全文获取类型
收费全文 | 296篇 |
免费 | 9篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 11篇 |
2017年 | 15篇 |
2016年 | 12篇 |
2015年 | 20篇 |
2014年 | 21篇 |
2013年 | 21篇 |
2012年 | 21篇 |
2011年 | 31篇 |
2010年 | 14篇 |
2009年 | 15篇 |
2008年 | 8篇 |
2007年 | 18篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1981年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有305条查询结果,搜索用时 472 毫秒
171.
Rishi K. Tyagi Anuradha Agrawal C. Mahalakshmi Zakir Hussain Husnara Tyagi 《In vitro cellular & developmental biology. Plant》2007,43(1):51-58
Up to 73% decrease in cost of media for plant regeneration and in vitro conservation was achieved in Curcuma longa cv Prathibha by using inexpensive carbon source and gelling agent. Laboratory reagent-grade sucrose was replaced by locally
available commercial sugar (market sugar or sugar cubes) as carbon source and bacteriological grade agar by isabgol (also
named isubgol) as gelling agent. No adverse effects on shoot regeneration and conservation on isabgol-gelled low-cost media
were observed as compared to that on agar-gelled control medium (CM). Some 33–56% cultures of C. longa survived up to 12 mo. on isabgol-gelled medium in comparison to only 16% on CM. Genetic stability of 12-month-old in vitro-conserved plants was assessed using 25 random amplified polymorphic DNA (RAPD) primers; no significant variation was observed
in RAPD profiles of mother plants and in vitro-conserved plantlets on CM and low-cost media. 相似文献
172.
gp130 is a shared signal-transducing membrane-associated receptor for several hematopoietic cytokines. The 30 A resolution cryo-electron microscopy (cryo-EM) structure of the Interleukin 11(IL-11)-IL-11 Receptor-gp130 extracellular complex reveals the architecture and dynamics of this gp130-containing signaling complex. Normal-mode analysis reveals a repertoire of conformational changes that could function in signal triggering. This suggests a concerted mechanism of signaling involving all the components of the complex. This could provide a general mechanism of signal transfer for cytokines utilizing the JAK-STAT signaling cascade. 相似文献
173.
Somvanshi RK Kumar A Kant S Gupta D Singh SB Das U Srinivasan A Singh TP Dey S 《Biochemical and biophysical research communications》2007,361(1):37-42
Cyclooxygenase (COX) is a key enzyme in the biosynthetic pathway leading to the formation of prostaglandins, which are mediators of inflammation [D.L. Dewitt, W.L. Smith, Primary structure of prostaglandin G/H synthase from sheep vesicular gland determined from the complementary DNA sequence, Proc. Natl. Acad. Sci. USA 85 (1988) 1412-1416, 1]. It exists mainly in two isoforms COX-1 and COX-2 [A. Raz, A. Wyche, N. Siegel, P. Needleman, Regulation of fibroblast cyclooxygenase synthesis by interleukin-1, J. Biol. Chem. 263 (1988) 3022-3028, 2]. The conventional non-steroidal anti-inflammatory drugs (NSAIDs) have adverse gastrointestinal side-effects, because they inhibit both isoforms [T.D. Warner, F. Guiliano, I. Vojnovic, A. Bukasa, J.A. Mitchell, J.P. Vane, Nonsteroid drug selectivities for cyclo-oxygenase-1 rather than cyclo-oxygenase-2 are associated with human gastrointestinal toxicity: a full in vitro analysis, Proc. Natl. Acad. Sci. USA 96 (1999) 7563-7568, 3; L.J. Marnett, A.S. Kalgutkar, Cyclooxygenase 2 inhibitors: discovery, selectivity and the future, Trends Pharmacol. Sci. 20 (1999) 465-469, 4; J.R. Vane, NSAIDs, Cox-2 inhibitors, and the gut, Lancet 346 (1995) 1105-1106, 5]. Therefore drugs which selectively inhibit COX-2, known as coxibs were developed. Recent reports on the harmful cardiovascular and renovascular side-effects of the anti-inflammatory drugs have led to the quest for a novel class of COX-2 selective inhibitors. Keeping this in mind, we have used the X-ray crystal structures of the complexes of the COX-1 and COX-2 with the known inhibitors for a rational, structure based approach to design a small peptide, which is potent inhibitor for COX-2. The peptides have been checked experimentally by in-vitro kinetic studies using surface plasmon resonance (SPR) and other biochemical methods. We have identified a tripeptide inhibitor which is a potential lead for a new class of COX-2 inhibitor. The dissociation constant (K(D)) determined for COX-2 with peptide WCS is 1.90x10(-10)M, the kinetic constant (K(i)) determined by spectrophotometry is 4.85x10(-9)M and the IC(50) value is 1.5x10(-8)M by ELISA test. 相似文献
174.
