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41.
We show that atoms or molecules subject to fields that couple their internal and translational (momentum) states may undergo a crossover from randomization (diffusion) to strong localization (sharpening) of their momentum distribution. The predicted crossover should be manifest by a drastic change of the interference pattern as a function of the coupling fields. 相似文献
42.
Gabyshev N Abe K Abe K Adachi I Aihara H Asano Y Aulchenko V Aushev T Bakich AM Bitenc U Bizjak I Blyth S Bondar A Bozek A Bracko M Brodzicka J Browder TE Chang P Chao Y Chen A Chen WT Cheon BG Chistov R Choi SK Choi Y Chuvikov A Cole S Dalseno J Danilov M Dash M Drutskoy A Eidelman S Enari Y Fratina S Gershon T Gokhroo G Golob B Gorisek A Hara T Hayashii H Hazumi M Hokuue T Hoshi Y Hou S Hou WS Hsiung YB Iijima T Imoto A Inami K Ishikawa A Itoh R Iwasaki M Iwasaki Y Kang JH Kang JS Kataoka SU 《Physical review letters》2006,97(24):242001
Using a sample of 152 x 10(6) BB pairs accumulated with the Belle detector at the KEKB e+e- collider, we study the decay mechanism of three-body charmed decay B- --> Lambdac+ ppi-. The intermediate two-body decay B--->Sigmac (2455)0 p is observed for the first time with a branching fraction of (3.7 +/- 0.7 +/- 0.4 +/- 1.0) x 10(-5) and a statistical significance of 8.4sigma. We also observe a low-mass enhancement in the (Lambdac+p) system, which can be parametrized as a Breit-Wigner function with a mass of (3.35(-0.02)(+0.01) +/-0.02) GeV/c2 and a width of (0.07(-0.03)(+0.04) +/-0.04) GeV/c2. We measure its branching fraction to be (3.9(-0.7)(+0.8) +/- 0.4 +/- 1.0) x 10(-5) with a statistical significance of 6.2sigma. The errors are statistical, systematic, and that of the Lambdac+-->pK- pi+ decay branching fraction. 相似文献
43.
Zhang LM Zhang ZP Li J Abe K Abe K Adachi I Aihara H Anipko D Arinstein K Asano Y Aushev T Bahinipati S Bakich AM Balagura V Barbero M Bay A Bedny I Belous K Bitenc U Bizjak I Blyth S Bondar A Bozek A Bracko M Brodzicka J Browder TE Chang MC Chang P Chao Y Chen A Chen WT Cheon BG Chistov R Choi SK Choi Y Choi YK Chuvikov A Cole S Dalseno J Danilov M Dash M Drutskoy A Eidelman S Gabyshev N Gershon T Go A Gokhroo G Golob B Gorisek A Ha HC Haba J Hara T Hastings NC Hayasaka K Hayashii H Hazumi M 《Physical review letters》2006,96(15):151801
We report the results of a search for D0-D0 mixing in D0 --> K+ pi- decays based on 400 fb(-1) of data accumulated by the Belle detector at KEKB. Both assuming CP conservation and allowing for CP violation, we fit the decay-time distribution for the mixing parameters x and y, as well as for the parameter R(D), the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays. The 95% confidence level region in the (x'2,y') plane is obtained using a frequentist method. Assuming CP conservation, we find x'2 < 0.72 x 10(-3) and -9.9 x 10(-3) < y' < 6.8 x 10(-3) at the 95% confidence level; these are the most stringent constraints on the mixing parameters to date. The no-mixing point (0,0) has a confidence level of 3.9%. Assuming no mixing, we measure R(D) = (0.377 +/- 0.008 +/- 0.005)%. 相似文献
44.
Carsten von Hänisch PD Dr. 《无机化学与普通化学杂志》2008,634(4):701-703
Synthesis and Metalation of the Diaminosiloxane O(SiiPr2NH2)2 The 1,3‐diaminoldisiloxane O(SiiPr2NH2)2 ( 1 ) was obtained from the reaction of O(SiiPr2Cl)2 with NH3. The reactions of 1 with AlEt3 or GaEt3 produced the compounds [O{SiiPr2N(H)MEt2}{SiiPr2NMEt}]2 ( 2 : M = Al; 3 : M = Ga). The crystal structures of 2 and 3 were determined by single crystal X‐ray diffraction, showing a polycyclic M4N4Si4O2 core structure of these molecules. 相似文献
45.
