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51.
Comparison of PCR and quantitative real-time PCR methods for the characterization of ruminant and cattle fecal pollution sources 总被引:1,自引:0,他引:1
Meredith R. Raith Catherine A. Kelty John F. Griffith Alexander Schriewer Stefan Wuertz Sophie Mieszkin Michele Gourmelon Georg H. Reischer Andreas H. Farnleitner Jared S. Ervin Patricia A. Holden Darcy L. Ebentier Jennifer A. Jay Dan Wang Alexandria B. Boehm Tiong Gim Aw Joan B. Rose E. Balleste W.G. Meijer Mano Sivaganesan Orin C. Shanks 《Water research》2013
The State of California has mandated the preparation of a guidance document on the application of fecal source identification methods for recreational water quality management. California contains the fifth highest population of cattle in the United States, making the inclusion of cow-associated methods a logical choice. Because the performance of these methods has been shown to change based on geography and/or local animal feeding practices, laboratory comparisons are needed to determine which assays are best suited for implementation. We describe the performance characterization of two end-point PCR assays (CF128 and CF193) and five real-time quantitative PCR (qPCR) assays (Rum2Bac, BacR, BacCow, CowM2, and CowM3) reported to be associated with either ruminant or cattle feces. Each assay was tested against a blinded set of 38 reference challenge filters (19 duplicate samples) containing fecal pollution from 12 different sources suspected to impact water quality. The abundance of each host-associated genetic marker was measured for qPCR-based assays in both target and non-target animals and compared to quantities of total DNA mass, wet mass of fecal material, as well as Bacteroidales, and enterococci determined by 16S rRNA qPCR and culture-based approaches (enterococci only). Ruminant- and cow-associated genetic markers were detected in all filters containing a cattle fecal source. However, some assays cross-reacted with non-target pollution sources. A large amount of variability was evident across laboratories when protocols were not fixed suggesting that protocol standardization will be necessary for widespread implementation. Finally, performance metrics indicate that the cattle-associated CowM2 qPCR method combined with either the BacR or Rum2Bac ruminant-associated methods are most suitable for implementation. 相似文献
52.
Three structures in Northeast Sichuan
A series of breakthroughs have recently been made in natural gas exploration in the northeastern part of Sichuan basin. Dukouhe Gas Field, Luojiazhai gas-beating structure and Tieshan slope gasbearing structure are proven rich in natural gas resources. The main gas reservoir of those structuresFeixianguan oolitic shoal - is likely to become another largescale gas reservoir in Sichuan basin after Carboniferous.…… 相似文献
53.
Malpas S.C. Leonard B.L. Guild S.-J. Ringwood J.V. Navakatikyan M. Austin P.C. Head G.A. Burgess D.E. 《IEEE engineering in medicine and biology magazine》2001,20(2):17-24
This article focuses on how sympathetic nerve activity (SNA) contributes to the variability seen in blood pressure. Specifically, it examines the following questions: why do oscillations occur at certain frequencies, why do only certain frequencies of oscillations in SNA induce oscillations in the vasculature, and what may be the functional purpose of these oscillations 相似文献
54.
KA Head 《Canadian Metallurgical Quarterly》1999,4(1):10-22
Ipriflavone, an isoflavone synthesized from the soy isoflavone daidzein, holds great promise in the prevention and treatment of osteoporosis and other metabolic bone diseases. It has been widely studied in humans and found effective for inhibiting bone resorption and enhancing bone formation, the net result being an increase in bone density and a decrease in fracture rates in osteoporotic women. While ipriflavone appears to enhance estrogen's effect, it does not possess intrinsic estrogenic activity, making it an attractive adjunct or alternative to conventional hormone replacement therapy. Preliminary studies have also found ipriflavone effective in preventing bone loss associated with chronic steroid use, immobility, ovariectomy, renal osteodystrophy, and gonadotrophin hormone-releasing hormone agonists. In addition, it holds promise for the treatment of other metabolic diseases affecting the bones, including Paget's disease of the bone, hyperparathyroidism, and tinnitus caused by otosclerosis. 相似文献
55.
