首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   71篇
  免费   2篇
电工技术   1篇
化学工业   8篇
机械仪表   2篇
建筑科学   1篇
能源动力   3篇
轻工业   17篇
无线电   12篇
一般工业技术   8篇
冶金工业   15篇
原子能技术   1篇
自动化技术   5篇
  2021年   3篇
  2018年   2篇
  2017年   1篇
  2016年   3篇
  2014年   5篇
  2013年   5篇
  2012年   2篇
  2011年   3篇
  2010年   1篇
  2009年   4篇
  2008年   1篇
  2007年   3篇
  2006年   3篇
  2005年   4篇
  2004年   1篇
  2003年   1篇
  2001年   2篇
  1999年   2篇
  1998年   3篇
  1997年   2篇
  1996年   3篇
  1995年   2篇
  1993年   6篇
  1992年   1篇
  1991年   2篇
  1990年   3篇
  1988年   1篇
  1987年   1篇
  1977年   1篇
  1976年   1篇
  1973年   1篇
排序方式: 共有73条查询结果,搜索用时 15 毫秒
11.
Laird No. 1 lentils micronized (high‐intensity infrared heat) to give internal temperatures of 138 and 170 °C were compared to unprocessed lentils stored at room temperature. Micronized lentils, which had been tempered to 33% moisture for 16 h, required less force to compress after cooking and contained increased levels of gelatinized starch and pectic substances but decreased levels of soluble protein, phytic acid, and neutral detergent fiber compared to the unprocessed lentils. Cell walls in the micronized lentil were less susceptible to fracture, and the microstructure was more open. Properties of the micronized lentils were better when the internal temperature reached 138 °C. When micronized to an internal temperature of 170 °C, cooked lentils were harder, possibly due to greater moisture losses and a change in the neutral detergent fiber. Micronization resulted in a slight darkening of the lentils, and this was accentuated at 170 °C.  相似文献   
12.
PCBs and other persistent organochlorine (OC) pesticides were analyzed in sediment cores collected from six lakes in Yukon Territory and one in northern British Columbia, Canada, with the objective of establishing sources and historical trends of these contaminants. DDT was found to be the most prominent OC in the sediment profiles of most of the lakes. Maximum sigmaDDT levels (3.47-2680 ng g(-1) dw) were observed in sediment slices dated to the 1950s from lakes near populated areas. In contrast, in more remote lakes (Hanson, Kusawa and Lindeman), the maximum sigmaDDT concentrations were observed in the sediments dated to the 1970s. Highest sigmaPCB and sigmaDDT concentrations were measured in sediments from Watson Lake, near a suspected PCB waste disposal site and in a region where DDT was heavily applied in the 1950s and 1960s. Elevated sigmaPCB concentrations [16.1-93.6 ng g(-1) dry weight (dw)] were also observed in sediments from lakes situated near populated areas, relative to Kusawa and Lindeman (11.1 and 12.7 ng g(-1) dw, respectively). Recent sigmaPCB fluxes ranged from 621 ng m(-2) y(-1) in Kusawa Lake to 16400 ng m(-2) y(-1) in Little Atlin Lake. The extremely high sedimentation rate (2050 g m(-2) y(-1)) in glacial fed Lindeman Lake gave rise to elevated fluxes of sigmaPCB (2410 ng m(-2) y(-1)) and other OCs, despite much lower concentrations in the sediment. Levels of hexachlorocyclohexanes (sigmaHCH), chlordane-related compounds (sigmaCHL), and chlorobenzenes (sigmaCBz) were in the low ng g(-1) (dw) range in all lake sediments, similar to concentrations previously reported for Arctic lakes in Canada, indicating that their major source was long range atmospheric transport. Contamination of the lakes with PCBs and DDT near populated areas of the Yukon Territory appears to be a result of regional activities rather than long range transport and deposition. The results also point to glacial runoff as a significant source of OCs to small, high elevation lakes (Lindeman), but not to larger lakes within the Yukon River drainage basin that are also affected by glacial sources (Kusawa, Laberge).  相似文献   
13.
