首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   413084篇
  免费   58502篇
  国内免费   23789篇
耳鼻咽喉   5277篇
儿科学   5837篇
妇产科学   7126篇
基础医学   41693篇
口腔科学   10384篇
临床医学   70118篇
内科学   72636篇
皮肤病学   6199篇
神经病学   29767篇
特种医学   15267篇
外国民族医学   213篇
外科学   49795篇
综合类   49909篇
现状与发展   116篇
一般理论   20篇
预防医学   32249篇
眼科学   11548篇
药学   33505篇
  334篇
中国医学   17399篇
肿瘤学   35983篇
  2024年   1657篇
  2023年   9641篇
  2022年   14007篇
  2021年   18713篇
  2020年   17010篇
  2019年   12610篇
  2018年   17899篇
  2017年   16916篇
  2016年   16878篇
  2015年   21956篇
  2014年   27721篇
  2013年   26901篇
  2012年   26071篇
  2011年   28838篇
  2010年   22341篇
  2009年   20932篇
  2008年   20107篇
  2007年   19056篇
  2006年   20259篇
  2005年   18573篇
  2004年   11875篇
  2003年   10671篇
  2002年   9279篇
  2001年   9223篇
  2000年   9352篇
  1999年   10628篇
  1998年   7458篇
  1997年   7321篇
  1996年   6243篇
  1995年   5577篇
  1994年   4273篇
  1993年   2988篇
  1992年   3549篇
  1991年   3031篇
  1990年   2611篇
  1989年   2363篇
  1988年   2052篇
  1987年   1668篇
  1986年   1431篇
  1985年   1195篇
  1984年   769篇
  1983年   664篇
  1982年   461篇
  1981年   430篇
  1980年   304篇
  1979年   281篇
  1978年   201篇
  1977年   203篇
  1976年   152篇
  1974年   172篇
排序方式: 共有10000条查询结果,搜索用时 421 毫秒
991.
作者利用交流电弧和光栅摄谱仪组装了能够绘制谱线轮廓曲线和准确测定谱线宽度的记录仪,用线宽增量法对生物材料(拟血清)中的主要成分Ca和微量元素Cu进行了测定。与黑度法相比,本实验结果的线性好,误差小,再现性有所提高。这些结果表明,用上述仪器装置和线宽增量法进行生物材料含量分析优于黑度法。  相似文献   
992.
运用人力资源管理策略 改革病房护理管理   总被引:3,自引:0,他引:3  
从发展成功管理的共同文化,创建优质服务病房;建立有效的护理人力资源管理支持系统,创建适合于专业护理的工作环境,确保护理质量;以病人为中心,以病人满意度作为衡量护理工作优劣的标准三个方面介绍了乐山市人民医院运用护理人力资源管理策略,改革病房护理管理,创建优质服务病房的实践经验及其效果。  相似文献   
993.
张力带固定与钢丝环扎治疗髌骨骨折疗效分析   总被引:11,自引:1,他引:10  
使用张力带固定、钢丝环扎与丝线环扎治疗髌骨骨折共65例,平均优良率91.52%,但优级疗效者张力带组是80%,钢丝及丝线环扎组分别是56%及56.5%。张力带内固定术后不需石膏外固定,利于膝关节早期功能锻炼与康复,疗效明显优于其它两种疗效(p<0.05),但术中操作要求准确细致。与钢丝环扎相比,丝线环扎荷包缝合具有可避免取出内固定的第二次手术的优点,两组疗效相似。  相似文献   
994.
995.
Background: Oncogenes and other molecular tumor markers that predict tumor aggressiveness may allow individualization and optimization of surgical therapy of intermediate-thickness malignant melanoma. We examined the expression of selected markers, including the HLA-DR antigen, the heat shock protein-70 (HSP-70), and the c-myc oncogene in primary melanoma and regional nodes and related these findings to metastatic potential and survival. Methods: Forty patients with primary melanoma (1.5–4.0 mm) were studied, all of whom had prophylactic lymph node dissection and were followed for 18 months to 7 years. The primary tissue and nodes were examined using immunohistochemical techniques for the presence of HLA-DR antigen and HSP-70 protein and the expression of the c-myc oncogene. Results: Of 40 patients, there were 23 with lesions 1 to 2.9 mm thick and 17 with lesions 3 to 4 mm thick. Nodal metastases were present in 25 of the 40 patients who had elective node dissection. HLA-DR antibody stained the primary tumor in 10 patients (25%), but there was no correlation with survival in this group. HLA-DR antibody stained the stroma and cellular infiltrates surrounding the primary tumor in 28 of 40 patients; in this group there was a correlation of HLA-DR staining of the peritumoral stroma with improved survival overall. HLA-DR staining of the peritumoral stroma also influenced survival when patients were stratified by tumor thickness groups 1 to 2.9 mm and 3 to 4 mm and presence of nodal metastases. HSP-70 was demonstrated in the primary tumor in 25% of patients, who were also shown to have significantly improved survival when compared with those whose primary tumor did not stain with HSP-70. C-myc was expressed in the primary tumor in 25%, but showed no correlation with survival. None of these proteins correlated with or predicted the presence of nodal metastases. Conclusion: We conclude that the use of specific molecular-oncogene markers in intermediate-thickness primary melanoma may identify patients at high risk for conventional treatment failure and reduced survival who may profit from more aggressive surgery, adjuvant therapy, or both.Presented at the 48th Annual Cancer Symposium of The Society of Surgical Oncology, Boston, Massachusetts, March 23–26, 1995.  相似文献   
996.
