首页 | 官方网站   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   424篇
  免费   32篇
  国内免费   4篇
工业技术   460篇
  2024年   2篇
  2023年   5篇
  2022年   10篇
  2021年   15篇
  2020年   23篇
  2019年   19篇
  2018年   16篇
  2017年   16篇
  2016年   14篇
  2015年   22篇
  2014年   21篇
  2013年   49篇
  2012年   25篇
  2011年   31篇
  2010年   25篇
  2009年   30篇
  2008年   20篇
  2007年   15篇
  2006年   14篇
  2005年   8篇
  2004年   6篇
  2003年   12篇
  2002年   4篇
  2001年   8篇
  2000年   4篇
  1999年   1篇
  1998年   5篇
  1997年   5篇
  1996年   6篇
  1995年   4篇
  1994年   1篇
  1992年   5篇
  1991年   2篇
  1990年   1篇
  1989年   4篇
  1988年   2篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1983年   3篇
  1980年   1篇
  1978年   1篇
  1975年   1篇
  1969年   1篇
排序方式: 共有460条查询结果,搜索用时 312 毫秒
451.
Iron sucrose and low-molecular-weight iron dextran (LMW-ID), two commonly used iron solutions, have been compared in terms of allergic adverse event profiles to date. However, the safety of total dose infusion of LMW-ID has been investigated by only one study in chronic kidney disease (CKD) (not dialysis) patients. Thus, we aimed to compare adverse event profiles of total and high-dose LMW-ID and iron sucrose infusions in a heterogenous renal patient group comprising CKD, hemodialysis, and peritoneal dialysis. In this retrospective chart review study, we included 110 predialysis CKD, 101 peritoneal dialysis, and 118 hemodialysis patients. We included a total of 329 patients who were administered parenteral iron sucrose or LMW-ID between September 2006 and April 2010. Adverse events were determined both by medical and nursing follow-up notes. Laboratory data and clinical characteristics were collected from patient charts. Adverse event rates were compared between iron sucrose and LMW-ID infusions. In a total of 329 patients, 530 infusions (3470 ampules) were administered. We detected adverse reaction in only 1 patient. This adverse reaction, which manifested as generalized pruritus, occurred in a patient who received 500 mg of iron sucrose infusion. There were neither anaphylactic reactions nor deaths associated with infusion of either preparation. We did not observe any other adverse event related to administration of 500 and 1000 mg of iron sucrose at single infusion. The results of this study showed comparable safety of total dose LMW-ID and high-dose iron sucrose in a heterogenous group of renal patients.  相似文献   
452.
The objective of this study was to obtain antibacterial active chitosan/poly(ethylene glycol) diacrylate macromere (CS/PEGM) semi‐IPN hydrogels near a neutral pH level by changing their pore size and morphology. These hydrogels were prepared from CS and PEGM with different molecular weights in the presence of pore‐forming agents, poly (ethylene glycol) (PEG) or sodium bicarbonate (NaHCO3), by using two different initiator system, namely chemical or UV. A combination of CS with PEG or NaHCO3 in the presence of PEGM could be able to create desired pore formation in both initiator systems. The antibacterial activity of hydrogels changed with the molecular weight (g/mol) of PEGM in the order 2000>400>8000. A chemical initiation system was found more suitable than the UV initiation system for antibacterial activity. Hydrogels showing the highest antibacterial activity on Staphylococcus aureus and Escherichia coli have medium or distributed pore size and interconnected pores. Hydrogels prepared with PEGM (Mn: 2000 g/mol) were proposed for antibacterial wound dressing and soft tissue regeneration applications owing to their antibacterial activity and elastic modulus. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42707.  相似文献   
453.
454.

Purpose

To evaluate the dry eye findings and Meibomian gland dysfunction as demonstrated with meibography in patients with lamellar ichthyosis.

