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   13983篇
  免费   61篇
  国内免费   1篇
教育   10577篇
科学研究   1356篇
各国文化   57篇
体育   631篇
综合类   1篇
文化理论   397篇
信息传播   1026篇
  2023年   9篇
  2022年   17篇
  2021年   41篇
  2020年   66篇
  2019年   130篇
  2018年   2300篇
  2017年   2215篇
  2016年   1676篇
  2015年   187篇
  2014年   213篇
  2013年   617篇
  2012年   300篇
  2011年   757篇
  2010年   907篇
  2009年   504篇
  2008年   713篇
  2007年   1216篇
  2006年   127篇
  2005年   443篇
  2004年   495篇
  2003年   404篇
  2002年   164篇
  2001年   39篇
  2000年   47篇
  1999年   26篇
  1998年   37篇
  1997年   39篇
  1996年   17篇
  1995年   28篇
  1994年   23篇
  1993年   26篇
  1992年   17篇
  1991年   20篇
  1990年   26篇
  1989年   25篇
  1988年   15篇
  1987年   11篇
  1986年   8篇
  1985年   5篇
  1984年   11篇
  1983年   15篇
  1982年   5篇
  1981年   11篇
  1980年   9篇
  1979年   6篇
  1978年   7篇
  1977年   7篇
  1976年   5篇
  1974年   7篇
  1972年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
AIMS/OBJECTIVES: To undertake an information-needs analysis of operating theatre staff in order to inform the development of a specialist library of the National Electronic Library of Health (NeLH). SETTING: Three hospitals in an NHS Trust in a rural county in the north of England. METHODS: In-depth interviews, during which staff were questioned in regard to their job roles and information needs, information-seeking behaviour, access to computers, use and perceptions of the NeLH, and what they would like from a specialist library. RESULTS: Information needs were found to concern direct care, professional and academic development, medical devices knowledge and administration. Currency and speed of delivery were the key information requirements. Poor communication appeared to be a major problem for many staff and inhibited efficient information exchange. When using the Web, both clinical and non-clinical staff searched in a similar fashion to health consumers generally, despite their need for highly specialist information. Most respondents reacted warmly to the idea of the proposed National Electronic Library for Theatre Staff (NeLTS) and made several practical suggestions for suitable material. However, access was problematic for nurses and might prove to be an obstacle to take-up of the Specialist Library. CONCLUSIONS: Communication difficulties, the fragmentation of data in the field and the consequent difficulties of finding information point to the need for an NeLTS. However, for this library to embrace and succeed with all the various groups that constitute the operating theatre staff, issues of access and digital literacy need to be addressed.  相似文献   
992.
993.
Rats confronted with the onset of a light gradient display a transient increase in locomotion called theactivity response (AR) and a dark preference (Godsil & Fanselow, 2004). These experiments demonstrate that the magnitude of the AR can be blunted with Pavlovian fear-conditioning procedures via associative and nonassociative fear. Although manifested in decreased locomotion, the blunted AR effect was not due to increased freezing or immobility behaviors. Instead, rats displayed reduced rearing and an increase in a class of behaviors calledstationary activity. These results suggest that the lighting differential supplied by the cue influences the topography of defensive behavior and reduces the expression of freezing. This procedure provides a means by which to examine learned and unlearned defensive responses to the same stimulus.  相似文献   
994.
Hogan AJ 《Endeavour》2012,36(2):77-84
What does it look like to be the carrier of a genetic disease? Carrier status may be determined through the visual analysis of both genotypic and phenotypic evidence. Over the past 70 years, clinical geneticists have depended upon multiple strategies for identifying disease carriers within a family. This has included pedigree analysis, which was based upon clinical observations of individual family members and, in recent decades, cytogenetic and molecular methods. Newer techniques have offered novel opportunities to actually see the suspected etiological markers of certain genetic diseases, such as Fragile X syndrome. The visualization of these markers has both clarified and confused previously observed inheritance patterns, in some cases leading to the development of newly distinct diagnostic categories. As a result, what it means to be affected by, or the carrier of, a genetic disease has continuously evolved.  相似文献   
995.
