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91.
We present the first study of the gluonic excitation in the three-quark (3Q) system in SU(3) lattice QCD with beta=5.8 and 16(3) x 32 at the quenched level. For the spatially fixed 3Q system, we measure the gluonic excited-state potential, which is responsible for the properties of hybrid baryons. The lowest gluonic-excitation energy in the 3Q system is found to be about 1 GeV in the hadronic scale. This large gluonic-excitation energy is expected to bring about the success of the simple quark model without gluonic modes. 相似文献
92.
Tobe M Isobe Y Tomizawa H Nagasaki T Aoki M Negishi T Hayashi H 《Chemical & pharmaceutical bulletin》2003,51(9):1109-1112
We investigated the chemical modifications of the nitroquinazoline derivative (1) through the replacement of the NH group at the C(4)-position with several N-alkyl groups to increase the lipophilicity at the C(4)-position. Among them, we found that the N-methyl analogue (5a) showed a 2-fold loss in the inhibitory activity toward tumor necrosis factor-alpha (TNF-alpha) production in vitro as compared with the NH analogue (1); however, 5a exhibited an oral inhibitory activity on TNF-alpha production with an ED50 value of 26 mg/kg, whereas 1 did not. Moreover, the oral bioavailability of 5a was higher than that of 1 (1, F=1%; 5a, F=21%), and the calculated ClogP value for 5a was higher than that for 1. These results suggest that the improved lipophilicity of 5a compared with that of 1 reflects its greater inhibitory activity on TNF-alpha production in vivo as well as oral bioavailability. 相似文献
93.
Morishita T 《Physical review letters》2001,87(10):105701
Pressure-induced phase transitions in liquid phosphorus have been studied by constant-pressure first-principles molecular dynamics simulations. By compressing a low-pressure liquid which consists of the tetrahedral P4 molecules, a structural phase transition from the molecular to polymeric liquid (a high-pressure phase) observed in the recent experiment by Katayama et al. [Nature (London) 403, 170 (2000)] was successfully realized. It is found that this transition is caused by a breakup of the tetrahedral molecules with large volume contraction. The same transition is also realized by heating. This indicates that only the polymeric liquid can stably exist at high temperature. 相似文献
95.
Toru Kojima 《Discrete Mathematics》2008,308(7):1282-1295
The bandwidth B(G) of a graph G is the minimum of the quantity max{|f(x)-f(y)|:xy∈E(G)} taken over all proper numberings f of G. The strong product of two graphs G and H, written as G(SP)H, is the graph with vertex set V(G)×V(H) and with (u1,v1) adjacent to (u2,v2) if one of the following holds: (a) u1 and v1 are adjacent to u2 and v2 in G and H, respectively, (b) u1 is adjacent to u2 in G and v1=v2, or (c) u1=u2 and v1 is adjacent to v2 in H. In this paper, we investigate the bandwidth of the strong product of two connected graphs. Let G be a connected graph. We denote the diameter of G by D(G). Let d be a positive integer and let x,y be two vertices of G. Let denote the set of vertices v so that the distance between x and v in G is at most d. We define δd(G) as the minimum value of over all vertices x of G. Let denote the set of vertices z such that the distance between x and z in G is at most d-1 and z is adjacent to y. We denote the larger of and by . We define η(G)=1 if G is complete and η(G) as the minimum of over all pair of vertices x,y of G otherwise. Let G and H be two connected graphs. Among other results, we prove that if δD(H)(G)?B(G)D(H)+1 and B(H)=⌈(|V(H)|+η(H)-2)/D(H)⌉, then B(G(SP)H)=B(G)|V(H)|+B(H). Moreover, we show that this result determines the bandwidth of the strong product of some classes of graphs. Furthermore, we study the bandwidth of the strong product of power of paths with complete bipartite graphs. 相似文献
96.
Toru Tsukioka 《Comptes Rendus Mathematique》2005,340(8):581-586
This Note is devoted to the study of the Fano manifolds X obtained by blow-up along a smooth curve C in a complex projective manifold Y. By the Mori theory, we can ensure the existence of an extremal contraction different from the blow-up . Here we give the complete classification of the corresponding pairs in the case where φ is a fiber type contraction of relative dimension 2, i.e. the general fibers of φ are del Pezzo surfaces. In Tsukioka (Thesis, Nancy University 1, 2005), the relative dimension 1 case is also considered. To cite this article: T. Tsukioka, C. R. Acad. Sci. Paris, Ser. I 340 (2005). 相似文献
97.
98.
99.
Defocusing digital particle image velocimetry (DDPIV), as a true three-dimensional (3D) measurement technique, allows for
the measurement of 3D velocities within a volume. Initially designed using a single CCD and 3-pinhole mask (Willert and Gharib
in Exp Fluids 12:353–358, 1992), it has evolved into a multi-camera system in order to overcome the limitations of image saturation due to multiple exposures
of each particle. In order to still use a single camera and overcome this limitation, we have modified the original single
CCD implementation by placing different color filters over each pinhole, thus color-coding each pinhole exposure, and using
a 3-CCD color camera for image acquisition. Due to the pinhole mask, there exists the problem of a significant lack of illumination
in a conventional lighting setup, which we have solved by backlighting the field-of-view and seeding the flow with black particles.
This produces images with a white background superimposed with colored triple exposures of each particle. A color space linear
transformation is used to allow for accurate identification of each pinhole exposure when the color filters’ spectrum does
not match those of the 3-CCD color camera. Because the imaging is performed with a multi-element lens instead of a single-element
lens, an effective pinhole separation, d
e, is defined when using a pinhole mask within a multi-element lens. Calibration results of the system with and without fluid
are performed and compared, and a correction of the effective pinhole separation, d
e, due to refraction through multiple surfaces is proposed. Uncertainty analyses are also performed, and the technique is successfully
applied to a buoyancy-driven flow, where a 3D velocity field is extracted. 相似文献
100.
Toru Minami Ryoji Kouno Tatsuo Okauchi Mitsuharu Nakamura Junji Ichikawa 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):689-692
The α-phosphonovinyl anions, generated in situ from treatment of β-hetero-substituted vinyl-phosphonates 1a-c with LDA (or LTMP), were trapped with various electrophiles such as chlorotriorganosilanes, chlorotrimethylgermane, chlorotriorganotins, dimethyl disulfide, and halogen to afford the corresponding β-hetero-substituted α-functionalized vinylphosphonates 2–14 in good to excellent yields. The Friedel-Crafts reaction of α-(silyl) or α-(germyl)phosphonoketene dithioacetals 2, 9 or 4 with acid chlorides gave α-acylated phosphonoketene dithioacetals 15–19 in 53–91 % yields. The palladium-catalyzed cross-coupling reaction of β-ethoxy-α-(tributylstannyl)vinylphosphonate 13 with a variety of organic halides (R = acyl, allyl, aryl etc.) provided β-ethoxy-α-substituted vinylphosphonates 20–25 in good to moderate yields. The palladium-mediated cross-coupling reaction of α-(iodo)-vinyl-phosphonates 7, 14 with terminal acetylenes afforded α-alkynylated vinylphosphonates 26–29 in 69–83 % yields. 相似文献