全文获取类型
收费全文 | 1723篇 |
免费 | 179篇 |
专业分类
1902篇 |
出版年
2022年 | 16篇 |
2021年 | 25篇 |
2020年 | 14篇 |
2019年 | 12篇 |
2018年 | 29篇 |
2017年 | 19篇 |
2016年 | 43篇 |
2015年 | 78篇 |
2014年 | 83篇 |
2013年 | 89篇 |
2012年 | 124篇 |
2011年 | 90篇 |
2010年 | 61篇 |
2009年 | 72篇 |
2008年 | 90篇 |
2007年 | 84篇 |
2006年 | 90篇 |
2005年 | 116篇 |
2004年 | 94篇 |
2003年 | 80篇 |
2002年 | 79篇 |
2001年 | 20篇 |
2000年 | 19篇 |
1999年 | 30篇 |
1998年 | 21篇 |
1997年 | 24篇 |
1996年 | 26篇 |
1995年 | 32篇 |
1994年 | 22篇 |
1993年 | 20篇 |
1992年 | 21篇 |
1991年 | 12篇 |
1990年 | 13篇 |
1989年 | 18篇 |
1988年 | 10篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1984年 | 10篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1977年 | 14篇 |
1975年 | 12篇 |
1974年 | 13篇 |
1973年 | 7篇 |
1969年 | 7篇 |
1968年 | 8篇 |
1966年 | 10篇 |
1965年 | 8篇 |
排序方式: 共有1902条查询结果,搜索用时 15 毫秒
31.
Gijsen HJ Berthelot D De Cleyn MA Geuens I Brône B Mercken M 《Bioorganic & medicinal chemistry letters》2012,22(2):797-800
The transient receptor potential A1 (TRPA1) channel has been implicated in a number of inflammatory and nociceptive processes, and antagonists of the TRPA1 receptor could offer a potential treatment for conditions such as inflammatory or neuropathic pain, airway disorders, and itch. In a high throughput screen aimed at the identification of TRPA1 antagonists, 4-phenyl-2-thioxo-1,2,3,4-tetrahydro-indeno[1,2-d]pyrimidin-5-one (1) was identified as a potent TRPA1 receptor antagonist. A series of analogous tricyclic 3,4-dihydropyrimidine-2-thiones has been prepared via the multi-component Biginelli reaction and subsequent derivatization. This has led to TRPA1 antagonists with potencies around 10nM for both rat and human derived TRPA1 receptors. The activity was shown to reside exclusively in the 4R-enantiomers. 相似文献
32.
33.
A physiological role for paraoxonase (PON1) is still uncertain, but it catalyzes the hydrolysis of toxic organophosphates. Evidence that the human genome contains twoPON1-like genes, designatedPON2andPON3,is presented here. HumanPON1andPON2each have nine exons, and the exon/intron junctions occur at equivalent positions.PON1andPON2genes are both on chromosome 7 in human and on chromosome 6 in the mouse. Turkey and chicken, like most birds, lack paraoxonase activity and are very susceptible to organophosphates. However, they have aPON-like gene with 70% identity with humanPON1, PON2,andPON3.Another unexpected finding is that the deduced amino acid sequences of PON2 in human, mouse, dog, turkey, and chicken and of human PON3 are all missing the amino acid residue 105, which is lysine in human PON1. The expanded number ofPONgenes will have important implications for future experiments designed to discover the individual functions, catalytic properties, and physiological roles of the paraoxonases. 相似文献
34.
35.
Macnair MR Bert V Huitson SB Saumitou-Laprade P Petit D 《Proceedings. Biological sciences / The Royal Society》1999,266(1434):2175-2179
The hyperaccumulation of metals by a rare class of plants is a fascinating and little understood phenomenon. No genetic analysis has been possible since no intraspecific variation is known for this character. Here, we report on crosses between the zinc-hyperaccumulating and -tolerant species Arabidopsis halleri and the non-hyperaccumulating, non-tolerant species Arabidopsis petraea. The F2 segregates for both characters and it appears that the two characters are genetically independent. The data for tolerance are consistent with a single major gene for this character (although the number of genes for hyperaccumulation cannot be determined), and is probably not very large. 相似文献
36.
37.
38.
Lactococcus lactis has many properties that are ideal for enhanced expression of membrane proteins. The organism is easy and inexpensive to culture, has a single membrane and relatively mild proteolytic activity. Methods for genetic manipulation are fully established and a tightly controlled promoter system is available, with which the level of expression can be varied with the inducer concentration. Here we describe our experiences with lactococcal expression of the mechanosensitive channel, the human KDEL receptor and transporters belonging to the ABC transporter family, the major facilitator superfamily, the mitochondrial carrier family and the peptide transporter family. Previously published expression studies only deal with the overexpression of prokaryotic membrane proteins, but in this paper, experimental data are presented for the overproduction of mitochondrial and hydrogenosomal carriers and the human KDEL receptor. These eukaryotic membrane proteins were expressed in a functional form and at levels amenable to structural work. 相似文献
39.
40.
Transporters and their roles in LAB cell physiology 总被引:3,自引:0,他引:3
Poolman B 《Antonie van Leeuwenhoek》2002,82(1-4):147-164