N-acetylcysteine as an antidote in methylmercury poisoning.   总被引:1,自引:0,他引:1       下载免费PDF全文
Methylmercury is a ubiquitous environmental pollutant and potent neurotoxin. Treatment of methylmercury poisoning relies almost exclusively on the use of chelating agents to accelerate excretion of the metal. The present study demonstrates that oral administration of N-acetylcysteine (NAC), a widely available and largely nontoxic amino acid derivative, produces a profound acceleration of urinary methylmercury excretion in mice. Mice that received NAC in the drinking water (10 mg/ml) starting at 48 hr after methylmercury administration excreted from 47 to 54% of the 203Hg in urine over the subsequent 48 hr, as compared to 4-10% excretion in control animals. When NAC-containing water was given from the time of methylmercury administration, it was even more effective at enhancing urinary methylmercury excretion and at lowering tissue mercury levels. In contrast, excretion of inorganic mercury was not affected by oral NAC administration. The ability of NAC to enhance methylmercury excretion when given orally, its relatively low toxicity, and is wide availability in the clinical setting indicate that it may be an ideal therapeutic agent for use in methylmercury poisoning.  相似文献   
997.
We describe a patient in whom long-term monoamine oxidase (MAO) inhibitor therapy was discontinued 20 days before surgery with general anesthesia. This patient developed severe perioperative hypotension after administration of 10 mg of bupivacaine through an epidural catheter, which was corrected only after potent vasopressor therapy. We attribute this hemodynamic instability to attenuation of this patient's sympathetic tone based on several mechanisms: (1) residual effect of long-term administration of MAO inhibitor that caused a decrease in the number of β-adrenergic receptors (adrenergic subsensitivity due to receptor down-regulation), (2) recovered MAO activity causing effective degradation of sympathetic amines, and (3) combined attenuating effects of general and epidural anesthesia on sympathetic tone.  相似文献   
998.
A considerable proportion of headache patients fulfill the criteria of "drug abuse" (definition according to the International Headache Society [IHS] criteria). These patients exhibit markedly reduced vigilance and continuous performance, as shown by the results of critical flicker frequency (CFF) analysis.
The present study deals with the question whether this impairment of vigilance and continuous performance is reversible. Forty-eight headache patients with drug abuse were investigated three times by means of CFF analysis: immediately before (A), immediately after (B), and 3 weeks after having finished (C) inpatient drug withdrawal.
Immediately after withdrawal, a significant decrease of headache intensity was observed. The CFF values, however, remained unchanged at a depressed level, probably due to withdrawal medication and the initial sedative side effects of thymoleptic agents (given as prophylaxis).
Three weeks after withdrawal, however, the CFF values were significantly improved, and were now within a range not far from the normal values known from a healthy general population. Thus, even after many years of drug abuse, headache patients have a good chance to improve their vigilance and continuous performance and to reach normal or close to normal levels.  相似文献   
999.
1000.
EDITORIAL COMMENT": The editorial committee found this case report irresistible as an example of triumph over misfortune and disability. Iatrogenic, accidental, prolonged and complete amnioreduction is unique in the editor's clinical experience and knowledge of the literature. Importantly the case also illustrates that conservative management of 'premature rupture of the membranes'can be successful. The favourable outcome may have been related to the abdominal rather than the usual cervical route of amnioreduction, and the restoration of normal liquor volume after the amnioreduction was discontinued. Moreover, in spontaneous rupture of the membranes the cause of the problem is likely to be persistent.
Summary: A successful outcome for an infant following complete iatrogenic amnioreduction at 20 weeks gestation is possible without any invasive medical treatment.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号