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141.
Narayanan Krishnamurthi Stefani Mulligan Padma Mahant Johan Samanta James J. Abbas 《Cognitive neurodynamics》2012,6(4):325-332
Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is now widely used to alleviate symptoms of Parkinson’s disease (PD). The specific aim of this study was to identify posture control measures that may be used to improve selection of DBS parameters in the clinic and this was carried out by changing the DBS stimulation amplitude. A dynamic posture shift paradigm was used to assess posture control in 4 PD STN-DBS subjects. Each subject was tested at 4 stimulation amplitude settings. Movements of the center of pressure and the position of the pelvis were monitored and several quantitative indices were calculated. The presence of any statistically significant changes in several normalized indices due to reduced/no stimulation was tested using the one-sample t test. The peak velocity and the average movement velocity during the initial and mid phases of movement towards the target posture were substantially reduced. These results may be explained in terms of increased akinesia and bradykinesia due to altered stimulation conditions. Thus, the dynamic posture shift paradigm may be an effective tool to quantitatively characterize the effects of DBS on posture control and should be further investigated as a tool for selection of DBS parameters in the clinic. 相似文献
142.
目的 了解BV及RBV患者的阴道微生态被彻底恢复与未被彻底恢复停药后的远期复发率差异.方法 137例BV患者(其中RBV 48例)被随机分成A、B两组.A组67例(其中RBV 19例),B组70例(其中RBV 29例).A组治疗至Amsel正常、Nugent评分≤3分、阴道菌群密集度Ⅱ~Ⅲ度且乳酸杆菌占明显优势、H2O2≥2μmol/L时停药;B组治疗至Amsel正常时停药.A、B两组停药后均随访6个月.结果 A组随访6个月复发率为22.39%、但B组高达63.08%.A组中BV患者随访6个月复发率为18.75%、B组为33.33%.A组中RBV患者随访2个月复发率为31.58%、但B组高达86.21%,随访3个月时B组全部复发.结论 动态监测阴道微生态评价指标,能客观指导临床BV治疗.BV患者、尤其RBV患者经个体化治疗,积极彻底恢复阴道微生态环境,明显降低了其远期复发率. 相似文献
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144.
Films of methylcellulose (MC), poly(ethylene glycol)400 (PEG400) plasticized MC, and MC gels (MC crosslinked with glutaraldehyde (GA)) were prepared by casting from aqueous solutions. The swelling test has shown that the MC gels were insoluble in water and that their crosslinking density increased with increasing GA and HCl concentrations. The effect of the addition of PEG400 or GA to MC was investigated through dynamic mechanical analysis (DMA). The DMA analysis of PEG400/MC blends has shown that PEG400 was compatible with MC and was an effective plasticizer since the curves of tan δ against temperature exhibited single peaks (corresponding to a single glass transition temperature), which were displaced to lower values with increasing PEG400 content. The thermogravimetric analysis (TGA) indicated that the thermal stability of MC was not affected by the chemical crosslinking. The tensile strength was slightly increased through crosslinking while the elongation was slightly decreased. The presence of moisture in MC hydrogels decreased the tensile strength and enhanced the elongation while the addition of PEG400 decreased the tensile strength but sharply increased the elongation. 相似文献
145.
146.
Background and aimAβ1−42 is an amyloidogenic peptide found within senile plaques extracted from those who died with a diagnosis of Alzheimer’s disease. The potent neurotoxicity of this peptide is related to its propensity to form aggregated conformations in vivo, a process that is influenced by the species and concentration of metal ions present within the local environment. This study examines the impact of different metals upon the early aggregatory behaviour and size of Aβ1−42 under simulated physiological conditions.MethodsThe size and aggregatory behaviour of Aβ1−42 in the presence and absence of metal ions was monitored during the initial 30 min of fibril formation in real-time using dynamic light scattering.ResultsIntensity scattering measurements showed a clear tendency towards aggregation with regards to Aβ1−42 only solutions (10 μM). Both equimolar Al3+ & Cu2+ lowered and stabilised the dimensions of Aβ1−42 aggregates; however, a diminutive but significant increase in size was still observed over a 30-min period. While excess Al3+ continued to supress the size of Aβ1−42, a 10-fold increase in the concentration of Cu2+ accelerated peptide aggregation relative to that observed for equimolar metal but not compared to Aβ1−42 alone.ConclusionThese results infer that Al3+ ions stabilise and aid in the maintenance of smaller, toxic intermediates while excess Cu2+ facilitates the formation of larger, more inert, amorphous species exceeding 1 μm in size. Furthermore, we propose that metal-induced toxicity of Aβ1−42 is reflective of their ability to preserve smaller oligomeric species in vitro. 相似文献
147.
Bruno César Feltes Conrado Pedebos Diego Bonatto Hugo Verli 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2579-2589
Background
Xeroderma Pigmentosum (XP) is a disease caused by mutations in the nucleotide excision repair (NER) pathway. Patients with XP exhibit a high propensity to skin cancers and some subtypes of XP can even present neurological impairments. During NER, DDB2 (XPE), in complex with DDB1 (DDB-Complex), performs the DNA lesion recognition. However, not much is known about how mutations found in XP patients affect the DDB2 structure and complex assembly. Thus, we searched for structural evidence associated with the role of three naturally occurring mutations found in XPE patients: R273H, K244E, and L350P.Methods
Each mutant was individually constructed and submitted to multiple molecular dynamics simulations, done in triplicate for each designed system. Additionally, Dynamic Residue Interaction Networks were designed for each system and analyzed parallel with the simulations.Results
DDB2 mutations promoted loss of flexibility in the overall protein structure, producing a different conformational behavior in comparison to the WT, especially in the region comprising residues 354 to 371. Furthermore, the DDB-complex containing the mutated forms of DDB2 showed distinct behaviors for each mutant: R273H displayed higher structural instability when complexed; L350P affected DDB1 protein-protein binding with DDB2; and K244E, altered the complex binding trough different ways than L350P.Conclusions
The data gathered throughout the analyses helps to enlighten the structural basis for how naturally occurring mutations found in XPE patients impact on DDB2 and DDB1 function.General significance
Our data influence not only on the knowledge of XP but on the DNA repair mechanisms of NER itself. 相似文献148.
Dynamical stress characterization and energy evaluation of single cardiac myocyte actuating on flexible substrate 总被引:2,自引:0,他引:2
Qin L Huang J Xiong C Zhang Y Fang J 《Biochemical and biophysical research communications》2007,360(2):352-356
Contractility estimation of cardiac myocyte is important for power evaluation of the cell in heart performance. In this paper, we used digital image correlation (DIC) method to obtain dynamic deformation field of the flexible substrate distributively actuated by single cardiac myocyte, which resulted in the dynamic history of traction forces of the cell during contraction-relaxation cycles. Furthermore, the resultant work and power of the single neonatal cardiac myocyte was evaluated to show the energy characteristics of the cells and the responses to the stiffness variation of the substrate. The method provides a useful tool to study behaviors of the cardiac myocytes interacted with the substrates. 相似文献
149.
在生化实验的基础上提出了血小板在凝血中作用的动力学模型,通过定性分析和数值模拟,得到:系统的启动存在一阈值,该阈值与血小板和凝血因子作用的吸附解离常数有密切的关系,即与血小板的存在与否直接相关;血小板的激活比率对系统的正平衡点的稳定性有重要的影响,与凝血启动后的最终状态有关;当刺激强度较小时,因子Ⅷ和Ⅸ对系统的解在定性与定量上没有明显的影响;当刺激强度较大时,因子Ⅷ和Ⅸ在凝血瀑布机制中起级联放大作 相似文献
150.