全文获取类型
收费全文 | 547篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
教育 | 247篇 |
科学研究 | 263篇 |
各国文化 | 3篇 |
体育 | 2篇 |
文化理论 | 3篇 |
信息传播 | 32篇 |
出版年
2023年 | 8篇 |
2022年 | 7篇 |
2021年 | 19篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 36篇 |
2017年 | 25篇 |
2016年 | 24篇 |
2015年 | 29篇 |
2014年 | 29篇 |
2013年 | 54篇 |
2012年 | 16篇 |
2011年 | 20篇 |
2010年 | 24篇 |
2009年 | 28篇 |
2008年 | 23篇 |
2007年 | 17篇 |
2006年 | 29篇 |
2005年 | 21篇 |
2004年 | 14篇 |
2003年 | 24篇 |
2002年 | 10篇 |
2001年 | 8篇 |
2000年 | 7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550条查询结果,搜索用时 15 毫秒
121.
Sanyal N Pramanik SK Pal R Chowdhury A 《Journal of Zhejiang University. Science. B》2006,7(3):202-208
Two sulfonylurea herbicides, metsulfuron methyl (Ally 20 WP) and chlorimuron ethyl (Classic 25 WP) were evaluated for their dissipation bchaviour in alluvial, coastal saline and laterite soils under laboratory incubated condition at 60% water holding capacity of soils and 30 ℃ temperature was maintained. In field study herbicides were applied twice for the control of grasses, annual and perennials broad leaves weeds and sedges in rice, wheat and soybean to find out the residual fate of both the herbicides on different matrices of respective crops after harvest. Extraction and clean up methodologies for the herbicides were standardized and subsequently analyzed by HPLC. The study revealed that the half-lives of metsulfuron methyl and chlorimuron ethyl ranged from 10.75 to 13.94 d irrespective of soils and doses applied. Field trials with rice, wheat and soybean also revealed that these two herbicides could safely be recommended for application as no residues were detected in the harvest samples. 相似文献
122.
Goswami BK Pandey RK Rathour KS Bhattacharya C Singh L 《Journal of Zhejiang University. Science. B》2006,7(11):873-875
INTRODUCTION Tomato (Lycopersicon esculentum, Mill.), an important vegetable crop is heavily attacked by root knot nematode, Meloidogyne spp. For the manage-ment of root knot nematodes although chemical nematicides were used till 1982, due to their high cost, toxic effect on beneficial soil borne microorganism and carcinogenic effect on human beings alternative approaches are practiced mainly through eco-friendly means like biological control agents, organic amendments, etc. (Singh and … 相似文献
123.
The purpose of this paper is to provide a reconnaissance of major academic libraries located in Australia, Canada, the U.K. and U.S.A. that have embraced Web 2.0 tools for enhancing library services. The research is based on a survey of websites of 277 university libraries. The checkpoints used for this evaluative study were given by Nguyen (2008) for evaluating various Web 2.0 tools. Additional checkpoints were arrived at after visiting and browsing the various sites. The findings of the study acknowledge the strength of Web 2.0 tools in improving library services for users. Really Simple Syndication (RSS), Instant Messaging (IM) and blogs are popular in academic libraries. The paper concludes by offering best practices for implementing Web 2.0 tools in academic libraries. 相似文献
124.
Arun Kumar B. S. Dhillon D. N. Rao Geetha Menon Hari Shankar L. K. Dhaliwal Maiti Leema Nomita Chandhiok Neeta Kumar Rohini Sehgal Suneeta Mittal Sumitu Sahdev Kandpal Shobha V. L. Jindal 《Indian journal of clinical biochemistry : IJCB》2012,27(4):405-409
Malondialdehyde (MDA) is widely used as oxidative stress biomarker in biomedical research. Plasma is stored in deep freezers generally till analysis. Effect of such storage on MDA values, which may be variable and prolong, was incidentally observed in the ongoing study which is to estimate oxidative stress with oral iron. Plasma from blood samples of pregnant women (20–30 years age) in third trimester of singleton pregnancy (n = 139), consuming oral iron tablets was stored at −20 °C with intention of MDA estimation, as soon as possible. However logistic problems led this storage for prolonged and variable period (1–708 days). When values of MDA estimated using “Ohkawa” 79 method and readings were plotted against time to check the temporal effect, it showed a hyperbolic curve. Standard deviation (SD) was lowest when samples were tested within 3 weeks time. The samples analyzed within 3 weeks had mean ± SD value of 31.59 ± 26.11 μmol/L, while 123.7 ± 93.97 and 366.5 ± 189.8 μmol/L for samples stored for 1–3 and 4 months to 1 year respectively. Mean ± SD were 539.9 ± 196.8 in the samples store for more than a year. Rate of change in values was also lowest (0.0433 μmol/L/day) in the samples tested within first 3 weeks, which rose to 1.2 μmol/L/day during 3 month’s storage. This rate peaked at storage of 120 days (1.87 μmol/L/day) and fell to 0.502 μmol/L/day in the second year of storage. It is concluded that at −20 °C, only 3 weeks of storage time should be considered valid for fairly acceptable stability in MDA values. 相似文献
125.