BACKGROUND: Agaricus bisporus is the premier cultivated edible mushroom but is usually considered to be of lesser value nutritionally and medicinally compared with other cultivated mushrooms. The objective of this study was to investigate the radical‐scavenging properties of methanolic extracts and the free radical‐processing enzyme activities of water extracts from A. bisporus fruit bodies. Analyses were performed on total fruit bodies from three strains and on separated stipe, cap and gills from one strain, all cultivated experimentally under the same conditions. RESULTS: EC50 values of scavenging ability on 1,1‐diphenyl‐2‐picrylhydrazyl radicals (DPPH?), scavenging ability on 2,2‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cations (ABTS?+) and reducing power of methanolic extracts from total fruit bodies ranged between 1.7 and 5.0 and were 1.1–1.9 times higher in a white hybrid than in two wild strains, cream and brown. The gills exhibited higher antioxidant activities relative to the stipe and cap. In water extracts, glutathione peroxidase activities were up to eight times higher than glutathione reductase activities and no difference was observed between strains. Catalase activity was highest in the brown wild strain. The only significant differences in free radical‐processing enzymes between the three parts of the mushroom were higher catalase activity in the gills and lower glutathione reductase activity in the stipe. CONCLUSION: The radical‐scavenging properties of the button mushroom are comparable to those of other edible mushrooms and dependent on the strain and on the section of the fruit body. Copyright © 2008 Society of Chemical Industry  相似文献   
14.
A previous study (Savoie et al, Blood 83:2715, 1994) identified eight transplant patients who acquired Epstein-Barr virus (EBV) infection during the peritransplant period. Three of these patients subsequently developed B-cell lymphoproliferative disease within 4 months of transplantation. Among these, there was a 16-year-old liver transplant patient who was negative for EBV at the time of transplant and who received an EBV-negative organ. After transplant, this patient was transfused with 9 U of packed red blood cells. Eight of the donors were EBV-positive and one was EBV-negative. We succeeded in obtaining spontaneous lymphoblastoid cell lines (LCLs) from the blood of three of these donors, one of whom also yielded a cord-blood line established with his throat-wash EBV. Blood from a fourth donor did not yield an LCL, but his throat washing did have transforming activity when inoculated onto cord-blood leukocytes. We initially could establish spontaneous LCLs only from the recipient's blood. However, a throat-wash sample taken 11 weeks later did show transforming activity. The recipient was shown to have acquired the EBV infection from one of eight EBV-seropositive blood donors. Analysis of fragment length polymorphisms after polymerase chain reaction amplification of the EBV BamHI-K fragment was used to establish strain identity. Western blot analysis for existence of size polymorphisms in three classes of Epstein-Barr nuclear antigens (EBNA-1, EBNA-2, and EBNA-3) confirmed the DNA results. It is noteworthy that the blood donor responsible for transmitting his EBV strain to the recipient had experienced clinical infectious mononucleosis 15 months before donating blood. Our results may, thus, indicate a requirement for leukodepletion of blood destined for immunosuppressed EBV-negative patients. Finally, blood donors with a recent history of infectious mononucleosis should probably be identified so that their blood is not given to EBV-negative transplant patients.  相似文献   
15.
Radiation level and protein conformation during irradiation may modify a protein's response to ionising energy and change its nutritional value. Effects of gamma irradiation on protein in-vitro digestibility and amino acid release were investigated using β-lactoglobulin as a model protein. Irradiation with 60Co was performed at a range of 1–50 kGy on liquid or frozen samples atAw 0.93, with pH adjusted to 5.2 or 7.0, and on dry samples atAw 0.13. Amino acid composition, in-vitro protein digestibility and amino acid release were not impaired by irradiation at the highest dose of 50 kGy. Thus the nutritional quality of β-lactoglobulin was not affected by irradiation in a dose range likely to be used in food processing.  相似文献   
16.
