全文获取类型
收费全文 | 888篇 |
免费 | 68篇 |
专业分类
956篇 |
出版年
2022年 | 18篇 |
2021年 | 22篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 22篇 |
2017年 | 18篇 |
2016年 | 26篇 |
2015年 | 35篇 |
2014年 | 41篇 |
2013年 | 78篇 |
2012年 | 72篇 |
2011年 | 65篇 |
2010年 | 45篇 |
2009年 | 42篇 |
2008年 | 67篇 |
2007年 | 50篇 |
2006年 | 51篇 |
2005年 | 41篇 |
2004年 | 31篇 |
2003年 | 53篇 |
2002年 | 43篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 10篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1978年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 7篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1954年 | 1篇 |
1951年 | 1篇 |
1943年 | 1篇 |
排序方式: 共有956条查询结果,搜索用时 15 毫秒
81.
Quintavalle M Sambucini S Summa V Orsatti L Talamo F De Francesco R Neddermann P 《The Journal of biological chemistry》2007,282(8):5536-5544
The hepatitis C virus encodes a single polyprotein that is processed by host and viral proteases to yield at least 10 mature viral proteins. The nonstructural (NS) protein 5A is a phosphoprotein, and experimental data indicate that the phosphorylation state of NS5A is important for the outcome of viral RNA replication. We were able to identify kinase inhibitors that specifically inhibit the formation of the hyperphosphorylated form of NS5A (p58) in cells. These kinase inhibitors were used for inhibitor affinity chromatography in order to identify the cellular targets of these compounds. The kinases casein kinase I (CKI), p38 MAPK, CIT (Citron Rho-interacting kinase), GAK, JNK2, PKA, RSK1/2, and RIPK2 were identified in the high affinity binding fractions of two NS5A hyperphosphorylation inhibitors (NS5A-p58-i). Even though these kinases are targets of the NS5A-p58-i, the only kinase showing an effect on NS5A hyperphosphorylation was confirmed to be CKI-alpha. Although this finding does not exclude the possibility that other kinase(s) might be involved in basal or regulatory phosphorylation of NS5A, we show here that NS5A is a direct substrate of CKI-alpha. Moreover, in vitro phosphorylation of NS5A by CKI-alpha resulted for the first time in the production of basal and hyperphosphorylated forms resembling those produced in cells. In vitro kinase reactions performed with NS5A peptides show that Ser-2204 is a preferred substrate residue for CKI-alpha after pre-phosphorylation of Ser-2201. 相似文献
82.
83.
After hyperventilation, systolic and diastolic blood pressure (BP) significantly decreased in 14 hypertensive patients (group 1), did not change in 9 (group 2) and increased in 8 (group 3). Basal BP, norepinephrine and dynorphin B levels were higher in group 1 than in groups 2 and 3. The decrease in BP after hyperventilation was associated with a decrease in plasma norepinephrine, Met-enkephalin and dynorphin B and an increase in beta-endorphin. Naloxone abolished the hyperventilation-induced BP and norepinephrine decreases. Our findings indicate that hyperventilation may select hypertensive patients with different sympatho-adrenergic activity and that the increase in beta-endorphin reduces BP response to hyperventilation in patients with high sympatho-adrenergic tone. 相似文献
84.
