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61.
62.
The creation of nano-structures in 3–5 semiconductors is currently of great interest. If the conventional route of pattern definition in a resist followed by pattern transfer is used, this implies in most cases electron beam lithography and some form of dry etching. Using electron beam lithography, patterns of 10nm width on 40nm centre to centre spacing can be transfered to metal lines on thin substrates; even on normal wafers, linewidths of 25nm on 60nm spacing are achievable with state of the art machines.If the creation of a raised structure is necessary because of the physics of the situation, it is important to consider the damage which may be introduced by dry etching. The methods by which dry etch damage can be revealed are discussed, and the ways in which it can be reduced mentioned. Progress towards understanding the microscopic nature of the damage will be reviewed. Examples are drawn from etching of GaAs/GaAlAs in Silicon tetrachloride and methane/hydrogen. 相似文献
63.
Greve BK Martin KL Lee PL Chupas PJ Chapman KW Wilkinson AP 《Journal of the American Chemical Society》2010,132(44):15496-15498
Scandium trifluoride maintains a cubic ReO(3) type structure down to at least 10 K, although the pressure at which its cubic to rhombohedral phase transition occurs drops from >0.5 GPa at ~300 K to 0.1-0.2 GPa at 50 K. At low temperatures it shows strong negative thermal expansion (NTE) (60-110 K, α(l) ≈ -14 ppm K(-1)). On heating, its coefficient of thermal expansion (CTE) smoothly increases, leading to a room temperature CTE that is similar to that of ZrW(2)O(8) and positive thermal expansion above ~1100 K. While the cubic ReO(3) structure type is often used as a simple illustration of how negative thermal expansion can arise from the thermally induced rocking of rigid structural units, ScF(3) is the first material with this structure to provide a clear experimental illustration of this mechanism for NTE. 相似文献
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66.
Liondas CA; Chrissoulidis DP 《The Quarterly Journal of Mechanics and Applied Mathematics》2007,60(3):275-287
This paper is intended to clarify a misunderstanding concerningthe source singularity of the electric Green's tensor for aperfectly conducting semi-infinite cone of circular cross-section.Tai's series expansion of the Green's tensor is known to lacka singular term at the source region. Jones has reconstructedthe solution to this problem and has pointed out the differencebetween his result and that of Tai. The aim of our paper isto demonstrate that, although Jones's closed-form solution iscorrect, there is a mistake in his comparison with Tai's seriessolution. We conclude that one of the two additional singularterms that Jones claims as missing from Tai's formula must beomitted. Besides, we compare Jones's closed-form solution withSmyshlyaev's solution to the very same problem. We concludethat the magnetic field expressions given by Jones and Smyshlyaevcoincide, but a singular term is missing from Smyshlyaev's expressionfor the electric field. 相似文献
67.
F. Wilkinson 《Journal of Chemical Sciences》1991,103(3):305-311
Recent progress which allows laser flash photolysis investigation of opaque materials by using diffuse reflectance from analysing
sources for the detection of laser induced transient species is described. Experimental details of nanosecond and picosecond
diffuse reflectance laser photolysis systems are presented and methods of analysis of data are discussed. The potential of
the technique for studying elementary reactions at interfaces is demonstrated with particular reference to bimolecular reactions
of (a) the triplet state of acridine adsorbed on various porous silica surfaces and (b) ion-electron recombination following
multi-photon ionisation of diphenyl polyenes adsorbed on γ-alumina. The mechanisms of formation and decay of these transient
adsorbed species are discussed. 相似文献
68.
Goodman TNT; Micchelli CA; Rodriguez G; Seatzu S 《IMA Journal of Numerical Analysis》1998,18(3):331-354
It is shown that, under certain conditions, orthonormalizingthe positive integer shifts of an exponentially decaying functionon the half line by the Gram-Schmidt process leads to a limitingprofile given by orthonormalizing all their integer shifts onthe whole line. These results derive from properties of Choleskyfactorization of bi-infinite and semi-infinite matrices. Anexample is provided by the negative exponential function andconjectures are given, supported by numerical evidence, forthe Gaussian and Lorentz function. 相似文献
69.
Sloutskin E Sapir Z Bain CD Lei Q Wilkinson KM Tamam L Deutsch M Ocko BM 《Physical review letters》2007,99(13):136102
Millimolar bulk concentrations of the surfactant cetyltrimethylammonium bromide (CTAB) induce spreading of alkanes, H(CH(2))(n)H (denoted C(n)) 12< or =n< or =21, on the water surface, which is not otherwise wet by these alkanes. The novel Langmuir-Gibbs film (LGF) formed is a liquidlike monolayer comprising both alkanes and CTAB tails. Upon cooling, an ordering transition occurs, yielding a hexagonally packed, quasi-2D crystal. For 11< or =n< or =17 this surface-frozen LGF is a crystalline monolayer. For 18< or =n< or =21 the LGF is a bilayer with a crystalline, pure-alkane, upper monolayer, and a liquidlike lower monolayer. The phase diagram and film structure were determined by x-ray, ellipsometry, and surface tension measurements. A thermodynamic theory accounts quantitatively for the observations. 相似文献
70.
Fusing multiple Bayesian knowledge sources 总被引:1,自引:0,他引:1
Eugene Santos Jr.John T. Wilkinson Eunice E. Santos 《International Journal of Approximate Reasoning》2011,52(7):935-947
We address the problem of information fusion in uncertain environments. Imagine there are multiple experts building probabilistic models of the same situation and we wish to aggregate the information they provide. There are several problems we may run into by naively merging the information from each. For example, the experts may disagree on the probability of a certain event or they may disagree on the direction of causality between two events (e.g., one thinks A causes B while another thinks B causes A). They may even disagree on the entire structure of dependencies among a set of variables in a probabilistic network. In our proposed solution to this problem, we represent the probabilistic models as Bayesian Knowledge Bases (BKBs) and propose an algorithm called Bayesian knowledge fusion that allows the fusion of multiple BKBs into a single BKB that retains the information from all input sources. This allows for easy aggregation and de-aggregation of information from multiple expert sources and facilitates multi-expert decision making by providing a framework in which all opinions can be preserved and reasoned over. 相似文献