Head Denise; Raz Naftali; Gunning-Dixon Faith; Williamson Adrienne; Acker James D. 《Canadian Metallurgical Quarterly》2002,17(1):72
This study examined the impact of age-related differences in regional cerebral volumes and cognitive resources on acquisition of a cognitive skill. Volumes of brain regions were measured on magnetic resonance images of healthy adults (aged 22-80). At the early stage of learning to solve the Tower of Hanoi puzzle, speed and efficiency were associated with age, prefrontal cortex volume, and working memory. A similar pattern of brain-behavior associations was observed with perseveration measured on the Wisconsin Card Sorting Test. None of the examined structural brain variables were important at the later stages of skill acquisition. When hypertensive participants were excluded, the effect of prefrontal shrinkage on executive aspects of performance was no longer significant, but the effect of working memory remained. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
Head W.J. Nguyen H.V. Kahle R.L. Bachman P.A. Jensen A.A. Watry S.J. 《Power Systems, IEEE Transactions on》1990,5(4):1137-1145
A study was undertaken by the Mid-Continent Area Power Pool to examine future power supply options from a regional perspective. The pool is modeled as a single utility, without regard to particular economic or operating characteristics of any individual utility or group of utilities. Extensive use is made of the generalized benders decomposition algorithm in the EPRI EGEAS computer program to model poolwide optimization of capacity additions. The selected methodology, which offers both computational efficiency and acceptable accuracy for such a large-scale study, is discussed. Finally, an overview of the analysis of results is given 相似文献
57.
The activation of latent transforming growth factor beta (L-TGFbeta) is essential for the action of TGFbeta, which, in turn, is involved in the regulation of expression of some progesterone-responsive genes. One mechanism by which TGFbeta is activated involves thrombospondin (TSP), a protein that binds extracellular proteins. Immunoreactive TSP (irTSP) protein and TSP-1 mRNA in myometrial tissues of ovulatory and pregnant women were localized by immunohistochemistry and in situ hybridization. IrTSP and TSP-1 mRNA were randomly distributed in myometrial smooth muscle cells of some, but not all, tissues of pregnant women at term before labor; but in some areas of most of these tissues, irTSP was intense and commonly localized extracellularly. Intense irTSP and TSP-1 mRNA in myocytes were more common in myometrium during labor. In myometrium from ovulatory women (n = 26), irTSP was localized primarily in vascular smooth muscle cells and was detected occasionally in scattered myocytes. Little TSP-1 mRNA was demonstrable by in situ hybridization in vessels or myocytes of myometrial tissue from ovulatory women (n = 7). By Northern analysis of total RNA, TSP-1 mRNA was detected in myometrial tissue of pregnant women and in human myometrial smooth muscle cells in culture. The levels of TSP-1 mRNA in myometrial tissues of pregnant women during labor (n = 18) were greater than those in myometrium at > 37 wk gestation before labor began (n = 25, p < 0.001). The ratios of TSP-1 to glyceraldehyde 3-phosphate dehydrogenase mRNAs in 3 myometrial tissues during oxytocin-induced labor were not statistically different from those in myometrium during spontaneous labor but were greater than those in myometrium before labor (p < 0.05). The level of TSP-1 mRNA in confluent human myometrial cells in culture was relatively high, was increased by treatment with fetal bovine serum, and was decreased by treatment with platelet-derived growth factor or activators of adenylyl cyclase or protein kinase C. Myometrial cells in culture constitute a useful model for studying the regulation of TSP-1 gene expression in human myometrium. 相似文献
58.
