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   601篇
  免费   3篇
  国内免费   1篇
教育   274篇
科学研究   285篇
各国文化   4篇
体育   4篇
综合类   1篇
文化理论   3篇
信息传播   34篇
  2023年   2篇
  2022年   7篇
  2021年   20篇
  2020年   5篇
  2019年   12篇
  2018年   38篇
  2017年   27篇
  2016年   27篇
  2015年   33篇
  2014年   34篇
  2013年   62篇
  2012年   21篇
  2011年   23篇
  2010年   26篇
  2009年   33篇
  2008年   24篇
  2007年   17篇
  2006年   30篇
  2005年   21篇
  2004年   16篇
  2003年   25篇
  2002年   13篇
  2001年   8篇
  2000年   7篇
  1999年   7篇
  1998年   13篇
  1997年   7篇
  1996年   3篇
  1995年   8篇
  1994年   4篇
  1993年   5篇
  1992年   5篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1987年   2篇
  1986年   2篇
  1985年   2篇
  1983年   2篇
  1979年   2篇
  1978年   2篇
  1977年   1篇
  1976年   2篇
  1975年   1篇
  1973年   1篇
  1962年   1篇
排序方式: 共有605条查询结果,搜索用时 172 毫秒
561.
For cutting down cost and improving the efficiency of enterprises, adoption of innovations in ICT especially in cloud computing applications is the need of the time in the highly competitive global environment. It has been noted that generally, the Indian MSMEs are not utilizing the CC applications for the promotion of their business activities and are not availing their benefits. Hence, in the present investigation, the critical success factors (CSFs) for cloud computing adoption (CCA) in the Indian micro, small and medium enterprises (MSMEs) are identified through an exhaustive literature review and expert opinions. The association between the identified factors is established by employing an interpretive structural modeling methodology that is a multi-criteria decision making (MCDM) approach. Later, the MICMAC analysis is carried out for identifying the factors having high influential power. The results of the study revealed that a CSF namely ‘previous technological experience’ is the most significant factor having the highest driving power. The findings of this research are intended to guide cloud service providers, enterprise managers, and governmental bodies in formulating the strategies and policies for effective implementation of cloud computing facilities and harness the benefits of the same. This study makes a significant contribution to the knowledge base of CC adoption for future research in the subject field.  相似文献   
562.
Post-secondary educational attainment is an increasingly important prerequisite to many valued outcomes. This paper examines the association of racially-specific high school course of study with student’s postsecondary educational attainment using ELS 2002–2012 and a comprehensive measure of course intensity derived from students’ patterns of course-taking. Results support a partial presence of racially-specific association of high school course of study. We also find that only Asian-American and American Indian/Alaskan Native students in the middle course intensity and Asian-American students in high course intensity ranges are more likely to obtain at least a 4-year college degree than same-race students in the low course intensity group. However, the same pattern is not evident for White, African-American, multi-racial, and Hispanic students, indicating that they do not experience the same benefit from academically rigorous courses of study. Also, educational expectations do not mediate the relationships among race, course of study, and postsecondary educational trajectory differently for students of different racial groups, i.e., they do not play a larger role in mediating the relationship between course of study and postsecondary educational trajectory for White students.  相似文献   
563.
Inherited metabolic disorders are a heterogeneous group of genetic conditions mostly occurring in childhood. They are individually rare but collectively numerous, causing substantial morbidity and mortality. We have retrospectively reviewed a total of eight hundred and sixty nine cases with different age groups that had been referred from several diagnostic centers and hospitals of India to the Department of Metabolism in Narayana Hrudayalaya, as cases suspected with inborn errors of metabolism. Advanced techniques applied were to diagnose the disorders of inborn errors of metabolism. Data analyzed indicates occurrence of several metabolic disorders in our population. The need to screen for an inborn error of metabolism arises out of the fact that most cases take to irreversible effects as time progress. Emphasis has to be laid on early detection and prompt management, which could help in alleviating symptoms and preventing complications and consequent incapacitation.  相似文献   
564.
In rats with streptozotocin induced severe diabetes mellitus, aqueous extract of Trichosanthes dioica fruits at a dose of 1000mg/kg body weight daily once for 28 days reduced the levels of fasting blood glucose, postprandial glucose, asparate amino transferase, alanine amino transferase, alkaline phosphatase, creatinine, urine sugar and urine protein where as total protein and body weight was increased. No toxic effect was observed during LD50. Our study suggests that further detailed toxicity studies and mechanism of action of T. dioica would be useful for undertaking human trials.  相似文献   
565.
This study was conducted to find out the possible underlying mechanism of various manifestation of fluorosis, a disease caused by excess ingestion of fluoride. For this the fluoride belt of Jaipur district was selected. The parameters selected were serum Parathyroid hormone, the levels of which are directly affected by fluoride intake. The levels of serum seromucoid, serum and leucocyte ascorbic acid, serum sialic acid (SSA) reflects ground substance metabolism. The study was conducted on two hundred children, selected from four areas (50 from each area) consuming water containing 2.4, 4.6, 5.6 and 13.6 mg/l of fluoride. Drinking water fluoride and serum fluoride were measured by Ion selective electrode method. Serum parathyroid by RIA and all other parameters were measured spectrophotometrically. The results revealed an increase in levels of fluoride, parathyroid hormone and seromucoid in serum with increasing water fluoride concentrations. Serum Calcium and serum ascorbic acid were found in normal range, how ever leucocyte ascorbic acid were decreased. A high positive correlation among fluoride concentration in drinking water and serum parathyroid hormone (r=0.967), and, serum parathyroid hormone and serum seromucoid concentration (r=0.935) was also observed The results indicated that secondary hyperparathyroidism due to hypocalcemic stress caused by excess fluoride ingestion disturbs normal metabolism of ground substance in calcified tissues of the body reflected as altered levels of the components of ground substance in the serum.  相似文献   
566.