Padma Nimmakayala Venkata Lakshmi Abburi Abhishek Bhandary Lavanya Abburi Venkata Gopinath Vajja Rishi Reddy Sridhar Malkaram Pegadaraju Venkatramana Asela Wijeratne Yan R. Tomason Amnon Levi Todd C. Wehner Umesh K. Reddy 《Molecular breeding : new strategies in plant improvement》2014,34(2):537-548
Watermelon (Citrullus lanatus var. lanatus) is one of the most important vegetable crops in the world. Molecular markers have become the tools of choice for resolving watermelon taxonomic relationships and evolution. Increased numbers of single nucleotide polymorphism (SNP) markers together with simple sequence repeat (SSR) markers would be useful for phylogenetic analyses of germplasm accessions and for linkage mapping for marker-assisted breeding with quantitative trait loci and single genes. We aimed to construct a genetic map based on SNPs (generated by Illumina Veracode multiplex assays for genotyping) and SSR markers and evaluate relationships inferred from SNP genotypes between 130 watermelon accessions collected throughout the world. We incorporated 282 markers (232 SNPs and 50 SSRs) into the linkage map. The genetic map consisted of 11 linkage groups spanning 924.72 cM with an average distance of 3.28 cM between markers. Because all of the SNP-containing sequences were assembled with the whole-genome sequence draft for watermelon, chromosome numbers could be readily assigned for all the linkage groups. We found that 134 SNPs were polymorphic in 130 watermelon accessions chosen for diversity studies. The current 384-plex SNP set is a powerful tool for characterizing genetic relatedness and for developing medium-resolution genetic maps. 相似文献
175.
176.
Stefan Peukert Rishi K. Jain Adrian Geisser Yingchuan Sun Rui Zhang Aaron Bourret Adam Carlson Jennifer DaSilva Arun Ramamurthy Joseph F. Kelleher 《Bioorganic & medicinal chemistry letters》2009,19(2):328-331
Ortho-biphenyl carboxamides, originally prepared as inhibitors of microsomal triglyceride transfer protein (MTP) have been identified as novel inhibitors of the Hedgehog signaling pathway. Structure–activity relationship studies for this class of compounds reduced MTP inhibitory activity and led to low nanomolar Hedgehog inhibitors. Binding assays revealed that the compounds act as antagonists of Smoothened and show cross-reactivity for both the human and mouse receptor. 相似文献
177.
Cost-effective in vitro conservation of banana using alternatives of gelling agent (isabgol) and carbon source (market sugar) 总被引:1,自引:0,他引:1
Anuradha Agrawal Rajkumari Sanayaima Rajesh Tandon Rishi K. Tyagi 《Acta Physiologiae Plantarum》2010,32(4):703-711
To decrease the cost of in vitro conservation of banana cv. Karpura Chakkarakeli (AAB; Mysore subgroup) without any adverse
effects on cultures, expensive components of medium such as sucrose and gelling agents, i.e. phytagel or agar (90% of the
total cost of the medium), were replaced with inexpensive alternates such as market sugar and isabgol, respectively (Experiment
1). In general, no significant effects of isabgol and market sugar were observed on shoot (1.0–1.3 shoots/shoot explant) and
root (1.5–2.0 roots/shoot explant) regeneration. Up to 12 months, 100% of cultures survived on isabgol-media, which was significantly
higher than that on agar-media (79–83%) and on phytagel-media (51–57%). Isabgol-media with or without other constituents of
medium were also tested for survival of banana cultures (Experiment 2); significant differences were observed for survival
of cultures (20–100%). Slow growth of the cultures on isabgol-media was attributed to low availability of free water and consequently
slower rate of transport of nutrients from isabgol matrix to the plantlets than that of other media tested, as evidenced by
significantly lower relative matric potentials (0.801 and 0.804) of isabgol-media. In vitro conservation-derived plants grown
in the field exhibited no significant morphological variations. The total cost of medium used for in vitro conservation of
banana was decreased by 59% by using isabgol as an alternate gelling agent to agar and phytagel. 相似文献
178.
