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101.
Chambliss CK Haverlock TI Bonnesen PV Engle NL Moyer BA 《Environmental science & technology》2002,36(8):1861-1867
Recovery and recycle of caustic reagents in industrial processes offer potential means of pollution prevention, as investigated herein for particular needs related to the cleanup of alkaline nuclear waste. Specifically, the recovery of hydroxide from alkaline media by liquid-liquid extraction can be effected utilizing weak hydroxy acids, as demonstrated for NaOH utilizing a series of lipophilic fluorinated alcohols and alkylated phenols dissolved in 1-octanol. Extraction efficiency follows the expected order of acidity of the hydroxy acids, the phenols being the most efficient extractants among the compounds tested. After extraction, NaOH is effectively recoverable from the organic phase upon contact with water. The weakest hydroxy acids are the most efficiently stripped, NaOH recovery being nearly quantitative in a single contact. In competitive extraction experiments, good selectivity for hydroxide recovery over other anions such as nitrate and chloride was demonstrated. Since the order of extraction favors larger anions, the exceptional preference for hydroxide implies that the extraction occurs by deprotonation of the hydroxy acids in a cation-exchange process. Stripping therefore occurs by hydrolysis to regenerate the neutral hydroxy acid, liberating NaOH to the aqueous phase. Since hydroxide equivalents rather than actual hydroxide ions are transferred to the solvent, the process is termed "pseudohydroxide extraction." Hydroxide recovery from a simulant of alkaline nuclear tank waste (Hanford DSSF simulant) was also demonstrated in repeated extraction and stripping cycles. 相似文献
102.
Greengold NL 《The Joint Commission journal on quality improvement》2002,28(6):340-348
BACKGROUND: In response to increasing national concerns about medical safety, product developers from a health services research and software group recently created a commercial Web-based program to address a wide variety of patient safety issues in the acute care setting. They also wanted to provide a program with credible, referenced, and up-to-date content, not just a technology infrastructure for reporting errors. SAFETY OPTIMIZER: This Web-based program, which has evolved over time, now features seven modules for assessing organizational risk and for implementing strategies to reduce risk. The Literature Module features detailed synopses that are graded and organized into summary statements to provide recommendations for improving patient safety. The Implementation/Tracking Module includes numerous risk-reduction strategies. The Incident Reporting Module enables the collection of data at the point of care on a variety of incidents, using either paper-based or on-line forms. Other modules offer opportunities to assess adherence to JCAHO patient safety standards, forecast the benefits of certain evidence-based guidelines, evaluate staff competency, and obtain information from a variety of key safety Web sites. EXPERIENCE TO DATE: The program is in use at more than 30 health care organization facilities and systems. It is still too early to provide quantitative data on the impact of this program on patient safety. CONCLUSIONS: It is hoped that vendor solutions such as the one described in this article will help organizations develop a practical and effective framework for addressing the wide range of issues in patient safety. 相似文献
103.
Hoffart N Cobb AK;Clinical Pathways Study Group 《The Joint Commission journal on quality improvement》2002,28(4):167-179
BACKGROUND: Many benefits have been associated with the use of clinical pathways, yet developing them can be costly, and implementing them is not always successful. A 300-bed Midwestern community hospital began a clinical pathways program in 1995, and by fall 1998, 15 pathways were in various stages of implementation, with 3 under development. Many challenges had been encountered, but hospital leaders were eager to find ways to increase pathway use. METHODS: A qualitative case study design was used to investigate four clinical pathways, two perceived as being "used" and two that were perceived as "not used". Each pathway was analyzed as a separate case, followed by cross-case analysis. Qualitative data were collected in 65 semistructured interviews with administrators, physicians, physicians' office staff, nurses, and allied health professionals at the hospital. Data were also collected through observation and document analysis. RESULTS: The two used pathways had been introduced as part of a larger change in care, whereas the two pathways not used had been introduced as stand-alone innovations. Confusing and inadequately developed aspects of the hospital's clinical pathways program included its purposes, the definition of pathway use, pathway procedures, accountability, education, and incentives. A new case management department, ongoing administrative support, and a sophisticated medical information system were viewed as supports for continued growth in the program. CONCLUSIONS: Implementation of clinical pathways was delayed and complicated by the varied perceptions of the program among stakeholders. Lack of clarity and consistency in how information about the program was communicated made it difficult for clinicians to develop a shared understanding of clinical pathways. 相似文献
104.
