全文获取类型
收费全文 | 4194篇 |
免费 | 647篇 |
国内免费 | 1101篇 |
出版年
2024年 | 7篇 |
2023年 | 85篇 |
2022年 | 121篇 |
2021年 | 203篇 |
2020年 | 191篇 |
2019年 | 255篇 |
2018年 | 196篇 |
2017年 | 170篇 |
2016年 | 177篇 |
2015年 | 287篇 |
2014年 | 331篇 |
2013年 | 332篇 |
2012年 | 392篇 |
2011年 | 407篇 |
2010年 | 306篇 |
2009年 | 262篇 |
2008年 | 293篇 |
2007年 | 276篇 |
2006年 | 274篇 |
2005年 | 188篇 |
2004年 | 234篇 |
2003年 | 235篇 |
2002年 | 206篇 |
2001年 | 111篇 |
2000年 | 92篇 |
1999年 | 78篇 |
1998年 | 61篇 |
1997年 | 33篇 |
1996年 | 18篇 |
1995年 | 17篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1950年 | 1篇 |
排序方式: 共有5942条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Stoichiometries, equilibrium constants and optical extinction coefficients of calcium-antipyrylazo III (An) complexing are determined with the analytical method described in article I of this series. Spcctrophotometric Ca titrations of An at the wavelengths 595 and 710 nm indicate overall dissociation equilibrium constants for the complexes CaAn, CaAn2 and Ca2An to be 4.5 × 10?4 M, 1.1 × 10?8 M2 and 1.5× 10?6 M2, respectively, extrapolated to zero ionic strength. Ca titrations of solutions containing An plus acetylcholine receptor protein give clear evidence that An binds to the protein to a large extent in the presence of Ca2+; furthermore, addition of acetylcholine results in release of protein-bound Ca and An. This is the first reported indication that antipyrylazo III binds to biological material and questions the usefulness of this dye as a Ca indicator in biological systems. 相似文献
5.
Skeletal myoblasts withdrawing from cell cycle is a prerequisite for myodifferentiation, while upon proliferation/differentiation transformation, a large portion of myoblasts will undergo apoptosis. Skeletal fibroblasts, residing in muscle tissue both during and post myogenesis, have been proofed to play pivotal roles in muscle development, while their effect on myoblast apoptosis being coincident with differentiation has not been reported. Using a membrane insert co‐culture system, we studied it and found that the mitochondrial pathway played a crucial role in myoblast apoptosis during differentiation, and fibroblasts promoted not only cell cycle withdrawal but also myoblast survival in a paracrine fashion, which was coupled with upregulations of β1 integrin, phosphorylated Akt and anti‐apoptotic protein Bcl2. To determine the effect of β1 integrin in the process, we transfected myoblasts with siRNA specific for β1 integrin before co‐culture and found that β1 integrin knockdown abolished anti‐apoptotic ability of myoblasts and inhibited Akt activation and Bcl2 expression. Blockage of PI3K/Akt pathway with wortmannin also seriously impaired the protective effect of fibroblasts on myoblasts and fibroblast‐induced Bcl2 expression. The data demonstrated that fibroblasts protected myoblasts from intrinsic apoptosis associated with differentiation, and β1 integrin‐PI3K/Akt pathway activation was required for the process. 相似文献
6.
7.
Khuram Shahzad Abdul Hai Nadeem Kizilbash Jawaria Ambreen Jamal Alruwaili 《Bioinformation》2013,9(9):471-476
DNA γ is approximately half of the size of Begomovirus DNA. It encodes a γC1 gene that is conserved in position and size. This
gene has the capacity to encode a 13 to 14 kDa protein comprising 118 amino acid residues. It has been shown earlier that γC1
protein is necessary for inducing symptoms of cotton leaf curl disease. The structure for γC1 (CLCuDγ01-Pakistan) is still
unknown. Therefore, a model of γC1 (CLCuDγ01-Pakistan) was developed using DoBo and I-TASSER servers followed by
validation by PROCHECK and VERIFY 3D servers. The developed model provides an insight in a role for this multifunctional
protein in causing Cotton Leaf Curl Disease (CLCuD). A possible function of this protein might be the suppression of RNAsilencing
in cotton plants. 相似文献
8.
9.
10.