全文获取类型
收费全文 | 810篇 |
免费 | 85篇 |
出版年
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 16篇 |
2017年 | 19篇 |
2016年 | 32篇 |
2015年 | 38篇 |
2014年 | 30篇 |
2013年 | 39篇 |
2012年 | 56篇 |
2011年 | 54篇 |
2010年 | 43篇 |
2009年 | 26篇 |
2008年 | 40篇 |
2007年 | 41篇 |
2006年 | 32篇 |
2005年 | 44篇 |
2004年 | 38篇 |
2003年 | 43篇 |
2002年 | 22篇 |
2001年 | 17篇 |
2000年 | 20篇 |
1999年 | 18篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 19篇 |
1991年 | 16篇 |
1990年 | 18篇 |
1989年 | 12篇 |
1988年 | 13篇 |
1987年 | 10篇 |
1986年 | 14篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1972年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1956年 | 1篇 |
1938年 | 1篇 |
排序方式: 共有895条查询结果,搜索用时 328 毫秒
881.
Induction of CAD gene amplification by restriction endonucleases in V79,B7 Chinese hamster cells 总被引:1,自引:0,他引:1
The restriction endonucleases PvuII, BamHI and EcoRI were tested for their ability to induce gene amplification in V79,B7 Chinese hamster cells. The results indicate that treatment with these enzymes efficiently increases the frequency of clones resistant to N-phosphonacetyl-L-aspartate, indicating induction of CAD gene amplification. 相似文献
882.
Rainbow trout red cells in vitro 总被引:1,自引:0,他引:1
A H Houston C A McCullough J Keen C Maddalena J Edwards 《Comparative biochemistry and physiology. A, Comparative physiology》1985,81(3):555-565
Washed rainbow trout erythrocytes incubated at 14 degrees C in Eagle's minimal essential medium and Cortland saline displayed sharp reductions in volume and water content, nucleoside triphosphate, K+ and Cl- concentrations. Mg2+ and, to a lesser extent, Na+ concentrations increased. Cellular to medium Cl- ratios were indicative of membrane hyperpolarization. Morphological irregularities were also observed. Oxygen consumption and hemoglobin system organization were not grossly affected. Supplementation with pyruvate stabilized nucleoside triphosphate concentrations for at least 24 hr, and reduced rates of volume and compositional change to some extent. Addition of norepinephrine at physiologically realistic levels led to stabilization of Cl- content and reductions in Mg2+ accumulation and water loss. Transient but modest increases in K+ and Ca2+ were coupled, under these circumstances, with some decrease in Na+ concentration. Factors which may contribute to the dysfunctional status of these cells in vitro are discussed. 相似文献
883.
884.
885.
GLUT4 translocation is not impaired after acute exercise in skeletal muscle of women with obesity and polycystic ovary syndrome 下载免费PDF全文
Wagner Silva Dantas José Antonio Miguel Marcondes Samuel Katsuyuki Shinjo Luiz Augusto Perandini Vanessa Olzon Zambelli Willian Das Neves Cristiano Roberto Grimaldi Barcellos Michele Patrocínio Rocha Viviane Dos Reis Vieira Yance Renato Tavares Dos Santos Pereira Igor Hisashi Murai Ana Lucia De Sá Pinto Hamilton Roschel Bruno Gualano 《Obesity (Silver Spring, Md.)》2015,23(11):2207-2215
886.
A Di Leonardo C Agnese P Cavolina A Maddalena G Sciandrello R Randazzo 《Genetical research》1989,53(3):201-206
Some HGPRT spontaneous revertants were isolated from a mutant line (E2) of V79 Chinese hamster cells and phenotypically characterized. Dot-Blot hybridization with a 32P-labelled HGPRT probe revealed an increase in the number of HGPRT sequences in some of these revertants, suggesting the occurrence of gene amplification. Cytogenetic analysis performed in three of these revertants showed a characteristic abnormally banding region (ABR) on the elongated p arm of the X chromosome. In situ hybridization in one revertant (RHE2) showed that the amplified sequences reside on the p+ arm of the X chromosome in two different localizations. Because of the very probably clonal origin of the revertant, these features indicate that the amplified sequences might rearrange after their integration into the chromosome. 相似文献
887.
Guido De Gregório Grimaldi Áthila Andrade Bertoncini 《Zeitschrift fur angewandte Ichthyologie》2021,37(4):611-614
Pugheadness has being recorded in a wide variety of fish families on both natural and non-natural environments, though encountering pughead fish in wild population is rare. Here, we present two new records of pugheadness in the wild, for Myrichthys ocellatus (Ophichthidae), and for Epinephelus marginatus (Epinephelidae). An up to date compilation of the 39 published pugheadness in fish is presented. We believe that with the advancement of information and communication technology in social networks, more records of deformities in fish species will show up through the lenses of citizen science. 相似文献
888.
889.
The verification of DNA sequences obtained from very old tissue sources as indeed ancient is a major point of discussion in the ancient DNA field. Proper controls and the use of the phylogenetic approach are the general methods employed for verification of the ancient DNA. Most studies have reported the recovery of extremely small amounts of nucleic acids which are sheared into rather small fragments. In addition, problems such as ‘PCR jumping’ can produce spurious sequence information. These observations suggest that random amplification techniques and the development of primers for highly informative but short target regions are essential for the further development of the ancient DNA field. 相似文献
890.
T Tancredi E Benedetti M Grimaldi C Pedone F Rossi M Saviano P A Temussi G Zanotti 《Biopolymers》1991,31(6):761-767
CD and nmr techniques have been used to study, in acetonitrile solution, the ion-complexing capability of cyclolinopeptide A (CLA), a cyclic nonapeptide of sequence cyclo-(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val) endowed with remarkable cytoprotective ability in vitro, and the conformation of the Ba(2+)/CLA complex. At room temperature, CLA in acetonitrile shows a proton nmr spectrum characteristic of the coexistence of many different conformers in intermediate exchange. The backbone contains a cis Pro-Pro bond, with all other peptide bonds in the trans conformation. CLA binds Ba2+ more tightly than the other cations studied, namely K+, Na+, Mg2+, and Ca2+; CD data are indicative of the presence of both 1:2 (sandwich) and 1:1 (equimolar) type complexes, depending on the Ba2+ ion concentration, whereas nmr data are consistent with an equimolar form. The relevant conformational features of the equimolar Ba2+/CLA complex are that the backbone contains all trans peptide bonds, a type I 6----3 beta-turn and a 3----1 gamma-turn (or a distorted 3----9 beta-turn). The global shape of the complexed peptide can be described as a bowl, with the concave (polar) side hosting Ba2+ and the convex side predominantly apolar. 相似文献