全文获取类型
收费全文 | 277056篇 |
免费 | 41840篇 |
国内免费 | 9017篇 |
专业分类
耳鼻咽喉 | 6258篇 |
儿科学 | 7285篇 |
妇产科学 | 5310篇 |
基础医学 | 16441篇 |
口腔科学 | 4126篇 |
临床医学 | 42281篇 |
内科学 | 66719篇 |
皮肤病学 | 8949篇 |
神经病学 | 20924篇 |
特种医学 | 10449篇 |
外国民族医学 | 40篇 |
外科学 | 53608篇 |
综合类 | 19537篇 |
现状与发展 | 88篇 |
一般理论 | 18篇 |
预防医学 | 16345篇 |
眼科学 | 6732篇 |
药学 | 14363篇 |
115篇 | |
中国医学 | 6546篇 |
肿瘤学 | 21779篇 |
出版年
2024年 | 1018篇 |
2023年 | 6363篇 |
2022年 | 5201篇 |
2021年 | 8493篇 |
2020年 | 9948篇 |
2019年 | 5787篇 |
2018年 | 11164篇 |
2017年 | 10874篇 |
2016年 | 11539篇 |
2015年 | 13480篇 |
2014年 | 21984篇 |
2013年 | 22337篇 |
2012年 | 15435篇 |
2011年 | 16211篇 |
2010年 | 17657篇 |
2009年 | 20170篇 |
2008年 | 13418篇 |
2007年 | 11610篇 |
2006年 | 13671篇 |
2005年 | 10336篇 |
2004年 | 7771篇 |
2003年 | 6321篇 |
2002年 | 5655篇 |
2001年 | 6844篇 |
2000年 | 5820篇 |
1999年 | 5827篇 |
1998年 | 4927篇 |
1997年 | 4659篇 |
1996年 | 4327篇 |
1995年 | 4131篇 |
1994年 | 2811篇 |
1993年 | 2058篇 |
1992年 | 2255篇 |
1991年 | 2198篇 |
1990年 | 1717篇 |
1989年 | 1737篇 |
1988年 | 1533篇 |
1987年 | 1296篇 |
1986年 | 1237篇 |
1985年 | 993篇 |
1984年 | 726篇 |
1983年 | 684篇 |
1982年 | 604篇 |
1981年 | 491篇 |
1980年 | 425篇 |
1979年 | 445篇 |
1978年 | 437篇 |
1977年 | 479篇 |
1975年 | 325篇 |
1972年 | 389篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
In primary visual cortex of hooded rats, pyramidal cells in layer V may be classified as long, medium, or short, on the basis of the layer in which the apical dendrite terminates. The present study determines which of these types of pyramidal cells project to the superior colliculus. Two different strategies were used to label corticotectal cells with horseradish peroxidase (HRP). In the first set of experiments, a large number of corticotectal cells were labeled by retrograde transport following injection of HRP into the superior colliculus. In the second set of experiments, single unit recording was used to identify corticotectal cells physiologically by antidromic activation from the superior colliculus. These cells were then impaled and labeled by intracellular iontophoresis of HRP. The results from both techniques suggest that only long pyramidal cells send an axon to the superior colliculus. These cells are distinguished by an apical dendrite that extends into layer I. We conclude that in hooded rats corticotectal cells in primary visual cortex are the long pyramids in layer V. 相似文献
104.
105.
106.
107.
108.
Forty samples of cord blood lymphocytes were isolated from 40 normal healthy full-term newborns. The initial 20 samples were used to determine the dose-response curve of three different thymic extracts (TP-1, bovine thymic extract; TG-15-I and TG-15-II, both porcine thymic extracts) and one of renal origin (KG-1) as a control of non-lymphoid organ extract, by measuring the E-rosette T cells. Results showed that E-rosette T cells increased significantly when the thymic extract concentration was increased to 12.5 micrograms/ml. However, there was no statistical difference between TP-1, TG-15-I and TG-15-II in the increase of E-rosette-forming cells. The remaining 20 samples were preincubated with 0, 12.5, 25 or 50 micrograms/ml of thymic extracts. It was observed that the lymphoproliferation, interleukin-2 (IL-2), gamma-interferon (IFN-gamma) and tumor necrotic factor (TNF) production were all significantly increased after thymic extract treatment. No statistical difference between these three thymic preparations in the stimulation of lymphoproliferative response was found. However, among the three thymic extracts, TP-1 appears to induce the highest amounts of IL-2, IFN-gamma and TNF. Of the TG-15-I and TG-15-II, the former stimulates higher IL-2 production whereas the latter enhances IFN-gamma and TNF production. The different immunostimulating effects and potencies that these three thymic extracts showed may reflect not only the species difference but also the difference in preparation procedures. Different components in these thymic extracts may be responsible for different biological activities. Results from these comparative studies may provide useful information in future clinical trials for the treatment of the primary immunodeficiency diseases according to their pathogenesis and may also indicate a possible beneficial effect of the combination of chemotherapy and thymic extracts. 相似文献
109.
Four Chinese patients (2 boys, 2 girls), ages 4–9 years, who had episodes of perception error of body schema and objects are reported. The metamorphopsia, which had been named Alice in Wonderland syndrome, is the major presentation. All of them were proved to have acute Epstein-Barr virus infection, as documented by positive heterophil antibody test and/or positive IgM antibody to Epstein-Barr virus capsid antigen. The duration of the perception disorder ranged from 1 week to 3 months. We believe that any young child presenting with Alice in Wonderland syndrome should undergo examination for Epstein-Barr virus infection; complete recovery from the disorder can be expected. 相似文献
110.