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911.
冯博 《中国实验动物学报》2009,17(3):216-218,I0006
目的建立黄磷及其化合物急性吸入致大鼠急性肺损伤(ALI)/急性呼吸窘迫综合征(ARDS)的模型。方法健康SD大鼠48只随机分为对照组以及实验组(0、4、12、24、48 h时间点处死)。采用自制染毒装置,间歇染毒形成ALI/ARDS模型。观察ALI/ARDS大鼠动脉血气分析以及肺系数和肺组织病理变化。结果肺损伤后大鼠动脉血气分析以及肺组织病理改变明显恶化,肺系数较对照组明显增大。结论成功地建立了黄磷及其化合物急性吸入致大鼠ALI/ARDS的模型,为黄磷及其化合物吸入中毒的防治研究提供良好实验基础,同时也适用于其他气体吸入致ARDS的实验研究。 相似文献
912.
Electricity generation and modeling of microbial fuel cell from continuous beer brewery wastewater 总被引:1,自引:0,他引:1
Electricity production and modeling of microbial fuel cell (MFC) from continuous beer brewery wastewater was studied in this paper. A single air-cathode MFC was constructed, carbon fiber was used as anode and diluted brewery wastewater (COD = 626.58 mg/L) as substrate. The MFC displayed an open-circuit voltage of 0.578 V and a maximum power density of 9.52 W/m3 (264 mW/m2). Using the model based on polarization curve, various voltage losses were quantified. At current density of 1.79 A/m2, reaction kinetic loss and mass transport loss both achieved to 0.248 V; while ohmic loss was 0.046 V. Results demonstrated that it was feasible and stable for producing bioelectricity from brewery wastewater; while the most important factors which influenced the performance of the MFC are reaction kinetic loss and mass transport loss. 相似文献
913.
In order to characterize the potentially deleterious effects of toxic Hg2+ and Cd2+ on lipid membranes, we have studied their binding to liposomes whose composition mimicked erythrocyte membranes. Fluorescence
spectroscopy utilizing the concentration dependent quenching of Phen Green™ SK by Hg2+ and Cd2+ was found to be a sensitive tool to probe these interactions at metal concentrations ≤1 μM. We have systematically developed
a metal binding affinity assay to screen for the interactions of Hg2+ or Cd2+ with certain lipid classes. A biomimetic liposome system was developed that contained four major lipid classes of erythrocyte
membranes (zwitterionic lipids: phosphatidylcholine and phosphatidylethanolamine; negatively charged: phosphatidylserine and
neutral: cholesterol). In contrast to Hg2+, which preferentially bound to the negatively charged phosphatidylserine compared to the zwitterionic components, Cd2+ bound stronger to the two zwitterionic lipids. Thus, the observed distinct differences in the binding affinity of Hg2+ and Cd2+ for certain lipid classes together with their known effects on membrane properties represent an important first step toward
a better understanding the role of these interactions in the chronic toxicity of these metals. 相似文献
914.
Non destructive and mathematical approaches of modeling can be very convenient and useful for plant growth estimation. The leaf of Elaeagnus mollis was taken as the object of research. Leaf length、 leaf width、SPAD value and different combinations of these variables were developed models to predict individual leaf area, saturated fresh weight, and dry weight of Elaeagnus mollis. Ten regression equations were compared. Select fitting the best model as a predictive model in leaf area, saturated fresh weight and dry weight. The three models were as follows: individual leaf area LA=3647+0383LW+0001LWS (R=0968), saturated fresh weight SFW=-0464+0081L+000008LWS (R=0963), and dry weight DW=-0094+0032W+00001LS (R=0960). The best prediction model of LA, SFW and DW was validated with the measured value. The results showed that the predicted values and measured values were highly consistent. It could be used to predict the LA, SFW and DW of actual unknown leaves. 相似文献
915.
916.