Guido Cipriani Alessandro Spadotto Irena Jurman Gabriele Di Gaspero Manna Crespan Stefano Meneghetti Enrica Frare Rita Vignani Mauro Cresti Michele Morgante Mario Pezzotti Enrico Pe Alberto Policriti Raffaele Testolin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,121(8):1569-1585
A collection of 1005 grapevine accessions was genotyped at 34 microsatellite loci (SSR) with the aim of analysing genetic diversity and exploring parentages. The comparison of molecular profiles revealed 200 groups of synonymy. The removal of perfect synonyms reduced the database to 745 unique genotypes, on which population genetic parameters were calculated. The analysis of kinship uncovered 74 complete pedigrees, with both parents identified. Many of these parentages were not previously known and are of considerable historical interest, e.g. Chenin blanc (Sauvignon × Traminer rot), Covè (Harslevelu selfed), Incrocio Manzoni 2–14 and 2–15 (Cabernet franc × Prosecco), Lagrein (Schiava gentile × Teroldego), Malvasia nera of Bolzano (Perera × Schiava gentile), Manzoni moscato (Raboso veronese × Moscato d’Amburgo), Moscato violetto (Moscato bianco × Duraguzza), Muscat of Alexandria (Muscat blanc à petit grain × Axina de tres bias) and others. Statistical robustness of unexpected pedigrees was reinforced with the analysis of an additional 7–30 SSRs. Grouping the accessions by profile resulted in a weak correlation with their geographical origin and/or current area of cultivation, revealing a large admixture of local varieties with those most widely cultivated, as a result of ancient commerce and population flow. The SSRs with tri- to penta-nucleotide repeats adopted for the present study showed a great capacity for discriminating amongst accessions, with probabilities of identity by chance as low as 1.45 × 10?27 and 9.35 × 10?12 for unrelated and full sib individuals, respectively. A database of allele frequencies and SSR profiles of 32 reference cultivars are provided. 相似文献
85.
Many analyses published in the last decade suggest that enzymes isolated from cold-adapted organisms are characterized by a higher flexibility of their molecular structure. Recently, it has been argued that all cold-adapted enzymes with catalytic efficiency greater than that of their mesophilic counterparts display local flexibility or rigidity that are likely to cooperate, each acting on specific areas of the enzyme structure. Here we report an analysis of the normalized thermal B-factor distributions in psychrophilic proteins compared with those of their mesophilic and thermophilic counterparts with the aim to detect statistically significant local variations of relative backbone flexibility possibly linked to cold adaptation. We utilized a strategy based mainly on intra-family comparison of local distribution of normalized B-factors. After careful statistical treatment of data, the picture emerging from our results suggests that the distribution of the flexibility in psychrophilic enzymes is locally more heterogeneous than in their respective mesophilic homologues. 相似文献
86.
An Autonomously Replicating Transforming Vector for Sulfolobus solfataricus 总被引:2,自引:0,他引:2 下载免费PDF全文
Raffaele Cannio Patrizia Contursi Mos Rossi Simonetta Bartolucci 《Journal of bacteriology》1998,180(12):3237-3240
A plasmid able to transform and to be stably maintained both in Sulfolobus solfataricus and in Escherichia coli was constructed by insertion into an E. coli plasmid of the autonomously replicating sequence of the virus particle SSV1 and a suitable mutant of the hph (hygromycin phosphotransferase) gene as the transformation marker. The vector suffered no rearrangement and/or chromosome integration, and its copy number in Sulfolobus was increased by exposure of the cells to mitomycin C. 相似文献
87.
Summary A case of D ring chromosome identified with trypsin banding as a 13 with loss of the bands p12 and q34 is reported. The clinical features characteristically associated with the loss of these specific segments were present. 相似文献
88.
In vitro leishmanicidal activity of a monoclonal antibody mimicking a yeast killer toxin 总被引:5,自引:0,他引:5
Savoia D Avanzini C Conti S Magliani V Frazzi R Polonelli L 《The Journal of eukaryotic microbiology》2002,49(4):319-323
The microbicidal effect of a monoclonal antiidiotypic antibody, mimicking the activity of a yeast killer toxin, characterized by a wide antimicrobial spectrum, has been evaluated in vitro against two relevant species of protozoan parasites, Leishmania major and Leishmania infantum. The antiidiotypic antibody exerted a significant and dose-dependent antileishmanial activity against parasite promastigotes in comparison to an irrelevant isotype-matched monoclonal antibody. This is the first demonstration that an antibody, which had been already shown to be fungicidal and bactericidal, may also exert a direct microbicidal activity against protozoa. 相似文献
89.
90.
Adelaide Greco Monica Ragucci Anna Rita Daniela Coda Alessandro Rosa Sara Gargiulo Raffaele Liuzzi Matteo Gramanzini Sandra Albanese Sabina Pappatà Marcello Mancini Arturo Brunetti Marco Salvatore 《PloS one》2013,8(10)