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21.
A quantum chemistry study was carried out to investigate the strength and nature of halogen bond interactions in HXeH···XCCY complexes, where X = Cl, Br and Y = H, F, Cl, Br, CN, NC, C2H, CH3, OH, SH, NH2. Examination of the electrostatic potentials V(r) of the XCCY molecules reveals that the addition of substituents has a significant effect upon the most positive electrostatic potential on the surface of the interacting halogen atom. We found that the magnitude of atomic charges and multipole moments depends upon the halogen atom X and is rather sensitive to the electron-withdrawing/donating power of the remainder of the molecule. An excellent correlation was found between the most positive electrostatic potentials on the halogen atom and the interaction energies. For either HXeH···ClCCY or HXeH···BrCCY complexes, an approximate linear correlation between the interaction energies and halogens multipole moments are established, indicating that the electrostatic and polarization interactions are responsible for the stability of the complexes. According to energy decomposition analysis, it is revealed that the electrostatic interactions are the major source of the attraction in the HXeH···XCCY complexes. Furthermore, the changes in the electrostatic term are mainly responsible for the dependence of interaction energy on the halogen atom. Graphical abstract
Electrostatic potential mapped on the surface of molecular electron density at the 0.001 electrons Bohr ?3 of HXeH. The color ranges in kcal mol?1 red >8.5, yellow 1.5 to 8.5, green ?5.5 to 1.5, blue <?5.5. Black and blue circles are referred to surface maxima and minima, respectively. 相似文献
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23.
Mehdi D. Esrafili 《Journal of molecular modeling》2013,19(3):1417-1427
In this work, computations of density functional theory (DFT) were carried out to investigate the nature of interactions in solid 2,6-dibromo-4-nitroaniline (DBNA). This system was selected to mimic the hydrogen/halogen bonding found within crystal structures as well as within biological molecules. DFT (M06-2X/6-311++G**) calculations indicated that the binding energies for different of interactions lie in the range between ?1.66 and ?9.77 kcal mol?1. The quantum theory of atoms in molecules (QTAIM) was applied to provide more insight into the nature of these interactions. Symmetry-adapted perturbation theory (SAPT) analysis indicated that stability of the Br···Br halogen bonds is predicted to be attributable mainly to dispersion, while electrostatic forces, which have been widely believed to be responsible for these types of interactions, play a smaller role. Our results indicate that, for those nuclei participating in hydrogen/halogen bonding interactions, nuclear quadrupole resonance parameters exhibit considerable changes on going from the isolated molecule model to crystalline DBNA. Figure
Electrostatic potential mapped on the surface of 2,6-dibromo-4-nitroaniline (DBNA) molecular electron density (0.001 e au?3). Color ranges for V S(r), in kcal?mol?1: red > 26.5, yellow 26.5–5.7, green 5.7– ?15.1, blue < ?15.1. Black circles Surface maxima, blue surface minima 相似文献
24.
Yun-Ching Chen Hannah Carter Jennifer Parla Melissa Kramer Fernando S. Goes Mehdi Pirooznia Peter P. Zandi W. Richard McCombie James B. Potash Rachel Karchin 《PLoS genetics》2013,9(1)
In the past few years, case-control studies of common diseases have shifted their focus from single genes to whole exomes. New sequencing technologies now routinely detect hundreds of thousands of sequence variants in a single study, many of which are rare or even novel. The limitation of classical single-marker association analysis for rare variants has been a challenge in such studies. A new generation of statistical methods for case-control association studies has been developed to meet this challenge. A common approach to association analysis of rare variants is the burden-style collapsing methods to combine rare variant data within individuals across or within genes. Here, we propose a new hybrid likelihood model that combines a burden test with a test of the position distribution of variants. In extensive simulations and on empirical data from the Dallas Heart Study, the new model demonstrates consistently good power, in particular when applied to a gene set (e.g., multiple candidate genes with shared biological function or pathway), when rare variants cluster in key functional regions of a gene, and when protective variants are present. When applied to data from an ongoing sequencing study of bipolar disorder (191 cases, 107 controls), the model identifies seven gene sets with nominal p-values0.05, of which one MAPK signaling pathway (KEGG) reaches trend-level significance after correcting for multiple testing. 相似文献
25.
