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1.
This work demonstrated a novel and potentially important application of two-dimensional small-angle X-ray scattering (2D-SAXS) to investigate powder compaction. SAXS from powder compacts of three materials commonly used for pharmaceutical tabletting exhibited azimuthal variations, with stronger intensity in the direction of the applied compaction force, relative to the transverse direction. This implied that compaction of a (macroscopic) powder could also produce changes on the molecular (nanometre) scale, which can be probed by 2D-SAXS. Two possible explanations for this effect were suggested. A combination of anisometric (i.e. elongated or flattened) granules with anisotropic morphologies could result in azimuthal variation in X-ray scattering due to granule orientation. It is expected that this mechanism would require relatively low packing density, so may operate during die filling. Granule re-orientation appeared less likely at higher packing densities and compaction pressures, however. Under these conditions, the changes in the 2D-SAXS patterns would be consistent with the powder granules becoming relatively flattened in the compression direction, with corresponding changes in their nano-scale morphology. The magnitude of this effect was found to vary between the materials used and increased with compaction pressure. This suggested that 2D-SAXS studies could provide useful information on force-transmission within a compressed powder. Further analysis of the data also suggested differences in the compaction mechanisms (i.e. granule re-orientation, deformation or fragmentation) between the materials studied. 相似文献
2.
3.
Analyzes the literature on 3 aspects of attachment—neurobiological influences, interpersonal and intrapersonal factors, and societal factors—in the psychological development of chronically disabled children. Evidence suggests that neurochemical substances such as cortisol and brain biogenic amine systems reciprocally interact with psychological and psychosocial factors to influence attachment. Interpersonal and intrapersonal factors such as temperamental characteristics of children, severity and type of disability, and family influences interact in the process of attachment. Social perceptions and prejudices about the disabled individual increase parental stress, and diminish parental involvement and resources, which are necessary for attachment. These 3 processes are powerful and interrelated forces in child development, with potential to modify social competence, neurological development, and psychosocial adjustment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
The injection of a strong organic base into milligram quantities of fats and oils dissolved in methylene chloride results
in a burst of chemiluminescence whose peak intensity is a function of the previous thermal oxidation history and of the degree
of unsaturation of the starting material. The flash of this induced chemiluminescence can be 108 times higher than the steady-state “spontaneous” chemiluminescence. The kinetics of the induced chemiluminescence are first
order in concentration and second order in time. The emission spectrum is broad and extends into the near infrared. A model
based on dioxetane chemiluminescence is proposed to explain the observed kinetics. 相似文献
5.
Examined the achieving styles, coping strategies, gender roles, and feminist attitudes of 125 prominent, highly achieving Black and White women (mean age 53.5 yrs) in the US. Multivariate analyses of variance were used to examine race differences and similarities; canonical regression analyses (MANOVAs) were used to examine relationships among achieving styles and the other sets of variables. Both similarities and differences between Black and White women were found, and achieving styles were significantly related to the other variables. Strengths, limitations, and implications of the study for counseling are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Using TAT data collected prior to entering management positions, sex differences in motive patterns related to leadership were examined in a 12-yr longitudinal study of 211 men and 180 women (aged 21–43 yrs at initial assessment) who entered a large utility corporation between 1977 and 1982. Ss were followed up in 1990 and recorded as to how far they had advanced in management level. While the results showed no sex differences in motivational predictors of attained management level, the content analysis revealed 2 distinct styles of power-related themes that distinguished the successful men from the successful women. The successful male managers were more likely to use reactive power themes while the successful female managers were more likely to use resourceful power themes. Differences between the sexes in the power themes were less pronounced among the managers who had remained in lower levels of management. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
Jacob Theodore; Fagin Robert; Perry Joseph; Van Dyke Ruth A. 《Canadian Metallurgical Quarterly》1975,11(3):393
Upper-, middle-, and lower-class parents were asked to explain a proverb which had both "growth" and "stability" interpretations to their 11- and 16-yr-old sons. The growth interpretation was overwhelmingly endorsed by most parents. With 16-yr-olds, lower-middle-class parents continued to endorse the growth interpretation; most upper-class parents endorsed the stability interpretation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Boris Kapilevich Yosef Pinhasi Ruth Arusi Michael Anisimov Danny Hardon Boris Litvak Yan Wool 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(11):1370-1381
A single-pixel imaging remote sensor operating at 330 GHz is described. It is based on a frequency modulated continuous wave
(FMCW) and aimed at detection of concealed objects for ranges up to 40 m. The system consists of 2 horn-lens antennas integrated
with a homodyne transceiver. The synthesized linear FMCW signal at X-band is multiplied by a factor of 32 to generate the
transmitted signal. An intermediate frequency (IF) signal obtained in the output port of the 2-nd harmonic mixer is employed
for image processing. Distance measurements were made by performing data acquisition unit based on LabView interface and resulting
in a range resolution about 1 cm. Examples of 2D and 3D images reconstructed with this sensor are presented. 相似文献
9.
Rui Liu Yuankun Cai Joong‐Mok Park Kai‐Ming Ho Joseph Shinar Ruth Shinar 《Advanced functional materials》2011,21(24):4744-4753
The organic light‐emitting diode (OLED)‐based sensing platform is gaining momentum due to unique attributes of the compact OLEDs that are used as excitation sources. This paper, however, points to issues related to this sensing platform that will affect many (bio)chemical sensing applications, in particular in photoluminescence (PL)‐based sensors operated in the advantageous time domain, where pulsed OLEDs are utilized. The issues are related to the post‐pulse electroluminescence (EL) profile, i.e., transient EL, which depends on the OLED materials and structure, and to the long‐wavelength tail of the typically broad‐band EL spectrum. Depending on materials and device structure, the transient EL may exhibit spikes peaking at ~100–200 ns and μs‐long tails. As shown, these interfere with the determination of PL decay times (that are related to analyte concentrations) of sensing elements. The results also indicate that the long‐wavelength tail of the EL spectrum contributes to the interfering post‐pulse μs‐long EL tail. Hence, it is shown that the choice of OLED materials, the use of microcavity (μC) OLEDs with tunable, narrower EL bands, and the use of UV OLEDs alleviate these issues, resulting in more reliable data analysis. Furthermore, a 2‐D uniform 2 μm‐pitch microlens array that was previously used for improving light extraction from the OLEDs (J.‐M. Park et al., Optics Express 2011 , 19, A786) is used for directional PL scattering toward the photodetector, which leads to a ~2.1–3.8 fold enhancement of the PL signal. This behavior is shown for oxygen sensing, which is the basis for sensing of bioanalytes such as glucose, lactate, ethanol, cholesterol, and uric acid. 相似文献
10.
Dragomir A. Nikogosyan D.N. Ruth A.A. Zagorul'ko K.A. Kryukov P.G. 《Electronics letters》2002,38(6):269-271
A new approach for producing long period fibre gratings by exposure of the optical fibre to high-intensity femosecond pulses λ = 264 nm is presented. Different types of fibres were investigated and it was found that strong attenuation peaks (16-28 dB) can be induced in H2-loaded fibres 相似文献