Stroke is the third leading cause of death and foremost cause of disability. Based on studies in CAD patients, a focus has been shifted on genetic and inflammatory markers as risk factors for stroke besides deranged lipid profile. The present study was aimed to ascertain the role of Lipoprotein (a), C-Reactive protein (CRP) levels and lipids in patients of ischemic stroke. The study was done in 82 subjects including 40 Computerized Tomography (CT) proven patients of ischemic stroke and 42 age and sex matched controls. Complete biochemical parameters including lipid profile were carried out on autoanalyzer using standard kits and reagents. Lipoprotein (a) [Lp(a)] was determined by immunoturbidimetric assay. Atherogenic indices (Total cholesterol/ HDL, LDL/HDL and Lipid Tetrad Index) were calculated using these lipid parameters. The CRP levels were measured semi-quantitatively by latex agglutination test method. Out of 40 stroke patients, 38 had abnormalities in lipid profile (As per ATP III guidelines). A significant difference was seen in serum cholesterol, LDL cholesterol and atherogenic indices between the patients and controls. The difference in CRP levels in cases and control subjects was highly significant (4.78±0.72 mg/dl vs 0.76 ±0.70, p<0.001). 96.5% of patients with raised CRP had abnormal lipid levels also. CRP levels in stroke patients showed significant correlation with total cholesterol and LDL (p<0.001), Lp (a) (p=0.002) and atherogenic indices (p<0.05). Raised CRP levels in stroke patients were significantly associated with large territory infarcts, severe disability and poor functional outcome (p<0.05).Genetic [Lp(a)], metabolic (deranged Lipid profile) and inflammatory factors (CRP) together are instrumental in causing cerebrovascular arteriosclerosis leading to ischaemic stroke and can be used as important markers to identify patients at risk of severe stroke and to institute aggressive preventive strategies.  相似文献   
567.
Increasing interest in multiple forms of nonacademic intelligences in addition to the well‐established intelligent quotient (IQ) to explain individual success has triggered a need for clear establishment of the theoretical and empirical connection among these constructs. As such, this article explores the interrelationship that exists among three forms of nonacademic intelligences: cultural, emotional, and social. Theoretical and practical implications are also discussed.  相似文献   
568.
It is well known that a fractional-order system with a continuous right hand side does not have finite-time stable equilibria, but the discontinuous case has remained elusive in literature. Thus, based on novel mathematical tools, recently published in literature, it is demonstrated that attaining finite-time stable equilibria is not possible for a fractional-order system, not even in the case of an impulsive or discontinuous feedback. In consequence, it is demonstrated that, for a fractional-order system, a Lyapunov stable equilibrium cannot be at the same time finite-time stable.  相似文献   
569.
Iron deficiency anemia is one of the causes that lead to significant mortality and morbidity among pregnant women and fetus. The present study was undertaken to explore oral iron supplementation can modify the metal contents in pregnant anemic women. Iron and folic acid supplementations was given to 500 anemic women (mild = 200, moderate = 200, and severe = 100) and 100 age matched non-anemic controls daily for 100 days. Blood index values and plasma trace minerals were estimated as per standard protocols. Haemoglobin and ferritin levels were found significantly increased (p < 0.001) in anemic and control subjects after treatment. Moreover, the serum transferring receptor levels and total iron binding capacity were found significantly decreased in all treated groups. Iron (Fe), zinc (Zn) and copper (Cu) levels were found increased (p < 0.01) after oral iron supplementation groups. Moreover, selenium (Se) manganese (Mn) and were found to be decreased in all treated groups. Data provides the conclusion that iron and folic acid supplementation recovered the essential trace minerals, except manganese, which may lead to various complications including peroxidation of vital body molecules resulting in increased risk for pregnant women as well as fetus.  相似文献   
570.
The documentation of lead toxicity (plumbism) dates back to the times when man learnt its various applications. This versatile heavy metal is non-degradable and its ability to get accumulated in the body that goes undiagnosed, makes it a serious environmental health hazard. Lead is now known to affect almost every organ/tissue of the human body. With irreversible effects on neurobiological development of young children and foetus, its toxicity has lasting implications on the human life. Outlining the symptoms, diagnosis and treatment therapy for lead poisoning, the present review elaborates the pathophysiological effects of lead on various organs. This will be of immense help to the health professionals so as to inculcate a better understanding of the lead poisoning which otherwise is asymptomatic. With chelation therapy being the classic path of treatment, new strategies are being explored as additive/adjunct therapy. It is now understood that lead toxicity is completely preventable. In this regard significant efforts are in place in the developed countries whereas much needs to be done in the developing countries. Spreading the awareness amongst the masses by educating them and reducing the usage of lead following stricter industry norms appears to be the only roadmap to prevent lead poisoning. Efforts being undertaken by the Government of India and other organisations are also mentioned.  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