全文获取类型
收费全文 | 973篇 |
免费 | 67篇 |
国内免费 | 1篇 |
学科分类
工业技术 | 1041篇 |
出版年
2024年 | 1篇 |
2023年 | 16篇 |
2022年 | 104篇 |
2021年 | 107篇 |
2020年 | 42篇 |
2019年 | 45篇 |
2018年 | 36篇 |
2017年 | 37篇 |
2016年 | 46篇 |
2015年 | 43篇 |
2014年 | 45篇 |
2013年 | 64篇 |
2012年 | 66篇 |
2011年 | 88篇 |
2010年 | 45篇 |
2009年 | 45篇 |
2008年 | 46篇 |
2007年 | 37篇 |
2006年 | 20篇 |
2005年 | 20篇 |
2004年 | 17篇 |
2003年 | 21篇 |
2002年 | 13篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 10篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1041条查询结果,搜索用时 15 毫秒
51.
Elisa de Almeida Jackix Elisa Bernardes Monteiro Helena Fonseca Raposo Emerielle Cristine Vanzela Jaime Amaya‐Farfán 《Journal of food science》2013,78(12):H1929-H1934
Several studies have shown that fruits and vegetables contribute to protect against degenerative pathologies such as cardiovascular diseases, diabetes, and cancer, mainly due to the presence of dietary fiber (DF) and polyphenols. Taioba (Xanthosoma sagittifolium) is an edible aroid widely grown in many parts of Africa, America, and Asia. The tubers portions of taioba are widely consumed; however, the leafy portions are generally discarded, despite their high nutritive value. In this study, we have partly characterized the DF of lyophiized taioba leaf (LTL), and assessed the possible protective effects on biochemical parameters and on bile acid (BA) production in colon and cecum, when fed to healthy rats for 4 wk. Forty‐five Wistar rats were assigned to either of 5 groups: group 1 received AIN 93G diet (CG: Control); group 2 received AIN 93G containing 2.5% of cellulose + 2.5% inulin (CEIN_5%); group 3 received AIN 93G containing 2.5% of cellulose + 2.5% taioba fiber (CETA_5%); group 4 received AIN 93G containing 5% cellulose + 2.5% taioba fiber (CETA_7.5%); group 5 received AIN 93G containing 5% cellulose + 2.5% of inulin (CEIN_7.5%). LTL showed high contents of total fiber, predominantly comprising insoluble DF with glucose as the major monomer. Rats receiving LTL had increased fecal mass and fat excretion, and improved BA profiles by diminishing the proportion of secondary acids, thus suggesting that consumption of taioba leaf may have the property of lowering the risk of colon cancer. 相似文献
52.
Objective: Studies examining psychological trauma or posttraumatic stress disorder (PTSD) in ethnoracial or sexual minority groups are relatively few. The Journal of Consulting and Clinical Psychology recently published 4 articles (Balsam, Lehavot, Beadnall, & Circo, 2010; Harrington, Crowther, & Shipherd, 2010; Lester, Resick, Young-Xu, & Artz, 2010; Marshall, Schell, & Miles, 2009) that examine trauma exposure and posttraumatic outcomes in ethnoracial and sexual minority samples. This commentary focuses on the overlap between traumatic stress and diversity studies in order to consider future areas in need of development. Method: Within the framework of a generalized overview of current trends in the study of traumatic stress, an assessment of the strengths and limitations of these 4 articles is provided. Populations and syndromes covered by the articles include ethnoracial differences in child maltreatment and adverse mental health outcomes among sexual minority participants, PTSD symptom elevations among Hispanic Americans, binge eating and the strong Black woman schema, and retention of African American female participants in cognitive behavioral psychotherapy trials for PTSD. Results: Recommendations to enhance culturally competent traumatic stress studies include increasing the examination of within-group cultural variability and key social, contextual, and cultural variables and constructs; examining the temporal sequencing of traumatic events and key transitions in sexual and ethnic minority identity development; and conducting prevention and treatment studies for those sexual minority children most at risk for maltreatment. Conclusions: By following these recommendations, the next generation of studies of traumatic stress studies will be enhanced. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
53.
54.
55.
Simone Fujii Ricardo Marcelo Reche Ribeiro Maria Brígida Dos Santos Scholz Elisabete Yurie Sataque Ono Cássio Egidio C Prete Eiko Nakagawa Itano Yoshio Ueno Osamu Kawamura Elisa Yoko Hirooka 《Food Additives & Contaminants》2006,23(9):902-909
The performance of an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on a monoclonal antibody (mAb) for ochratoxin A (OTA) detection was evaluated in a comparative study with high-performance liquid chromatography (HPLC) analysis using 68 freshly harvested coffee samples from the North of Paraná State, Brazil. The anti-OTA mAb showed high specificity and low cross-reactivity with OTA analogues (OTB and OTalpha), but cross-reacted with OTC. This ic-ELISA showed a detection limit of 3.75 ngg-1 sample, when compared to 0.80 ngg-1 by HPLC, with an ic-ELISA/HPLC correlation coefficient of 0.90. As regards OTA analysis of these coffee samples, natural contamination was detected in 10 samples (14.7%) by both methods, where the ic-ELISA values (range 3.9-7.3 ngg-1) were 1.1 to 1.6-fold higher than HPLC data (2.7-4.7 ngg-1). Five samples (7.4%) were OTA positive (range 0.84-1.30 ngg-1) only by HPLC assay, probably due to the higher detection limit reached by ic-ELISA. OTA was undetectable in 53 samples (77.9%) by both methods, while all positive samples (range 0.84-7.30 ngg-1) showed OTA levels lower than 8 ngg-1 (maximum limit recommended by the European Union). The matrix interference of green coffee was minimized by dilution of sample extracts before carrying out the ELISA assay. This mAb-based ic-ELISA can be effectively applied for OTA screening in coffee, because it is simple, sensitive and sample preparation is easy. 相似文献
56.
