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91.
Ebtisam A. Aldaais Scott Crittenden 《Journal of Polymer Science.Polymer Physics》2019,57(24):1684-1691
We incorporate the Boltzmann factors for inter‐monomer bending energy into the monomer growth direction choice in Rosenbluth's algorithm to model chains of arbitrary nearest‐neighbor rigidity. This allows for the consideration of compact (bent state lower in energy), free (straight and bent state equal in energy), or extended chains (bent state higher). We validate against, and compare to, various other results, showing very good agreement with known results for short chains and demonstrate the ability to model chains up to 500 segments long, far beyond the length at which the normal Rosenbluth method becomes unstable for reasonable nonzero bending energies. This approach is easily generalizable both to other energies determinable during chain growth, for example, polymers composed of more than one type of monomer with differing monomer interaction energies, as well as to other chain production algorithms. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1684–1691 相似文献
92.
Two-Photon-Induced CO-Releasing Molecules as Molecular Logic Systems in Solution,Polymers, and Cells
Dr. Vadde Ramu Dr. Gandra Upendar Reddy Dr. Jingjing Liu Patrick Hoffmann Dr. Rudrakant Sollapur Dr. Ralf Wyrwa Dr. Stephan Kupfer Prof. Dr. Christian Spielmann Dr. Sylvestre Bonnet Prof. Dr. Ute Neugebauer Dr. Alexander Schiller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8453-8458
Phototherapeutic applications of carbon monoxide (CO)-releasing molecules are limited because they require harmful UV and blue light for activation. We describe two-photon excitation with NIR light (800 nm)-induced CO-release from two MnI tricarbonyl complexes bearing 1,8-naphthalimide units ( 1 , 2 ). Complex 2 behaves as a logic OR gate in solution, nonwovens, and in HeLa cells. CO release, indicated by fluorescence enhancement, was detected in solution, nonwoven, and HeLa cells by single- (405 nm) and two-photon (800 nm) excitation. The photophysical properties of 1 and 2 have been measured and supported by DFT and TDDFT quantum chemical calculations. Both photoCORMs are stable in the dark in solution and noncytotoxic, leading to promising applications as phototherapeutics with NIR light. 相似文献
93.
94.
Joseph D. Martin 《Annalen der Physik》2019,531(10)
Mildred Dresselhaus is known for her influential research on the physics of carbon. Her wide‐ranging influence as a physics teacher, although well‐known to her students, has been less thoroughly examined. Exploring how Dresselhaus grew into her role teaching solid state physics at MIT reveals much about how that subfield evolved. 相似文献
95.
Influence theory is a foundational theory of physics that is not based on traditional empirically defined concepts, such as positions in space and time, mass, energy, or momentum. Instead, the aim is to derive these concepts, and their empirically determined relationships, from a more primitive model. It is postulated that there exist things, which are call particles, that influence one another in a discrete and directed fashion resulting in a partially ordered set of influence events. The problem of consistent quantification of the influence events is considered. Observers are modeled as particle chains (observer chains) as if an observer were able to track a particle and quantify the influence events that the particle experiences. From these quantified influence events, consistent quantification of the universe of events based on the observer chains is studied. Herein, the kinematics and dynamics of particles from the perspective of influence theory are both reviewed and further developed. 相似文献
96.
Dr. Jinghui Zhang Lei Gong Xiaoshuang Zhang Dr. Mengliang Zhu Chaorui Su Qing Ma Dr. Dongdong Qi Prof. Yongzhong Bian Prof. Hongwu Du Prof. Jianzhuang Jiang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(61):13842-13848
Two-photon excited fluorescent (TPEF) materials are highly desirable for bioimaging applications owing to their unique characteristics of deep-tissue penetration and high spatiotemporal resolution. Herein, by connecting one, two, or three electron-deficient zinc porphyrin units to an electron-rich triazatruxene core via ethynyl π-bridges, conjugated multipolar molecules TAT-(ZnP) n (n=1–3) were developed as TPEF materials for cell imaging. The three new dyes present high fluorescence quantum yields (0.40–0.47) and rationally improved two-photon absorption (TPA) properties. In particular, the peak TPA cross section of TAT-ZnP (436 GM) is significantly larger than that of the ZnP reference (59 GM). The δTPA values of TAT-(ZnP)2 and TAT-(ZnP)3 further increase to 1031 and up to 1496 GM, respectively, indicating the effect of incorporated ZnP units on the TPA properties. The substantial improvement of the TPEF properties is attributed to the formation of π-conjugated quadrapole/octupole molecules and the extension of D -π-A-D systems, which has been rationalized by density function theory (DFT) calculations. Moreover, all of the three new dyes display good biocompatibility and preferential targeting ability toward cytomembrane, thus can be superior candidates for TPEF imaging of living cells. Overall, this work demonstrated a promising strategy for the development of porphyrin-based TPEF materials by the construction and extension of D -π-A-D multipolar array. 相似文献
97.
