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261.
High gradient magnetic field separators have been widely used in a variety of biological applications. Recently, the use of magnetic separators to remove malaria-infected red blood cells (pRBCs) from blood circulation in patients with severe malaria has been proposed in a dialysis-like treatment. The capture efficiency of this process depends on many interrelated design variables and constraints such as magnetic pole array pitch, chamber height, and flow rate. In this paper, we model the malaria-infected RBCs (pRBCs) as paramagnetic particles suspended in a Newtonian fluid. Trajectories of the infected cells are numerically calculated inside a micro-channel exposed to a periodic magnetic field gradient. First-order stiff ordinary differential equations (ODEs) governing the trajectory of particles under periodic magnetic fields due to an array of wires are solved numerically using the 1st to 5th order adaptive step Runge-Kutta solver. The numerical experiments show that in order to achieve a capture efficiency of 99% for the pRBCs it is required to have a longer length than 80 mm; this implies that in principle, using optimization techniques the length could be adjusted, i.e., shortened to achieve 99% capture efficiency of the pRBCs. 相似文献
262.
A numerical technique based on the finite difference and collocation methods is presented for the solution of generalized Kuramoto-Sivashinsky (GKS) equation. The derivative matrices between any two families of B-spline functions are presented and are utilized to reduce the solution of GKS equation to the solution of linear algebraic equations. Numerical simulations for five test examples have been demonstrated to validate the technique proposed in the current paper. It is found that the simulating results are in good agreement with the exact solutions. 相似文献
263.
The osmotic coefficients of lithium chloride, lithium bromide, and lithium nitrate in 2-propanol have been measured by the isopiestic method at 25°C. Sodium iodide was used as the isopiestic standard. The molality ranges covered were from 0.2 to 1.5 for LiCl and LiBr, and to 1.9 mol-kg-1 for LiNO3. The system of equations developed by Clegg–Pitzer and Pitzer were used to fit each set of osmotic coefficients. The experimental osmotic coefficient data are successfully correlated with these models. The parameters from the fit were used to calculate the mean molal activity coefficients. 相似文献
264.
Claude Schweitzer Zahra Mehrdad Astrid Noll Erich‐Walter Grabner Reinhard Schmidt 《Helvetica chimica acta》2001,84(9):2493-2507
We have studied the charge‐transfer‐induced deactivation of nπ* excited triplet states of benzophenone derivatives by O2(3Σ), and the charge‐transfer‐induced deactivation of O2(1Δg) by ground‐state benzophenone derivatives in CH2Cl2 and CCl4. The rate constants for both processes are described by Marcus electron‐transfer theory, and are compared with the respective data for a series of biphenyl and naphthalene derivatives, the triplet states of which have ππ* configuration. The results demonstrate that deactivation of the locally excited nπ* triplets occurs by local charge‐transfer and non‐charge‐transfer interactions of the oxygen molecule with the ketone carbonyl group. Relatively large intramolecular reorganization energies show that this quenching process involves large geometry changes in the benzophenone molecule, which are related to favorable Franck‐Condon factors for the deactivation of ketone‐oxygen complexes to the ground‐state molecules. This leads to large rate constants in the triplet channel, which are responsible for the low efficiencies of O2(1Δg) formation observed with nπ* excited ketones. Compared with the deactivation of ππ* triplets, the non‐charge‐transfer process is largely enhanced, and charge‐transfer interactions are less important. The deactivation of singlet oxygen by ground‐state benzophenone derivatives proceeds via interactions of O2(1Δg) with the Ph rings. 相似文献