Methods

Twenty-four eyes of 12 patients with lamellar ichthyosis (Group 1) and twenty-four eyes of 12 healthy individuals (Group 2) were enrolled. Comprehensive eye examination along with corneal and conjunctival fluorescein staining with Oxford scoring, tear film break-up time, Schirmer 1 test, ocular surface disease index (OSDI) score assessment, and evaluation of upper and lower eyelid Meibomian glands using infrared filter of slit-lamp biomicroscope (SL-D701, TOPCON, Tokyo, Japan) were performed. The Meibomian glands were graded from grade 0 (no loss of Meibomian glands) to grade 3 (gland dropout >2/3 of the total Meibomian glands).

Results

The mean ages of Group 1 and Group 2 were 25.3 ± 15.6 years (range, 9–61 years) and 25.3 ± 13.3 years (range, 9–52 years), respectively (p = 0.997). No significant difference in terms of best-corrected visual acuity, Schirmer 1 test and Oxford scores were detected in between groups. Mean tear film break-up time was lower (p = 0.013), and OSDI score, lower, upper and total (upper + lower) meiboscores were significantly higher in Group 1 as compared with Group 2 (p < 0.001, p = 0.001, p = 0.001, p = 0.001, respectively).

Conclusion

Lamellar ichthyosis is associated with evaporative type dry eye disease with decreased tear film break-up time, normal Schirmer 1 values and Meibomian gland dysfunction that can objectively be demonstrated with meibography. For this reason, in order to prevent undesired complications, these patients should be examined and treated for dry eye disease especially targeting Meibomian gland dysfunction.  相似文献   
455.
ABSTRACT

