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排序方式: 共有667条查询结果,搜索用时 31 毫秒
111.
Dr. Clara Illescas 《Chemphyschem》2023,24(20):e202300307
A computational study of Be4++H(2s, 2p) collisions has been carried out employing the Classical Trajectory Monte Carlo (CTMC) method for the impact energy range from 20 keV/u to 1000 keV/u. The integral n partial cross sections for H(n) excitation and Be3+(n) electron capture and, the total ionization and electron capture cross sections are calculated and compared to recent semiclassical results. A general good agreement is observed for the n partial and total electron capture and ionization cross sections. The comparative study of the three inelastic processes show no significant differences between both excited targets. 相似文献
112.
Hector Castro-Abril Jónathan Heras Jesús del Barrio Laura Paz Clara Alcaine Marina Pérez Aliácar Diego Garzón-Alvarado Manuel Doblaré Ignacio Ochoa 《Macromolecular bioscience》2023,23(10):2300108
Mechanical interactions between cells and their microenvironment play an important role in determining cell fate, which is particularly relevant in metastasis, a process where cells invade tissue matrices with different mechanical properties. In vitro, type I collagen hydrogels have been commonly used for modeling the microenvironment due to its ubiquity in the human body. In this work, the combined influence of the stiffness of these hydrogels and their ultrastructure on the migration patterns of HCT-116 and HT-29 spheroids are analyzed. For this, six different types of pure type I collagen hydrogels by changing the collagen concentration and the gelation temperature are prepared. The stiffness of each sample is measured and its ultrastructure is characterized. Cell migration studies are then performed by seeding the spheroids in three different spatial conditions. It is shown that changes in the aforementioned parameters lead to differences in the mechanical stiffness of the matrices as well as the ultrastructure. These differences, in turn, lead to distinct cell migration patterns of HCT-116 and HT-29 spheroids in either of the spatial conditions tested. Based on these results, it is concluded that the stiffness and the ultrastructural organization of the matrix can actively modulate cell migration behavior in colorectal cancer spheroids. 相似文献
113.
We show the influence of species present in precursor solution during formation of lead halide perovskite materials on the structural defects of the films. The coordination of lead by competing solvent molecules and iodide ions dictate the type of complexes present in the films. Depending on the processing conditions all PbIS5+, PbI2S4, PbI3S3?, PbI4S22?, PbI5S23?, PbI64?and 1D (Pb2I4)n chains are observed by absorption measurements. Different parameters are studied such as polarity of the solvent, concentration of iodide ions, concentration of solvent molecules and temperature. It is concluded that strongly coordinating solvents will preferentially form species with a low number of iodide ions and less coordinative solvents generate high concentration of PbI6?. We furthermore propose that all these plumbate ions may act as structural defects determining electronic properties of the photovoltaic films. 相似文献
114.
Roberto Frigerio Clara Löh Cristina Pagliantini Roman Sauer 《Israel Journal of Mathematics》2016,216(2):707-751
Simplicial volumes measure the complexity of fundamental cycles of manifolds. In this article, we consider the relation between the simplicial volume and two of its variants — the stable integral simplicial volume and the integral foliated simplicial volume. The definition of the latter depends on a choice of a measure preserving action of the fundamental group on a probability space. 相似文献
115.
Bis(pyridinium) iodonium(I) tetrafluoroborate (IPy2BF4), a solid and stable reagent, can be used to transform n-pentenyl orthoesters (NPOEs) and n-pentenyl glycosides (NPGs) into glycosyl fluorides. The latter pair constitutes a new set of semiorthogonal glycosyl donors that can be used in glycosylation strategies, alone or in combination with NPOEs. 相似文献
116.
Pereira C Patrício S Silva AR Magalhães AL Carvalho AP Pires J Freire C 《Journal of colloid and interface science》2007,316(2):570-579
Copper (II) acetylacetonate was immobilised directly onto two clays, laponite (Lap) and K10-montmorillonite (K10), and after their amine functionalisation with (3-aminopropyl)triethoxysilane (APTES). All the materials were characterised by nitrogen adsorption isotherms at -196 degrees C, elemental analysis, TG-DSC, XRD, and IR spectroscopy. The K10-based materials were also characterised by XPS. The APTES-functionalised K10 showed higher copper loading than K10, indicating that the clay functionalisation enhanced the complex immobilisation; on the contrary, in Lap-based materials higher metal content was obtained by direct complex anchoring, probably due to the delaminated nature of Lap which induced the particles aggregation on functionalisation with APTES. All the results pointed out that the Cu complex was anchored onto the amine-functionalised clays by Schiff condensation between the amine groups of anchored APTES and the carbonyl groups of the acetylacetonate ligand, whereas direct immobilisation proceeded mostly through interaction between the metal centre and the clay surface hydroxyl groups. 相似文献
117.
