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101.
Genetic analysis of the population structure of the western blacklegged tick, Ixodes pacificus Cooley & Kohls, was conducted using allozymes. This vector tick transmits the Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, in the far-western United States. It ranges from British Columbia to Baja California and disjunct populations are present in Oregon, Nevada, Utah, and Arizona. Host-seeking adult ticks were collected from vegetation across the range of the species and were partially fed on rabbits prior to analysis. Twelve putative loci were resolved using starch gel electrophoresis. One locus, glucose-6-phosphate isomerase, formed an apparent north/south latitudinal cline and showed significant geographic structure. None of the remaining loci exhibited much genetic differentiation. Estimates of gene flow were high relative to other arthropods. Isolation-by-distance analysis suggests a recent and rapid range expansion. We conclude that the overall lack of differentiation is due high rates of gene flow. 相似文献
102.
Comparative reactivity and efficiency of eight Indian, six US, two African and one Middle East sources of rock phosphates for growing rice on laterite, red and alluvial soils under flooded conditions were evaluated in pot and laboratory experiments. When applied to moist aerobic soils, 15 days prior to flooding and transplanting rice, all the Indian sources were as poor as theno phosphate control in the three soil types, in respect of P availability in soil, grain yield response and P uptake by rice. North Carolina rock phosphate used in this study was as good as superphosphate in the laterite and red soils, but was also as poor as control in the black soil.NH4 -citrate was found to interfere in the colorimetric determination of citrate soluble P by the vanado-molybdate colour method. A modified sulpho-molybdate-Sn Cl2 blue colour method could successfully be used to determine 2–8µg P in the presence of 0.02 to 0.2 meq NH4 -citrate, especially in rocks containing small amounts of citrate soluble P. All the Indian, as well as Idaho, Missouri and Tennessee rock phosphates were found to be less reactive as they contained much lower amounts of citrate extractable P in eight successive extracts as compared to North Carolina rock phosphate.The cumulative citrate soluble P of 10 rock phosphates determined experimentally in eight successive extracts was significantly correlated with their reported a0 (length of a axis of unit apatite crystal), mole ratio of CO3/PO4 or weight ratio of F/P2O5 of rocks. In the absence of X-ray and computer facilities, these regression equations were used to calculate the a0, CO3/PO4, F/P2O5, ACS, empirical formula and the apatite content of the unknown Indian rock samples. The Indian rock phosphates had a lower degree of CO3 and F substitution for PO4 in the apatite crystal, giving low ACS values and hence were less reactive. This might explain their lower efficiency for direct application for growing rice, obtained in the present experiment. These Indian rock phosphates had also lower apatite content. The use of the statistical method was limited to francolites alone. Scope for the use of this method for other unknown francolite rock phosphate samples has been discussed. 相似文献
103.
Sufficient conditions for a full order observer design for deterministic linear time-invariant differential difference systems is suggested. The observer parameters are constrained so that its coefficient matrices corresponding to delayed and nondelayed states commute. Then, a desired degree of stability for the observer can be achieved. 相似文献
104.
Performed 2 experiments with 91 experimentally naive high school students to study the comparative influence of frequency and meaningfulness (m) on free recall. In Exp. I, the free-recall scores of 3 lists of words matched for m but varying in frequency levels were compared. In Exp. II, free recall of 3 lists of words matched for their frequency but varying in their m values were compared. Findings reveal that it is the frequency and not m of the words that influences free-recall, and that the influence of frequency is noticeable in the early trials of free-recall learning. Findings are discussed in terms of the existing theories of verbal learning. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
105.
Argues that the genetic and social variables were so confounded in S. Scarr and R. A. Weinberg's (see record 1977-07996-001) article on Black children adopted by White families that the results are consistent with virtually any theory of race differences in IQ. It is difficult to see any scientific or applied value in transracial adoption studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
106.
107.
In the first part of the paper, several equations of motion by different groups of workers are critically examined. Exact
equations of motion are then developed. This form is then quasi-linearised into a ballistic formulation. The geometrical motion
of a spinning projectile, in the presence of a cubic restoring moment is analysed in the cross-flow plane. It is observed
that the trajectories assume a cuspidal form at the lower and upper range of the travel, when the angular momentum parameter
coincides with these points. In general, both steady and unsteady precessional motions are presented. 相似文献
108.
N.C. Mohanty 《Information Sciences》1977,13(1):35-50
A large number of equal energy signals of period 2n ? 1, n ? 0 can be generated from signal generators described by primitive and irreducible polynomials of a degree n and whose correlation is small. Binary signals are generated using difference set sequences. Trace functions are used to find initial states of the shift register which generates difference set sequences. Periodic and nonperiodic auto and cross correlation of binary signals are studied and their bounds are derived. Then ternary signals are obtained from the binary signals that have lower correlation than the binary signals. 相似文献
109.
110.
Meher P.K. Mohanty B.K. Chandra Patra J. 《Circuits and Systems II: Express Briefs, IEEE Transactions on》2008,55(2):151-155
A systolic-like modular architecture is presented for hardware-efficient implementation of two-dimensional (2-D) discrete wavelet transform (DWT). The overall computation is decomposed into two distinct stages; where column processing is performed in stage-1, while row processing is performed in stage-2. Using a new data-access scheme and a novel folding technique, the computation of both the stages are performed concurrently for transposition-free implementation of 2-D DWT. The proposed design can offer nearly the same throughput rate, and requires the same or less the number of adders and multipliers as the best of the existing structures. The storage space is found to occupy most of the area in the existing 2-D DWT structures but the proposed structure does not require any on-chip or off-chip storage of input samples or storage/transposition of intermediate output. The proposed one, therefore, involves considerably less hardware complexity compared with the existing structures. Apart from that, it has less duration of cycle period in comparison to the existing structures, and has a latency of cycles while all the existing structures have latency of cycles, the filter order being small compared to the input size . 相似文献