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121.
Koichi Kan Jinfeng Yang Kimihiro Norizawa Takafumi Kondoh Yoichi Yoshida Atsushi Ogata 《Radiation Physics and Chemistry》2011,80(12):1323-1326
A novel method to generate high-power THz radiation is proposed. If a beam with a bunch length on the order of 100 fs is injected into an electron–hole plasma of a semiconductor with a plasma frequency on the order of THz, THz wake fields are coherently generated. If the beam moves on the axis of a hollow tube covered by a metal, the frequency spectrum of the radiation is composed of discrete components. Monochromatic radiation is obtained by making only the lowest frequency component coherent. 相似文献
122.
Yuki Nagao Yuzuru Imai Jun Matsui Tomoyuki Ogawa Tokuji Miyashita 《The Journal of chemical thermodynamics》2011,43(4):613-616
We synthesized seven partially protonated poly(aspartic acids)/sodium polyaspartates (P-Asp) with different average molecular weights to study their proton transport properties. The number-average degree of polymerization (DP) for each P-Asp was 30 (P-Asp30), 115 (P-Asp115), 140 (P-Asp140), 160 (P-Asp160), 185 (P-Asp185), 205 (P-Asp205), and 250 (P-Asp250). The proton conductivity depended on the number-average DP. The maximum and minimum proton conductivities under a relative humidity of 70% and 298 K were 1.7 · 10?3 S cm?1 (P-Asp140) and 4.6 · 10?4 S cm?1 (P-Asp250), respectively. Differential thermogravimetric analysis (TG-DTA) was carried out for each P-Asp. The results were classified into two categories. One exhibited two endothermic peaks between t = (270 and 300) °C, the other exhibited only one peak. The P-Asp group with two endothermic peaks exhibited high proton conductivity. The high proton conductivity is related to the stability of the polymer. The number-average molecular weight also contributed to the stability of the polymer. 相似文献
123.
Takafumi Shibuta 《Journal of Pure and Applied Algebra》2011,215(12):2829-2842
We give algorithms for computing multiplier ideals using Gröbner bases in Weyl algebras. To this end, we define a modification of Budur-Musta?aˇ-Saito’s generalized Bernstein-Sato polynomial. We present several examples computed by our algorithm. 相似文献
124.
Iwasaki Y Matsui R Suzuki T Nakazaki A Kobayashi S 《Chemical & pharmaceutical bulletin》2011,59(4):522-524
We have developed a high-yielding and stereoselective vinylogous Mukaiyama aldol reaction (VMAR) of α-haloenals. Contrary to the simple α,β-unsaturated aldehyde, α-haloenals were found to be reactive affording the corresponding VMAR adducts in excellent yields. Some transformations of VMAR adducts by Pd-mediated cross-coupling were also examined in order to demonstrate the synthetic utility of VMAR of α-haloenals. 相似文献
125.
Imoto M Matsui Y Takeda M Tamaki A Taniguchi H Mizuno K Ikeda H 《The Journal of organic chemistry》2011,76(15):6356-6361
Observations show that nitroanilines exhibit an unusually high S(N)Ar reactivity with OH(-) in aqueous media in reactions that produce nitrophenols. S(N)Ar reaction of 4-nitroaniline (2a) in aqueous NaOH for 16 h yields 4-nitrophenol (4a) quantitatively, whereas a similar reaction of 4-nitrochlorobenzene (1a) gave 4a in 2% yield together with recovered 1a in 97%, suggesting that the leaving ability of the NH(2) group far surpasses that of Cl under these conditions. An essential feature of S(N)Ar reactions of nitroanilines is probably that the NH(2) leaving group participates in a hydrogen-bonding interaction with H(2)O. Density functional theory (DFT) calculations for a set of 4-nitroaniline, OH(-), and H(2)O suggest a possible formation of a Meisenheimer complex stabilized by hydrogen-bonding interactions and a six-membered ring structure. The results obtained here contrast with conventional S(N)Ar reactivity profiles in which nitroanilines are nearly unreactive with nucleophiles in organic solvents. 相似文献
126.
We present a reaction scheme of silver containing 5-substituted uracils (N) bridge formation with two silver ions to a silver-mediated base pair [N-Ag(2)-N] by using the conductor-like polarizable continuum model (CPCM)-B3LYP/aug-cc-pVDZ level of theory. The whole reaction scheme is divided into the following three steps: (1) silver ion binding and deprotonation, (2) silver ion transfer, and (3) dimer formation and structural fluctuation. With a new pK(a) computing scheme proposed in our previous studies, it is found that a silver coordination decreases the pK(a) of N by 2.5-3.0 pK(a) units, which is an important clue for silver-ion selectivity by N. Judging from the calculation, we revealed that the silver ion transfer reaction and the dimerization reaction occur spontaneously. Moreover, both reactions are independent of the C5 ligand in N so that the deprotonation reaction, which is the first step of this scheme, plays a key role in forming the [N-Ag(2)-N] pairing. 相似文献
127.
128.
Noriaki Nishiguchi Takafumi Kinuta Yoko Nakano Dr. Takunori Harada Dr. Nobuo Tajima Tomohiro Sato Prof. Dr. Michiya Fujiki Prof. Dr. Reiko Kuroda Prof. Dr. Yoshio Matsubara Dr. Yoshitane Imai 《化学:亚洲杂志》2011,6(4):1092-1098
The solid‐state chiral optical properties of a 4‐(2‐arylethynyl)‐benzoic acid/amine supramolecular organic fluorophore can be controlled by changing the arylethynyl group of the achiral 4‐(2‐arylethynyl)‐benzoic acid component molecule rather than the chirality of the amine component molecule. 相似文献
129.
Journal of Theoretical Probability - We study multivariate stochastic recurrence equations (SREs) with triangular matrices. If coefficient matrices of SREs have strictly positive entries, the... 相似文献
130.
Hiroshi Mukai Shoji Miyazaki Shigeo Umetani Sorin Kihara Masakazu Matsui 《Analytica chimica acta》1989
Solvent extraction of europium (III), zinc (II) cobalt (II) with α-acyl-d-camphor and optically active isomers of quinine and quinidine was studied in order to obtain information on chirality recognition based on adduct formation between a chiral metal chelate and optically active isomers. It was possible to differentiate clearly between the adduct formation of quinine and that of quinidine in the synergic extraction of cobalt and europium with 3-heptafluorobutyryl- d-camphor and cobalt with 3-trifluoroacetyl-d-camphor. 相似文献