Fisher DL Laurie NE Glaser R Connerney K Pollatsek A Duffy SA Brock J 《Human factors》2002,44(2):287-302
Driver education classes were once seen as a remedy for young drivers' overinvolvement in crashes, but research results from the early 1970s were disappointing. Few changes in the content or methods of instruction occurred until recently, but this could change rapidly. Personal computers (PCs) can now present videos or photorealistic simulations of risky, cognitively demanding traffic scenarios that require quick responses without putting the participant at risk. As such programs proliferate, evaluating their effectiveness poses a major challenge. We report the use of a fixed-base driving simulator to study the effects of both experience on the road and PC-based risk awareness training on younger drivers' part-task simulator driving performance in risky traffic scenarios. We ran three groups of drivers on the simulator: one group first trained on the PC (younger, inexperienced drivers) and two groups who received no PC training (younger, inexperienced and experienced drivers). Overall, the younger, inexperienced drivers who were trained on a PC operated their vehicles in risky scenarios in ways that differed measurably from those of the untrained younger, inexperienced drivers and, more important, in ways that we believe would decrease their exposure to risk considering that, on average, their behavior was more similar to the behavior of the untrained, experienced drivers. More research is needed to demonstrate whether these findings apply on the open road to the larger population of younger drivers. However, at least initially, the research suggests that PC-based risk awareness training programs have the potential to reduce the high crash rate among younger, inexperienced drivers. 相似文献
105.
Constantinos Djouvas Nancy D. Griffeth Nancy A. Lynch 《Electronic Notes in Theoretical Computer Science》2006,164(4):67-82
A hard problem in network testing is verifying the correctness of a class of networks, as well as the actual networks under test. In practice, at most a few networks (sometimes only one) are actually tested. Thus an important question is how to select one or more networks that are sufficiently representative to apply the results to a class of networks. We present a model-based technique for selecting a representative network. The central theorem establishes that the representative network displays any faults present in any network of the class. This paper introduces the concept of “self-similarity,” which is used to select the network, and presents the results of an experiment in testing one class of networks. 相似文献
106.
Spinrad Tracy L.; Eisenberg Nancy; Cumberland Amanda; Fabes Richard A.; Valiente Carlos; Shepard Stephanie A.; Reiser Mark; Losoya Sandra H.; Guthrie Ivanna K. 《Canadian Metallurgical Quarterly》2006,6(3):498
The differential relations of children's emotion-related regulation (i.e., effortful control and impulsivity) to their personality resiliency, adult-rated popularity, and social competence were examined in children who were 4.5-7.9 years old and who were remeasured 2 years later. Parents and teachers reported on all constructs, and children's attentional persistence was observed. Structural equation modeling was used to test the mediating role of resiliency on the relations between regulation/control and popularity using two-wave longitudinal data. The results provide some evidence of the mediating role of resiliency in the relations between effortful control and popularity, provide some evidence of bidirectional effects, and also buttress the view that emotional regulation should be differentiated into effortful and reactive forms of control. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
107.
