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31.
32.
Davila Anne-Marie Marchal Rémy Vandecasteele Jean-Paul 《Journal of industrial microbiology & biotechnology》1994,13(4):249-257
Summary Sophorose lipids stand out as biosurfactants with a wide potential for industrial application and which can be produced in good yield from glucose and a lipidic cosubstrate.Candida bombicola CBS 6009 (ATCC 22214) was used in the present study. The influence of the lipidic cosubstrate on various aspects of production performance of these glycolipids (final concentration, yield) and on product composition (in particular, the structure of the hydroxy fatty acid vegetable and animal oils, markedly influenced product composition. In terms of production performance, the best substrates were oils or esters rich in C18:0 and C18:1 fatty acids. Optimal overall performance was obtained with esters (340 g L–1 sophorose lipids with rapeseed esters). Conclusions drawn from the results allow predictive evaluation of lipidic industrial substrates. 相似文献
33.
One of the most important fundamental questions connecting chemistry to biology is how chemistry scales in complexity up to biological systems where there are innumerable possible pathways and competing processes. With the development of ultrabright electron and x-ray sources, it has been possible to literally light up atomic motions to directly observe the reduction in dimensionality in the barrier crossing region to a few key reaction modes. How do these chemical processes further couple to the surrounding protein or macromolecular assembly to drive biological functions? Optical methods to trigger photoactive biological processes are needed to probe this issue on the relevant timescales. However, the excitation conditions have been in the highly nonlinear regime, which questions the biological relevance of the observed structural dynamics. 相似文献
34.
LDL的氧化修饰和氧化修饰LDL的组成和结构变化 总被引:8,自引:1,他引:7
与低密度脂蛋白(LDL)相比,氧化修饰LDL(O-LDL)的组成、结构和生物学特性发生了深刻的变化,而组成和结构的改变是生物学特性改变的基础.本文根据最近文献资料.结合我们实验室的工作.对LDL的氧化修饰、O-LDL的组成、结构改变,以及它们的机理作一简要综述. 相似文献
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摘要 目的:探讨高危结直肠腺瘤的影响因素,构建风险预测模型并验证。方法:回顾性分析2021年1月至2021年12月期间在江苏大学附属人民医院进行诊疗的1408例结直肠腺瘤患者的资料,根据病理特征分为高危结直肠腺瘤组(759例)和非高危结直肠腺瘤组(649例)。采用Logistic回归分析筛选高危结直肠腺瘤的独立危险因素并建立风险预测模型,并验证预测模型的应用效能。结果:Logistic回归分析结果显示,病灶部位为直肠、高血压、高脂血症、年龄≥53岁、吸烟是高危结直肠腺瘤的独立危险因素(P<0.05)。基于以上因素建立预测高危结直肠腺瘤风险的列线图模型,经Hosmer-Lemeshow检验和受试者工作特征曲线(ROC)分析显示,该风险预测模型具有较好的拟合度和预测效能,可以用于高危腺瘤的风险预测。结论:病灶部位为直肠、高血压、高脂血症、年龄≥53岁、吸烟是高危结直肠腺瘤的独立危险因素,临床医生可尽早对高危患者进行预防性干预以减缓高危腺瘤的发生。 相似文献
37.
蝮蛇毒碱性磷脂酶A_2基因的克隆 总被引:2,自引:0,他引:2
从蝮蛇毒腺中抽提总RNA.利用人工合成寡核苷酸引物作逆转录,以cDNA为模板进行体外扩增,获得磷脂酶A2(简称PLA2)基因,克隆至pBS-ks载体中。通过对3个碱性PLA2(简称BPLA2)基因单独克隆分别作DNA全序列分析,推导pro-BPLA2由138个氨基酸残基构成,与已测定的部分氨基酸序列比较,基本相符。该基因成功的克隆,不仅推导出BPLA2的蛋白质全序列,也为进一步开展蛇毒功能肽蛋白质工程的研究工作打下了良好的基础。 相似文献
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Summary The ability of time-averaged restrained molecular dynamics (TARMD) to escape local low-energy conformations and explore conformational space is compared with conventional simulated-annealing methods. Practical suggestions are offered for performing TARMD calculations with ligand-receptor systems, and are illustrated for the complex of the immunosuppressant FK506 bound to Q50R,A95H,K98I triple mutant FKBP-13. The structure of 13C-labeled FK506 bound to triple-mutant FKBP-13 was determined using a set of 87 NOE distance restraints derived from HSQC-NOESY experiments. TARMD was found to be superior to conventional simulated-annealing methods, and produced structures that were conformationally similar to FK506 bound to wild-type FKBP-12. The individual and combined effects of varying the NOE restraint force constant, using an explicit model for the protein binding pocket, and starting the calculations from different ligand conformations were explored in detail.Abbreviations DG
distance geometry
- dmFKBP-12
double-mutant (R42K,H87V) FKBP-12
- FKBP-12
FK506-binding protein (12 kDa)
- FKBP-13
FK506-binding protein (13 kDa)
- HSQC
heteronuclear single-quantum coherence
- KNOE
force constant (penalty) for NOE-derived distance restraints
- MD
molecular dynamics
- NOE
nuclear Overhauser effect
- SA
simulated annealing
- TARMD
molecular dynamics with time-averaged restraints
- tmFKBP-13
triple-mutant (Q50R,A95H,K98I) FKBP-13
- wtFKBP-12
wild-type FKBP-12 相似文献
40.
Summary A new program for molecular dynamics (MD) simulation and energy refinement of biological macromolecules, OPAL, is introduced. Combined with the supporting program TRAJEC for the analysis of MD trajectories, OPAL affords high efficiency and flexibility for work with diferent force fields, and offers a user-friendly interface and extensive trajectory analysis capabilities. Salient features are computational speeds of up to 1.5 GFlops on vector supercomputers such as the NEC SX-3, ellipsoidal boundaries to reduce the system size for studies in explicit solvents, and natural treatment of the hydrostatic pressure. Practical applications of OPAL are illustrated with MD simulations of pure water, energy minimization of the NMR structure of the mixed disulfide of a mutant E. coli glutaredoxin with glutathione in different solvent models, and MD simulations of a small protein, pheromone Er-2, using either instantaneous or time-averaged NMR restraints, or no restraints.Abbreviations D
diffusion constant in cm2/s
- Er-2
pheromone 2 from Euplotes raikovi
- GFlop
one billion floating point operations per second
- Grx(C14S)-SG
mixed disulfide between a mutant E. coli glutaredoxin, with Cys14 replaced by Ser, and glutathione
- MD
molecular dynamics
- NOE
nuclear Overhauser enhancement
- rmsd
root-mean-square deviation
-
density in g/cm3 相似文献