全文获取类型
收费全文 | 574篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
教育 | 259篇 |
科学研究 | 276篇 |
各国文化 | 3篇 |
体育 | 3篇 |
文化理论 | 3篇 |
信息传播 | 33篇 |
出版年
2023年 | 8篇 |
2022年 | 9篇 |
2021年 | 20篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 40篇 |
2017年 | 26篇 |
2016年 | 27篇 |
2015年 | 30篇 |
2014年 | 28篇 |
2013年 | 55篇 |
2012年 | 17篇 |
2011年 | 22篇 |
2010年 | 26篇 |
2009年 | 29篇 |
2008年 | 24篇 |
2007年 | 17篇 |
2006年 | 31篇 |
2005年 | 23篇 |
2004年 | 14篇 |
2003年 | 25篇 |
2002年 | 12篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 6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 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1979年 | 1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577条查询结果,搜索用时 0 毫秒
41.
Ipsita Choudhury R. Jothimalar Arun Kumar Patra 《Indian journal of clinical biochemistry : IJCB》2012,27(3):265-269
Hypertension, a well known risk factor for various cardiovascular, peripheral vascular and renal events is an important public health challenge. Renin angiotensin system (RAS) being the most vital pathogenic mechanism of hypertension is mediated by a key component; the angiotensin converting enzyme (ACE). The present study was aimed to know the relationship of ACE gene polymorphism and the possible risk of development of hypertension in south Indian population. The study included 101 clinically diagnosed hypertensive patients without any associated disease condition and 81 age and sex matched apparently healthy controls. Genotyping was performed using a polymerase chain reaction, (PCR) amplification of the intron 16 fragment harboring the 287 bp Alu repeat sequence. Three possible genotypes D/D, I/I homozygous and I/D heterozygous were analyzed where the D/D genotypes corresponds to higher ACE levels (D-Deletion, I-Insertion). The PCR products were separated on 2 % agarose gel. Statistical analysis was performed using SPSS.15 software program. We found a significance in frequency of D/D genotype in the hypertensive patients compared to the control group (p = 0.0005, odd’s ratio = 4.157). This suggested that ACE (D/D) genotypes are more prone for the development of hypertension. This is relatively a pilot study; but nevertheless may assist in identifying the pathophysiological cause of hypertension. 相似文献
42.
Tapas Kumar Ghosh K.C. Panda 《Library Collections, Acquisitions, and Technical Services》2010,34(2-3):45-50
The vital task of the libraries attached to the educational institutions of higher learning is the collection development of information resources as per the requirements of the users. The Central Library of IITs have long been recognized their responsibility to support the study and research of their parent institutions with the rich collection development of information resources both in print as well as electronic format to cater the needs of the academic communities as per the multi-disciplinary and diverse academic program of the respective institutions where greater emphasis on collection of serials, the essential and integral component of updated scholarly communication. The study provides a vivid picture about the current status of serials collection in the libraries attached to the Premier Institutions of India in the field of science and technology to boost up the academic performances. 相似文献
43.
44.
45.
46.
47.
Shubham Goel Ravinder Kumar Munish Kumar Vikram Chopra 《Information processing & management》2019,56(3):1053-1066
In the whole world, the internet is exercised by millions of people every day for information retrieval. Even for a small to smaller task like fixing a fan, to cook food or even to iron clothes persons opt to search the web. To fulfill the information needs of people, there are billions of web pages, each having a different degree of relevance to the topic of interest (TOI), scattered throughout the web but this huge size makes manual information retrieval impossible. The page ranking algorithm is an integral part of search engines as it arranges web pages associated with a queried TOI in order of their relevance level. It, therefore, plays an important role in regulating the search quality and user experience for information retrieval. PageRank, HITS, and SALSA are well-known page ranking algorithm based on link structure analysis of a seed set, but ranking given by them has not yet been efficient. In this paper, we propose a variant of SALSA to give sNorm(p) for the efficient ranking of web pages. Our approach relies on a p-Norm from Vector Norm family in a novel way for the ranking of web pages as Vector Norms can reduce the impact of low authority weight in hub weight calculation in an efficient way. Our study, then compares the rankings given by PageRank, HITS, SALSA, and sNorm(p) to the same pages in the same query. The effectiveness of the proposed approach over state of the art methods has been shown using performance measurement technique, Mean Reciprocal Rank (MRR), Precision, Mean Average Precision (MAP), Discounted Cumulative Gain (DCG) and Normalized DCG (NDCG). The experimentation is performed on a dataset acquired after pre-processing of the results collected from initial few pages retrieved for a query by the Google search engine. Based on the type and amount of in-hand domain expertise 30 queries are designed. The extensive evaluation and result analysis are performed using MRR, [email protected], MAP, DCG, and NDCG as the performance measuring statistical metrics. Furthermore, results are statistically verified using a significance test. Findings show that our approach outperforms state of the art methods by attaining 0.8666 as MRR value, 0.7957 as MAP value. Thus contributing to the improvement in the ranking of web pages more efficiently as compared to its counterparts. 相似文献
48.
Sonika Gupta Niraj Shende Swati Banerjee Satish Kumar M. V. R. Reddy Bhaskar C. Harinath 《Indian journal of clinical biochemistry : IJCB》2002,17(1):5-8
Tuberculosis remains major health problem in India and developing countries Immunodiagnosis has important role in screening,
diagnosis and management of tuberculosis. SEVA TB ES-31 antigen has shown potential in detecting tuberculous IgG antibody
in earlier studies from our laboratory. In the present study we have analysedSEVA TB ES-31 antigen specific immunoglobulinsIgM, IgA and IgG in clinically and bacteriologically confirmed pulmonary tuberculosis cases to determine the usefulness of specific immunoglobulin
class in the diagnosis of patients attending the hospital.
Of the 30 cases of pulmonary tuberculosis 25 (83.3%) were positive for IgG, 19 (63.3%) for IgM and 16 (53.3%) for IgA. On
combining IgG and IgM positivity, sensitivity was increased to 93.3%. While combining IgG and IgA positivity, sensitivity
increased to 90%. However specificity was decreased to 66.6% and 70% for both of these combinations respectively. It could
be envisaged from this study that IgG antibody detection against ES-31 antigen showed acceptable sensitivity (83.3%) and specificity
(86.6%) compared to IgM or IgA alone or in combination. When immune responses were analysed according to degree of sputum
positivity, IgG response was observed to be predominant in all grades, compared to IgM or IgA antibody. The addition of IgM
or IgA as an adjunct test increases the sensitivity but at the cost of specificity. Hence the detection of IgG alone is more
useful compared to IgM or IgA assay, in detecting tuberculosis disease cases coming to the hospital. 相似文献
49.
50.