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991.
Two novel blue pigments, rosacyanins A1 and A2, were isolated from the petals of Rosa hybrida cv. ‘M'me. Violet’. Their structures were elucidated on the basis of high-resolution Fourier transform ion cyclotron resonance mass spectroscopy (HR-FT-ICR-MS), FABMS/MS/MS, 1H, 13C and two-dimensional NMR. The molecular formulas of rosacyanin A1 (1) and A2 (2) are C56H37O31 and C63H41O35, respectively. The structures of rosacyanins A1 and A2 consisted of a common chromophore containing cyanidin with a galloyl group link between positions 4 and 5 of the hydroxyl group of the flavylium nucleus and tellimagrandins (1 or 2). These pigments in which anthocyanidin nuclei linked to ellagitannin through an ether bond are the first compounds isolated from natural sources. 相似文献
992.
Ichikawa T Aoki T Takeuchi Y Yanagida T Ide T 《Langmuir : the ACS journal of surfaces and colloids》2006,22(14):6302-6307
The effects of annexin A5 on the lateral diffusion of single-molecule lipids and single-molecule proteins were studied in an artificial lipid bilayer membrane. Annexin A5 is a member of the annexin superfamily, which binds preferentially to anionic phospholipids in a Ca2+-dependent manner. In this report, we were able to directly monitor single BODIPY 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (DHPE) and ryanodine receptor type 2 (RyR2) labeled with Cy5 molecules in lipid bilayers containing phosphatidylserine (PS) by using fluorescence microscopy. The diffusion coefficients were calculated at various annexin A5 concentrations. The diffusion coefficients of BODIPY-DHPE and Cy5-RyR2 in the absence of annexin A5 were 4.81 x 10(-8) cm(2)/s and 2.13 x 10(-8) cm(2)/s, respectively. In the presence of 1 microM annexin A5, the diffusion coefficients of BODIPY-DHPE and Cy5-RyR2 were 2.2 x 10(-10) cm(2)/s and 9.5 x 10(-11) cm(2)/s, respectively. Overall, 1 microM of annexin A5 was sufficient to induce a 200-fold decrease in the lateral diffusion coefficient. Additionally, we performed electrophysiological examinations and determined that annexin A5 has little effect on the function of RyR2. This means that annexin A5 can be used to immobilize RyR2 in a lipid bilayer when imaging and analyzing RyR2. 相似文献
993.
Giordani C Wakai C Okamura E Matubayasi N Nakahara M 《The journal of physical chemistry. B》2006,110(31):15205-15211
Self-diffusion coefficients (D) are measured for normal (nondeuterated) and deuterated cholesterol-d(6) (C26 and C27 methyl groups deuterated) in 1-octanol, chloroform, and cyclohexane at concentrations of 1-700 mM by varying the impurity water concentration (>2 mM) and temperature (30-50 degrees C). The pulsed field gradient spin-echo (PGSE) (1)H and (2)H NMR were used, respectively, at 600 and 92 MHz. At 30 degrees C, the hydrodynamic radius (R) obtained at 20 mM from the D value and solvent viscosity is 5.09, 7.07, and 6.17 A, respectively, in 1-octanol, chloroform, and cyclohexane when the impurity water is negligible. The R value in 1-octanol is the smallest and comparable with the average length of the molecular axes for the cholesterol molecule. In 1-octanol, R is invariant against the concentration variation, whereas in chloroform, R is larger and increases almost linearly with cholesterol concentration. At the highest concentration, 700 mM, the R in chloroform is 13.5 and 16.7 A, respectively, when the impurity water is at negligible and saturated concentrations. The R value larger than that in hydrogen-bonding 1-octanol indicates that cholesterol forms an aggregate through hydrogen bonding. The aggregate structure is confirmed by comparing NOESY spectra in chloroform and 1-octanol. The NOESY analysis reveals the presence of one extra cross peak (C4-C19) in chloroform compared to 1-octanol. Because the carbon atoms related to the cross peak are close to the hydroxyl group (C3-OH), cholesterol molecules are considered to be not piled but are found to be OH-centered in the aggregate. This is supported also by larger rotational hydrodynamic radii measured on cholesterol deuterated at positions C2, C3, C4, and C6. This shows that the aggregate formation is driven by the hydrogen-bonding between cholesterol molecules. 相似文献
994.
Iiduka Y Wakahara T Nakajima K Tsuchiya T Nakahodo T Maeda Y Akasaka T Mizorogi N Nagase S 《Chemical communications (Cambridge, England)》2006,(19):2057-2059
Although Sc2C84 has been widely believed to have the form Sc2@C84, the present 13C NMR study reveals that it is a scandium carbide metallofullerene, Sc2C2@C82, which has a C82(C(3v)) cage. 相似文献
995.
