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41.
Herein, we report an addition to the toolbox for the monitoring and quantification of the hydrolytic decay of pentose-1-phosphates, which are known to be elusive and difficult to quantify. This communication describes how apparent equilibrium shifts of a nucleoside phosphorolysis reaction can be employed to calculate hydrolytic loss of pentose-1-phosphates based on the measurement of post-hydrolysis equilibrium concentrations of a nucleoside and a nucleobase. To demonstrate this approach, we assessed the stability of the relatively stable ribose-1-phosphate at 98 °C and found half-lives of 1.8–11.7 h depending on the medium pH. This approach can be extended to other sugar phosphates and related reaction systems to quantify the stability of UV-inactive and hard-to-detect reaction products and intermediates. 相似文献
42.
Quinones are electroactive species that have shown great promise for redox flow batteries due to the ability to tune their properties and to act as both negative and positive electrolytes. The following review outlines highlights of work in the last couple of years working to provide materials with higher stability, solubility, and performance. Developments toward stable negolytes have provided opportunities for potential commercial opportunities when paired with alternate chemistries. However, the stability of quinones in high potential electrolytes is still not sufficient and the number of potential quinones limited. 相似文献
43.
Enrico Falcone Ikhlas M. M. Ahmed Dr. Valentina Oliveri Dr. Francesco Bellia Dr. Bertrand Vileno Dr. Youssef El Khoury Prof. Petra Hellwig Prof. Peter Faller Prof. Graziella Vecchio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(8):1871-1879
Mounting evidence supports the role of amyloidogenesis, oxidative stress, and metal dyshomeostasis in the development of neurodegenerative disorders. Parkinson's Disease is characterized by α-synuclein (αSyn) accumulation and aggregation in brain regions, also promoted by Cu2+. αSyn is modified by reactive carbonyl species, including acrolein (ACR). Notwithstanding these findings, the interplay between ACR, copper, and αSyn has never been investigated. Therefore, we explored more thoroughly the effects of ACR on αSyn using an approach based on LC-MS/MS analysis. We also evaluated the influence of Cu2+ on the protein carbonylation and how the ACR modification impacts the Cu2+ binding and the production of Reactive Oxygen Species (ROS). Finally, we investigated the effects of ACR and Cu2+ ions on the αSyn aggregation by dynamic light scattering and fluorescence assays. Cu2+ regioselectively inhibits the modification of His50 by ACR, the carbonylation lowers the affinity of His50 for Cu2+ and ACR inhibits αSyn aggregation both in the presence and in the absence of Cu2+. 相似文献
44.
45.
Prof. Dr. Frank Heinrich Aria Salyapongse Akari Kumagai Dr. Fernando G. Dupuy Karpur Shukla Dr. Anja Penk Prof. Dr. Daniel Huster Prof. Dr. Robert K. Ernst Dr. Anna Pavlova Prof. Dr. James C. Gumbart Prof. Dr. Berthony Deslouches Prof. Dr. Y. Peter Di Prof. Dr. Stephanie Tristram-Nagle 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(28):6247-6256
In the quest for new antibiotics, two novel engineered cationic antimicrobial peptides (eCAPs) have been rationally designed. WLBU2 and D8 (all 8 valines are the d -enantiomer) efficiently kill both Gram-negative and -positive bacteria, but WLBU2 is toxic and D8 nontoxic to eukaryotic cells. We explore protein secondary structure, location of peptides in six lipid model membranes, changes in membrane structure and pore evidence. We suggest that protein secondary structure is not a critical determinant of bactericidal activity, but that membrane thinning and dual location of WLBU2 and D8 in the membrane headgroup and hydrocarbon region may be important. While neither peptide thins the Gram-negative lipopolysaccharide outer membrane model, both locate deep into its hydrocarbon region where they are primed for self-promoted uptake into the periplasm. The partially α-helical secondary structure of WLBU2 in a red blood cell (RBC) membrane model containing 50 % cholesterol, could play a role in destabilizing this RBC membrane model causing pore formation that is not observed with the D8 random coil, which correlates with RBC hemolysis caused by WLBU2 but not by D8. 相似文献
46.