46.
Gunter Heymann Jan F. Riecken Sudhindra Rayaprol Sandra Christian Rainer Pöttgen Prof. Dr. Hubert Huppertz PD Dr. 《无机化学与普通化学杂志》2007,633(1):77-82
The high‐pressure (HP) modification of CePdSn was synthesized under multianvil high‐pressure (10.5 GPa) high‐temperature (1100 °C) conditions from the normal‐pressure (NP) modification. The structures of both modifications were studied by X‐ray powder and single crystal diffraction: TiNiSi type, Pnma, a = 754.1(2), b = 470.6(1), c = 798.4(3) pm, wR2 = 0.0333, 945 F2 values, 20 variables for NP‐CePdSn and ZrNiAl type, , a = 760.03(5), c = 416.06(3) pm, wR2 = 0.0443, 248 F2 values, 13 variables for HP‐CePdSn. The structural chemistry of both modifications is goverened by platinum centered trigonal prisms. The platinum and tin atoms in NP‐CePdSn and HP‐CePdSn build up a three‐dimensional [PdSn] network in which the cerium atoms fill channels. Susceptibility measurements on HP‐CePdSn reveal an experimental magnetic moment of 2.55(1) μB/Ce atom in the paramagnetic region. At 5 K a paramagnetic‐to‐antiferromagnetic transition is evident from magnetization and specific heat measurements. 相似文献
47.
Matthias Weil PD Dr. 《无机化学与普通化学杂志》2007,633(8):1217-1222
Single crystals of a third modification of Ag2Te2O6 (denoted as Ag2Te2O6–III) and of Ag4TeO5 have been obtained as minor by‐products during hydrothermal phase formation experiments in the system Ag‐Hg‐Te‐O. The crystal structure of Ag2Te2O6–III (P21/c, Z = 4, a = 6.4255(10), b = 6.9852(11), c = 13.204(2) Å, β = 90.090(3)°, 1885 independent reflections, R[F2 > 2σ(F2)] = 0.0334, wR2(F2 all) = 0.0817) comprises tellurium in oxidation states +IV and +VI and is topologically related to the structure of the Ag2Te2O6–I modification, which consists of similar layers and interjacent layers of Ag+ cations. Ag4TeO5 (C2/c, Z = 8, a = 16.271(2), b = 6.0874(10), c = 11.4373(16) Å, β = 106.730(10)°, 2372 independent reflections, R[F2 > 2σ(F2)] = 0.0288, wR2(F2 all) = 0.0737) is made up of a layer‐like arrangement of isolated [TeVI2O10] double octahedra and of Ag+ cations situated both in layers parallel and inside the layers of the anionic moieties. 相似文献
48.
Dr. Dominique Bruns Dr. Daniel Merk Dr. Karthiga Santhana Kumar PD Dr. Martin Baumgartner Prof. Dr. Gisbert Schneider 《ChemistryOpen》2019,8(10):1303-1308
Constructive machine learning aims to create examples from its learned domain which are likely to exhibit similar properties. Here, a recurrent neural network was trained with the chemical structures of known cell-migration modulators. This machine learning model was used to generate new molecules that mimic the training compounds. Two top-scoring designs were synthesized, and tested for functional activity in a phenotypic spheroid cell migration assay. These computationally generated small molecules significantly increased the migration of medulloblastoma cells. The results further corroborate the applicability of constructive machine learning to the de novo design of druglike molecules with desired properties. 相似文献
49.
We show that coupled-spin network manipulations can be made highly effective by repeated projections of the evolving quantum states onto diagonal density-matrix states (populations). As opposed to the intricately crafted pulse trains that are often used to fine-tune a complex network's evolution, the strategy hereby presented derives from the "quantum Zeno effect" and provides a highly robust route to guide the evolution by destroying all unwanted correlations (coherences). We exploit these effects by showing that a relaxationlike behavior is endowed to polarization transfers occurring within a N-spin coupled network. Experimental implementations yield coupling constant determinations for complex spin-coupling topologies, as demonstrated within the field of liquid-state nuclear magnetic resonance. 相似文献
50.