
2007年 | 264篇 |
2006年 | 272篇 |
2005年 | 226篇 |
2004年 | 193篇 |
2003年 | 160篇 |
2002年 | 186篇 |
2001年 | 119篇 |
2000年 | 103篇 |
1999年 | 72篇 |
1998年 | 51篇 |
1997年 | 35篇 |
1996年 | 59篇 |
1995年 | 51篇 |
1994年 | 44篇 |
1993年 | 52篇 |
1992年 | 41篇 |
1991年 | 45篇 |
1990年 | 29篇 |
1989年 | 26篇 |
1988年 | 29篇 |
1987年 | 23篇 |
1986年 | 19篇 |
1985年 | 30篇 |
1984年 | 23篇 |
1983年 | 24篇 |
1982年 | 20篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1972年 | 5篇 |
排序方式: 共有4908条查询结果,搜索用时 15 毫秒
1.
Kang Il Yoo Ji Yeong Jeon Su Jeong Ryu Giri Nam Hyewon Youn Eun Young Choi 《Experimental & molecular medicine》2015,47(2):e140
In allogeneic transplantation, including the B6 anti-BALB.B settings, H60 and H4 are two representative dominant minor histocompatibility antigens that induce strong CD8 T-cell responses. With different distribution patterns, H60 expression is restricted to hematopoietic cells, whereas H4 is ubiquitously expressed. H60-specific CD8 T-cell response has been known to be dominant in most cases of B6 anti-BALB.B allo-responses, except in the case of skin transplantation. To understand the mechanism underlying the subdominance of H60 during allogeneic skin transplantation, we investigated the dynamics of the H60-specific CD8 T cells in B6 mice transplanted with allogeneic BALB.B tail skin. Unexpectedly, longitudinal bioluminescence imaging and flow cytometric analyses revealed that H60-specific CD8 T cells were not always subdominant to H4-specific cells but instead showed a brief dominance before the H4 response became predominant. H60-specific CD8 T cells could expand in the draining lymph node and migrate to the BALB.B allografts, indicating their active participation in the anti-BALB.B allo-response. Enhancing the frequencies of H60-reactive CD8 T cells prior to skin transplantation reversed the immune hierarchy between H60 and H4. Additionally, H60 became predominant when antigen presentation was limited to the direct pathway. However, when antigen presentation was restricted to the indirect pathway, the expansion of H60-specific CD8 T cells was limited, whereas H4-specific CD8 T cells expanded significantly, suggesting that the temporary immunodominance and eventual subdominance of H60 could be due to their reliance on the direct antigen presentation pathway. These results enhance our understanding of the immunodominance phenomenon following allogeneic tissue transplantation. 相似文献
2.
In this paper, we shall find the uniquerational price associated with the exchange option. Also, we find the decomposition of Snell envelope and value function of the American exchange option. 相似文献
3.
4.
Band bending at the Ni/Si(100)-2×1 interface has been monitored by using Si 2p core level photoemission spectra. Two nickel-induced Si 2p components appear in the initial interaction between Ni and Si(100)-2×1, which is confined at the top surface and the first subsurface layers. At Ni coverage less than 0.0375 ML, Ni atoms prefer the adamantane interstitial sites on the first subsurface, but switch to the pedestal sites on Si dimer rows at higher Ni coverage. The change in the preferred occupation sites of Ni atoms on the Si(100)-2×1 surface strongly affects the amount of band bending shift. The shift towards higher binding energy, when Ni atoms occupy the adamantane interstitial sites, is attributed to metal-induced-gap states. While Ni atoms occupy the pedestal sites, the band bending shift is reduced which is attributed to the passivation of surface states. 相似文献
5.
Gil Tae Hwang 《Tetrahedron letters》2004,45(18):3543-3546
We describe the design and properties of a pyrene-labeled deoxyuridine that can be inserted efficiently into oligodeoxynucleotides using phosphoramidite chemistry. An oligonucleotide incorporating the pyrene-labeled deoxyuridine is a sensitive fluorescence probe that can discriminate between perfect and single-base-mismatched pairing by changes in its fluorescence intensity. 相似文献
6.
We examine several interesting relationships and expressions involving Fourier-Feynman transform, convolution product and
first variation for functionals in the Fresnel class F(B) of an abstract Wiener space B. We also prove a translation theorem and Parseval's identity for the analytic Feynman integral.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
Aiqing Zhang Xiangdan Li Changwoon Nah Keejun Hwang Myong‐Hoon Lee 《Journal of polymer science. Part A, Polymer chemistry》2003,41(1):22-29
A soluble aromatic polyimide was chloromethylated via a reaction with chloromethyl methyl ether in the presence of tin(IV) chloride to produce a new starting material for the modification of aromatic polyimides. The chemical structure of the resulting polymer was confirmed by 1H NMR and Fourier transform infrared spectroscopy. The maximum number of chloromethyl groups per repeat unit was 1.81. The chloromethylated polyimide was stable up to 250 °C and soluble in both chloroform and tetrahydrofuran. So that its utilization for further modification could be demonstrated, cinnamic acid was reacted with the formed polyimide, and it produced a new photosensitive polyimide with a cinnamoyl side chain. The photosensitivity of the resulting polyimide was investigated with ultraviolet spectroscopic methods. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 22–29, 2003 相似文献
8.
9.
Seok‐Ho Hwang Kyung Soo Yoo Charles N. Moorefield Sang‐Won Lee George R. Newkome 《Journal of Polymer Science.Polymer Physics》2004,42(8):1487-1495
A series of metallodendrimers, assembled by means of bis(terpyridinyl)Ru(II) connectivity on poly(propylene imine) dendrimer scaffolds, with homogeneous or heterogeneous surfaces, were prepared. Differential scanning calorimetry and thermogravimetric analysis were used to determine their thermal behavior, glass‐transition temperatures, and the decomposition kinetics and temperatures; no synergy effects for these properties were observed for the heterogeneously surfaced constructs in contrast to the corresponding homogeneously coated materials, which exhibited different values depending on their surface functionalities. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1487–1495, 2004 相似文献
10.
We propose means for computing the Fourier expansions of periodic
functions appearing in higher moments of the sum-of-digits
function and in the solutions of some divide-and-conquer
recurrences. The expansions are shown to be absolutely
convergent. We also give a new approach to efficiently compute
numerically the coefficients involved to high precision. 相似文献