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841.
Mohammad Behbahani Mohsen Taghizadeh Akbar Bagheri Hadi Hosseini Mani Salarian Atieh Tootoonchi 《Mikrochimica acta》2012,178(3-4):429-437
We describe a nanostructured ion-imprinted polymer (IIP) for the selective preconcentration of Ni(II) ions. It was obtained by bulk polymerization from 2-vinylpyridine (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2′-azobisisobutyronitrile (the initiator), alizarin red S (the nickel-binding ligand), and nickel (the template ion) in acetonitrile solution. The IIP particles were characterized by elemental analysis, X-ray diffraction, Fourier transform IR spectroscopy, thermogravimetric and differential thermal analysis, and by scanning electron microscopy. Imprinted Ni(II) ions were removed from the polymeric structure using 5 % HCl as the eluting solvent. The material is capable of selectively binding Ni(II) from solutions at pH values between (pH 8.0 being best). Both the sorption and desorption process occur within 5 min. The maximum sorbent capacity of the ion imprinted polymer is 73 mg g?1. Following desorption, Ni(II) was determined by FAAS, with relative standard deviation and limit of detection of 3.4 % and 0.15 ng mL?1, respectively. The method was applied to the determination of nickel in certified reference materials (soil and polymetallic gold ore), fish, vegetables, river sediments, and river water. Figure
In this study, a novel nano structure Ni(II) ion imprinted polymer has been synthesized for faster extraction of Ni(II) ions from various matrices. This SPE technique was successfully applied for separation, determination, and preconcentration of nickel from food and environmental samples. This method is simple, rapid, and reliable and it is found to be a selective and sensitive method for determination of trace levels of Ni(II) ions. 相似文献
842.
Yasar Arafat Abbasi Akbar Ali Muhammad Haleem Khan Muhammad Mufazzal Saeed Kashif Naeem 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(1):277-283
The extraction behavior of nalidixic acid (HNA) in CH2Cl2 has been studied for various di- and trivalent metal ions such as Cu(II), Fe(II), Ni(II), Mn(II), Sb(II), Co(II), Sc(III),
Y(III), Nd(III) and Eu(III) from aqueous buffer solutions of pH 1–7 with 0.1 mol dm−3 nalidixic acid in dichloromethane. Separation factors of Sc(III) from these metals has shown that its clean separation is
possible at pH 3.4–4. The parameters affecting the extraction of Sc(III) were optimized. The composition of the extracted
adduct was determined by slope analysis method that came out to be Sc(NA)3. Extraction of Sc(III) was studied in the presence of various cations and anions. Among the anions studied only fluoride,
citrate and oxalate have significant interference whereas, Fe(III) has reduced the extraction to 53% that can be removed by
using ascorbic acid as reducing agent. The proposed extraction system proved good stability up to six extraction-stripping
stages for the extraction of Sc(III). 相似文献
843.
Mehdi Sheykhan Hossein Mohammadnejad Jafar Akbari Akbar Heydari 《Tetrahedron letters》2012,53(24):2959-2964
A highly efficient magnetically recoverable nano-catalyst was fabricated. The material synthesized has been fully characterized by vibrating sample magnetometry (VSM), X-ray powder diffraction, scanning and transmission electron microscopy, FT-IR, and the Brunauer-Emmett–Teller (BET) isotherm method. An investigation of its catalytic activity showed it to be a unique heterogeneous Lewis acid catalyst for the synthesis of α-hydroxy and α-aminophosphonates, giving a total turnover number ?450 for five consecutive runs. The catalyst is superparamagnetic having a ‘magnetization (left behind after an external magnetic field is removed)’ to ‘magnetic saturation’ ratio of about 0.0008, and thus could be easily separated by the use of an external magnetic field and was not agglomerated by exposure to magnetic fields. 相似文献
844.
Khan AS Mujer CV Alefantis TG Connolly JP Mayr UB Walcher P Lubitz W Delvecchio VG 《Journal of chemical information and modeling》2006,46(1):111-115
The potential devastation resulting from an intentional outbreak caused by biological warfare agents such as Brucella abortus and Bacillus anthracis underscores the need for next generation vaccines. Proteomics, genomics, and systems biology approaches coupled with the bacterial ghost (BG) vaccine delivery strategy offer an ideal approach for developing safer, cost-effective, and efficacious vaccines for human use in a relatively rapid time frame. Critical to any subunit vaccine development strategy is the identification of a pathogen's proteins with the greatest potential of eliciting a protective immune response. These proteins are collectively referred to as the pathogen's immunome. Proteomics provides high-resolution identification of these immunogenic proteins using standard proteomic technologies, Western blots probed with antisera from infected patients, and the pathogen's sequenced and annotated genome. Selected immunoreactive proteins can be then cloned and expressed in nonpathogenic Gram-negative bacteria. Subsequently, a temperature shift or chemical induction process is initiated to induce expression of the PhiX174 E-lysis gene, whose protein product forms an E tunnel between the inner and outer membrane of the bacteria, expelling all intracellular contents. The BG vaccine system is a proven strategy developed for many different pathogens and tested in a complete array of animal models. The BG vaccine system also has great potential for producing multiagent vaccines for protection to multiple species in a single formulation. 相似文献
845.