Sanjana Bhagat Pradeep Kumar Patra Amar Singh Thakur 《Indian journal of clinical biochemistry : IJCB》2012,27(4):394-399
This study was undertaken to determine the association of inflammatory biomarker, oxidative stress and antioxidant capacity marker with fetal haemoglobin (HbF) level among sickle cell trait and sickle cell disease (SCD) patients in Chattisgarh. The study group consisted of 51 SCD (SS) patients with painful episode, 49 SCD (SS) patients with steady state, 50 sickle cell trait (AS) and 50 controls. Malondialdehyde (MDA), CRP, total antioxidant power (FARP), total thiol and HbF levels were quantified. We found a significant positive (p < 0.0001) association between CRP and MDA levels and its inverse association with HbF level in SS patients. We also observed that antioxidant capacity had significantly positively (p < 0.0001) associated with HbF level. The protective effect of HbF was found, because the increase in HbF levels resulted in decrease in lipid peroxidation and inflammation in SCD patients. A decrease in the HbF level and its antioxidant capacity has been associated with the pathogenesis of SCD. These finding may explain the high level of HbF is ameliorating oxidative stress and inflammation in SCD patients. 相似文献
126.
Ghizal Fatima Abbas Ali Mahdi Siddharth Kumar Das Baby Anjum Nar Singh Verma Puneet Kumar Ragini Shrivastava 《Indian journal of clinical biochemistry : IJCB》2012,27(4):340-343
The present study was designed to test the hypothesis of a circadian variation in circulating levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in women with fibromyalgia syndrome (FMS). Serum levels of IL-6 and TNF-α were measured at 4 h intervals of the day in 50 women with FMS satisfying American College of Rheumatology criteria for FMS (age 36.68 ± 9.89) as well as 50 healthy control women (age 32.82 ± 10.53). Serum TNF-α levels were substantially increased in patients with FMS but showed no circadian variation. In contrast, no difference in the levels of IL-6 was found. Moreover, there was also no circadian variation in both the groups of patients and controls. We conclude that no circadian pattern exists in the circulating levels of serum IL-6 and TNF-α in patients with FMS, although TNF-α levels are found raised in patients with FMS. 相似文献
127.
Members of 82 student groups involved in a Team Learning instructional format were surveyed with the Group Style Instrument (GSI) to examine the possible dimensions of team oriented behaviors and individualistically oriented behaviors. Exploratory factor models and confirmatory factor models were compared to find the best factor structure fit. The GSI was found to have dimensions that were team and individualistically oriented. From a second sample data was collected across four months on the group process and group performance of culturally non-diverse and culturally diverse groups. Data were evaluated in two significant ways. First, the team orientation and individual orientation dimensions were used to define interpersonal processing. Second, the team process dimensions were used to define interpersonal processing. Second, the team process dimensions were examined further to evaluate their relation to group performance. Early on the diverse teams showed less team orientation and more individual orientation than non-diverse teams, but through frequent feedback on task and interpersonal processing, the diverse teams caught up by the third time period. By the end, diverse teams maintained high team orientation but also allowed a reasonable extent of individual orientation. The diverse teams were beginning to utilize diversity to their advantage. Team and Individualistic orientations showed significant relations to team performance across time. Suggestions are given for future research. 相似文献
128.
Tracey Kumar 《Multicultural Perspectives》2018,20(2):111-116
Given changes in the U.S. school-age population, it is crucial that colleges of education prepare teacher candidates to work effectively with students from diverse backgrounds. Because diversity constitutes such a small portion of the curriculum in many teacher education programs, it is crucial that teacher educators find creative ways to incorporate diversity into the courses they teach. In this article a teacher educator at a predominantly White institution in the American Southeast describes how she introduces culturally relevant pedagogy and connects it to the content, activities, and assessments included in the remainder of a course. 相似文献
129.
An evaluation of an interactive media-based science education project is reported. One of the unique features of the evaluation is the application of a general program evaluation which stresses the assessment of contextual/environmental factors. The rationale is that without adequate facilitation and support from the context, large scale projects would have limited impact on education reform. The model was applied to a major, National Science Foundation funded, science teacher education project at Vanderbilt University. The findings revealed that a number of factors must come together for project success. They are: an environment conducive to innovation and development; strong administrative interest and commitment to further the cause of the project; faculty interest and commitment to be actively involved in the project and to integrate project ideas into their own practices. In addition, strong technical support is vital for research and developments efforts in technology-based science education projects. 相似文献
130.
Satish Kumar 《Resonance》1999,4(2):37-47
In this part of the article we have identified fuzzy uncertainty as being distinct from probabilistic uncertainty. We have
understood the notion of a fuzzy set, and seen important operations that can be performed on such sets. Lastly, a geometrical
interpretation of the fuzzy set and its attendant operations were discussed. In Part 2, we will develop a framework for reasoning
based on fuzzy sets, and review a simple application. 相似文献