考察了Saccharomyces cerevisiae FL1酵母菌株在固体平板上的生长动力学过程及2种渗透剂对不同生理阶段的酵母细胞增殖行为的影响.建立了一个数学模型,该模型可以预测固体培养过程中生物量随时间的变化情况,结果表明,模型预测值与实际值能够很好符合,将该模型应用于考察氯化钠和甘油对细胞增殖行为的影响,结果揭示,氯化钠显著抑制指数生长期和平衡期细胞分裂,降低酵母比生长速率和生物量;甘油对平衡期细胞增殖有促进作用,提高比生长速率和生物量;甘油与氯化钠之间存在协同作用,0.15M甘油不能减弱高盐的应激作用。 相似文献
917.
918.
Youjiro Tamura Akira Ito Masami Saito 《Computer methods in biomechanics and biomedical engineering》2017,20(3):273-283
We propose a muscle contraction model that is essentially a model of the motion of myosin motors as described by a Langevin equation. This model involves one-dimensional numerical calculations wherein the total force is the sum of a viscous force proportional to the myosin head velocity, a white Gaussian noise produced by random forces and other potential forces originating from the actomyosin structure and intra-molecular charges. We calculate the velocity of a single myosin on an actin filament to be 4.9–49 μm/s, depending on the viscosity between the actomyosin molecules. A myosin filament with a hundred myosin heads is used to simulate the contractions of a half-sarcomere within the skeletal muscle. The force response due to a quick release in the isometric contraction is simulated using a process wherein crossbridges are changed forcibly from one state to another. In contrast, the force response to a quick stretch is simulated using purely mechanical characteristics. We simulate the force–velocity relation and energy efficiency in the isotonic contraction and adenosine triphosphate consumption. The simulation results are in good agreement with the experimental results. We show that the Langevin equation for the actomyosin potentials can be modified statistically to become an existing muscle model that uses Maxwell elements. 相似文献
919.
Endo-β-mannanase is a hemicellulase that is present in tomato fruit, and plays a role in its ripening. This enzyme protein
is detectable in the cultivar Walter, but it is inactive due to the absence of the terminal four amino acids from its carboxyl-end.
To elucidate why this deletion eliminates the activity of endo-β-mannanase, a molecular dynamics (MD) study was conducted
on the conformation of the enzyme at normal and elevated temperatures. The root mean square deviations, root mean square fluctuations
per residue, and secondary structural evolution during MD simulations were analyzed. Differences in stability and dynamics
between the active and inactive endo-β-mannanases were documented; the inactive form has a lower stability than the active
one. The loss of key amino acids from the C-terminal end of the protein indirectly affects the conformation of the catalytic
Glu318 and stability of active site because of interactions between residues at the C-terminus and the rest of protein. 相似文献
920.
Trichlorophenols are weak acids of high hydrophobicity and are able to transport protons across the mitochondrial membrane. Thus the proton motive force is dissipated and the ATP production decreased. In situ Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR) experiments with 2,4,5-trichlorophenol (TCP) adsorbed to model membranes resulted in good evidence for the formation of the TCP-heterodimer. Two surfaces were examined: a dipalmitoyl phosphatidic acid (DPPA) monolayer and a planar DPPA/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer. TCP was adsorbed from 1 to 3 mM solutions at pH 6.0 to the lipid layers leading to surface layers at the water/lipid interface. Difference spectra showed an effect on DPPA acyl chains even when it was covered with POPC. Time-resolved measurements revealed two distinct adsorption processes, which were assigned to TCP and its deprotonated anion (phenoxide), respectively. For DPPA/POPC bilayers, the adsorption of TCP was faster than that of its phenoxide, whereas adsorption of both species to DPPA monolayers proceeded with similar velocity. In both cases, phenoxide formation at the membrane was found to be delayed with respect to phenol adsorption. Phenoxide and phenol were retained after replacing the TCP solution with buffer. For the retained species, we estimated a phenol/phenoxide molar ratio of 1 at pH 6.0 (pKa=6.94 for TCP), demonstrating strong evidence for heterodimer formation. 相似文献