Yamada S Misono T Iwai Y Masumizu A Akiyama Y 《The Journal of organic chemistry》2006,71(18):6872-6880
We have developed a new class of pyridine catalyst for asymmetric acylation of sec-alcohols having a conformation switch system in which interconversion between self-complexation and uncomplexation is induced by acylation and deacylation steps, respectively. Kinetic resolution of various sec-alcohols is performed by the asymmetric acylation with isobutyric anhydride using 0.05 to 0.5 mol % catalyst 1a with s values of up to 30. In addition, dl-diols are also resolved in a similar manner in good selectivity. Moreover, asymmetric desymmetrization of meso-1,X-diols (X = 2-6) are achieved in the presence of 0.5-5 mol % catalyst 1a. A working model for the reaction mechanism is proposed on the basis of the (1)H NMR measurements, X-ray structural analyses, and AM1 and DFT calculations, where the conformation switch system governed by an intramolecular cation-pi interaction between a pyridinium ring and a thiocarbonyl group would play a key role to attain both good selectivity and high catalytic activity. 相似文献
996.
On Singularity of Energy Measures on Self-Similar Sets II 总被引:1,自引:0,他引:1
We provide a criterion for the energy measures of regular Dirichletforms on post-critically finite self-similar sets to be singularwith respect to every self-similar measure. A probabilisticinterpretation of the singularity is also discussed. 2000 MathematicsSubject Classification 60G30 (primary), 28A80, 31C25, 60J60(secondary). 相似文献
997.
Mitsuhiro Kanakubo Takafumi Aizawa Hiroshi Nanjo Yasuo Kameda Yuko Amo Takeshi Usuki 《Fluid Phase Equilibria》2010
X-ray diffraction measurements for the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM][BF4], mixed with CO2 were carried out at high pressures using our developed polymer cell. The intermolecular distribution functions obtained for [BMIM][BF4]–CO2 mixtures showed that CO2 molecules are preferentially solvated to the [BF4]− anion. The similar preferential solvation was previously observed in analogous 1-btuyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF6], with a different anion, which is in harmony with the present results in [BMIM][BF4]–CO2. 相似文献
998.
Yuko Araki Sadanori Konishi Shuichi Kawano Hidetoshi Matsui 《Annals of the Institute of Statistical Mathematics》2009,61(4):811-833
We consider the problem of constructing functional regression models for scalar responses and functional predictors, using
Gaussian basis functions along with the technique of regularization. An advantage of our regularized Gaussian basis expansions
to functional data analysis is that it creates a much more flexible instrument for transforming each individual’s observations
into functional form. In constructing functional regression models there remains the problem of how to determine the number
of basis functions and an appropriate value of a regularization parameter. We present model selection criteria for evaluating
models estimated by the method of regularization in the context of functional regression models. The proposed functional regression
models are applied to Canadian temperature data. Monte Carlo simulations are conducted to examine the efficiency of our modeling
strategies. The simulation results show that the proposed procedure performs well especially in terms of flexibility and stable
estimates. 相似文献
999.
Itaru Okamoto Dr. Kenji Iwamoto Yuko Watanabe Yoko Miyake Dr. Akira Ono Dr. 《Angewandte Chemie (International ed. in English)》2009,48(9):1648-1651
DNA duplexes containing 5‐modified uracil pairs (5‐bromo, 5‐fluoro, and 5‐cyanouracil) bind selectivity to metal ions. Their selectivity is sensitive to the pH value of the solution (see picture), as the acidities of the modified uracil bases vary according to the electron‐withdrawing properties of the substituents.
1000.
The effect of Ph‐OH group content on gelation time, mechanical properties, hydrophobicity, and cellular adhesiveness of hydrogels produced from carboxymethylcellulose derivatives is investigated. A higher Ph‐OH group content induces faster gelation and yields more brittle and hydrophobic gels. After 4 h of seeding, a larger number of L929 fibroblasts adhere to the hydrogel of the CMC‐Ph that contains 15.4 Ph‐OH groups per 100 repeat units of uronic acid (97% adhesion rate) than to the gel of CMC‐Ph with only 8.4 Ph‐OH groups (62% adhesion rate). The results demonstrate that controlling the Ph‐OH group content is an effective and useful way to control cellular adhesion and proliferation on the hydrogels, as well as gelation time and mechanical properties of the gels.