全文获取类型
收费全文 | 445257篇 |
免费 | 41037篇 |
国内免费 | 30916篇 |
专业分类
耳鼻咽喉 | 3263篇 |
儿科学 | 5575篇 |
妇产科学 | 4990篇 |
基础医学 | 49705篇 |
口腔科学 | 7302篇 |
临床医学 | 62324篇 |
内科学 | 60591篇 |
皮肤病学 | 4874篇 |
神经病学 | 21784篇 |
特种医学 | 16372篇 |
外国民族医学 | 256篇 |
外科学 | 40319篇 |
综合类 | 83011篇 |
现状与发展 | 105篇 |
一般理论 | 35篇 |
预防医学 | 32285篇 |
眼科学 | 12528篇 |
药学 | 48238篇 |
518篇 | |
中国医学 | 28519篇 |
肿瘤学 | 34616篇 |
出版年
2024年 | 1490篇 |
2023年 | 6567篇 |
2022年 | 16995篇 |
2021年 | 21642篇 |
2020年 | 16817篇 |
2019年 | 14039篇 |
2018年 | 14422篇 |
2017年 | 13727篇 |
2016年 | 12775篇 |
2015年 | 19717篇 |
2014年 | 24721篇 |
2013年 | 22395篇 |
2012年 | 33167篇 |
2011年 | 37381篇 |
2010年 | 24946篇 |
2009年 | 20226篇 |
2008年 | 24909篇 |
2007年 | 24772篇 |
2006年 | 23949篇 |
2005年 | 22834篇 |
2004年 | 15064篇 |
2003年 | 14634篇 |
2002年 | 12120篇 |
2001年 | 10470篇 |
2000年 | 10291篇 |
1999年 | 10536篇 |
1998年 | 6630篇 |
1997年 | 6524篇 |
1996年 | 5030篇 |
1995年 | 4681篇 |
1994年 | 3959篇 |
1993年 | 2569篇 |
1992年 | 3078篇 |
1991年 | 2701篇 |
1990年 | 2230篇 |
1989年 | 1925篇 |
1988年 | 1631篇 |
1987年 | 1473篇 |
1986年 | 1205篇 |
1985年 | 851篇 |
1984年 | 481篇 |
1983年 | 347篇 |
1982年 | 181篇 |
1981年 | 219篇 |
1980年 | 142篇 |
1979年 | 192篇 |
1978年 | 76篇 |
1977年 | 53篇 |
1974年 | 43篇 |
1972年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
To study the pathological and histochemical characteristics of lesions in piglet livers infected with Taenia saginata asiatica (T. saginata asiatica) throughout the different stages, piglets were fed with eggs of T. saginata asiatica and raised in isolation in an animal center to establish the T. saginata asiatica infection model with normal piglets as control. The pathological changes in the piglet livers were observed after the infection
using liver sections stained with hematoxylin and eosin. Histochemical methods were used to check the changes in lipid, glycogen
and protein content in the liver. The data collected by image analysis were analyzed statistically with Statistical Package
for the Social Science. The results show that T. saginata asiatica-exposed piglets were indeed infected. Inflammatory reactions began on the fourth day and progressed rapidly. Kupffer cell
hyperplasia, hepatic hydropic degeneration and ballooning degeneration were found in the 10th–20th days after infection. Hepatic
central veins and hepatic sinusoids were dilated and congested. Spotty necrosis occurred in some local liver tissues. In the
40th–60th days, granulomatous reactions and mild hepatocirrhosis were the main lesions. In the 70th–80th days, hepatocirrhosis
and bile duct proliferation were observed in the liver. In the different stages, lipid drops were increased while glycogen
and protein levels were decreased to some degree. There was a significant difference in metabolism between the infected group
and the control group (P < 0.01). It is concluded that pigs are the favorable intermediate host of T. saginata asiatica and its infection can result in serious pathological and histochemical lesions in host organs.
Translated from Journal of Guiyang Medical College, 2006, 31(4): 296–300 [译自: 贵阳医学院学报] 相似文献
43.
44.
