全文获取类型
收费全文 | 12793篇 |
免费 | 25篇 |
国内免费 | 27篇 |
专业分类
教育 | 9713篇 |
科学研究 | 1434篇 |
各国文化 | 9篇 |
体育 | 435篇 |
综合类 | 69篇 |
文化理论 | 392篇 |
信息传播 | 793篇 |
出版年
2023年 | 5篇 |
2022年 | 33篇 |
2021年 | 41篇 |
2020年 | 51篇 |
2019年 | 37篇 |
2018年 | 2206篇 |
2017年 | 2122篇 |
2016年 | 1588篇 |
2015年 | 166篇 |
2014年 | 194篇 |
2013年 | 227篇 |
2012年 | 292篇 |
2011年 | 786篇 |
2010年 | 920篇 |
2009年 | 507篇 |
2008年 | 708篇 |
2007年 | 1215篇 |
2006年 | 123篇 |
2005年 | 429篇 |
2004年 | 485篇 |
2003年 | 389篇 |
2002年 | 159篇 |
2001年 | 21篇 |
2000年 | 34篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1997年 | 22篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1992年 | 3篇 |
1991年 | 8篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1984年 | 2篇 |
1981年 | 2篇 |
1973年 | 2篇 |
1920年 | 1篇 |
1889年 | 1篇 |
1885年 | 3篇 |
1882年 | 6篇 |
1880年 | 5篇 |
1877年 | 1篇 |
1872年 | 1篇 |
1871年 | 1篇 |
1867年 | 2篇 |
1860年 | 1篇 |
1852年 | 1篇 |
1843年 | 1篇 |
1838年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Bharti Jain J. Kumarasamy Chandrakala Gholve Savita Kulkarni M. G. R. Rajan 《Indian journal of clinical biochemistry : IJCB》2017,32(2):193-199
Serum thyroglobulin (Tg) and thyroid stimulating hormone (TSH) measurements have evolved as important analytes for monitoring the prognosis of patients with differentiated thyroid cancer, post-thyroidectomy. Individual analyte immunoassay is the current practice in clinical pathology, but the simultaneous assay for all relevant analytes for a given disease, can reduce assay costs, improve patient compliance and give the clinician more information for an unequivocal diagnosis. Microarray immunoassay (MI) can achieve this goal and, hence, we have developed and validated a immuno-radiometric MI for quantitation of serum TSH and Tg by using highly micro-porous polycarbonate (PC) track-etched membranes (TEM) to immobilize the monoclonal anti-TSH and polyclonal anti-Tg antibodies in ~1 mm diameter spots. Non-competitive immunoassays were performed using mixture of 125I labeled monoclonal anti-TSH and anti-Tg antibodies. Phosphorimager was used to quantify the bound radioactivity. TSH and Tg were detected with detection limit of 0.07 µIU/ml and 0.13 ng/ml respectively, which is lower than the clinically required cut-off level. The assay showed: acceptable intra-assay precision within 20 % and recovery in the range of 76–111.2 %. MI compared well with the established immunoradiometric assay (IRMA) with r = 0.98, p < 0.01 (n = 41). No cross-reactivity was seen between the immobilized antibodies. Although two hormones are addressed in this report, MI using PC TEM and isotopic/non-isotopic tracers has the potential for highly automated multiplexed analysis. 相似文献
85.
86.
87.
文化是人类在社会实践过程中所获得和创造的物质财富和精神财富的总和。文化既是一种社会现象,又是一种历史现象,是一个民族赖以生存和发展的主要动力。近年来,我国文化事业发展繁荣兴盛,文化软实力不断增强。但随着社会开放度和包容度的提高,受文化商业化的影响,出现了娱乐至上的理念。文化泛娱乐化冲击着大学生的理想信念,弱化了大学生的政治取向,使大学生对历史产生误解,产生了消极的思想和行为,误导了大学生的价值取向。我们必须高度警惕文化过度娱乐化,保护好我们的精神家园,守护好大学生的理想信念。高校必须坚守住思想阵地,强化思想政治教育功能,积极应对文化泛娱乐化产生的问题,这是当前思想政治教育需要高度关注的事。 相似文献
88.
The earliest ovules in the Late Devonian (Famennian) are surrounded by a cupule that is involved in both protection and pollination, and generally have free integumentary lobes. Here we report a new taxon from the Famennian of China, Guazia dongzhiensis gen. et sp. nov. The terminally borne ovule is apparently acupulate (without cupule) and has four radially arranged wing-like integumentary lobes that are extensively fused, and folded lengthwise and inwards. Guazia provides evidence that not all Devonian seeds possess a cupule and it increases their diversity in integumentary lobes. This genus also suggests that the integuments develop new functions, probably including wind dispersal at the expense of the cupules. 相似文献
89.
90.
Bhupendra Pal Singh Shailendra Dwivedi Urmila Dhakad Ramesh Chandra Murthy Vimal Kumar Choubey Apul Goel Satya Narayan Sankhwar 《Indian journal of clinical biochemistry : IJCB》2016,31(1):50-56
Deficiency or excess of certain trace elements has been considered as risk factor for prostate cancer. This study was aimed to detect differential changes and mutual correlations of selected trace elements in prostate cancer tissue versus benign prostatic hyperplasia tissue. Zinc, copper, iron, calcium and selenium were analysed in histologically proven 15 prostate cancer tissues and 15 benign prostatic hyperplasia tissues using atomic absorption spectrophotometer. Unpaired two tailed t test/Mann–Whitney U test and Pearson correlation coefficient were used to compare the level of trace elements, elemental ratios and their interrelations. As compared to benign prostatic tissue, malignant prostatic tissue had significantly lower selenium (p = 0.038) and zinc (p = 0.043) concentrations, a lower zinc/iron ratio (p = 0.04) and positive correlation of selenium with zinc (r = 0.71, p = 0.02) and iron (r = 0.76, p = 0.009). Considerably divergent interrelationship of elements and elemental ratios in prostate cancer versus benign prostatic hyperplasia was noted. Understanding of differential elemental changes and their interdependence may be useful in defining the complex metabolic alterations in prostate carcinogenesis with potential for development of element based newer diagnostic, preventive and therapeutic strategies. Further studies may be needed to elucidate this complex relationship between trace elements and prostate carcinogenesis. 相似文献