全文获取类型
收费全文 | 791篇 |
免费 | 99篇 |
出版年
2021年 | 17篇 |
2020年 | 8篇 |
2019年 | 12篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 23篇 |
2015年 | 43篇 |
2014年 | 30篇 |
2013年 | 44篇 |
2012年 | 42篇 |
2011年 | 43篇 |
2010年 | 20篇 |
2009年 | 22篇 |
2008年 | 35篇 |
2007年 | 21篇 |
2006年 | 40篇 |
2005年 | 27篇 |
2004年 | 26篇 |
2003年 | 22篇 |
2002年 | 17篇 |
2001年 | 18篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 7篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 11篇 |
1989年 | 17篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 17篇 |
1985年 | 14篇 |
1984年 | 12篇 |
1983年 | 8篇 |
1982年 | 13篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1978年 | 11篇 |
1977年 | 14篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1974年 | 14篇 |
1973年 | 10篇 |
1972年 | 10篇 |
1971年 | 9篇 |
1970年 | 6篇 |
1969年 | 9篇 |
1968年 | 8篇 |
1967年 | 10篇 |
1966年 | 6篇 |
排序方式: 共有890条查询结果,搜索用时 15 毫秒
831.
Sudeep Bose Surajit Ganguly Sachin Kumar Fredric R. Boockfor 《Neurochemical research》2016,41(6):1390-1400
Recent evidence reveals that prolactin gene expression (PRL-GE) in mammotropes occurs in pulses, but the molecular process(es) underlying this phenomenon remains unclear. Earlier, we have identified an E-box (E-box133) in the rat PRL promoter that binds several circadian elements and is critical for this dynamic process. Preliminary analysis revealed a Pit-1 binding site (P2) located immediately adjacent to this E-box133 raising the possibility that some type of functional relationship may exist between these two promoter regions. In this study, using serum shocked GH3 cell culture system to synchronize PRL-GE activity, we determined that Pit-1 gene expression occurred in pulses with time phases similar to that for PRL. Interestingly, EMSA analysis not only confirmed Pit-1 binding to the P2 site, but also revealed an interaction with factor(s) binding to the adjacent E-box133 promoter element. Additionally, down-regulation of Pit-1 by siRNA reduced PRL levels during pulse periods. Thus, using multiple evidences, our results demonstrate clearly that the Pit-1 P2 site is necessary for PRL-GE elaboration. Furthermore, the proximity of this critical Pit-1 binding site (P2) and the E-box133 element coupled with the evidences of a site-to-site protein interactions suggest that the process of PRL-GE pulse activity might involve more dynamic and intricate cross-talks between promoter elements that may span some, or all, of the proximal region of the PRL promoter in driving its pulsatile expression. 相似文献
832.
833.
When methyl parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate), an organophosphorous insecticide, was added to an exponentially
growing culture ofChlorella protothecoides and the effects were followed for 12 days, the following observations were made: a) In autotrophic culture the cell number
and the chlorophyll content decreased as compared to the control. These changes paralleled the inhibition of the rate of net
photosynthesis, suggesting that the photosynthetic apparatus was the primary target of the insecticide action. b) The inhibition
of cell growth (on cell number basis) also occurred in the case of heterotrophic culture at 100μM insecticide concentration
but the inhibition was less as compared to that of an autotrophic culture. c) The cell diameter in treated culture increased
by 10–20% in both autotrophic and heterotrophic cultures. The observations, (b) and (c) suggest that apart from the photosynthetic
apparatus, the insecticide has other sites of action, but the sensitivity of these sites to the insecticide is less than that
of the photosynthetic apparatus 相似文献
834.
835.
Sporulation was repressed in the parent strain by various carbon sources whereas glucose-resistant mutants were resistant to them but not to glycerol 2-phosphate. Both mycobacillin and dipicolinic acid synthesis were repressed in the parent by some of the compounds tested, viz. glucose, pyruvate and glycerol 2-phosphate. However, these syntheses in the glucose-resistant mutants were not repressed by glucose and pyruvate but were repressed by glycerol 2-phosphate. The possible interrelationship between sporulation, dipicolinic acid and mycobacillin synthesis is discussed in light of these findings. 相似文献
836.
In high-throughput biotechnology and structural biology, molecular cloning is an essential prerequisite for attaining high yields of recombinant protein. However, a rapid, cost-effective, easy clone screening protocol is still required to identify colonies with desired insert along with a cross check method to certify the expression of the desired protein as the end product. We report an easy, fast, sensitive and cheap visual clone screening and protein expression cross check protocol employing gold nanoparticle based plasmonic detection phenomenon. This is a non-gel, non-PCR based visual detection technique, which can be used as simultaneous high throughput clone screening followed by the determination of expression of desired protein. 相似文献
837.
