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41.
42.
Laser-induced acoustic wave generation/propagation/interaction in water in various internal channels
Seung Hwan Ko Daeho Lee Heng Pan Sang-Gil Ryu Costas P. Grigoropoulos Nick Kladias Elias Panides Gerald A. Domoto 《Applied Physics A: Materials Science & Processing》2010,100(2):391-400
Short pulsed laser-induced single acoustic wave generation, propagation, interaction within a water-filled internal channel
are experimentally and numerically studied. A large-area, short-duration, single-plane acoustic wave was generated by the
thermoelastic interaction of a homogenized nanosecond pulsed laser beam with a liquid–solid interface and propagated at the
speed of sound in water. Laser flash Schlieren photography was used to visualize the transient interaction of the plane acoustic
wave in various internal channel structures ((a) sudden expansion and contraction channels, (b) bifurcating channels, (c) gradual
contraction wall channels and (d) a cylinder). Fairly good agreement between the experimental results and numerical simulation
is observed. 相似文献
43.
We consider an elliptic system in divergence form with measurable coefficients in a nonsmooth bounded domain to find a minimal regularity requirement on the coefficients and a lower level of geometric assumption on the boundary of the domain for a global W 1,p , 1 < p < ∞, regularity. It is proved that such a W 1,p regularity is still available under the assumption that the coefficients are merely measurable in one variable and have small BMO semi-norms in the other variables while the domain can be locally approximated by a hyperplane, a so called δ-Reifenberg domain, which is beyond the Lipschitz category. This regularity easily extends to a certain Orlicz-Sobolev space. 相似文献
44.
Ji Yeon Choi Ji-Eun Bae Joon Bum Kim Doo Sin Jo Na Yeon Park Yong Hwan Kim Ha Jung Lee Seong Hyun Kim So Hyun Kim Hong Bae Jeon Hye-Won Na Hyungjung Choi Hong-Yeoul Ryu Zae Young Ryoo Hyun-Shik Lee Dong-Hyung Cho 《Molecules (Basel, Switzerland)》2021,26(17)
Primary cilia mediate the interactions between cells and external stresses. Thus, dysregulation of primary cilia is implicated in various ciliopathies, e.g., degeneration of the retina caused by dysregulation of the photoreceptor primary cilium. Particulate matter (PM) can cause epithelium injury and endothelial dysfunction by increasing oxidative stress and inflammatory responses. Previously, we showed that PM disrupts the formation of primary cilia in retinal pigment epithelium (RPE) cells. In the present study, we identified 2-isopropylmalic acid (2-IPMA) as a novel inducer of primary ciliogenesis from a metabolite library screening. Both ciliated cells and primary cilium length were increased in 2-IPMA-treated RPE cells. Notably, 2-IPMA strongly promoted primary ciliogenesis and restored PM2.5-induced dysgenesis of primary cilia in RPE cells. Both excessive reactive oxygen species (ROS) generation and activation of a stress kinase, JNK, by PM2.5 were reduced by 2-IPMA. Moreover, 2-IPMA inhibited proinflammatory cytokine production, i.e., IL-6 and TNF-α, induced by PM2.5 in RPE cells. Taken together, our data suggest that 2-IPMA ameliorates PM2.5-induced inflammation by promoting primary ciliogenesis in RPE cells. 相似文献
45.
Ra You Wongi Park Eric Carlson Seong Ho Ryu Min Jeong Shin Edward Guzman 《Liquid crystals》2019,46(2):316-325
We produced controlled heliconical structures of a twist-bend nematic (NTB) liquid-crystal (LC) phase in nanoconfinement in a porous anodic aluminium oxide (AAO) film. The structural parameters of the NTB phase such as conical angle and helical pitch can be modulated by varying the surface energy of the inner surface of the porous AAO film, done by using different self-assembled monolayers (SAMs). The LC molecules tend to be more freely packed, thus forming a larger conical angle, when placed on the tri-deca-fluoro-1,1,2,2-tetrahydrooctyl-trichlorosilane (FOTS)-treated substrate, which has a relatively low surface energy. In contrast, the molecules form a more tightly packed structure, and thus a smaller conical angle, when placed on the 2-(methoxy(polyethyleneoxy)-propyl)trimethoxysilane (PEG 6/9)-treated substrate, which has higher surface energy. This work improves our collective understanding of self-assembled heliconical structures in the NTB phase. 相似文献
46.