The research octane (RON) and motor octane (MON) numbers, carefully measured in standardized tests, are the principal parameters for characterizing autoignition of gasoline in engines. Increasingly, engines operate under different conditions of temperature, pressure, and mixture strength from those in these tests. As a result, RON and MON values become an incomplete guide to the onset of knock, and the octane index (OI), an octane number under operational conditions, is often measured. Values of the OI were measured with different fuels in a controlled autoignition single-cylinder engine, at different initial temperatures and pressures, at the instant of 10% heat release. Fundamental understanding of engine autoignition was sought by finding the OIs of different non-primary reference fuels (non-PRFs) by identifying the corresponding PRFs that give 10% heat release under identical conditions. The autoignition delay times of the PRFs were obtained from the shock tube data, for different temperatures and pressures, of the Aachen group. It was sufficiently accurate to equate the delay time of a non-PRF to that of the corresponding PRF under the same conditions for 10% heat release. The PRFs exhibited a higher value of the inverse pressure exponent for the delay time than the non-PRFs. Together with different temperature dependencies, these gave autoignition delay times of non-PRFs that could be higher than those of their associated RONs. This tendency increased with pressure and decreased with temperature and was most marked with olefenic and toluenic fuels. This could result in values of the OI that were higher than the RON of the fuel. This is important because, for a number of evolutionary reasons, engine pressures are tending to increase and temperatures to decrease. 相似文献
59.
The cardiac hypertrophy observed in hypertension is thought to be responsible for the accompanying deficiency in the baroreflex control of heart rate. In this study, we assessed the baroreflex relationship between heart rate and arterial pressure on a group of seven rabbits during a normotensive period, during the early phase of angiotensin II (Ang II)-induced hypertension II week) (50 ng/kg per minute i.v. via osmotic minipumps), after 7 weeks of continuous hypertension, then 2 days after Ang II was stopped, and finally 7 days after Ang II. Left ventricles were weighed for measurement of left ventricular weight-body weight ratio. One week of intravenous Ang II infusion produced hypertension (mean arterial pressure from 80 +/- 2 up to 115 +/- 8 mm Hg), with significantly increased heart rate and hematocrit. The heart rate-arterial pressure baroreflex curve was shifted to the right, with a significant 45% reduction in the gain of the reflex (-6.4 +/- 1.5 to -3.5 +/- 0.2 beats per minute/mm Hg). After 7 weeks of Ang II, arterial pressure was still elevated (112 +/- 4 mm Hg) and the gain of the baroreflex curve still somewhat attenuated, although it was no longer markedly different from normotensive levels (gain, -5.09 +/- 0.95, 20% reduction from normotensive level). Two days after the Ang II infusion was stopped, arterial pressure had returned to normotensive levels, although hematocrit and heart rate remained elevated. At this time, the baroreflex curve was similar to prehypertensive control levels, with no further changes when measured again 7 days after Ang II. Cardiac hypertrophy was present when measured at 7 days after angiotensin (left ventricular weight-body weight ratio: 1.78 +/- 0.05 versus 1.35 +/- 0.04 g/kg, hypertensive versus normotensive, P < .05). Thus, although Ang II infusion produced an initial deficit in the baroreflex control of heart rate, this effect became less as the hypertension continued. Furthermore, although cardiac hypertrophy developed, its presence did not appear to be sufficient to produce a decrease in barosensitivity independent of raised arterial pressure. 相似文献
60.
The purpose of this project was to develop a rugged and efficient solar lantern. The lantern was designed to meet the requirements of persons who reside in areas in which access to the electrical grid is limited and whose resources do not permit import of electrical generation capabilities. A representative of a missionary organization operating in Africa developed the original set of specifications for the solar lantern. It will be used by the local school children for doing homework in the evening. These specifications prioritized reliability, ease of operation, rugged construction, portability, and low cost. The resulting design was realized in a single prototype. The design and construction of the prototype was completed as a student/faculty project in the Junior Engineering Clinic course at Rowan University in Glassboro, NJ. It was funded and directed by ETM Solar Works, a New York-based corporation. 相似文献