全文获取类型
收费全文 | 154篇 |
免费 | 4篇 |
专业分类
化学 | 129篇 |
晶体学 | 1篇 |
力学 | 1篇 |
数学 | 13篇 |
物理学 | 14篇 |
出版年
2023年 | 1篇 |
2022年 | 11篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 4篇 |
2013年 | 8篇 |
2012年 | 9篇 |
2011年 | 9篇 |
2010年 | 12篇 |
2009年 | 12篇 |
2008年 | 11篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1992年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有158条查询结果,搜索用时 0 毫秒
91.
Chebel FX Ratusznei SM Rodrigues JA Zaiat M Foresti E 《Applied biochemistry and biotechnology》2006,133(2):171-188
The performance of an anaerobic sequencing batch reactor (ASBR) was assessed when submitted to increasing organic load with different influent concentrations and cycle lengths. The 5-L mechanically stirred (75 rpm) ASBR contained 2 L of granular biomass and treated 2 L of synthetic wastewater per cycle. Volumetric organic loads (VOLs) from 0.66 to 2.88 g of chemical oxygen demand (COD)/(L x d) were applied by using influent concentrations from 550 to 3,600 mg of COD/L in 8- and 12-h cycles. Reactor stability was maintained for VOLs from 0.66 to 2.36 g of COD/(L x d), with organic matter removal efficiencies for filtered samples (epsilonF) between 84 and 88%. For VOLs from 0.78 to 2.36 g of COD/(L x d) at an influent concentration of 2,000 mg of COD/L, when cycle length was reduced from 12 to 8 h, epsilonF did not vary, yet showed a very distinct behavior from the other conditions. In addition, two operation strategies were studied for VOLs with approximately similar values of 2.36 and 2.08 g of COD/(L x d). One involved operation with an influent concentration of 2,000 mg of COD/L and an 8-h cycle, whereas the other involved an influent concentration of 2,600 mg of COD/L and a 12-h cycle. Only the former resulted in system stability and efficiency. These results indicate that besides organic load, influent concentration and cycle length play a significant role in ASBR systems. 相似文献
92.
Adsorption of polyaromatic hydrocarbons on single wall carbon nanotubes of different functionalities and diameters 总被引:2,自引:0,他引:2
Gotovac S Yang CM Hattori Y Takahashi K Kanoh H Kaneko K 《Journal of colloid and interface science》2007,314(1):18-24
Adsorption from toluene solution of phenanthrene and tetracene on single wall carbon nanotubes (SWCNT) is measured. Comparison of adsorbents such as laser ablation and HipCO samples reveals multiple factors influencing the adsorption mechanism. Acid functionalized carbon nanotubes have shown markedly increased adsorbability for the polyaromatic molecules. The linear tetracene molecule's adsorption is more promoted on nanotubes with increasing diameter, but also additionally with presence of the carboxylic groups. The adsorption mechanisms on carboxylic sites and on the bold, non-functionalized large-diameter nanotubes are suggested and supported by detailed characterization of the SWCNTs applied. 相似文献
93.
94.
95.
Suzana Aleksić Huaping Huang Zoran D. Mitrović Stojan Radenović 《Journal of Fixed Point Theory and Applications》2018,20(4):147
The main purpose of this paper is to generalize, improve and complement several famous results in b-metric spaces. Moreover, an essential estimation of b-quasi-contraction in b-metric spaces is given. We also establish some new results for multi-valued mappings in the metric and b-metric concept. We explore some different proof techniques which provide short proofs of the results. 相似文献
96.
Gao G Cheng JT Kindrachuk J Hancock RE Straus SK Kizhakkedathu JN 《Chemistry & biology》2012,19(2):199-209
Highlights? Biomembrane interactions of surface-tethered host defense peptides are studied ? Polymer brush-tethered IDR-1010cys showed enhanced biomembrane interactions ? Mechanism of action of surface-tethered peptides is different from its soluble form 相似文献
97.
