全文获取类型
收费全文 | 136篇 |
免费 | 5篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 41篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 8篇 |
能源动力 | 1篇 |
轻工业 | 17篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 3篇 |
一般工业技术 | 16篇 |
冶金工业 | 35篇 |
原子能技术 | 1篇 |
自动化技术 | 13篇 |
出版年
2023年 | 1篇 |
2022年 | 9篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 8篇 |
2010年 | 9篇 |
2009年 | 4篇 |
2008年 | 8篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1976年 | 2篇 |
排序方式: 共有141条查询结果,搜索用时 0 毫秒
41.
Steinmiller Caren L.; Roehrs Timothy A.; Harris Erica; Hyde Maren; Greenwald Mark K.; Roth Thomas 《Canadian Metallurgical Quarterly》2010,18(3):277
Basal sleepiness–alertness modulates drug effects. Sleepiness produced by sleep restriction leads to increased nociceptive sensitivity, suggesting opioid analgesia may also be modulated by sleepiness–alertness. This study compared thermal nociceptive sensitivity in sleepy versus nonsleepy participants after codeine or placebo. Twelve healthy normal adults, 18 to 35 years of age, had an 8-hr nocturnal polysomnogram (NPSG) followed by a Multiple Sleep Latency Test (MSLT; Carskadon and Dement, 1987). All had sleep efficiencies > 80% on their NPSG; 6 had average MSLT ≥ 8 min (nonsleepy group) and 6 had latencies 相似文献
42.
43.
Comfort-related feedforward information: occupants’ choice of cooling strategy and perceived comfort
Anita Meinke Maren Hawighorst Andreas Wagner Jörg Trojan 《Building Research & Information》2017,45(1-2):222-238
ABSTRACTApproaches to provide feedforward information to building occupants about the impact of potential actions on individual thermal comfort levels are scarce. Even less is known about the effect of such information on the decision process of occupants to interact with their built environment and their level of comfort after such decisions. In a naturalistic study, participants (N?=?76) were given a choice of four actions to counteract thermal discomfort induced by constantly rising room temperatures: removing a piece of clothing, opening the window, switching on the ceiling fan or switching on the air-conditioning. After receiving information about the potential change in comfort and energy consumption of these options, they had to confirm or revise their choice. The vast majority of participants initially chose to open the windows (N?=?28) or remove a piece of clothing (N?=?37); only a few chose the ceiling fan (N?=?2) or the air-conditioning (N?=?9). About one-third (N?=?23) revised their choice of action; most of them (N?=?15) indicated an influence from the provided information. In conclusion, feedforward information can be a useful tool to combat overheating problems by increasing energy-aware behaviour and thermal acceptance. 相似文献
44.
45.
Dirk Sebastiaan van Maren Ming Yang Zheng Bing Wang 《Canadian Metallurgical Quarterly》2011,137(1):90-99
The high sediment load of the Yellow River results in rapid infilling of its reservoirs when sediment is not regularly flushed. Simultaneously, the downstream reaches of the Yellow River experience extremely high siltation rates, which are reduced when sediment is retained in its reservoirs. To minimize siltation in the reservoirs and the downstream river bed, water and sediment are released from the reservoir in a controlled way through flushing experiments. In this paper, we analyze the effect of such a flushing event on the downstream river bed through data analysis and numerical modeling. Sedimentation may be minimized by relating the amount of sediment released from the reservoir to the sediment available for release through operational monitoring and by releasing relatively clear water after turbid water. Despite this flushing of sediment, the reservoir will eventually fill up, and more sediment released again into the lower Yellow River. The change in discharge magnitude and frequency brought about by the reservoir will then probably result in increased siltation rates in the lower Yellow River compared to the predam situation. 相似文献
46.
47.
Kopp M Irschik H Pradella S Müller R 《Chembiochem : a European journal of chemical biology》2005,6(7):1277-1286
Myxobacteria show a high potential for the production of natural compounds that exhibit a wide variety of antibiotic, antifungal, and cytotoxic activities. The genus Sorangium is of special biotechnological interest because it produces almost half of the secondary metabolites isolated from these microorganisms. We describe a transposon-mutagenesis approach to identifying the disorazol biosynthetic gene cluster in Sorangium cellulosum So ce12, a producer of multiple natural products. In addition to the highly effective disorazol-type tubulin destabilizers, S. cellulosum So ce12 produces sorangicins, potent eubacterial RNA polymerase inhibitors, bactericidal sorangiolides, and the antifungal chivosazoles. To obtain a transposon library of sufficient size suitable for the identification of the presumed biosynthetic gene clusters, an efficient transformation method was developed. We present here the first electroporation protocol for a strain of the genus Sorangium. The transposon library was screened for disorazol-negative mutants. This approach led to the identification of the corresponding trans-acyltransferase core biosynthetic gene cluster together with a region in the chromosome that is likely to be involved in disorazol biosynthesis. A third region in the genome harbors another gene that is presumed to be involved in the regulation of disorazol production. A detailed analysis of the biosynthetic and regulatory genes is presented in this paper. 相似文献
48.
