全文获取类型
收费全文 | 717939篇 |
免费 | 66178篇 |
国内免费 | 49524篇 |
专业分类
耳鼻咽喉 | 5787篇 |
儿科学 | 8505篇 |
妇产科学 | 8003篇 |
基础医学 | 77677篇 |
口腔科学 | 12281篇 |
临床医学 | 100624篇 |
内科学 | 94366篇 |
皮肤病学 | 7514篇 |
神经病学 | 33993篇 |
特种医学 | 26252篇 |
外国民族医学 | 376篇 |
外科学 | 64535篇 |
综合类 | 137459篇 |
现状与发展 | 176篇 |
一般理论 | 75篇 |
预防医学 | 53913篇 |
眼科学 | 19951篇 |
药学 | 78828篇 |
877篇 | |
中国医学 | 48710篇 |
肿瘤学 | 53739篇 |
出版年
2024年 | 2519篇 |
2023年 | 10209篇 |
2022年 | 26707篇 |
2021年 | 33882篇 |
2020年 | 26580篇 |
2019年 | 21377篇 |
2018年 | 22576篇 |
2017年 | 22268篇 |
2016年 | 20152篇 |
2015年 | 31442篇 |
2014年 | 38973篇 |
2013年 | 36479篇 |
2012年 | 54056篇 |
2011年 | 60496篇 |
2010年 | 41789篇 |
2009年 | 34093篇 |
2008年 | 41320篇 |
2007年 | 41305篇 |
2006年 | 39701篇 |
2005年 | 37876篇 |
2004年 | 24714篇 |
2003年 | 23354篇 |
2002年 | 19544篇 |
2001年 | 16569篇 |
2000年 | 16333篇 |
1999年 | 16485篇 |
1998年 | 10395篇 |
1997年 | 10220篇 |
1996年 | 7927篇 |
1995年 | 7452篇 |
1994年 | 6265篇 |
1993年 | 4132篇 |
1992年 | 4845篇 |
1991年 | 4151篇 |
1990年 | 3529篇 |
1989年 | 2977篇 |
1988年 | 2524篇 |
1987年 | 2239篇 |
1986年 | 1771篇 |
1985年 | 1329篇 |
1984年 | 780篇 |
1983年 | 519篇 |
1982年 | 285篇 |
1981年 | 310篇 |
1980年 | 208篇 |
1979年 | 251篇 |
1978年 | 86篇 |
1977年 | 64篇 |
1974年 | 54篇 |
1973年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Evaluation of adhesive strength of five dental adhesive cements and two visible light-activated composite resins 总被引:2,自引:0,他引:2
C X Zhang 《中华口腔医学杂志》1987,22(5):298-300
32.
33.
Comparison of PET, MRI, and CT with pathology in a proven case of Alzheimer's disease 总被引:1,自引:0,他引:1
Positron emission tomography (PET) with fluorodeoxyglucose (FDG), magnetic resonance imaging (MRI), and CT were carried out in a patient with Alzheimer's disease 16 months before he died. At autopsy, the gross appearance of the brain correlated with MRI and CT, which showed some regional atrophy. These were much less revealing than PET, which correlated with microscopic findings of neuronal loss and proliferation of glia. In areas of moderately impaired local cerebral metabolic rate of glucose, as revealed by reduced FDG uptake, there was some gliosis, primarily around the numerous senile plaques. In areas of severe metabolic impairment, there was a profound loss of neurons, extensive gliosis, and a diminished appearance of plaques. PET-FDG is a better measure of the severity of Alzheimer's disease than MRI or CT, because it reflects the degree of neuronal pathology. 相似文献
34.
郝建新 《北京中医药大学学报(中医临床版)》2002,9(1):34-37
上世纪末曾有人提出我国的中药产业将成为本世纪的“朝阳产业”,口号甚是鼓舞人心。但结合我国中药产业的现状分析,却不容乐观。想在本世纪的头几年达到蓬勃兴盛的状态可能还有很大差距。问题在哪里,笔者以为,除了中药生产企业本身存在诸多问题外,关键还在于针对中药学本身的现代研究没有取得明显的突破性进展。以致我国有关中药研发的政策、法 相似文献
35.