In this paper we prove the equivalence of the frame property and the closedness for a weighted shift-invariant space $$ V^p_\mu(\Phi) = \left\{\sum \limits^{r}_{i=1} \sum \limits_{j \in \mathbb{Z}^d} c_{i}(j)\phi_{i}(\cdot-j)\left \vert {\{c_{i}(j)\}}_{j \in \mathbb{Z}^{d}} \in {\ell_{\mu}^{p}}\right.\right\}, \quad p \in [1, \infty], $$ which corresponds to ${{\Phi = \Phi^r = (\phi_1, \phi_2, . . . , \phi_r)^T \in (W^{1}_\omega)^r}}$ . We, also, construct a sequence Φ2k+1 and the sequence of spaces ${{V^{p}_{\mu} (\Phi^{2k+1})}}$ , ${k \in {\mathbb N}}$ , on ${\mathbb R}$ , with the useful properties in sampling, approximations and stability. 相似文献
98.
In this paper, we introduce the concept of generalized g-quasi-contractions in the setting of cone b-metric spaces over Banach algebras. By omitting the assumption of normality we establish common fixed point theorems for the generalized gquasi-contractions with the spectral radius r(λ) of the g-quasi-contractive constant vector λ satisfying r(λ) ∈ [0,1/s) in the setting of cone b-metric spaces over Banach algebras, where the coefficient s satisfies s ≥ 1. The main results generalize, extend and unify several well-known comparable results in the literature. 相似文献
99.
One of the most important physicochemical parameters of a molecule that determines its bioactivity is its lipophilicity. Cluster analysis (CA), principal component analysis (PCA), and sum of ranking differences (SRD) were used to compare the lipophilic parameters of twenty phenylacetamide derivatives, obtained experimentally as chromatographic retention data in the presence of different solvents and calculated by different mathematical methods. All the applied methods of multivariate analysis gave approximately similar grouping of the studied lipophilic parameters. In the attempt to group the investigated compounds in respect of their lipophilicity, the obtained results appeared to be dependent on the applied chemometric method. The CA and PCA, grouped the compounds on the basis of the nature of the substituents R1 and R2, indicating that they determine to a great extent the lipophilicity of the investigated molecules. Unlike them, the SRD method could not be used to group the studied compounds on the basis of their lipophilic character. 相似文献
100.
Bezerra RA Rodrigues JA Ratusznei SM Canto CS Zaiat M 《Applied biochemistry and biotechnology》2011,165(1):347-368
Currently, there is an increasing demand for the production of biodiesel and, consequently, there will be an increasing need
to treat wastewaters resulting from the production process of this biofuel. The main objective of this work was, therefore,
to investigate the effect of applied volumetric organic load (AVOL) on the efficiency, stability, and methane production of
an anaerobic sequencing batch biofilm reactor applied to the treatment of effluent from biodiesel production. As inert support,
polyurethane foam cubes were used in the reactor and mixing was accomplished by recirculating the liquid phase. Increase in
AVOL resulted in a drop in organic matter removal efficiency and increase in total volatile acids in the effluent. AVOLs of
1.5, 3.0, 4.5 and 6.0 g COD L−1 day−1 resulted in removal efficiencies of 92%, 81%, 67%, and 50%, for effluent filtered samples, and 91%, 80%, 63%, and 47%, for
non-filtered samples, respectively, whereas total volatile acids concentrations in the effluent amounted to 42, 145, 386 and
729 mg HAc L−1, respectively. Moreover, on increasing AVOL from 1.5 to 4.5 g COD L−1 day−1 methane production increased from 29.5 to 55.5 N mL CH4 g COD−1. However, this production dropped to 36.0 N mL CH4 g COD−1 when AVOL was increased to 6.0 g COD L−1 day−1, likely due to the higher concentration of volatile acids in the reactor. Despite the higher concentration of volatile acids
at the highest AVOL, alkalinity supplementation to the influent, in the form of sodium bicarbonate, at a ratio of 0.5–1.3 g NaHCO3 g CODfed−1, was sufficient to maintain the pH near neutral and guarantee process stability during reactor operation. 相似文献