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1.
This article examines the usefulness ofvocabulary richness for authorship attributionand tests the assumption that appropriatemeasures of vocabulary richness can capture anauthor's distinctive style or identity. Afterbriefly discussing perceived and actualvocabulary richness, I show that doubling andcombining texts affects some measures incomputationally predictable but conceptuallysurprising ways. I discuss some theoretical andempirical problems with some measures anddevelop simple methods to test how wellvocabulary richness distinguishes texts bydifferent authors. These methods show thatvocabulary richness is ineffective for largegroups of texts because of the extremevariability within and among them. I concludethat vocabulary richness is of marginal valuein stylistic and authorship studies because thebasic assumption that it constitutes awordprint for authors is false.  相似文献   
2.
A 28 mW/MHz at 80 MHz structured-custom RISC microprocessor design is described. This 32-b implementation of the PowerPC architecture is fabricated in a 3.3 V, 0.5 μm, 4-level metal CMOS technology, resulting in 1.6 million transistors in a 7.4 mm by 11.5 mm chip size. Dual 8-kilobyte instruction and data caches coupled to a high performance 32/64-b system bus and separate execution units (float, integer, loadstore, and system units) result in peak instruction rates of three instructions per clock cycle. Low-power design techniques are used throughout the entire design, including dynamically powered down execution units. Typical power dissipation is kept under 2.2 W at 80 MHz. Three distinct levels of software-programmable, static, low-power operation-for system power management are offered, resulting in standby power dissipation from 2 mW to 350 mW. CPU to bus clock ratios of 1×, 2×, 3×, and 4× are implemented to allow control of system power while maintaining processor performance. As a result, workstation level performance is packed into a low-power, low-cost design ideal for notebooks and desktop computers  相似文献   
3.
Viral RNA load has been shown to indicate disease stage and predict the rapidity of disease progression in human immunodeficiency virus type 1 (HIV-1)-infected individuals. We had previously demonstrated that feline immunodeficiency virus (FIV) RNA levels in plasma correlate with disease stage in infected cats. Here we expand upon those observations by demonstrating that plasma virus load is 1 to 2 logs higher in cats with rapidly progressive FIV disease than in long-term survivors. Differences in plasma FIV RNA levels are evident by 1 to 2 weeks after infection and are consistent throughout infection. We also evaluated humoral immune responses in FIV-infected cats for correlation with survival times. Total anti-FIV antibody titers did not differ between cats with rapidly progressive FIV disease and long-term survivors. These findings indicate that virus replication plays an important role in FIV disease progression, as it does in HIV-1 disease progression. The parallels in virus loads and disease progressions between HIV-1 and FIV support the idea that the accelerated disease model is well suited for the study of therapeutic agents directed at reducing lentiviral replication.  相似文献   
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Hoover HL 《Applied optics》1986,25(3):359-368
Photochemical damage of ocular tissues by solar radiation depends on the spectral composition of the radiation in the environment, the geometry of the coupling of that radiation to the eye, the spectral transmittances of the ocular components and any auxiliary lenses used, the spectral sensitivity of the irradiated tissue, the accumulated exposure dose, and the action of repair processes. This paper provides formulas for quantitative estimation of corneal, lenticular, and retinal UV irradiances from the sunlit environment under clear sky conditions. Applications of these formulas for ocular irradiation will be presented in subsequent papers for the cornea, lens, and retina, and the results will be evaluated using weighting functions for the sensitivity of ocular tissue.  相似文献   
7.
A technique is described for ensemble-averaging the light wave emerging from a turbid medium, enabling the recovery of optical information that is otherwise lost in a speckle pattern. The technique recovers both an amplitude and a phase function for a wave that has been corrupted by severe scattering, without the use of holography. With the phase estimated, an ensemble-averaged field is constructed that can be backprojected to form an image of the object obscured by the scattering medium. Experimental results suggest that the technique can resolve two object points whose signals are unresolved on the exit surface of a diffuser.  相似文献   
8.
Computer vision has historically been taught as a graduate subject since few examples of the discipline were being practiced in mainstream engineering. In recent years, the incorporation of multimedia into embedded devices has drawn some vision topics into mainstream attention. Examples of consumer products include digital video recorders, cellular phones, and automobile collision-avoidance systems. This paper describes the development of an undergraduate course that incorporates some vision topics into the larger context of embedded computing. Traditional topics, such as processor types, dynamic power management, and real-time scheduling, are taught alongside relevant vision topics, such as codecs, concurrent interfaces, and multimedia signal acquisition, storage, and rendering. In lab work, the students program hardware to operate as a digital video camera. While the primary goal for the course is to teach embedded computing, a secondary goal for the course is to entice students into graduate study in computer vision. However, a major developmental point was to justify the vision content in the context of how it serves the needs of students not opting for graduate study, as well as how the course would impact students working in other related graduate research areas.  相似文献   
9.
The Swelling Power (SP), Water Binding Capacity (WBC) and rate of rehydration of Add-Back (A–B) and Freeze-Thaw (F–T) potato granules treated with 0.2% monoglyceride decreased during the initial 14 weeks of storage by an average of 25.5 (F–T) and 27.3% (A–B) at 4°C and by 11.1 (F–T) and 12.0% (A–B) at 25°C. However, the moisture content showed an opposite trend, increasing by 5.9 (F–T) and 7.5% (A–B) at 4°C and by 3.6 (F–T) and 4.9% (A–B) at 25°C. Storage beyond 14 weeks at 4°C resulted in increases in SP, WBC and rate of rehydration and decreases in moisture content. However, such a trend was not observed at 25°C. The percentage decreases in SP (during the initial 14 weeks) of treated granules (A–B and F–T) were lower than those of untreated granules by an average of 11.0% at 4°C and 10.5% at 25°C. The extent of starch matrix-cell wall separation and the intensity of the “V” diffraction pattern of an X-ray analysis increased during storage, with greater increases being found at 4°C.  相似文献   
10.
Native potato, waxy corn, corn, wheat, filed pea and lentil starches were autoclaved at 15 psi, 121°C for 1min. Scanning electron micrographs of the native and autoclaved starches showed no changes in granular surfaces and shapes. In all starches, the X-ray intensities at most of the d-spacings between 3-18 Å increased upon autoclaving, being more pronounced in potato. The X-ray patterns of cereals and legumes remained unchanged, while that of tuber (potato) became more cereal-like. Differential scanning calorimetry of the starch samples revealed that autoclaving increased the gelatinization transition temperatures of wheat but decreased that of potato; the changes observed in waxy corn, corn, field pea and lentil starches were very small. The gelatinization enthalpy of all native starches decreased upon autoclaving while the percentage decrease was highly marked in potato. Image analysis of the native and autoclaved starches revealed changes in the granule size distribution patterns. Also, the population mean area of all native starch granules considerably increased upon autoclaving. Acetyl binding capacity, measured at 5% and 10% acetic anhydride addition levels, was higher in autoclaved than in native starches. Furthermore, autoclaving had no influence on starch cationization, studied at 3% and 6% reagent addition levels. The results indicated that the changes in starch molecular organization caused by autoclaving enhanced its reactivity towards acetylation but not cationization.  相似文献   
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