Clara Baldoli Claudio Oldani Prasanna Ramani Paolo Ferruti Patrizia Mussini 《Journal of organometallic chemistry》2007,692(6):1363-1371
Carboxy-terminated polyvinylpyrrolidin-2-one (PVP) has been used as a new water-soluble and biocompatible polymeric support for a series of ferrocene labeled amino acid and peptide nucleic acid (PNA) monomer derivatives 4-7. The organometallic polymer-conjugates thus obtained are new and potentially useful as water-soluble electrochemically active probes for biomolecules. In view of such application, their electrochemical activity has been evaluated and has proved very high notwithstanding the complexity and bulkiness of the molecule, affording detection limits down to 10−8 M in the aqueous medium. 相似文献
118.
López JC Bernal-Albert P Uriel C Valverde S Gómez AM 《The Journal of organic chemistry》2007,72(26):10268-10271
The combination of bis(pyridinium)iodonium (I) tetrafluoroborate (IPy2BF4), and hydrogen fluoride pyridine (HF-py) forms an iodine monofluoride (IF) synthetic equivalent that can be used in the preparation of partially unprotected glycosyl fluorides from partially unprotected n-pentenyl glycosides and thioglycosides, thus avoiding the need for the protection/deprotection steps normally required in that transformation. 相似文献
119.
Huihai Yang Man-Kit Cheung Grace Gar-Lee Yue Ping-Chung Leung Chun-Kwok Wong Clara Bik-San Lau 《Molecules (Basel, Switzerland)》2021,26(19)
Herba Patriniae (HP) are medicinal plants commonly used in colorectal cancer (CRC) patients. In this study, network pharmacology was used to predict the active components and key signaling pathways of HP in CRC. Patrinia heterophylla, one type of HP, was chosen for validation of the network pharmacology analysis. The phytochemical profile of Patrinia heterophylla water extract (PHW) was determined by UHPLC-MS. MTT, RT-PCR, and Western blot assays were performed to evaluate the bioactivities of PHW in colon cancer cells. Results showed that 15 potentially active components of HP interacted with 28 putative targets of CRC in the compound–target network, of which asperglaucide had the highest degree. Furthermore, the ErbB signaling pathway was identified as the pathway mediated by HP with the most potential against CRC. Both RT-PCR and Western blot results showed that PHW significantly downregulated the mRNA and protein levels of EGFR, PI3K, and AKT in HCT116 cells. Asperglaucide, present in PHW, exhibited an anti-migratory effect in HCT116 cells, suggesting that it could be an active component of PHW in CRC treatment. In conclusion, this study has provided the first scientific evidence to support the use of PHW in CRC and paved the way for further research into the underlying mechanisms of PHW against CRC. 相似文献
120.
Summary Several mobile phase parameters were investigated for controlling enantioselective retention and resolution on a chiral stationary
phase made in-house. The chiral selector was the enzyme amyloglucosidase, which was immobilized onto a silica support via
reductive amination. The influences of the mobile phase pH, concentration and type of uncharged organic modifier, ionic strength
and column temperature on enantios-electivity were studied. The analysis time for resolving enantiomers could be adjusted
with only a minor decrease in enantioselectivity by using a high ionic strength mobile phase buffer. This indicated a retention
mechanism involving ion-exchange interactions. It was further confirmed by the decreasing enantioselectivity of amines when
using a mobile phase pH below the isoelectric point of the native protein. Interesting effects were observed when the organic
modifier concentration was increased and also when the column temperature was raised. Both retention and enantioselectivity
increased with increasing concentration of 2-propanol in the mobile phase. Examples are given where both enantioselectivity
and retention increased with increasing column temperature. Thermodynamic studies were performed to calculate the entropy
and enthalpy constants. The results showed that, depending on mobile phase composition, the enantioselective retention may
be caused by differences in entropy or enthalpy. 相似文献