LD Field  FH Savoie 《Canadian Metallurgical Quarterly》1993,21(6):783-90; discussion 790
Twenty consecutive patients with superior labral anterior and posterior lesions of the shoulder involving the biceps attachment to the labrum (Snyder types II and IV) were repaired arthroscopically and reviewed post-operatively to evaluate the efficacy of the technique in the management of this recently described injury pattern. Follow-up time averaged 21 months (range, 12 to 42). All patients were managed by an arthroscopic repair technique that included debridement of the frayed labrum and abrasion of the superior glenoid neck, followed by the placement of multiple sutures into the torn labrum-biceps tendon complex using a Caspari suture punch. Patients were reexamined, and the results were quantitated with the shoulder evaluation form of the American Shoulder and Elbow Surgeons and with the Rowe rating scale. On evaluation, all patients obtained good or excellent results. This suture technique is recommended in the management of unstable superior labral detachment lesions of the shoulder.  相似文献   
17.
A Layer 1 Virtual Private Network (L1‐VPN) has two models for service management: the resource‐partition based model and the domain‐service based model. In this paper, we present a network management tool for resource‐partition based L1‐VPNs. A Transaction Language One (TL1) proxy is designed to achieve resource partitioning at the network element level. Building on top of a TL1 proxy, we implemented a User‐Controlled LightPath (UCLP) system to support physical network brokers to assign and allocate virtually dedicated resources to customers, and to enable customers to directly manage their resources. With such a capability, customers are able to create wide area networks based on their traffic pattern, and to adjust their traffic pattern based on available resources. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.  相似文献   
18.
The Label Distribution Protocol (LDP) needs to recover its state information after a control plane failure, so that the established connections in the data plane are not disrupted by any new connection set-up. We propose a backup mechanism to store the LDP state information in an upstream neighbour node. The backup LDP state information is synchronized with the original LDP state information in a downstream node when the LDP sets up or tears down connections. Then, we propose a two-step LDP state information recovery, which uses a fast LDP state information recovery to recover what labels are idle before a control plane failure, and a detailed LDP state information recovery to fully recover all LDP state information. The fast LDP state information recovery is realized as part of the LDP initialization, allowing a restarting LDP session to process new connection set-up requests as soon as possible, without interfering existing connections. The detailed LDP state information recovery performs in the background in parallel to the normal LDP operations. When an LDP connection teardown requires the LDP state information that has not yet been recovered, an on-demand query based LDP state information recovery is conducted. The performance analysis demonstrates that our proposal achieves fast LDP recovery for the core label state information. It features scalable LDP state information storage and recovery by only involving a pair of neighbour nodes.  相似文献   
19.
20.
The layer 1 virtual private network (LlVPN) technology supports multiple user networks over a common carrier transport network. Emerging L1VPN services allow: L1VPNs to be built over multiple carrier networks; L1VPNs to lease or trade resources with each other; and users to reconfigure an L1VPN topology, and add or remove bandwidth. The trend is to offer increased flexibility and provide management functions as close to users as possible, while maintaining proper resource access right control. In this article two aspects of the L1VPN service and management architectures are discussed: management of carrier network partitions for L1VPNs, and L1VPN management by users. We present the carrier network partitioning at the network element (NE) and L1VPN levels. As an example, a transaction language one (TL1) proxy is developed to achieve carrier network partitioning at the NE level. The TL1 proxy is implemented without any modifications to the existing NE management system. On top of the TL1 proxy, a Web services (WS)-based L1VPN management tool is implemented. Carriers use the tool to partition resources at the L1VPN level by assigning resources, together with the WS-based management services for the resources, to L1VPNs. L1VPN administrators use the tool to receive resource partitions from multiple carriers and partner L1VPNs. Further resource partitioning or regrouping can be conducted on the received resources, and leasing or trading resources with partner LlVPNs is supported. These services offer a potential business model for a physical network broker. After the L1VPN administrators compose the use scenarios of resources, and make the use scenarios available to the L1VPN end users as WS, the end users reconfigure the L1VPN without intervention from the administrator. The tool accomplishes LlVPN management by users  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号