全文获取类型
收费全文 | 502篇 |
免费 | 22篇 |
国内免费 | 12篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 10篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 20篇 |
2017年 | 10篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 18篇 |
2013年 | 46篇 |
2012年 | 14篇 |
2011年 | 22篇 |
2010年 | 18篇 |
2009年 | 15篇 |
2008年 | 19篇 |
2007年 | 33篇 |
2006年 | 24篇 |
2005年 | 28篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 23篇 |
2001年 | 15篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 12篇 |
1995年 | 11篇 |
1994年 | 11篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 9篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
排序方式: 共有536条查询结果,搜索用时 31 毫秒
21.
《Journal of molecular biology》2021,433(12):166837
Protein phase separation has emerged as a novel paradigm to explain the biogenesis of membraneless organelles and other so-called biomolecular condensates. While the implication of this physical phenomenon within cell biology is providing us with novel ways for understanding how cells compartmentalize biochemical reactions and encode function in such liquid-like assemblies, the newfound appreciation of this process also provides immense opportunities for designing and sculpting biological matter. Here, we propose that understanding the cell’s instruction manual of phase separation will enable bioengineers to begin creating novel functionalized biological materials and unprecedented tools for synthetic biology. We present FASE as the synthesis of the existing sticker-spacer framework, which explains the physical driving forces underlying phase separation, with quintessential principles of Scandinavian design. FASE serves both as a designer condensates catalogue and construction manual for the aspiring (membraneless) biomolecular architect. Our approach aims to inspire a new generation of bioengineers to rethink phase separation as an opportunity for creating reactive biomaterials with unconventional properties and to encode novel biological function in living systems. Although still in its infancy, several studies highlight how designer condensates have immediate and widespread potential applications in industry and medicine. 相似文献
22.
S Tsuji 《Biotechnic & histochemistry》2013,88(1):29-34
We describe here the chemical induction of premature condensed chromosomes in human peripheral lymphocytes after culture for 6 h. Many have attempted this induction without culture or with short-term culture, because this technique permits prompt cytogenetic biodosimetry of radiation accidents. Lymphocytes were separated from blood, incubated in the presence of phytohemagglutinin, ATP, and p34cdc2/cyclin B kinase, then treated with calyculin A during the last hour. The culture medium was supplemented with a lower concentration of fetal calf serum than conventionally used to minimize its possible interference with the effects of these drugs. We obtained, rarely, a suitable morphology of premature chromosome condensation in short-term cultured lymphocytes for conventional chromosome aberration analysis. 相似文献
23.
Devappa S. Lamani K. R. Venugopala Reddy H. S. Bhojya Naik K. S. R. Pai Ravishankar Kumar Fasiulla 《Nucleosides, nucleotides & nucleic acids》2013,32(8):591-605
This article deals with the synthesis of 4-(2-hydroxyquinolin-3-yl)-6-phenyl-5,6-dihydropyrimidin derivatives (2a–f), on condensation with various aromatic aldehydes and ketones in aqueous ethanolic NaOH solution yielding the corresponding chalcones (3). These chalcones were further reacted with thiourea/urea in the presence of a base, which led to the formation of the titled derivatives (2a–f). The newly synthesized heterocyles were characterized by elemental analysis, FTIR, 1HNMR, and electronic and mass spectral data. The compounds (2a and 2b) were evulated for in vitro cyctotoxicity against human breast adenocarcinoma cell (MCF-7). In MTT cytotoxicity studies, both quinolinde derivatives were found most effective. The binding interaction behavior of the compound (2a) and (2d) with calf thymus-DNA (CT-DNA) was studied by electronic spectra, viscosity measurements, and thermal denaturation studies. On binding to CT-DNA, the absorption spectrum underwent bathochromic and hypochromic shifts. The binding constant (Kb) observed 4.3 × 105 M?1 for (2a), and 3.8 × 105 M?1 for (2d) suggested that compound (2a) binds more strongly with base pairs than (2d). 相似文献
24.