S Bose 《Biochemical and biophysical research communications》1985,130(1):16-21
Addition of dibromothymoquinone (DBMIB) to isolated chloroplast thylakoids reduces cytochrome f in the dark. Reduced cytochrome f is oxidised when the thylakoids are illuminated, and is re-reduced in the subsequent darkness. The rate of re-reduction in the dark is faster after red (650 nm) illumination than after far red (713 nm) illumination. In the presence of DCMU or upon heat treatment or at high (greater than 10 microM) concentration of DBMIB the rate of dark reduction after red illumination becomes slower and equal to that after far red illumination, suggesting that photosystem II electron transfer at least upto plastoquinone facilitates DBMIB-mediated reduction of cytochrome f in the thylakoids. 相似文献
838.
Somnath Mandal Pranita Bose Sangeeta Dawar A. P. Rajarani I. M. Santha 《Journal of plant biochemistry and biotechnology.》2011,20(1):102-109
In the recent years tremendous progress has been achieved in deconstructing the oil biosynthetic pathways, majority of which is in Arabidopsis. Glycolysis is fundamental to this process as it is the cardinal supplier of precursors for fatty acid metabolism. Recent reports suggest that modification and expression of pyruvate kinase (PK), a crucial regulatory enzyme involved in glycolysis is one of the plausible ways to alter seed oil content in plants. In the present study we evaluated the kinetic behavior and expression profiling of pyruvate kinase, associated with seed development in a major oilseed crop B. juncea. Developmental profiling of the enzyme showed that enzyme activity was highest during middle stage (35 DAF) of seed development which is strongly corroborated by the expression profiling of the enzyme using RT-PCR approach. Oil accumulation pattern also correlated with the enzyme expression study. Comparative activity profiling from different tissues showed seedlings to have elevated activity than other tissues. For kinetic characterization, the enzyme was partially purified by 12.3 fold using DEAE-Sephadex column and showed a narrow pH optimum of 7.0. In presence of saturated substrate concentration, the enzyme exhibited hyperbolic kinetics for both ADP and PEP with Km (Michaelis constant value) for PEP and ADP was found to be 178.5 and 96.45 μM respectively. ATP and citrate are the most significant allosteric effectors of the partially purified PK. Study on isozymes of PK resulted in a single band. 相似文献
839.
Partha Pratim Bose Surajit Bhattacharjee Shuvendu Singha Santanu Mandal Gautam Mondal Priya Gupta Bishnu P. Chatterjee 《Biochemistry and Biophysics Reports》2016
BackgroundLectins are highly important biomolecules to study several biological processes. A novel α-D-glucose/mannose specific lectin was isolated from the seeds of litchi fruits (Litchi chinensis) and its various biophysical and biochemical properties were studied.MethodsPurification was done by successive Sephadex G 100 and Con A-Sepharose 4B affinity chromatography. SDS-PAGE, Surface Plasmon Resonance (SPR), steady state absorbance, fluorescence, time-correlated single-photon counting, circular dichroism and antibiofilm activity by measuring total protein estimation and azocasein degradation assay have been performed.ResultsThe purified lectin is a homodimer of molecular mass ~ 54 kDa. The amount of lectin required for hemagglutination of normal human O erythrocytes was 6.72 µg/ml. Among the saccharides tested, Man-α-(1,6)-Man was found to be the most potent inhibitor (0.01 mM) determined by hemagglutination inhibition assay. Steady state and time resolved fluorescence measurements revealed that litchi lectin formed ground state complex with maltose (Ka=4.9 (±0.2)×104 M?1), which indicated static quenching (Stern-Volmer (SV) constant Ksv=4.6 (±0.2)×104 M?1). CD measurements demonstrated that litchi lectin showed no overall conformational change during the binding process with maltose. The lectin showed antibiofilm activity against Pseudomonus aeruginosa.ConclusionsA novel homodimeric lectin has been purified from the seeds of litchi fruits (Litchi chinensis) having specificity for α-d-glucose/mannose. The thermodynamics and conformational aspects of its interaction with maltose have been studied in detail. The antibiofilm activity of this lectin towards Pseudomonus aeruginosa has been explored.General significanceThe newly identified litchi lectin is highly specific for α-d-glucose/mannose with an important antibiofilm activity towards Pseudomonus aeruginosa. 相似文献
840.
H R Bose 《Biochimica et biophysica acta》1992,1114(1):1-17