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81.
Nitsa Ne'eman Daphna Marbach Limor Chen-Konak Keren Kaufman-Francis Merav Berkovich Shulamit Levenberg Noah Lotan Sarit Sivan 《Israel journal of chemistry》2013,53(9-10):821-828
Biodegradable constructs, providing both mechanical support to growing tissues and timed release of biological agents, are highly desired in tissue engineering. This study aimed to develop a platform technology that responds to these challenges. Accordingly, we report herein on model systems in which microspheres of poly(suberic anhydride), containing all-trans retinoic acid (atRA), and poly(d,l -lactic acid-co-glycolic acid), containing bovine serum albumin (BSA), were co-sintered at room temperature, using a solvent/nonsolvent mixture. These scaffolds release about 60% of atRA and negligible amounts of BSA within the first five days, followed by slower and steady release of BSA. They have pores of 150–500 μm and a compressive modulus of 200 kPa. Myoblasts and fibroblasts were seeded on the loaded scaffolds and both showed enhanced proliferation rates. Based on sound thermodynamic principles of polymer science, this technology demonstrates an as yet unachieved degree of versatility. It allows for the tailoring of “intelligent” scaffolds that preserve the integrity of the incorporated agents and of advanced modalities to release various drugs in a scheduled manner. 相似文献
82.
Abstract Geostatistical methods are grouped in two main divisions: univariate and multivariate. When there is adequate amount of primary data, univariate methods such as kriging and SGS give a good representation of property distribution in the reservoir, but practical difficulties appear when there is no sufficient data. In such a case it is necessary to choose multivariate geostatistical methods in which some covariables are contributed to model the primary variable. Multivariate geostatistics is a broad term that encompasses all geostatistical methods that utilize more than one variable to predict some physical property of the earth. Bivariate geostatistics is obviously the simplest subset of the multivariate techniques and thus the standard cokriging technique can be called multivariate geostatistics. Cokriging estimates the unsampled value using the primary and secondary variable values from all primary variable sampled locations and also the covariable at an unsampled location, thus there is a need to construct the secondary and cross covariograms. Hence, it is a time-consuming approach. Collocated cokriging is a valuable alternative to full cokriging, which overcomes these problems. It only requires the covariable sample to be available at every location where the principal variable must be estimated. The authors used this in the framework of sequential simulation to produce various realizations. They compare moving average, kriging, and SGS as univariate methods to collocated cokriging and collocated cosimulation as multivariate methods by porosity modeling of an Iranian oil field, although there were only 7 wells available. 相似文献
83.
Muhammad Taher Abuelma'Atti 《International Journal of Electronics》2013,100(2):177-181
This comment shows that circuits for active simulation of grounded inductors with plus-type second-generation current-conveyors (CCII + s) and grounded passive elements can be systematically derived from Sedra-Smith gyrator realization. In addition to the available realizations, new circuit topologies are presented. Some of the new topologies can yield inductance forms which are not realizable using the available topologies. Also, a new topology for realizing pure inductance without recourse to element matching conditions is presented. 相似文献
84.
Sequential point estimation of means of generalized U-statistics is considered. Based on a well defined stopping rule, the proposed sequential (estimation) procedure is shown to be asymptotically (first order) risk-efficient. Asymptotic distributions of sequential generalized U-statistics and the allied stopping times are also studied. 相似文献
85.
Takahiko Hara 《Sequential Analysis》2013,32(2):115-124
The paper deals with two kinds of location-slippage testing problems.The alternative hypothesis says that there is a single slippage in one kind of problems,and that there are multiple slippages in the other kind. In a location slippage model, by using Robbins' inequality, Robbins-Lai's invariant confidence sequences for slippage are constructed for both of the problems and sequential slippage tests using those confidence sequences are proposed. 相似文献
86.
T.N. Sriram 《Sequential Analysis》2013,32(3-4):247-252
Sequential bootstrapping for branching processes with immigration is proposed. The asymptotic validity of a sequential bootstrap estimator of the offspring mean in is estabilished for all values of m ? (0, 1]. This result is to be constrasted with the standard (non-sequential)bootstrapping where the bootstrap estimator estimator has been shown to asymptotically invalid (see, Sriram (1992)). 相似文献
87.
The steady state availability of 1-out-of-2 : G repairable system is obtained under the assumption that the life time of a component in standby position follows exponential distribution. It's nonparmetric estimator is proposed. The asymptotic properties of the estimator are used to provide the fixed width coinfience interval with specified coverage probability and testing of hypothesis problem using sequential procedure. 相似文献
88.
Toshio Honda 《Sequential Analysis》2013,32(3-4):239-251
Suppose that {Xn} is a strongly mixing process with unknow marginal density f(x) and that we estimate f(x) by a kernel estimator [fcirc]n(x|hn)and want to achive the MISE no larger than some preassigned postive number w. However,the appropriate sample size n*depends on a functional of the unknow density function. Therefore some sequential procedure is required and we adopt a fully sequential procedure. In this paper we investigate the asymptotic properties of the procedure and show that the producure is asymptotically efficient in a certain sense as w→0. The results are almost the same in the i.i.d. setting. our result extend a class of models to which the methodology can be applied. For example economic variable,experiments on a single subject in which obervation are not indepent, and so on. 相似文献
89.
90.
Symons Frank J.; Tapp John; Wulfsberg Anna; Sutton Kelly A.; Heeth William L.; Bodfish James W. 《Canadian Metallurgical Quarterly》2001,9(3):269
Accumulated evidence shows that biology and the environment can mediate self-injurious behavior (SIB) in persons with mental retardation. Whether pharmacological treatment alters the environmental mediation of self-injury is unclear. Opioid antagonist effects on sequential dependencies for self-injury were studied in the context of experimental single-subject double-blind placebo-controlled designs. Direct observational data were collected for 4 adult subjects in real time on daily rate of SIB and staff interactions. Clinically significant reductions (i.e., ≥ 33%) in SIB rate were observed for 3 of the 4 subjects. For all subjects, the magnitude of the sequential dependency between staff behavior and self-injury was significantly greater during treatment with naltrexone than during treatment with a placebo. Results are discussed in relation to behavioral mechanisms of action regulating medication effects for self-injury. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献