Saba Hasan Anis Ahmad Abhinav Purwar Nausheen Khan Rishi Kundan Garima Gupta 《Bioinformation》2013,9(5):238-242
This study investigates the mechanisms as well as strategies for purification and characterization of potential enzymes involved in
pathogenesis of entomopathogenic fungi. The test strain of Verticillium lecanii that was screened, during the present investigation,
proved to be an efficient producer of protein and polysaccharide degrading enzymes (amylase, protease, and lipase), hence
indicating versatility in biochemical mechanisms. Halo zones produced colony growth of V. lecanii on agar confirmed activity of
protease, amylase and lipase enzyme by the V. lecanii isolate. Enzymatic Index (EI) observed were: Protease – 2.195, Amylase-
2.196, Lipase- 2.147. Spectrophotometric analysis of enzymatic activity of V.lecanii at five different pH – 3, 5, 7, 9, 11 revealed that
highest proteolytic activity of the V. lecanii isolate was reported at pH 7 and 9 whereas proteolytic activity was minimum at acidic
pH 3. Maximum amylolytic activity of V. lecanii on the 7th day of inoculation was at pH 3 i.e. in an acidic environment in contrast to
neutral pH 7. Maximum lipolytic activity of V. lecanii was found at pH 7. Since enzyme production in entomopathogenic fungi is
specific and forms an important criterion for successful development as well as improvement of mycoinsecticides, hence a
significant conclusion from the present analysis is the degree of variation in secretion of enzymes in test strain of Verticillium lecanii. 相似文献
179.
The hemochromatosis associated proteins HFE and Transferrin Receptor 2 (TFR2) have been shown to be important for the proper regulation of hepcidin. A number of in vitro studies using transient overexpression systems have suggested that an interaction between HFE and TFR2 is required for the regulation of hepcidin. This model of iron sensing which centers upon the requirement for an interaction between HFE and TFR2 has recently been questioned with in vivo studies in mice from our laboratory and others which suggest that Hfe and Tfr2 can regulate hepcidin independently of each other. To re-examine the postulated interaction between Hfe and Tfr2 we developed a novel expression system in which both proteins are stably co-expressed and used the proximity ligation assay to examine the interactions between Hfe, Tfr1 and Tfr2 at a cellular level. We were able to detect the previously described interaction between Hfe and Tfr1, and heterodimers between Tfr1 and Tfr2; however no interaction between Hfe and Tfr2 was observed in our system. The results from this study indicate that Hfe and Tfr2 do not interact with each other when they are stably expressed at similar levels. Furthermore, these results support in vivo studies which suggest that Hfe and Tfr2 can independently regulate hepcidin. 相似文献
180.
Shariq I. Sherwani Sheila Pabon Rishi B. Patel Muzzammil M. Sayyid Thomas Hagele Sainath R. Kotha Ulysses J. Magalang Krishna R. Maddipati Narasimham L. Parinandi 《Cell biochemistry and biophysics》2013,67(2):317-329
Mercury, especially methylmercury (MeHg), is implicated in the etiology of cardiovascular diseases. Earlier, we have reported that MeHg induces phospholipase D (PLD) activation through oxidative stress and thiol-redox alteration. Hence, we investigated the mechanism of the MeHg-induced PLD activation through the upstream regulation by phospholipase A2 (PLA2) and lipid oxygenases such as cyclooxygenase (COX) and lipoxygenase (LOX) in the bovine pulmonary artery endothelial cells (BPAECs). Our results showed that MeHg significantly activated both PLA2 (release of [3H]arachidonic acid, AA) and PLD (formation of [32P]phosphatidylbutanol) in BPAECs in dose- (0–10 μM) and time-dependent (0–60 min) fashion. The cPLA2-specific inhibitor, arachidonyl trifluoromethyl ketone (AACOCF3), significantly attenuated the MeHg-induced [3H]AA release in ECs. MeHg-induced PLD activation was also inhibited by AACOCF3 and the COX- and LOX-specific inhibitors. MeHg also induced the formation of COX- and LOX-catalyzed eicosanoids in ECs. MeHg-induced cytotoxicity (based on lactate dehydrogenase release) was protected by PLA2-, COX-, and LOX-specific inhibitors and 1-butanol, the PLD-generated PA quencher. For the first time, our studies showed that MeHg activated PLD in vascular ECs through the upstream action of cPLA2 and the COX- and LOX-generated eicosanoids. These results offered insights into the mechanism(s) of the MeHg-mediated vascular endothelial cell lipid signaling as an underlying cause of mercury-induced cardiovascular diseases. 相似文献