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71.
E. Abele R. Abele K. Rubina Yu. Popelis A. Gaukhman E. Lukevics 《Chemistry of Heterocyclic Compounds》1998,34(10):1123-1126
The halogenation of propargyl ethers of heterylaldoximes and ketoximes in interphase catalytic systems CX4 (X=Cl, Br)/solid KOH/18-crown-6 leads selectively to the formation of the corresponding O-(halopropargyl)oximes.
Latvian Institute of Organic Synthesis, Riga LV-1006. e-mail: kira@osi.lanet.lv. Translated from Khimiya Geterotsiklicheskikh
Soedinenii, No. 10, pp. 1325–1328. 相似文献
72.
K. Rubina Yu. Popelis Yu. Gol'dberg M. Shimanskaya 《Chemistry of Heterocyclic Compounds》1992,28(12):1406-1410
Alkylation of pyridylphenyl ketoximes with alkyl, allyl, and benzyl halides in conditions of phase-transfer catalysis yields the corresponding O-esters with a good yield. Partial Z,E -isomerization takes place during the reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1641–1645, December, 1992. 相似文献
73.
99mTc‐Tin‐nano colloid is a radiopharmaceutical that can be useful in evaluation of the patients with breast cancer. The current method for preparation requires a lengthy boiling water bath procedure, and the recommended quality control procedure is cumbersome and time consuming. Using a microwave oven, the heating time necessary to provide a maximum labeling efficiency has been reduced to 10 second. A new mini paper chromatography (MPC) system has been developed to analyze the radiochemical purity (RCP) of the labeled preparation involving two different developing solvents. The recommended thin layer chromatography (TLC) system involving the use of an Al2O3 coated plate requires an average time for drying and development of 34.5 ± 0.44 min (n = 30) to complete, whereas the new MPC system has an average developing time of 2.1 ± 0.2 min (n = 20). For RCP values the MPC and TLC methods are correlated closely (r = 0.94). The combined use of the microwave oven heating method and over quick quality control system will facilitate the rapid emergency use of 99mTc‐Tin‐nano colloid. 相似文献
74.
Syed Qaiser Shah Muhammad Rafiullah Khan 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):215-219
Extraction of europium(III) from nitric acid medium by a solution of tri-n-butylphosphate (TBP) and n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in the room temperature ionic liquid, 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide
(amimNTf2 where a = butyl or hexyl or octyl), was studied. The distribution ratio of (152+154)Eu(III) in TBP-CMPO/bmimNTf2 was measured as a function of various parameters such as the concentrations of nitric acid, CMPO and NaNO3. Remarkably large distribution ratios were observed for the extraction of europium(III) when bmimNTf2 acted as diluent. The stoichiometry of metal-solvate in organic phase was determined by the slope analysis of extraction
data. 相似文献
75.
Syed Qaiser Shah Aakif Ullah Khan Muhammad Rafiullah Khan 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):131-136
Garenoxacin (GXN) was modified to its dithiocarbamate followed by radiolabeling with technetium-99m (99mTc) through [99mTc-N]2+ core. The suitability of the 99mTcN–Garenoxacin dithiocarbamate (GXND) complex as a potential multiresistant Staphylococcus aureus (MDRSA) and penicillin-resistant Streptococci (PRSC) infection radiotracer was assessed in artificially infected rats (AFRT). The radiolabeled complex was investigated
for its radiochemical purity (RCP), permanence in serum using HPLC and TLC methods. In vitro binding with MDRSA and PRSC was
performed at 37 °C. The 99mTcN–GXND showed maximum RCP of 98.00 ± 0.22% and remained more than 90% stable up to 4 h. The 99mTcN–GXND showed saturated in vitro binding with living MDRSA and PRSC, respectively. The complex showed normal biodistribution
in healthy rats (HRT), however in AFRT, seven fold uptakes was observed in infected muscle as compared to inflamed and normal
muscles. Based on the high RCP, stability in serum, better in vitro binding with bacteria, biodistribution behavior and the
target to non-target (infected to inflamed muscle) ratio, we recommend the 99mTcN–GXND complex for in vivo investigation of MDRSA and PRSC infection in human. 相似文献
76.