H Hawighorst PG Knapstein MV Knopp W Weikel G Brix I Zuna SO Sch?nberg M Essig P Vaupel G van Kaick 《Canadian Metallurgical Quarterly》1998,58(16):3598-3602
Dynamic studies of Gd-based contrast agents in magnetic resonance imaging (MRI) are increasingly being used for tumor characterization as well as for therapy response monitoring. Because detailed knowledge regarding the pathophysiological properties, which in turn are responsible for differences in contrast enhancement, remains fairly undetermined, it was the aim of this study to: (a) examine the association of standard and pharmacokinetic analysis of time-intensity curves in dynamic MRI with histomorphological markers of tumor angiogenesis [microvessel density (MVD) and vascular endothelial growth factor (VEGF)]; and (b) determine the ultimate value of a histomorphological and a dynamic MRI approach by the correlation of those data with disease outcome in patients with primary cancer of the uterine cervix. Pharmacokinetic parameters (amplitude, A; exchange rate constant, k21) and standard parameters [the maximum signal intensity increase over baseline (SI-I) and the steepest signal intensity-upslope per second (SI-U/s)] were calculated from a contrast-enhanced dynamic MRI series in 37 patients with biopsy-proven primary cervical cancer. On the surgical whole mount specimens, histomorphological markers of tumor angiogenesis (MVD and VEGF) were compared to MRI-derived parameters. For MRI and histomorphological data, Kaplan-Meier survival curves were calculated and compared using log-rank statistics. A significant association was found between MVD and A (P < 0.01) and SI-I (P < 0.05). No significant relationships were observed between VEGF expression and all dynamic MRI parameters. Kaplan-Meier curves based on k21 and SI-U/s showed that tumors with high k21 and SI-U/s values had a significantly (P < 0.05 and 0.001, respectively) worse disease outcome than did tumors with low k21 and SI-U/s values. None of the histomorphological gold standard markers for assessing tumor angiogenesis (MVD and VEGF) had any significant power to predict patient survival. It is concluded that in patients with uterine cervical cancer: (a) the pathophysiological basis for differences in dynamic MRI is MVD but not VEGF expression; (b) a functional, dynamic MRI approach (both standard and pharmacokinetic analysis) may be better suited to assess angiogenic activity in terms of patient survival than are the current histomorphological-based markers of tumor angiogenesis; and (c) compared with standard analysis, a simple pharmacokinetic analysis of time-intensity curves is not superior to assess MVD or patient survival. 相似文献
49.
50.
Kirsten Maren Kienzler Inna Rudenko Jumanazar Ruzimov Nazar Ibragimov John P. A Lamers 《Food Security》2011,3(1):53-64
Winter wheat is the most important cereal in Uzbekistan. Although the processing industry recognizes the low quality of local
wheat, the present land use policy prioritizes production quantity, and wheat of better quality is imported to improve local
flour. Yet, with increasing world market prices, Uzbekistan has to decide whether to continue allocating considerable resources
for imports or to start investing in local quality improvements. This study therefore analyzed wheat production in the Khorezm
region of Uzbekistan by (a) assessing the economic feasibility of local production vs. imports; and by (b) evaluating the
current N-fertilizer management at field level in order to identify options for improving quality. Demand for wheat in the
region currently falls short of supply by 79,000 t but under favorable world market prices, funds for importing additional
wheat could be covered by cotton sales. Prices above $148 USD t−1 support the present land use policy to cultivate wheat but the baking quality of the crop is low. Higher N rates and/or an
additional application of N at anthesis significantly increased grain quality. Additional costs for changes in N management,
however, are currently not compensated by the price premiums at the State mills. Thus, in the absence of price incentives,
it is unrealistic to expect producers to maximize quality production. Consequently, administrators must give quality greater
attention by creating incentives through price differentials for higher quality, and encouraging awareness programs on wheat
quality and improved on-field N management. 相似文献