Bahareh Khodashenas Mehdi Ardjmand Azim Akbarzadeh Khiyavi 《Journal of biomolecular structure & dynamics》2020,38(15):4644-4654
AbstractCommunicated by Ramaswamy H. Sarma 相似文献
26.
Mehdi Forouzesh Adil Askerovich Mamedov Amirasad Pourabadeh Mojgan Hosseini 《Journal of biomolecular structure & dynamics》2020,38(12):3750-3756
Abbreviations COM center of mass distance MD molecular dynamics MM-PBSA Molecular Mechanics Poisson–Boltzmann Surface Area Nb nanobody PlGF placenta growth factor Rg radius of gyration RMSD root mean-square deviation SASA solvent-accessible surface area VEGF vascular endothelial growth factor 相似文献
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Hossein Abbaszadeh Farzaneh Ghorbani Mehdi Derakhshani Aliakbar Movassaghpour Mehdi Yousefi 《Journal of cellular physiology》2020,235(2):706-717
Mesenchymal stem cells (MSCs) have been revealed to hold great potential for the development of new treatment approaches for various diseases. However, the clinical use of these cells is limited due to their tumorigenic effects. The therapeutic benefits of MSCs are largely dependent on paracrine factors including extracellular vesicles (EVs). EVs are nano-sized bilayer membrane structures containing lipids, microRNAs and proteins which play key roles in cell-to-cell communications. Because of their lower immunogenicity, tumorigenicity, and easier management, EVs have emerged as a new promising alternative to whole-cell therapy. Therefore, this paper reviews current preclinical studies on the use of EVs derived from human umbilical cord MSCs (hucMSCs) as a therapeutic approach in treatment of several diseases including neurological, cardiovascular, liver, kidney, and bone diseases as well as the cutaneous wound, inflammatory bowel disease, cancers, infertility, and other disorders. 相似文献
29.
Vahid Mahdavi Moosa Saber Hooshang Rafiee-Dastjerdi Ali Mehrvar Mehdi Hassanpour 《Archives Of Phytopathology And Plant Protection》2013,46(7):841-848
Exposing to sub-lethal and low lethal doses of pesticides may cause changes in natural enemy behavioural, such as functional, response. In this study, the effects of chlorpyrifos, carbaryl, abamectin and spinosad were evaluated on the functional response of the Habrobracon hebetor to different densities of last instar larvae of Anagasta kuehniella Zeller. Young adult females of the parasitoid were exposed to LC30 of chlorpyrifos, carbaryl, abamectin and spinosad that were 0.32, 4.03, 3.05 and 17.51?mg a.i./l for 24?h, respectively. Host densities of 2, 4, 8, 16, 32 and 64 were offered to treated young females for 2?h in 10-cm Petri dishes and then the parasitism data were recorded. Experiments were conducted in eight replications. Functional response type was determined using logistic regression and the parameters were appraised by non-linear regression using statistical analysis software. Functional response was type Ш in control and insecticide treatments. Searching efficiency in control, chlorpyrifos-, carbaryl-, abamectin- and spinosad-treated wasps were 0.008?±?0.002, 0.002?±?0.0009, 0.0034?±?0.0013, 0.0076?±?0.002 and 0.0073?±?0.002?h?1and handling times were 1.38?±?0.1, 7.64?±?1.01, 3.3?±?0.315, 1.55?±?0.1 and 1.46?±?0.11?h, respectively. Chlorpyrifos and carbaryl had the highest effect on searching efficiency of H. hebetor. Spinosad and abamectin showed less adverse effect on the functional response parameters. Finally, after conducting the advanced field studies, spinosad and abamectin may be used as a compatible chemical material with biological control agent in integrated pest management programmes. 相似文献
30.
Plasmonics - In this paper, we propose an ultra-compact high-speed electro-optical modulator with extremely low energy consumption based on silicon-polymer-metal hybrid plasmonic waveguide. Spatial... 相似文献