Miral V. Lunagariya Khyati P. Thakor Bharat H. Pursuwani 《Nucleosides, nucleotides & nucleic acids》2013,32(8):455-483
AbstractSquare planar mononuclear platinum(II) complexes having general formula [Pt(Ln)Cl2], (where, Ln?=?L1–4) were synthesized with neutral bidentate heterocyclic 1,3,5-trisubstituted bipyrazole based ligands. The synthesized compounds were characterized by physicochemical method such as TGA, molar conductance, micro-elemental analysis and magnetic moment, and spectroscopic method such as, FT-IR, UV–vis, 1H NMR, 13C NMR and mass spectrometry. Biological applications of the compounds were carried out using in vitro brine shrimp lethality bioassay, in vitro antimicrobial study against five different pathogens, and cellular level cytotoxicity against Schizosaccharomyces pombe (S. Pombe) cells. Pt(II) complexes were tested for DNA interaction activities using electronic absorption titration, viscosity measurements study, fluorescence quenching technique and molecular docking assay. Binding constants (Kb) of ligands and complexes were observed in the range of 0.23–1.07?×?105?M?1 and 0.51–3.13?×?105?M?1, respectively. Pt(II) complexes (I–IV) display an excellent binding tendency to biomolecule (DNA) and possess comparatively high binding constant (Kb) values than the ligands. The DNA binding study indicate partial intercalative mode of binding in complex-DNA. The gel electrophoresis activity was carried out to examine DNA nuclease property of pUC19 plasmid DNA. 相似文献
25.
《Electromagnetic biology and medicine》2013,32(2):93-107
Electromagnetic (EM) phenomena have long been implicated in biological development, but few detailed, practical mechanisms have been put forth to connect electromagnetism with morphogenetic processes. This work describes a new hypothesis for plant leaf veination, whereby an endogenous electric field forming as a result of a coherent Frohlich process, and corresponding to an EM resonant mode of the developing leaf structure, is capable of instigating leaf vascularisation. In order to test the feasibility of this hypothesis, a three-dimensional, EM finite-element model (FEM) of a leaf primordium was constructed to determine if suitable resonant modes were physically possible for geometric and physical parameters similar to those of developing leaf tissue. Using the FEM model, resonant EM modes with patterns of relevance to developing leaf vein modalities were detected. On account of the existence of shared geometric signatures in a leaf's vascular pattern and the electric field component of EM resonant modes supported by a developing leaf structure, further theoretical and experimental investigations are warranted. Significantly, this hypothesis is not limited to leaf vascular patterning, but may be applicable to a variety of morphogenetic phenomena in a number of living systems. 相似文献
26.
27.
28.
Bhargav A. Patel Charles R. Ashby Diane Hardej Tanaji T. Talele 《Bioorganic & medicinal chemistry letters》2013,23(20):5523-5527
A focused library of rhodanine compounds containing novel substituents at the C5-position was synthesized and tested in vitro against a panel of clinically relevant MRSA strains. The present SAR study was based on our lead compound 1 (MIC = 1.95 μg/mL), with a focus on identifying optimal C5-arylidene substituents. In order to obtain this objective, we condensed several unique aromatic aldehydes with phenylalanine-derived rhodanine intermediates to obtain C5-substituted target rhodanine compounds for evaluation as anti-MRSA compounds. These efforts produced three compounds with significant efficacy: 23, 32 and 44, with MIC values ranging from 0.98 to 1.95 μg/mL against all tested MRSA strains as compared to the reference antibiotics penicillin G (MIC = 15.60–250.0 μg/mL) and ciprofloxacin (MIC = 7.80–62.50 μg/mL) and comparable to that of vancomycin (MIC = 0.48 μg/mL). In addition, compounds 24, 28, 37, 41, 46 and 48 (MIC = 1.95–3.90 μg/mL) were efficacious against all MRSA strains. The majority of the synthesized compounds had bactericidal activity at concentrations only two to fourfold higher than their MIC. Overall, the results suggest that compounds 23, 32 and 44 may be of potential use in the treatment of MRSA infections. 相似文献
29.
The production of actinomycin D was examined using Streptomyces antibioticus growing on a complex medium based on glucose and casein hydrolyzate. Purification of the medium to remove calcium increased actinomycin production by about one-third and prevented production of a characteristic brown pigment. The sensitivity to magnesium concentrations was less than was reported by Katz et al.,11) while similar requirements were found for zinc and iron. 相似文献
30.
《Bioscience, biotechnology, and biochemistry》2013,77(8):1453-1462
(-)-Podorhizol (1) was stereoselectively synthesized by erythro preferential aldol condensation of 3,4,5-trimethoxy- benzaldehyde with potassium enolate from (+)-(R)-3- (3,4-methylenedioxybenzyl)-4-butanolide (2) (erythro:threo=85:15). Erythro selectivity was observed in the aldol condensation of many alkoxybenzaldehydes with potassium enolate from (+)-γ-butyrolactone 2. However, benzaldehydes having methoxy groups at both the 2 and 6 positions gave threo selectivity in the aldol condensation with potassium enolate from (+)-γ-butyrolactone 2. 相似文献