全文获取类型
收费全文 | 153547篇 |
免费 | 45402篇 |
国内免费 | 1956篇 |
专业分类
耳鼻咽喉 | 2436篇 |
儿科学 | 5847篇 |
妇产科学 | 3145篇 |
基础医学 | 25191篇 |
口腔科学 | 6199篇 |
临床医学 | 19928篇 |
内科学 | 36812篇 |
皮肤病学 | 8762篇 |
神经病学 | 17915篇 |
特种医学 | 5197篇 |
外国民族医学 | 7篇 |
外科学 | 23721篇 |
综合类 | 4656篇 |
现状与发展 | 7篇 |
一般理论 | 55篇 |
预防医学 | 10327篇 |
眼科学 | 3045篇 |
药学 | 11500篇 |
23篇 | |
中国医学 | 2755篇 |
肿瘤学 | 13377篇 |
出版年
2023年 | 716篇 |
2022年 | 1689篇 |
2021年 | 3924篇 |
2020年 | 6415篇 |
2019年 | 12412篇 |
2018年 | 12233篇 |
2017年 | 12879篇 |
2016年 | 13586篇 |
2015年 | 14212篇 |
2014年 | 14870篇 |
2013年 | 16024篇 |
2012年 | 10028篇 |
2011年 | 9846篇 |
2010年 | 12282篇 |
2009年 | 8253篇 |
2008年 | 6431篇 |
2007年 | 5402篇 |
2006年 | 5200篇 |
2005年 | 4585篇 |
2004年 | 4246篇 |
2003年 | 4082篇 |
2002年 | 3709篇 |
2001年 | 2912篇 |
2000年 | 2551篇 |
1999年 | 1814篇 |
1998年 | 670篇 |
1997年 | 568篇 |
1996年 | 500篇 |
1995年 | 454篇 |
1994年 | 426篇 |
1993年 | 292篇 |
1992年 | 870篇 |
1991年 | 725篇 |
1990年 | 690篇 |
1989年 | 660篇 |
1988年 | 563篇 |
1987年 | 563篇 |
1986年 | 471篇 |
1985年 | 397篇 |
1984年 | 303篇 |
1983年 | 249篇 |
1982年 | 138篇 |
1981年 | 153篇 |
1980年 | 125篇 |
1979年 | 251篇 |
1978年 | 182篇 |
1977年 | 122篇 |
1976年 | 127篇 |
1975年 | 131篇 |
1974年 | 120篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
Jing‐Ping Zhang Limin Zheng Jiang‐Hai Wang Karl‐Eric Magnusson Xin Liu 《Phytotherapy research : PTR》2009,23(6):844-850
Ganoderma sinensis has been used widely in Oriental countries for the prevention and treatment of various diseases including cancer. Previous studies have shown that the lipid extract from Ganoderma exhibits direct cytotoxicity against tumor cells. Here, it is reported that the lipid extract from germinating G. sinensis spores, at lower concentrations that have no direct tumoricidal activity, induce potent antitumor immune responses in human monocytes/macrophages. Upon stimulation with the lipid extract, monocytes/macrophages exhibited markedly increased production of proinflammatory cytokines and surface expression of costimulatory molecules. Conditioned medium from stimulated cells effectively suppressed the growth of tumor cells. Apparently, the lipid extract triggered macrophage activation via a mechanism different from that associated with LPS. Moreover, it was observed that the lipid extract could partially re‐establish the antitumor activity of the immunosuppressive tumor‐associated macrophages. These results indicated that in addition to its direct tumoricidal activity, the lipid extract from G. sinensis spores could exert antitumor activity by stimulating the activation of human monocytes/macrophages. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
46.
47.
48.