Julia Leitl Dr. Andrew R. Jupp Dr. Evi R. M. Habraken Verena Streitferdt Dr. Peter Coburger Dr. Daniel J. Scott Prof. Dr. Ruth M. Gschwind Prof. Dr. Christian Müller Dr. J. Chris Slootweg Prof. Dr. Robert Wolf 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(35):7788-7800
Salt metathesis of 1-methyl-2,4,6-triphenylphosphacyclohexadienyl lithium and chlorobis(pentafluorophenyl)borane affords a 1-phospha-7-bora-norbornadiene derivative 2 . The C≡N triple bonds of nitriles insert into the P−B bond of 2 with concomitant C−B bond cleavage, whereas the C≡C bonds of phenylacetylenes react with 2 to form λ4-phosphabarrelenes. Even though 2 must formally be regarded as a classical Lewis adduct, the C≡N and C≡C activation processes observed (and the mild conditions under which they occur) are reminiscent of the reactivity of frustrated Lewis pairs. Indeed, NMR and computational studies give insight into the mechanism of the reactions and reveal the labile nature of the phosphorus–boron bond in 2 , which is also suggested by detailed NMR spectroscopic studies on this compound. Nitrile insertion is thus preceded by ring opening of the bicycle of 2 through P−B bond splitting with a low energy barrier. By contrast, the reaction with alkynes involves formation of a reactive zwitterionic methylphosphininium borate intermediate, which readily undergoes alkyne 1,4-addition. 相似文献
47.
Mathias Mallmann Sebastian Wendl Dr. Philipp Strobel Dr. Peter J. Schmidt Prof. Dr. Wolfgang Schnick 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(28):6257-6263
Nitridophosphates exhibit an intriguing structural diversity with different structural motifs, for example, chains, layers or frameworks. In this contribution the novel nitridophosphate Sr3P3N7 with unprecedented dreier double chains is presented. Crystalline powders were synthesized using the ammonothermal method, while single crystals were obtained by a high-pressure multianvil technique. The crystal structure of Sr3P3N7 was solved and refined from single-crystal X-ray diffraction and confirmed by powder X-ray methods. Sr3P3N7 crystallizes in monoclinic space group P2/c. Energy-dispersive X-ray and Fourier-transformed infrared spectroscopy were conducted to confirm the chemical composition, as well as the absence of NHx functionality. The optical band gap was estimated to be 4.4 eV using diffuse reflectance UV/Vis spectroscopy. Upon doping with Eu2+, Sr3P3N7 shows a broad deep-red to infrared emission (λem=681 nm, fwhm≈3402 cm−1) with an internal quantum efficiency of 42 %. 相似文献
48.
Dr. Lidia A. Maslovskaya Dr. Andrei I. Savchenko Prof. Elizabeth H. Krenske Dr. Sharon Chow Tina Holt Dr. Victoria A. Gordon Dr. Paul W. Reddell Carly J. Pierce Prof. Peter G. Parsons Prof. Glen M. Boyle Prof. Andrei G. Kutateladze Prof. Craig M. Williams 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(51):11862-11867
Structurally unique halimanes EBC-232 and EBC-323, isolated from the Australian rainforest plant Croton insularis, proved considerably difficult to elucidate. The two diastereomers, which consist an unusual oxo-6,7-spiro ring system fused to a dihydrofuran, were solved by unification and consultation of five in silico NMR elucidation and prediction methods [i.e., ACDLabs, olefin strain energy (OSE), DP4, DU8+ and TD DFT CD]. Structure elucidation challenges of this nature are prime test case examples for empowering future AI learning in structure elucidation. 相似文献
49.
Dr. Lenka Štacková Marina Russo Dr. Lucie Muchová Vojtěch Orel Prof. Libor Vítek Dr. Peter Štacko Prof. Petr Klán 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(58):13184-13190
Carbon monoxide (CO) is an endogenous signaling molecule that controls a number of physiological processes. To circumvent the inherent toxicity of CO, light-activated CO-releasing molecules (photoCORMs) have emerged as an alternative for its administration. However, their wider application requires photoactivation using biologically benign visible and near-infrared (NIR) light. In this work, a strategy to access such photoCORMs by fusing two CO-releasing flavonol moieties with a NIR-absorbing cyanine dye is presented. These hybrids liberate two molecules of CO in high chemical yields upon activation with NIR light up to 820 nm and exhibit excellent uncaging cross-sections, which surpass the state-of-the-art by two orders of magnitude. Furthermore, the biocompatibility and applicability of the system in vitro and in vivo are demonstrated, and a mechanism of CO release is proposed. It is hoped that this strategy will stimulate the discovery of new classes of photoCORMs and accelerate the translation of CO-based phototherapy into practice. 相似文献