Natural gas stands out among fossil fuels because it is relatively cleaner. It is also an important energy source type for several fields such as electricity production, industry, and heating, etc. Due to the poor capacity of Turkey in terms of natural gas sources, the demand is supplied by producer countries. Hence, accurate forecasting for the demand is of critical importance for Turkey, which imports 99% of its natural gas consumption. In the current literature about demand forecasting, most studies were conducted on an annual basis. However, the seasonal effect on the demand for natural gas cannot be foreseen through annual studies. Besides, to deal with some situations such as seasonal balancing, peak shaving, and gas supply shortage in monthly demand, forecasting models that capture the seasonal trend are needed. Therefore, in this study, a new grey seasonal forecast model has been presented and Turkey’s monthly natural gas demand was predicted via the proposed model. Performance of that model was compared with SGM(1,1) and SARIMA (p,d,q) x (P,D,Q)s. The obtained results show the superiority of the proposed model. By using this model, Turkey’s monthly natural gas demand was forecasted up until the year 2025. The proposed model allows us to capture seasonal patterns more successfully. In case this seasonal behavior continues, Turkey’s natural gas demand is expected to increase by %20 until 2025. At this point, the outcomes of the study provide important information to decision-makers to be able to determine reliable and stable energy policies.  相似文献   
456.
Epigenetic responses due to environmental changes alter chromatin structure, which in turn modifies the phenotype, gene expression profile, and activity of each cell type that has a role in the pathophysiology of a disease. Pulmonary diseases are one of the major causes of death in the world, including lung cancer, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), pulmonary hypertension (PH), lung tuberculosis, pulmonary embolism, and asthma. Several lines of evidence indicate that epigenetic modifications may be one of the main factors to explain the increasing incidence and prevalence of lung diseases including IPF and COPD. Interestingly, isolated fibroblasts and smooth muscle cells from patients with pulmonary diseases such as IPF and PH that were cultured ex vivo maintained the disease phenotype. The cells often show a hyper-proliferative, apoptosis-resistant phenotype with increased expression of extracellular matrix (ECM) and activated focal adhesions suggesting the presence of an epigenetically imprinted phenotype. Moreover, many abnormalities observed in molecular processes in IPF patients are shown to be epigenetically regulated, such as innate immunity, cellular senescence, and apoptotic cell death. DNA methylation, histone modification, and microRNA regulation constitute the most common epigenetic modification mechanisms.  相似文献   
457.
We report the investigation of boron substitution on structural, electrical, thermal, and thermoelectric properties of Ca3−xBxCo4O9 (x=0, 0.5, 0.75, and 1) in the temperature range between 300 K and 5 K. X-ray diffraction studies show that the Ca3Co4O9 phase is successfully preserved as the majority phase in the x=0.5 sample despite the small size of boron ions. Electrical transport measurements confirm that B3+ substitution for Ca2+ causes an increase in resistivity due to the decrease in carrier concentration. x=0.5 sample is found to have a Seebeck coefficient of 181 μV/K at room temperature which is ~1.5 times higher than that of the pure Ca3Co4O9. Our results indicate that the chemical pressure due to the large ionic radii difference between B3+ (0.27 Å) and Ca2+ (1 Å) enhances the thermoelectric properties as long as the unique crystal structure of Ca3Co4O9 is preserved.  相似文献   
458.
Sm0.2Ce0.8O1.9- 30% Na2CO3 (Sm doped ceria (SDC)-30N) nano-composite electrolytes were densified in a single step via cold sintering process (CSP). At 200°C and 450 MPa of uniaxial pressure, samples up to 97% of their theoretical density could be obtained. The effect of processing parameters, such as temperature, uniaxial pressure, processing duration, and moisture content, on the densification of the nano-composite electrolytes was investigated. The thermal, microstructural, and electrical properties of nano-composites were investigated by differential scanning calorimetry, X-ray diffractometer, scanning electron microscope, and EIS analysis. SDC crystallite sizes were found to be around 25 nm, barely coarsened after CSP by which the true nano nature of the nano-composite could be preserved. Because, by conventional processing high density values could not be attained and high processing temperatures in excess of 600°C had to be used, promoting particle coarsening. The highest total electrical conductivity was found to be 2.2 × 10−2 S cm−1 at 600°C, with an activation energy of 0.83 eV for SDC-30N nano-composites. The present investigation revealed that the implementation of cold sintering technique resulted in significant enhancements in the densification of nano-composite electrolytes, thereby rendering them suitable for efficient utilization in SOFC applications, as compared to the conventional production methods.  相似文献   
459.
This paper presents a meta-synthesis conducted to identify, compare and synthesize published qualitative data related to the Maggie's Centres, as a paradigmatic architectural example in the provision of non-institutional cancer support. These centres are internationally renowned for their unique architecture, where the careful design of indoors and outdoors spaces plays a critical role in their agenda for supporting care. Previous research has thoroughly analysed this approach to therapeutic environments, not only confirming the importance of designed space as originally conceived in Maggie's philosophy but also identifying precise supporting effects associated with specific elements within their design. This paper aims to provide a new reading of Maggie's contribution to cancer support by offering an examination of all these data through the lens of biophilia, which clarifies the impact of design decisions connected to nature on cancer patients' lives. The analytic process included a systematic search strategy, extraction and classification of salient concepts using an open-coding approach, and lastly an interpretive evaluation. The systematically selected data helped to identify and rank the biophilic design parameters that appear the most critical for promoting and supporting human health and wellbeing in non-clinical therapeutic environments, from the user's perspective. It also provided a compilation of distinctive design interventions related to biophilic parameters, which provides benchmark information for future research and design guidance in these environments.  相似文献   
460.
Water, which plays an important role in human life, has been depleted as a result of changing consumption patterns, climate change and increasing population, and water scarcity has emerged as one of the most pressing issues facing the world in the coming years. One solution to this problem is to make more efficient and sustainable use of existing water resources. In this context, the study aims to investigate the effects of consumers' environmental and economic concerns on sustainable water consumption behaviour, as well as the mediating role of water-saving behaviour in these effects. For this purpose, it was discovered that environmental and economic concerns have positive effects on sustainable water consumption behaviour as a result of an analysis of data collected from 591 consumers in Turkey via the online survey method; it was determined that environmental concerns have no effect on water-saving behaviour, whereas economic concerns have a positive effect on water-saving behaviour. According to the findings of the mediation analysis, water-saving behaviour only serves to mediate the effect of economic concerns on sustainable water consumption behaviour.  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-23

京公网安备 11010802026262号