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251.
252.

Background  

The effects of the murine monoclonal anti-PcrV antibody Mab166 on acute lung injury induced by Pseudomonas aeruginosa were analyzed in a rat model.  相似文献   
253.
The reaction of aminoacrylonitrile, a species of astrochemical interest, with Ni(+)((2)D(5/2)) was investigated by means of mass spectrometry techniques and density functional theory calculations. The dominant fragmentations in the MIKE spectrum correspond to the loss of [C2,N,H3], HCN, and NH3, the loss of H2 being very minor. The structure and bonding of the different aminoacrylonitrile-Ni(+) complexes were investigated at the B3LYP/6-311G(d,p) level of theory. The same approach was employed in our survey of the corresponding potential energy surface. This survey indicates that the [C2,N,H3] neutral product can be formed either as ketenimine (CH2CNH) or acetonitrile. The formation of the latter is significantly more exothermic but involves slightly higher activation barriers; so very likely, both isomers are produced along the reaction process. The lost of HNC is not competitive with the loss of HCN, because when the former is formed the products lie higher in energy and the corresponding mechanisms involve energy barriers above the entrance channel. The loss of NH3 is associated with the formation of a complex between cyanoacetylene, HCCCN, which is very abundant in the interstellar media, and Ni(+).  相似文献   
254.
Invariant cross-sections are presented for the inclusive reaction p + p → πo + anything, Measurements of large transverse momentum πo's (2.5 GeV/c<p<9 GeV/c) were made near 90° at the CERN ISR at five centre-of-mass energies (√s = 23.5, 30.6, 44.8, 52.7 and 62.4 GeV. At large p, the invariant cross-sections are seem to vary with s and p, in good agreement with a fit of the form Ap?nF(p/√s), with n≈8 and F(p/√s)≈exp(?26p/√s).  相似文献   
255.
The possible mechanism of photoprotection by polyphenolic extracts of honeybush and the two most abundant polyphenols found in honeybush, hesperidin and mangiferin were determined using a mouse model. Ethanol: acetone soluble extracts and pure honeybush compounds were applied topically to the skin of SKH-1 mice before daily exposures to ultraviolet B (UVB) (180 mJ/cm2) for 10 days. The honeybush extracts reduced signs of sunburn, such as erythema, peeling and hardening of the skin and also significantly (P < 0.05) reduced edema, epidermal hyperplasia and the induction of cyclooxygenase-2 (COX-2), ornithine decarboxylase (ODC), GADD45 and OGG1/2 expression. The fermented honeybush extract significantly (P < 0.05) reduced lipid peroxidation and depletion of the antioxidant enzymes catalase and superoxide dismutase. Hesperidin and mangiferin were less effective. These results show that extracts of honeybush and to some extent, hesperidin and mangiferin, renders protection against UVB-induced skin damage. The mechanisms investigated suggest that honeybush extracts protected the skin via modulation of induced-oxidative damage, inflammation and cell proliferation. Other specific biological properties such as modulation of signaling pathways could also be involved.  相似文献   
256.
We present the first search for heavy, long-lived particles that decay to photons at a hadron collider. We use a sample of gamma + jet + missing transverse energy events in pp[over] collisions at square root[s] = 1.96 TeV taken with the CDF II detector. Candidate events are selected based on the arrival time of the photon at the detector. Using an integrated luminosity of 570 pb(-1) of collision data, we observe 2 events, consistent with the background estimate of 1.3+/-0.7 events. While our search strategy does not rely on model-specific dynamics, we set cross section limits in a supersymmetric model with [Formula: see text] and place the world-best 95% C.L. lower limit on the [Formula: see text] mass of 101 GeV/c(2) at [Formula: see text].  相似文献   
257.
We present a search for excited and exotic electrons (e(*)) decaying to an electron and a photon, both with high transverse momentum. We use 202 pb(-1) of data collected in pp collisions at sqrt[s] = 1.96 TeV with the Collider Detector at Fermilab II detector. No signal above standard model expectation is seen for associated ee(*) production. We discuss the e(*) sensitivity in the parameter space of the excited electron mass M(e(*)) and the compositeness energy scale Lambda. In the contact interaction model, we exclude 132 GeV/c(2)相似文献   
258.
We report on the results of a search for standard model Higgs bosons produced in association with W bosons from pp[over] collisions at sqrt[s]=1.96 TeV. The search uses a data sample corresponding to approximately 1 fb(-1) of integrated luminosity. Events consistent with the W-->lnu and H-->bb[over] signature are selected by triggering on a high-p(T) electron or muon candidate and tagging one or two of the jet candidates as having originated from b quarks. A neural network filter rejects a fraction of tagged charm and light-flavor jets, increasing the b-jet purity in the sample. We observe no excess lnubb[over] production beyond the background expectation, and we set 95% confidence level upper limits on the production cross section times branching fraction sigma(pp[over]-->WH)Br(H-->bb[over]) ranging from 3.9 to 1.3 pb, for specific Higgs boson mass hypotheses in the range 110 to 150 GeV/c2, respectively.  相似文献   
259.
Summary Quantitative structure-activity relationships were performed on a set of 5-nitrofuran derivatives. The correlation parameters used were hydrophobicity and connectivity. The former was measured by means of the capacity factor (log k o ) obtained by HPLC and the latter through the molecular valence connectivity index1 v obtained by computational methods. The biological activity data considered were growth inhibition percentages ofT. cruzi (GI % (48 h)) and half-maximal inhibitory concentration of Glutathione Reductase (I0.5 (max)). Good adjustment, r=0.98, was obtained if a logarithmic model is used for I0.5 (max) correlations. When GI% is considered, correlations were poorer and the consideration of both structural parameters was necessary for their improvement, r=0.94.  相似文献   
260.
The gas-phase reactions between Ca(2+) and thiourea are investigated by means of electrospray ionization/mass spectrometry experiments. The MS/MS spectra of [Ca(thiourea)](2+) complexes show the appearance of new doubly charged species formed by the loss of NH(3) and HNCS. Other intense peaks at m/z 43, 56, 60, 73, 76 and 98 are also observed, and assigned to monocations produced in different coulomb-explosion processes. The structures and bonding characteristics of the different stationary points of the [Ca(thiourea)](2+) potential energy surface (PES) were theoretically studied by DFT calculations carried out at B3LYP/cc-pWCVTZ level. The analysis of the topology of this PES permits to propose different mechanisms for the loss of ammonia and HNCS, and to identify, the m/z 43, 56, 60, 73, 76 and 98 peaks as H(2)NCNH(+), CaNH(2) (+), H(2)NCS(+), CaSH(+), thiourea(+) and CaNCS(+) ions respectively. There are significant dissimilarities between the reactivity of urea and thiourea, which are related to the lower ionization energy of the latter, and to the fact that thioenols are intrinsically more stable than enols with respect to the corresponding keto forms.  相似文献   
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