Elisa Barney Smith David Monn Harsha Veeramachaneni Koichi Kise Alessio Malizia Leon Todoran Adnan El-Nasan Rolf Ingold 《International Journal on Document Analysis and Recognition》2003,6(3):200-206
This document is a collection of four working group reports in the areas of digital libraries, document image retrieval, layout analysis, and Web document analysis. These reports were the outcome of discussions by participants at the Fifth IAPR International Workshop on Document Analysis Systems held in Princeton, NJ on 19-21 August 2002.Published online: 16 March 2004 相似文献
57.
Affatato S Mattarozzi A Taddei P Robotti P Soffiatti R Sudanese A Toni A 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2003,217(1):1-8
Total hip replacement has become one of the most successful orthopaedic procedures. However, complications due to infections may give serious problems and have devastating consequences for the hip implant. The use of a temporary three-dimensional polymethylmethacrylate (PMMA) cement spacer may be an alternative to solve infections in hip implants, improving the lives of patients awaiting reimplantation. In order to evaluate their wear behaviour, five PMMA Spacer-G femoral heads were tested against five post-mortem pelves in a hip joint simulator with bovine calf serum as lubricant. The surface of the worn spacers was characterized by scanning electron microscopy (SEM) analysis; all the samples revealed a similar morphology, showing areas characterized by different degrees of wear. Particle debris was isolated from the lubricant and PMMA particles and bone fractions were quantified. The amount of debris was found to be higher than where no-temporary prostheses were used. However, this result is acceptable since wear debris is removed by lavage irrigation when the Spacer-G is explanted. On the basis of these data, it is considered that the use of the cement Spacer-G could be a promising approach to the treatment of complicated infections of the hip joint. Therefore, Spacer-G is worthy of further research. 相似文献
58.
There is public concern about the magnitude of the problem of large truck crashes in the US. Fatalities in large truck crashes have not declined much; however, more large trucks are driving more miles than ever before while fatalities per mile driven have dropped substantially. This study examined how the public health burden of large truck crashes versus the risk per unit of travel has changed over 25 years.The present study focused on the US vehicle occupants in fatal crashes involving a large truck during 1975-1999. Occupant fatalities per 100000 population, per 10000 licensed drivers, per 10000 registered trucks and per 100 million vehicle-miles of travel (VMT) were calculated to determine trends in occupant deaths in large truck crashes.In 1999, large truck crashes resulted in 3916 occupant deaths in passenger vehicles and 747 in large trucks. Passenger vehicle occupant deaths in large truck crashes per 100000 population have increased somewhat since 1975 (1.28 in 1975 and 1.44 in 1999). There have been appreciable declines in occupant deaths per truck VMT since 1975, but the percentage reduction has been greater for occupants of large trucks (67%) than for passenger vehicle occupants (43%). However, truck drivers are at elevated risk of dying relative to their numbers in the workforce. Overall large truck involvements in fatal crashes per truck VMT decreased more than passenger vehicle involvements per passenger VMT (PVMT; 68% versus 33% decreases for single-vehicle crashes and 43% versus 23% for multiple-vehicle crashes). Large truck involvement in fatal crashes has dropped substantially when measured per unit of travel, but the public health burden of large truck crashes, as measured by deaths per 100000 population, has not improved over time because of the large increase in truck mileage. Research is needed on measures to better protect both occupants of large trucks and passenger vehicle occupants colliding with them. 相似文献
59.
Revenue-collection data from toll roads allow for accurate estimates of miles driven by vehicle type and, when combined with crash data, valid estimates of crash involvements per mile driven. Data on vehicle-miles traveled and collisions were obtained from toll road authorities in Florida. Kansas, and New York. In addition, state crash files and published vehicle-miles of travel were obtained for toll roads in Illinois. Indiana, Ohio, and Pennsylvania. Large commercial motor vehicles were significantly underinvolved in single-vehicle crashes on all state toll roads. In five states, commercial motor vehicles were significantly overinvolved in multiple-vehicle crashes relative to passenger vehicles; the exceptions were Kansas, where they had significantly lower multiple-vehicle involvement rates, and Indiana. where there were no significant differences in multiple-vehicle involvements by vehicle type. The risk of commercial motor vehicle involvement in multiple-vehicle crashes resulting in deaths or serious injuries was double that of passenger vehicles in the two states (Ohio and Pennsylvania) that identified serious injuries. Whether crash rates, on toll roads of commercial motor vehicles are higher or lower than those of passenger vehicles appears to depend on the type of crash, specific toll road. and traffic density. 相似文献
60.
Pieri Luca Serino Silvia Cipresso Pietro Mancuso Valentina Riva Giuseppe Pedroli Elisa 《Virtual Reality》2022,26(2):639-648
Virtual Reality - One important feature of a neuropsychological test is its ecological validity, which defines how much patients’ test scores are linked to real-life functioning. However,... 相似文献