To analyse the association of high sensitivity C-reactive (hsCRP) protein levels and −717A/G single nucleotide polymorphism of CRP with acute myocardial infarction (AMI) in the Indian population. Study population included 100 MI cases wherein 32 patients had experienced previous MI (MI-Group-1), 68 MI cases were recruited at presentation (MI-Group-2) and equal number of age and gender matched healthy individuals. hsCRP levels were determined by ELISA and genotyping of −717A/G was carried out by polymerase chain reaction-based restriction digestion method. The −717A/G genotypes did not influence hsCRP level and their distribution did not differ between groups. However, in the present study hsCRP demonstrated significant correlation with BMI in controls of both the genders and with triglycerides in females of AMI at presentation who otherwise are with low risk profile. Identifying traditional risk factors associated with inflammation may help in controlling the acute event.  相似文献   
996.
Breast cancer is one of the most frequent malignancies in the world. Available staging procedures to detect breast cancer are bone scan, chest X-ray, liver ultrasonography, computerized tomography, estimation of tumor markers like carbohydrate antigen (CA15-3) and carcino embryonic antigen. These procedures are expensive and may not be required in all cases. Out of 70 patients studied, 55 had normal CA15-3 and 15 had elevated levels of Ca15-3. Eight (14.5%) of the 55 patients with normal CA15-3 had abnormal bone scan. Fifteen patients had CA15-3 levels above the normal range and among these 9 (60%) had abnormal bone scan. While prime facie it would appear that a high level of CA15-3 correlate with abnormal bone scan, it is also true that the numbers are small at present and conclusions about the validity of CA15-3 as marker of bone metastasis may be premature.  相似文献   
997.
Elite rugby union teams currently employ the latest technology to monitor and evaluate the physical demands of training and games on their players. Tackling has been shown to be the most common cause of injury in rugby union, yet current player monitoring technology does not effectively evaluate player tackling measurements. Currently, to evaluate measurements specific to player tackles, a time-consuming manual analysis of player sensor data and video footage is required. The purpose of this work is to investigate tackle modeling techniques which can be utilised to automatically detect player tackles and collisions using sensing technology already being used by elite international and club level rugby union teams. This paper discusses issues relevant to automatic tackle analysis, describes a technique to detect tackles using sensing data and validates the technique by comparing automatically detected collisions to manually labeled collisions using data from elite club and international level players. The results of the validation show that the system is able to consistently identify collisions with very few false positives and false negatives, achieving a recall and precision rating of 0.933 and 0.958, respectively. The aim is that the automatically detected tackles can provide coaching, medical and strength and conditioning staff with objective tackle-specific measurements, in real time, which can be used in injury prevention and rehabilitation strategies.  相似文献   
998.
This case addresses the relationship between sport and digital spaces by introducing students to strategic marketing processes related to developing a team-managed fan website. The case was created in conjunction with three former members of the Cleveland Cavaliers who helped create www.cavfanatic.com, the official fan site of the team. Key areas addressed within the case study are brand development, brand communication, and brand extension. The case follows a new hire, Natalie, as she joins the new media team of www.cavfanatic.com. The sport marketers she works with review the development of the website and provide information on the strategic development process they went through. In the end, Natalie is charged with looking forward and developing further strategies to continue to engage the Cavaliers fans and to develop the CavFanatic brand.  相似文献   
999.
##正##Dr.Gruntzig et al.(1979) successfully completed the world's first percutaneous coronary intervention (PCI),a percutaneous transluminal coronary  相似文献   
1000.
The aim of this study is to build two mathematical models of canine ionic currents specific to right atria and left atria.The canine left atria mathematical model was firstly modified from the Ramirez-Nattel-Courtemanche(RNC) model using the recently available experimental data of ionic currents and was further developed based on our own experimental data.A model of right atria was then built by considering the differences between right atria and left atria.The two developed models well reproduced the exper...  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