Lei Wang Moyi Sun Yuegui Jiang Lianjia Yang Delin Lei Chao Lu Yinghua Zhao Pu Zhang Yaowu Yang Jianhu Li 《Journal of oral and maxillofacial surgery》2006,64(4):636-641
PURPOSE: Perineural invasion is a frequent occurrence in salivary adenoid cystic carcinoma (ACC) and may prevent complete surgical resection. Studies have indicated that nerve growth factor (NGF) and its high-affinity receptor tyrosine kinase A (TrkA) may play a role in perineural invasion in several malignancies in which perineural invasion is observed. The present study was conducted to investigate the expression of NGF and TrkA in salivary ACC and to examine the effects of NGF on adhesion, migration and invasion capacities of a salivary ACC cell line (SACC-83) in vitro. PATIENTS AND METHODS: Expression of NGF and TrkA was explored using immunohistochemistry in paraffin-embedded tissues of 32 cases of salivary ACC. The effects of NGF on in vitro adhesion, migration, and invasion capacities of the SACC-83 cell line were examined using an MTT assay and a modified Boyden chamber assay respectively. RESULTS: In ACC specimens, 31 (96.9%) and 32 (100%) tumors showed immunoreactivity for NGF and TrkA respectively. Significant correlations were found between NGF/TrkA expression levels and perineural invasion (P < .05). In cell adhesion assay, the percent adherences of SACC-83 cells co-cultured with 25 ng/ml NGF at 1.5 hours and 5, 25 ng/ml NGF at 6 hours were significantly higher than that co-cultured with 0 ng/ml NGF (P < .05). However, high concentration of NGF (500 ng/ml) resulted in a significant inhibition of invasion (P < .05). CONCLUSION: Overexpression of NGF and TrkA in human salivary ACC tissues may constitute a reason for perineural invasion in salivary ACC. 相似文献
45.
46.
四氧嘧啶诱发糖尿病大鼠血管紧张素的变化 总被引:1,自引:0,他引:1
实验观察了四氧嘧啶诱发糖尿病大鼠连续饲养110d后体内肾素一血管紧张素系统的变化。结果表明,血浆和心脏的血管紧张素Ⅱ含量无明显变化,而肾脏的AngⅡ含量却明显低于正常对照组。另外,心脏的心钠素(ANP)含量在糖尿病大鼠与正常对照组之间无差别,血中的糖化血红蛋白含量基本无变化。上述结果表明,糖尿病大鼠早期心脏可能无明显损伤,而肾脏的肾素一血管紧张素系统活性降低。 相似文献
47.
C L Li 《中华整形烧伤外科杂志》1990,6(4):262-4, 317
An analysis of serum free amino acid profiles in 8 patients dying from major burns revealed that free amino acid began to decrease in shock period, decrease 31.12% in infection period and 41.3% before death in comparison with the control group. The amount of BCAA-also decrease 36.27% in infection period and 56.83% before death. If the serum free amino acid in major burn drops steadily, the prognosis will be worse. 相似文献
48.
49.
TF Leung WC Tsoi CK Li KW Chik MMK Shing PMP Yuen 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(6):705-777
We describe a 15-y-old girl with Fechtner-like syndrome, who is the first Chinese reported to have this rare syndrome. She presented with left homonymous hemianopia and neuroimaging revealed haemorrhage in both parietal and occipital lobes. Peripheral blood smear showed macrothrombocytopenia and intracytoplasmic inclusion bodies inside leucocytes. Thrombocytopenia and proteinuria responded to intravenous immunoglobulin and pulsed methylprednisolone. This case illustrates that life-threatening haemorrhage can occur in patients with Fechtner syndrome. Although there was no effective treatment reported in the literature, high dose steroid and immunoglobulin seemed to be useful in our patient. Our patient also had nephritic-nephrotic syndrome with renal insufficiency, which is unusual in adolescent female patients. 相似文献
50.
本文对以重组淋球菌IgA蛋白酶为抗原制备的7株特异性McAb的特性进行了初步研究。结果有5株(1C8、1E5、1F11、1G3和2E6)能中和淋球菌IgA蛋白酶活性。经相加试验初步证明,其中1F11、2G3与其它3株McAb的作用位点不同。因此,淋球菌IgA蛋白酶至少存在3个中和表位。 相似文献