Majid Peyravi Masoomeh Akhfash Ardestani Ali Akbar Babaluo Mir Karim Razavi Aghjeh Seyed Roohollah Pishghadam Elham Jannatdoust 《高分子科学》2010,28(4):597-605
<正>Segmented block copolymer based on nylon6(N6) and polyethylene oxide(PEO) with stochiometric ratio was synthesized via a two-step process.The first step represents end capping of N6 in the presence of adipic acid leading to carboxy terminated N6,and the second one is polycondensation of the latter product with PEO in the presence of catalyst and thermostabilizer to form a high molecular weight multi-block copolymer.Several methods were applied to characterize the synthesized copolymer such as Fourier transform infrared spectroscopy,proton nuclear magnetic resonance spectroscopy,differential thermal analysis,differential scanning calorimetry,X-ray diffraction and atomic force microscopy. The obtained results confirmed the multi-block structure for copolymer with a very high degree of micro-phase separation. Atomic force microscopy micrographs indicated that the morphology was the dispersion of high stiffness nanostructured polyamide(PA) domains in the amorphous region of PEO matrix,which can be very important in their performance for membrane processes. 相似文献
846.
Ali Akbar Khandar Ray J. Butcher Marjan Abedi Seyed Abolfazl Hosseini-Yazdi Mehmet Akkurt M. Nawaz Tahir 《Polyhedron》2010
Utilizing a new 20-membered macrocyclic Schiff base ligand with two coordination sites formed from the [2+2] condensation of 1,3-diaminopropane and benzene-1,3-dicarboxaldehyde in the presence of CuX (X = Cl−, Br−, I−) salts, air-stable dicopper(I) complexes were synthesized in acetonitrile, intramolecularly linked via two halide groups, and characterized by different physico-chemical techniques. The single crystal X-ray diffraction technique indicates these complexes consist of two N2X2 donor sets that have distorted tetrahedral coordination environments around the copper(I) ions. In these halogen-bridged binuclear Cu2LX2 systems the Cu?Cu separation can be controlled, as this distance is reduced on increasing the halide size and hence the X?X repulsion, with the rigidity of the macrocycle playing a significant role. 相似文献
847.
Akbar H. Borzabadi Omid S. Fard 《Journal of Computational and Applied Mathematics》2009,232(2):449-454
In this paper an iterative approach for obtaining approximate solutions for a class of nonlinear Fredholm integral equations of the second kind is proposed. The approach contains two steps: at the first one, we define a discretized form of the integral equation and prove that by considering some conditions on the kernel of the integral equation, solution of the discretized form converges to the exact solution of the problem. Following that, in the next step, solution of the discretized form is approximated by an iterative approach. We finally on some examples show the efficiency of the proposed approach. 相似文献
848.
We establish some fixed point theorems for fuzzy contractive and fuzzy locally contractive mappings on a compact metric space with the d∞-metric for fuzzy sets. Our results generalized well-known classical results of Edelstein. 相似文献
849.
High output power 40 GHz 1.55 μm passively mode-locked surface-etched distributed Bragg reflector (DBR) lasers with monolithically integrated semiconductor optical amplifiers are reported. These are based on an optimized AlGaInAs/InP epitaxial structure with a three quantum well active layer and an optical trap layer. The device produces near transform limited Gaussian pulses with a pulse duration of 3.3 ps. An average output power during mode-locked operation of 130 mW was achieved with a corresponding peak power of >1 W. 相似文献
850.
We study meson-meson interactions using an extended q
2
[`(q)]2 (g)\bar q^2 (g) basis that allows calculating coupling of an ordinary meson-meson system to a hybrid-hybrid one. We use a potential model
matrix in this extended basis which at quark level is known to provide a good fit to numerical simulations of a q
2
[`(q)]2\bar q^2 system in pure gluonic theory for static quarks in a selection of geometries. We use a combination of resonating group method
formalism and Born approximation to include the quark motion using wave functions of a q[`(q)]q\bar q potential within a cluster. This potential is taken to be quadratic for ground states and has an additional smeared $\frac{1}
{r}$\frac{1}
{r} (Gaussian) for the matrix elements between hybrid mesons. For the parameters of this potential, we use values chosen to 1)
minimize the error resulting from our use of a quadratic potential and 2) best fit the lattice data for differences of Σ
g
and Π
u
configurations of the gluonic field between a quark and an antiquark. At the quark (static) level, including the gluonic
excitations, was noted to partially replace the need for introducing many-body terms in a multiquark potential. We study how
successful such a replacement is at the (dynamical) hadronic level of relevance to actual hard experiments. Thus we study
the effects of both gluonic excitations and many-body terms on mesonic transition amplitudes and the energy shifts resulting
from the second-order perturbation theory (i.e. from the respective hadron loops). The study suggests introducing both energy and orbital excitations in wave functions of
scalar mesons that are modelled as meson-meson molecules or are supposed to have a meson-meson component in their wave functions. 相似文献