Serum aminogram changes were prospectively studied in 95 patients with enteric fistula and intraabdominal infection who was under total parenteral nutrition (TPN) therapy with Anfuming 14s. In patients with sepsis and starvation, the aminogram showed remarkably low total free amino acids before TPN therapy. In 81 survivors, free amino acids increased gradually to normal in 2 weeks after use of TPN and in 14 dead cases increased rapidly to a significantly higher peak at terminal stage. Both in survivors and nonsurvivors, phenylalanine level remained high during the study. In response to infection, proline was also elevated but to a lesser degree; the ratio of branched chain amino acid (BCAA) to aromatic amino acid (AAA) was lower than normal and the decrease of arginine was parallel to the severity of infection. We conclude that the ideal amino acids preparation for the starvated and septic patients should be high in BCAA and arginine but low in phenylalanine, administration of inappropriate exogenous amino acids in decompensated metabolic septic patients may bring about more harm than benefit, and in septic patients that the levels of serum phenylalanine and proline are elevated persistently along with the decrease of arginine level is a useful prognostic indication. 相似文献
36.
37.
护理工作中院内感染相关问题与对策 总被引:5,自引:2,他引:3
目的 :提出护理工作与院内感染相关问题与对策。方法 :通过监测 ,找出护理工作引起院内感染存在的问题及薄弱环节 ,并制定相应对策。结果 :建立严格的控制感染的管理制度 ,层层落实把关 ,主动和独立地判断出行之有效的预防措施。结论 :在感染管理工作中严格认真执行消毒、灭菌、无菌操作 ,最大限度地避免因护理工作失误而引起的医院内感染 相似文献
38.
The neuroprotective effects of dizocilipine maleate (MK-801), a noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptor/channel, were tested in the 4-vessel occlusion rat model of forebrain ischemia. Adult Wistar rats, treated intraperitoneally with MK-801 or saline using several different treatment paradigms were subjected to 5 (n = 208) or 15 (n = 62) min of severe, transient forebrain ischemia. In saline-treated animals, 15 min of ischemia (n = 13) produced extensive and consistent loss of pyramidal neurons in the CA1 zone of hippocampus. The degree and distribution of cell loss were not reduced by single dose preischemic administration of MK-801 at 1 (n = 7), 2.5 (n = 4), or 5 mg/kg (n = 8). In other animals subjected to 15 min of forebrain ischemia, multiple doses of MK-801 (5, 2.5, and 2.5 mg/kg) given immediately and at approximately 8 and 20 hr after cerebral reperfusion (n = 5) did not alter CA1 injury compared to saline-treated controls (n = 5). Five minutes of forebrain ischemia in saline-treated animals, (n = 82) resulted in significantly fewer (p less than 0.001) dead CA1 pyramidal cells and a greater variance compared to animals subjected to 15 min of ischemia. Power analysis of the preliminary saline-treated animals subjected to 5 min of ischemia (n = 22) indicated that 60 animals per group were necessary to detect a 15% difference between MK-801 and vehicle-treated groups. Multidose treatment with MK-801 (1 mg/kg) given 1 hr prior to 5 min of ischemia (n = 60) and again at approximately 8 and 16 hr after recirculation failed to attenuate hippocampal injury.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
39.
Xiaoguang Chen Yi Li Lei Wang Mark Katakowski Lijie Zhang Jieli Chen Yongxian Xu Subhash C. Gautam Michael Chopp 《Neuropathology》2002,22(4):275-279
Intravenous administration of human bone marrow stromal cells (hMSCs) after middle cerebral artery occlusion (MCAo) in rats provides functional benefit. We tested the hypothesis that these functional benefits are derived in part from hMSC production of growth and trophic factors. Quantitative sandwich enzyme‐linked immunosorbent assay (ELISA) of hMSCs cultured with normal and MCAo brain extracts were performed. hMSCs cultured in supernatant derived from ischemic brain extracts increased production of brain‐derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). These neurotrophins and angiogenic growth factors increased in a post‐ischemia time‐dependent manner. The hMSC capacity to increase expression of growth and trophic factors may be the key to the benefit provided by transplanted hMSCs in the ischemic brain. 相似文献
40.
We used the perfused hemicorpus preparation to measure individual rates of protein synthesis and degradation. Using fed animals, perfused either with or without insulin, muscle protein synthesis and hemicorpus protein degradation rates were similar, but myofibrillar protein degradation was clearly increased in the uremic preparations. When the animals were fasted, differences in the rates of skeletal muscle protein turnover were apparent. Uremic rats lost more wt at both 24 and 48 hr of fasting when compared to either ad libitum fed or pair-fed controls who started fasting at body wts equivalent to our uremic rats. The accelerated wt loss was accompanied by lower rates of protein synthesis, higher degradation rates, and greater net protein catabolism in our uremic rats. Alterations in body lipid content were present in uremia and correlated with the rate of protein degradation in both control and uremic rats. These data demonstrated that even in the fed state, uremia is associated with subtle alterations in skeletal muscle protein turnover. When stressed, these alterations become more pronounced. Insufficient stores of body lipids, either due to inadequate nutrition or altered metabolism, may contribute to the alterations in muscle protein turnover seen in chronic renal insufficiency. 相似文献