A radical chain addition of allyl bromides 2 to alkenylcyclopropanes 1 resulted in [3+2] annulation to give 2-bromomethylalkenylcyclopentanes 3 in good yields(16 examples). In this reaction, two kinetically fast radical reactions, cyclopropylcarbinyl radical-ring-opening and 5-exo-radical cyclization, preceded the β-fragmentation of a bromine radical to make the formal cycloaddition possible. 相似文献
47.
Ashraful Alam Hidetoshi Ohta Tatsuya Yamamoto Satoshi Ogawa Ryu Sato 《Heteroatom Chemistry》2007,18(3):239-248
Naphthalene‐1‐sulfonic acid dimethylamides were treated with n‐BuLi and elemental sulfur or selenium to afford dinaphtho[1,2‐b:2′,1′‐d]thiophenes and selenophenes, respectively. This is the first example of making two C S/Se bonds and a C C bond in a single step at room temperature and also demonstrates a useful method for the synthesis of both thiophenes and selenophenes on naphthalene. In the case of the reactions of elemental selenium, diselenides were also obtained along with dinaphtho[1,2‐b:2′,1′‐d]selenophenes. The structure of dinaphtho[1,2‐b:′,1′‐d]thiophene was characterized by X‐ray crystallography as a representative molecule. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:239–248, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20291 相似文献
48.
The present study uses laboratory measurements to investigate the void fraction of an overtopping flow on a structure. The
overtopping flow, also called green water, was generated by the impingement of a plunging breaking wave on the structure following
the Froude similarity of an extreme hurricane wave and a simplified offshore structure. The flow is multi-phased and turbulent
with significant aeration. A fiber optic reflectometer (FOR) and bubble image velocimetry (BIV) were employed to measure the
void fraction and velocity in the flow, respectively, and to determine the water level on the deck. Mean properties of void
fraction and velocity were obtained by ensemble-averaging and time-averaging the repeated instantaneous measurements. The
temporal and spatial distributions of void fraction reveal that the flow is very highly aerated near the front of green water
and has relatively low aeration near the deck surface. The mean void fraction and velocity distributions were also depth-averaged
for simplicity and potential use in engineering applications. Using the measured data, similarity profiles for depth-averaged
void fraction, depth-averaged velocity, and water level were found. The study suggests that using only the velocity data is
insufficient if the flow momentum or the flow rate is to be determined. The accuracy of the void fraction measurements was
validated by comparing the directly measured water volume of the overtopping flow with the calculated water volume based on
the measured velocity and void fraction. 相似文献
49.
Scott W. Lefevre Heungyeal Choi Taihyun Chang Chang Y. Ryu 《Journal of polymer science. Part A, Polymer chemistry》2009,47(24):2547-2555
In this article, we have investigated a temperature-rise fractionation procedure for poly(3-hexyl thophene) (P3HT) and poly(3-octyl thophene) (P3OT) that provides well-defined molecular weight (MW) fractions with improved molecular weight distributions (MWD) when compared with Soxhlet extraction. This process involves dispersing the material over C18-boned silica stationary phase in a jacketed column and using incremental rises in column temperature (Tcol) to gradually improve solvent quality and selectively dissolve higher molecular weight samples with a narrow polydispersity (PDI). Fractionation of P3HT with ΔTcol = 5 °C in methylene chloride (MC) yielded 7 fractions ranging from Mp of 20 to 53 kg/mol with an average PDI of 1.80 compared with a mother sample of 3.10. Predominant recovery of P3HT was acquired for fractions with Tcol > 20 °C (30 wt %). Subsequent separation of P3OT in methylene chloride, with a reduced ΔTcol of 3 °C per fraction, due to increased solubility from the longer alkyl chain, generated 8 fractions with a weight range of Mn = 22 to 57 kg/mol with an mean PDI of 1.23 with the mother sample having PDI = 2.34, demonstrating the tunability of this method. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2547–2555, 2009 相似文献
50.