全文获取类型
收费全文 | 936篇 |
免费 | 58篇 |
国内免费 | 1篇 |
出版年
2024年 | 2篇 |
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 11篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 25篇 |
2014年 | 32篇 |
2013年 | 47篇 |
2012年 | 61篇 |
2011年 | 59篇 |
2010年 | 39篇 |
2009年 | 44篇 |
2008年 | 56篇 |
2007年 | 74篇 |
2006年 | 68篇 |
2005年 | 42篇 |
2004年 | 59篇 |
2003年 | 55篇 |
2002年 | 56篇 |
2001年 | 17篇 |
2000年 | 12篇 |
1999年 | 16篇 |
1998年 | 12篇 |
1997年 | 11篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 13篇 |
1992年 | 6篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1970年 | 2篇 |
排序方式: 共有995条查询结果,搜索用时 109 毫秒
1.
2.
3.
Gza dm Ferenc Jo Pter Temesvri Ern Dux Pter Szerdahelyi 《Neurochemistry international》1987,10(4):529-532
Kinetic parameters of the albumin transport were measured during and after an acute hypoxic insult evoked in newborn piglets by experimental bilateral pneumothorax. Adenylate cyclase activity was determined in the cerebral microvessels isolated by ultracentrifugation from different stages of brain damage. A decrease of the adenylate cyclase activity was observed in the cerebral microvessels of animals with acute hypoxic condition. However, the adenylate cyclase activity was found to be increased significantly in the microvessels during recirculation.
The activation of adenylate cyclase in the microvessel wall may be of pathogenetic importance in the development of vasogenic brain oedema. 相似文献
4.
Mutation detection using nucleotide analogs that alter electrophoretic mobility. 总被引:5,自引:3,他引:2 下载免费PDF全文
A simple primer extension assay has been developed to distinguish homologous DNA segments differing by as little as a single nucleotide. DNA strands are synthesized with one of the four natural nucleotides replaced with an analog that affects electrophoretic mobility. DNAs that are the same length but differ in the number of analog molecules per strand exhibit different mobilities on a sequencing gel. In combination with the polymerase chain reaction (PCR; 1, 2), this method has been used to distinguish mutant and normal alleles of the human insulin receptor gene that differ by a single-base substitution. The method appears to be generally applicable to the detection of any nucleotide polymorphism in any segment of DNA. 相似文献
5.
DNA polymorphisms amplified by arbitrary primers are useful as genetic markers. 总被引:1015,自引:32,他引:983 下载免费PDF全文
J G Williams A R Kubelik K J Livak J A Rafalski S V Tingey 《Nucleic acids research》1990,18(22):6531-6535
Molecular genetic maps are commonly constructed by analyzing the segregation of restriction fragment length polymorphisms (RFLPs) among the progeny of a sexual cross. Here we describe a new DNA polymorphism assay based on the amplification of random DNA segments with single primers of arbitrary nucleotide sequence. These polymorphisms, simply detected as DNA segments which amplify from one parent but not the other, are inherited in a Mendelian fashion and can be used to construct genetic maps in a variety of species. We suggest that these polymorphisms be called RAPD markers, after Random Amplified Polymorphic DNA. 相似文献
6.
T-cell receptor alpha locus V(D)J recombination by-products are abundant in thymocytes and mature T cells. 总被引:16,自引:1,他引:15 下载免费PDF全文
In addition to the assembled coding regions of immunoglobulin and T-cell receptor (TCR) genes, the V(D)J recombination reaction can in principle generate three types of by-products in normal developing lymphocytes: broken DNA molecules that terminate in a recombination signal sequence or a coding region (termed signal or coding end molecules, respectively) and DNA molecules containing fused recombination signal sequences (termed reciprocal products). Using a quantitative Southern blot analysis of the murine TCR alpha locus, we demonstrate that substantial amounts of signal end molecules and reciprocal products, but not coding end molecules, exist in thymocytes, while peripheral T cells contain substantial amounts of reciprocal products. At the 5' end of the J alpha locus, 20% of thymus DNA exists as signal end molecules. An additional 30 to 40% of the TCR alpha/delta locus exists as remarkably stable reciprocal products throughout T-cell development, with the consequence that the TCR C delta region is substantially retained in alpha beta committed T cells. The disappearance of the broken DNA molecules occurs in the same developmental transition as termination of expression of the recombination activating genes, RAG-1 and RAG-2. These findings raise important questions concerning the mechanism of V(D)J recombination and the maintenance of genome integrity during lymphoid development. 相似文献
7.
8.
In vivo definition of the functional origin of replication (ori(+ )) of the promiscuous plasmid pLS1
The nocR gene of Agrobacterium tumefaciens Ti plasmid pTiT37 is the regulatory gene of the nopaline catabolism (noc) operon of pTiT37. We have cloned and sequenced nocR, which encodes a DNA-binding protein. The deduced amino acid sequence is similar to those of members of the LysR family of prokaryotic activator proteins. Gel retardation experiments demonstrated that the NocR protein binds to the nocR promoter in both the presence and absence of nopaline. The increased mobility of the complex and alterations in the DNase I footprints revealed a nopaline-induced conformational change in the NocR-DNA complex. Sequence analysis of the NocR binding site indicated the presence immediately downstream of the –10 sequence of the nocR promoter of a 12 by putative operator overlapping a consensus gyrase recognition sequence and an 18 by long alternating purine-pyrimidine sequence. These results suggest that nopaline-induced alterations in the NocR protein-nocR promoter complex might control gene expression in the noc operon. 相似文献
9.
István Papp László Dorgai Péter Papp Erzsébet Jónás Ferenc Olasz László Orosz 《Molecular & general genetics : MGG》1993,240(2):258-264
Bacteriophage 16-3 inserts its genome into the chromosome of Rhizobium meliloti strain 41 (Rm41) by site-specific recombination. The DNA regions around the bacterial attachment site (attB) and one of the hybrid attachment sites bordering the integrated prophage (attL) were cloned and their nucleotide sequences determined. We demonstrated that the 51 by region, where the phage and bacterial DNA sequences are identical, is active as a target site for phage integration. Furthermore it overlaps the 3 end of a putative proline tRNA gene. This gene shows 79% similartiy to the corresponding proline tRNA-like genomic target sequence of certain integrative plasmids in Actinomycetes. 相似文献
10.