Johanson Chris-Ellyn; Lundahl Leslie H.; Lockhart Nancy; Schubiner Howard 《Canadian Metallurgical Quarterly》2006,14(2):99
Ten cocaine-dependent participants were trained to discriminate between intravenous saline and 20 mg/70 kg cocaine. During the first session, saline and cocaine injections were alternated twice, with each separated by 1 hr. The injections were identified by letter codes. During the next 3 sessions, 12 trials were conducted, with saline and cocaine administered 6 times each in pseudorandom order. Thirty minutes following each injection, participants were asked to identify the injection by letter code. Seven of the 10 learned the discrimination (at least 10 trials correct). To evaluate sensitivity, the investigators tested participants with different doses of cocaine in test sessions. In the next phase, methamphetamine (5 and 10 mg/70 kg) and pentobarbital (50 and 100 mg/70 kg) were given intravenously during test sessions to determine whether the discrimination exhibited pharmacological class selectivity. During the evaluation of sensitivity and selectivity, training sessions were interspersed. As dose of cocaine increased, the number of participants identifying the test dose as cocaine increased, demonstrating sensitivity. The higher doses of methamphetamine and pentobarbital substituted for cocaine. The physiological and subjective effects of cocaine and methamphetamine were stimulant-like and dose related. Pentobarbital produced no physiological changes but increased Visual Analog Scale ratings of Sedation, Good Drug Effect, and High. This failure to demonstrate pharmacological selectivity may be related to participants' learning a drug-vs.-no-drug discrimination, and thus it may be necessary to alter training procedures in future studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
Murphy James G.; Barnett Nancy P.; Colby Suzanne M. 《Canadian Metallurgical Quarterly》2006,14(3):339
College student alcohol abuse remains a significant public health problem, and there is a need for theory-driven and empirically based models to guide prevention efforts. Behavioral theories of choice assume that the decision to consume alcohol is influenced by the relative value of alcohol versus other available activities. In the present study, a sample of college student drinkers (N=108; 56% female, 44% male) who had previously completed a mandatory alcohol intervention completed a measure of alcohol-related and alcohol-free activity participation and enjoyment. The goals of the study were to examine the influence of drinking quantity and contextual variables on activity enjoyment and to identify enjoyable alcohol-free activities that take place on evenings when students might otherwise be drinking. Overall, students found alcohol-related activities more enjoyable than alcohol-free activities, and drinking quantity was positively related to enjoyment. However, alcohol-free activities such as watching movies, going to the theater or museums, going to bars or parties, hanging out with friends, eating at restaurants, and engaging in creative activity were generally as enjoyable as drinking. Alcohol-free activities that included peers or dates were more enjoyable than solitary activities. Men were less likely to engage in alcohol-free activities that included peers and reported less enjoyment related to alcohol-free activities than did women. Further research is required to identify procedures for increasing participation in alcohol-free activities and to determine whether increased alcohol-free activity participation results in decreased alcohol consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
109.
Susanna M. Leung John. C. Little Troy Holst Nancy G. Love 《Canadian Metallurgical Quarterly》2006,132(2):181-189
The oxygen-transfer characteristics of an upflow biological aerated filter filled with angular clay media were determined over a wide range of gas and liquid flow rates. Liquid-side, oxygen-transfer coefficients (KLa) were measured using a nitrogen gas stripping method under abiotic conditions and were found to increase as both gas and liquid superficial velocity increases, with values ranging from 12 to 110?h?1 based on empty bed volume. The effect of gas and liquid velocity, wastewater to clean water ratio, and temperature dependence was correlated to within ±20% of the experimental KLa value. Stagnant gas holdup is roughly double in wastewater compared to clean water, but the dynamic gas holdup is the same. The oxygen-transfer coefficient is directly proportional to the dynamic gas holdup. Stagnant gas holdup does not influence the rate of oxygen transfer. The results suggest that dynamic gas holdup largely determines the specific interfacial area (a), whereas the interstitial liquid velocity largely controls the oxygen-transfer coefficient (KL). 相似文献
110.
Conventionally, activated sludge units are aerated continuously for the biological oxidation of organic carbon and ammonium. The respiration of the microflora which develops is tightly coupled to adenosine triphosphate (ATP) formation. (ATP is the energy currency of the cell, growth is proportional to the ATP formed). A management strategy is reported here which uses alternating periods of aeration and non-aeration (AAA process), then respiration is uncoupled from ATP formation and hence from cell growth. Less sludge is formed but the removal of Biochemical Oxygen Demand (BOD) is no less efficient.
In addition, ammonium is oxidized to nitrate during aeration and is then denitrified in the non-aerated period. Savings of 25% to 40% in aeration charges have been demonstrated. This entails no change in the physical design of the plant, no reductant is needed for denitrification, foam is reduced and the sludge settles well. The final effluent demands less chlorine and has a low nitrogen content. The control of the periods of air on/air off can be automated in response to the rate of uptake of dissolved oxygen (DO). 相似文献
In addition, ammonium is oxidized to nitrate during aeration and is then denitrified in the non-aerated period. Savings of 25% to 40% in aeration charges have been demonstrated. This entails no change in the physical design of the plant, no reductant is needed for denitrification, foam is reduced and the sludge settles well. The final effluent demands less chlorine and has a low nitrogen content. The control of the periods of air on/air off can be automated in response to the rate of uptake of dissolved oxygen (DO). 相似文献