We study the effect of symmetry energy on the fragment production for the reactions 20 10 Ne10+ 20 10 Ne10 and 197 79 Au118 + 197 79 Au118 for the incident energy range of 50–1000 MeV/nucleon using isospin-dependent quantum molecular dynamics (IQMD) model. Our study shows that the density-dependent symmetry energy plays a significant role in multiplicity of fragments produced at low energy. Moreover, sensitivity of density-dependent symmetry energy decreases with increase in neutron content of colliding system. We also compare the symmetry energy suggested by different groups. A comparative study of experimental results with theoretical calculations of IQMD shows that the density-dependent symmetry energy is a good probe to explain the multiplicity of the fragments at low energy. 相似文献
77.
Rubina Munir Noman Javid Muhammad Zia-ur-Rehman Muhammad Zaheer Rahila Huma Ayesha Roohi Muhammad Makshoof Athar 《Molecules (Basel, Switzerland)》2021,26(16)
In this article, a synthesis of N’-(benzylidene)-2-(6-methyl-1H-pyrazolo[3,4-b]quinolin-1-yl)acetohydrazides and their structural interpretation by NMR experiments is described in an attempt to explain the duplication of some peaks in their 1H- and 13C-NMR spectra. Twenty new 6-methyl-1H-pyrazolo[3,4-b]quinoline substituted N-acylhydrazones 6(a–t) were synthesized from 2-chloro-6-methylquinoline-3-carbaldehyde (1) in four steps. 2-Chloro-6-methylquinoline-3-carbaldehyde (1) afforded 6-methyl-1H-pyrazolo[3,4-b]quinoline (2), which upon N-alkylation yielded 2-(6-methyl-1H-pyrazolo[3,4-b]quinolin-1-yl)acetate (3). The hydrazinolysis of 3 followed by the condensation of resulting 2-(6-methyl-1H-pyrazolo[3,4-b]quinolin-1-yl)acetohydrazide (4) with aromatic aldehydes gave N-acylhydrazones 6(a–t). Structures of the synthesized compounds were established by readily available techniques such as FT-IR, NMR and mass spectral studies. The stereochemical behavior of 6(a–t) was studied in dimethyl sulfoxide-d6 solvent by means of 1H NMR and 13C NMR techniques at room temperature. NMR spectra revealed the presence of N’-(benzylidene)-2-(6-methyl-1H-pyrazolo[3,4-b]quinolin-1-yl)acetohydrazides as a mixture of two conformers, i.e., E(C=N)(N-N) synperiplanar and E(C=N)(N-N) antiperiplanar at room temperature in DMSO-d6. The ratio of both conformers was also calculated and E(C=N) (N-N) syn-periplanar conformer was established to be in higher percentage in equilibrium with the E(C=N) (N-N) anti-periplanar form. 相似文献
78.
The first highly efficient, diastereo- and regioselective transition metal-catalyzed addition of metal hydrides (stannanes, silanes, and germanes) and bimetallic species (ditins and silyltins) to cyclopropenes has been developed. It was shown that the addition across the double bond of cyclopropenes is generally controlled by steric factors and proceeds from the least hindered face. This methodology represents a powerful and atom-economic approach toward a wide variety of highly substituted stereodefined cyclopropylmetals, useful building blocks unavailable by other methods. 相似文献
79.
Hillary Straub Pavel Ryabchuk Marina Rubina Michael Rubin 《Molecules (Basel, Switzerland)》2022,27(20)
Enantiomerically enriched cyclopropyl ethers, amines, and cyclopropylazole derivatives possessing three stereogenic carbon atoms in a small cycle are obtained via the diastereoselective, formal nucleophilic substitution of chiral, non-racemic bromocyclopropanes. The key feature of this methodology is the utilization of the chiral center of the cyclopropene intermediate, which governs the configuration of the two adjacent stereocenters that are successively installed via 1,4-addition/epimerization sequence. 相似文献
80.
Rizi Ai M. Qaiser Fatmi Chia-en A. Chang 《Journal of computer-aided molecular design》2010,24(10):819-827
T-Analyst is a user-friendly computer program for analyzing trajectories from molecular modeling. Instead of using Cartesian
coordinates for protein conformational analysis, T-Analyst is based on internal bond-angle-torsion coordinates in which internal
torsion angle movements, such as side-chain rotations, can be easily detected. The program computes entropy and automatically
detects and corrects angle periodicity to produce accurate rotameric states of dihedrals. It also clusters multiple conformations
and detects dihedral rotations that contribute hinge-like motions. Correlated motions between selected dihedrals can also
be observed from the correlation map. T-Analyst focuses on showing changes in protein flexibility between different states
and selecting representative protein conformations for molecular docking studies. The program is provided with instructions
and full source code in Perl. 相似文献