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61.
Magnetic resonance diffusion imaging of ovarian masses: a first experience with 12 cases 总被引:2,自引:0,他引:2
Sarty GE Kendall EJ Loewy J Dhir A Olatunbosun OA Pierson RA 《Magma (New York, N.Y.)》2004,16(4):182-193
Objective: The objective of the study was to determine the feasibility of using apparent diffusion coefficient (ADC) measurement for the differential diagnosis of malignancy in ovarian masses. Materials and methods: Twelve cases involving ovarian masses were imaged using spin echo diffusion magnetic resonance imaging (MRI). Five cases involved malignant ovarian masses, on the basis of postoperative histologic examination, and the rest involved benign masses. The ovarian masses were imaged in vivo (10 cases) before surgery and ex vivo (8 cases) after surgical resection. Diffusion-weighted data were corrected for motion using the phase data from unweighted data in nine cases. Multifactorial analysis of variance was used to evaluate the effects of malignancy, location (in vivo versus ex vivo), and motion correction on the measurement of ADC intensity and texture. Results: Motion correction caused an undesirable spatial smoothing of the ADC maps and a significant interaction (
) was found between location and motion correction. ADC value (
) and texture (
) differences were found between malignant and nonmalignant ovarian masses. Conclusion: Measurement of ADC intensity and texture has the potential to differentially diagnose malignancy in individual ovarian masses if the problem of image motion artifact can be eliminated through the use of faster imaging sequences.Acknowledgements. The cooperation of Dr. Vance Chow in the acquisition of the in vivo diffusion MRI data is gratefully acknowledged. Thanks to Ron Borowsky for discussions on the statistical data analysis. Data management, final data analysis, and figure preparation was completed by Jennifer Hadley. This work was supported by the Canadian Institutes for Health Research (CIHR) and the Saskatchewan Health Services Utilization and Research Commission (HSURC). 相似文献
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Boneschans B Wessels A van Staden J Zovko M Zorc B Bergh J 《Drug development and industrial pharmacy》2003,29(2):155-160
An improved method of piroxicam benzoate synthesis was described, and an isocratic reversed-phase high-performance liquid chromatography method for its determination was developed and fully validated. The method was found to be specific, precise (relative standard deviation 0.3%), accurate (mean recovery 99.9%), and robust. Limit of detection was estimated at 0.055 µg mL-1 and limit of quantification at 0.185 µg mL-1. The kinetics of piroxicam benzoate hydrolysis in aqueous buffer solutions (pH 1.1 and 10), simulated gastric and intestinal fluids was studied. The hydrolysis followed first-order kinetics. The following rate constants were obtained at pH 10: k = 1.8 × 10-3 hr-1 at 37°C and k = 3.4 × 10-2 hr-1 at 60°C. In acidic media, no significant hydrolysis was observed after 24 hr. During the 24-hr period in simulated intestinal fluid, only 10.9% of the starting ester was hydrolyzed. 相似文献
64.
The periodic event scheduling problem (PESP), in which events have to be scheduled repeatedly over a given period, is a complex and well-known discrete problem with numerous real-world applications. The most prominent of them is to find periodic timetables in public transport. Although even finding a feasible solution to the PESP is NP-hard, recent achievements demonstrate the applicability and practicability of the periodic event scheduling model. In this paper we propose different approaches to improve the modulo network simplex algorithm (Nachtigall and Opitz, 2008 [17]), which is a powerful heuristic for the PESP problem, by exploiting improved search methods in the modulo simplex tableau and larger classes of cuts to escape from the many local optima. Numerical experiments on large-scale railway instances show that our algorithms not only perform better than the original method, but even outperform a state-of-the-art commercial MIP solver. 相似文献
65.
Anita Hansbo 《Calcolo》1999,36(2):75-101
We consider a time discretization method for a parabolic initial boundary value problem obtained from a combination of an
A-stable single step method of order p and a lower order method with good smoothing properties. Such methods, including the Crank–Nicolson method combined with
the backward Euler method, were analyzed in Hilbert space by Luskin and Rannacher, and nonsmooth data error estimates of order
p were obtained. We extend this result to Banach space, and also consider approximations of the time derivative. Further, we
apply the results to obtain error estimates in the supremum norm for fully discrete methods obtained by discretizing the space
variable by a finite element method.
Received: February 1998/ Accepted: November 1998 相似文献
66.
Hall Gordon C. Nagayama; Bansal Anita; Lopez Irene R. 《Canadian Metallurgical Quarterly》1999,11(2):186
Meta-analyses were performed on 25 comparative Minnesota Multiphasic Personality Inventory (MMPI) and MMPI-2 studies of 1,428 male African Americans versus 2,837 male European Americans, 12 studies of 1,053 female African Americans versus 1,470 female European Americans, and 13 studies of 500 male Latino Americans and 1,345 male European Americans. Aggregate effect sizes suggest higher scores for ethnic minority groups than for European Americans on some MMPI/MMPI-2 scales and lower scores on others. However, none of the aggregate effect sizes suggest substantive differences from either a statistical or clinical perspective. The MMPI and MMPI-2 apparently do not unfairly portray African Americans and Latinos as pathological. Effect sizes across studies generally did not vary as a function of sociodemographic variables, research setting, or use of the MMPI versus MMPI-2. It is recommended that additional between- and within-ethnic groups psychopathology research continue. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Anita S.Becker 《电子产品世界》2001,(14):42-44,52
因特网家电(IA)是任何具有因特网访问能力的电器的总称.确实,一类全新的设备,便携式无线Web图形输入板,正从WeB设备中脱颖而出,成为潜在的“杀手锏“.新型设备(包括智能电话、PDA),正源源不断地进入市场.由于这些重量轻、笔记本大小的因特网访问设备方便、实用,所以很多电脑生产商和供应商也无法抗拒这个巨大市场的魅力.
…… 相似文献
69.
Cunningham Michael R.; Barbee Anita P.; Pike Carolyn L. 《Canadian Metallurgical Quarterly》1990,59(1):61
The multiple motive hypothesis of physical attractiveness suggests that women are attracted to men whose appearances elicit their nurturant feelings, who appear to possess sexual maturity and dominance characteristics, who seem sociable, approachable, and of high social status. Those multiple motives may cause people to be attracted to individuals who display an optimal combination of neotenous, mature, and expressive facial features, plus desirable grooming attributes. Three quasi-experiments demonstrated that men who possessed the neotenous features of large eyes, the mature features of prominent cheekbones and a large chin, the expressive feature of a big smile, and high-status clothing were seen as more attractive than other men. Further supporting the multiple motive hypothesis, the 2nd and 3rd studies indicated that impressions of attractiveness had strong relations with selections of men to date and to marry but had a curvilinear relation with perceptions of a baby face vs a mature face. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.