G J Blauw P van Brummelen P C Chang P Vermeij P A van Zwieten 《Journal of cardiovascular pharmacology》1989,14(1):14-21
The influence of age on the regional arterial and venous effects of serotonin (5-HT) was investigated in 13 young (aged 22-31 years) and seven older (aged 50-69 years) healthy volunteers. Single-dose infusions of 5-HT (1, 10, and 80 ng/kg/min) and of the 5-HT2 receptor antagonist ritanserin (50, 150, and 500 ng/kg/min) were administered into the brachial artery. Subsequently, the relative arterial and venous effects of the highest dose of 5-HT were investigated. Forearm blood flow (FBF) and maximum venous outflow (MVO) were measured by venous occlusion plethysmography. Heart rate (HR) and intraarterial (i.a.) blood pressure were recorded semicontinuously. In both age groups, 5-HT induced an initial transient arterial dilation, followed by a persistent increase in FBF for the doses of 1 and 10 ng/kg/min and a relative small decrease in FBF for the highest dose. In both age groups, the highest dose of 5-HT induced a similar large reduction in MVO (p less than 0.05 for both). The reduction in MVO was attenuated by ritanserin (500 ng/kg/min, p less than 0.05 for both groups). In the younger subjects, this dose of ritanserin also unmasked an arterial dilator effect of the highest dose of 5-HT (p less than 0.05). The single infusions of ritanserin did not influence FBF significantly in either study group. No significant differences were observed between the age groups. These results show that in the forearm of healthy subjects arterial and venous vascular responses to 5-HT were not age-related. In the arterial vascular bed, 5-HT acted predominantly as a vasodilator; at high doses, mainly venous vasoconstriction was observed.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
49.
Henry Ho‐Lung Chan 《Clinical & experimental optometry》2005,88(6):410-414
The first‐order kernel analysis in multifocal electroretinogram (mfERG) using low contrast stimulation is suggested as a way to detect the inner retinal responses in animal studies. In this case report, this protocol is applied to human patients with glaucoma to demonstrate the possibility of using mfERG as a tool to detect glaucomatous damage. Two patients with glaucoma were recruited and had mfERG measurements with the 103‐scaled hexagonal stimulus pattern at low (50 per cent) contrast. Their responses were analysed and compared with those from normal subjects with the mfERG measured under the same condition. In the normal subjects, there were obvious oscillatory components on the ascending and descending limbs of the first‐order kernel response to 50 per cent contrast. In the glaucomatous patients, the oscillatory component on the descending limb was obviously diminished. In addition, this component was significantly diminished in the quadrant with a glaucomatous visual field defect. This suggests that the low‐contrast stimulation condition in mERG measurement may provide a good way to detect glaucomatous damage and this may help in clinical diagnosis of glaucoma. 相似文献
50.
Wan-Ling Ho Tien-Wu Yang Wei-Chu Chi Hong-Jen Chang Li-Min Huang Mei-Hwei Chang 《台湾医志》2005,104(6):398-401
BACKGROUND AND PURPOSE: This study investigated the characteristics of intussusception in Taiwanese children of different age groups, including the incidence, length of hospitalization and hospital costs. METHODS: Children with a diagnosis of intussusception who were hospitalized from 1999 through 2001 were identified from a nationwide health insurance claims database. The incidence of intussusception was calculated by age, gender, and season. Length of hospitalization and hospital costs were also analyzed. RESULTS: A total of 6988 cases of intussusception were identified in Taiwan from 1999 to 2001. Among them, 4859 cases occurred in children below 15 years of age. The average incidence among children below age 15 years was 34.5 per 100,000, with a peak incidence of 118.8 per 100,000 observed among children younger than 24 months old. The highest incidence of intussusception in Taiwanese children occurred between 12 and 24 months of age. According to the data for patients below 15 years of age hospitalized for intussusception in year 2000, males were more likely to be affected than females (61.3% vs 38.7%). Intussusception-related hospitalizations were rare in infants in the first few months of life, increased in those 6 to 12 months old, and peaked among children 1 to 3 years old. Among the 952 patients with intussusception admitted to hospitals in 2000, 297 (31.2%) received surgery, incurring higher median medical costs (New Taiwan Dollars [NT dollars] 42,265 or US dollars 1234) and longer median hospital stay (6.2 days) than the 655 patients who did not require surgery (NT dollars 6290 or US dollars 185 for hospitalization of 2.4 days). CONCLUSIONS: The study found that the incidence of intussusception peaked in the second year of life in Taiwanese children. There was also a male predominance and lack of seasonal variation in incidence. 相似文献