Summary The partition of the spin probe TEMPO between the fluid lipid phase of single-walled vesicles of dipalmitoylphosphatidylcholine
and the aqueous bulk solution have been used to investigate the interaction of monovalent ions with polar head of neutral
phospholipids. The study has been performed by electron spin resonance (ESR) spectroscopy in the temperature range of (20÷60)°C
and in the presence of (0÷3) M 1∶1 electrolyte. In the absence of electrolyte the spin probe TEMPO reveals the characteristic
order→disorder DPPC main phase transition atT
m≈37°C, while the pretransition occurs atT
p≈27.5°C. On increasing the ionic strength of the dispersion medium it results for the partition coefficient,P
C, that, at each temperature,P
C(3)>P
C(2)>P
C(1)>P
C(0). Correspondingly, the pretransition disappears and theT
m value downshifts from ≈37°C with 0 M electrolyte to ≈34°C with 3M salt in the order:T
m(3)>T
m(2)>T
m(1)>T
m(0). The results suggest an increase in the net surface charge density of vesicles due to high ionic-strength values. The
alteration of the electric interactions occurring into the polar zone of DPPC bilayer reduces the hindrances which, in turn,
favour the enhancement of TEMPO partitioning in the hydrophobic core of phospholipid bilayers.
The authors of this paper have agreed to not receive the proofs for correction. 相似文献
98.
G. R. Mason G. A. Beer M. S. Dixit S. K. Kim J. A. MacDonald A. Olin R. M. Pearce 《Nuclear Physics A》1980,340(2):240-248
Energies and lorentzian widths of pionic K X-ray transitions have been measured in liquid 3He with improved accuracy. The strong interaction on the π3He 1s level is found to be attractive and to produce an increase in the K transition energies of 34 ± 4 eV; the measured lorentzian width is 36 ±7 eV. Measured values are also presented for K X-ray energies in liquid π4He and μ4He, the lorentzian width of the 1s level in π4He, and relative intensities of K X-ray transitions in π3He, π4He and μ4He. The measurements are compared with those of others and with recent theoretical calculations. 相似文献
99.
C. Biely R. Hanel S. Thurner 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,67(3):285-289
We consider social systems in which agents are not only characterized by their states but also have the freedom to choose
their interaction partners to maximize their utility. We map such systems onto an Ising model in which spins are dynamically
coupled by links in a dynamical network. In this model there are two dynamical quantitieswhich arrange towards a minimum energy
state in the canonical framework:the spins, si, and the adjacency matrix elements, cij.The model is exactly solvable because microcanonical partition functions reduce to productsof binomial factors as a direct
consequence of the cij minimizing energy. We solve the system for finite sizes and for the two possible thermodynamic limits and discussthe phase
diagrams. 相似文献
100.
Theoretical studies on the one- and two-photon absorption properties of azulenylporphyrins and azulene-fused porphyrins 下载免费PDF全文
The electronic structures, one-photon absorption (OPA) and
two-photon absorption (TPA) properties of the azulenylporphyrins and
azulene-fused porphyrins have been comparatively studied by using
DFT/B3LYP/6-31G(d) and the ZINDO/SDCI method. With the number of
azulenyl groups increasing, the OPA wavelengths of all molecules are
red-shifted in 400--600~nm and the two-photon absorption cross section
is gradually enlarged. The azulene-fused structures facilitate an
expanding conjugated area and increasing TPA cross section. The
origin of TPA properties of studied compounds is studied with a
two-level model. In summary, the azulene-fused porphyrins exhibit
strong two-photon absorption. 相似文献