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   81549篇
  免费   5363篇
  国内免费   2202篇
耳鼻咽喉   475篇
儿科学   1194篇
妇产科学   2414篇
基础医学   8838篇
口腔科学   1333篇
临床医学   7823篇
内科学   7841篇
皮肤病学   529篇
神经病学   9164篇
特种医学   2230篇
外国民族医学   2篇
外科学   5526篇
综合类   11753篇
现状与发展   10篇
一般理论   1篇
预防医学   11085篇
眼科学   830篇
药学   12636篇
  117篇
中国医学   2812篇
肿瘤学   2501篇
  2024年   254篇
  2023年   1322篇
  2022年   2356篇
  2021年   3226篇
  2020年   2963篇
  2019年   2437篇
  2018年   2531篇
  2017年   2516篇
  2016年   2740篇
  2015年   2726篇
  2014年   5131篇
  2013年   7023篇
  2012年   4804篇
  2011年   5336篇
  2010年   4049篇
  2009年   4124篇
  2008年   4162篇
  2007年   3865篇
  2006年   3466篇
  2005年   2936篇
  2004年   2517篇
  2003年   2150篇
  2002年   1687篇
  2001年   1451篇
  2000年   1245篇
  1999年   1047篇
  1998年   1026篇
  1997年   985篇
  1996年   833篇
  1995年   790篇
  1994年   748篇
  1993年   665篇
  1992年   630篇
  1991年   576篇
  1990年   496篇
  1989年   436篇
  1988年   430篇
  1987年   402篇
  1986年   380篇
  1985年   502篇
  1984年   420篇
  1983年   269篇
  1982年   279篇
  1981年   251篇
  1980年   235篇
  1979年   152篇
  1978年   139篇
  1977年   123篇
  1976年   88篇
  1974年   49篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
目的观察Agilent 2100 Bioanalyzer 芯片分析系统(以下简称Bioanalyzer)在基因差异表达研究中的应用。方法应用限制性显示技术分别从正常和热休克处理后的酿酒酵母细胞中分离出cDNA片段,然后再用Bioanalyzer和传统的琼脂糖凝胶电泳技术对RD-PCR产物进行检测分析。结果Bioanalyzer能更快速、敏感地分离和显示差异表达的基因片段,并且通过对差异片段进行定量比较,发现了数个表达有明显差异的基因片段。结论Bioanalyzer在基因差异表达研究中具有重要的应用价值。  相似文献   
73.
BACKGROUND AND OBJECTIVES: Evaluation of long-term results using a thermal balloon endometrial ablation technique to treat menorrhagia and hypermenorrhea, considered dysfunctional uterine bleedings. METHODS: A single-arm, prospective study with long-term follow-up of 48 months at the department of obstetrics and gynecology, University of Kiel, Germany. Following hysteroscopic evaluation of the uterine cavity and fractionated curettage, the Cavaterm endometrial thermal ablation technique was performed on 70 patients over the age of 40 with menorrhagia and hypermenorrhea in whom medical treatment had previously failed. The study included a group of 10 patients with adenomyosis and uterine fibroids. RESULTS: In 65 patients, a complete 48-month follow-up evaluation was possible: 58% of patients reported amenorrhea and 33% hypomenorrhea. Nine percent of patients remained eumenorrheic. Fifty percent of the small group with failed indications for the procedure had to undergo a hysterectomy. CONCLUSIONS: The Cavaterm thermal coagulation system in the earlier mode of application (15 minutes at a temperature of 70 degrees C and a pressure of 200 mm Hg) is a safe and highly effective method of endometrial ablation resulting in a minimal amount of posttreatment menstrual bleeding.  相似文献   
74.
目的 :研究老年人不同疾病时骨密度 (BMD)的分布情况。方法 :用DXADAS 6 0 0EX型骨密度仪对183例老年患者进行左侧远程桡骨加尺骨BMD检测。结果 :内分泌疾病组、消化道疾病组和其它疾病组的患病率分别为 72 7% ,2 0 6 %和 31 4 %。T值比较 :三组差异明显 (P <0 0 0 1)。累积骨丢失率 (ABLR)比较 :前一组明显高于后两组病人 (P <0 0 1)。BMD比较中 ,内分泌和其它疾病组明显低于消化道疾病组 (P <0 0 0 1)。相关分析显示 ,内分泌和消化道疾病组的年龄变化与BMD呈正相关 (r =0 5 19P <0 0 0 1和r =0 5 89P <0 0 0 1) ,内分泌疾病组和其它疾病组的体重变化与BMD呈正相关 (r=0 918P <0 0 0 1和r =0 338P <0 0 0 1)。结论 :老年人骨质疏松 (OP)患病率以内分泌疾病组最高 ,消化道疾病组较低 ;随年龄和体重增加 ,BMD降低加重。  相似文献   
75.
76.
Permissive herpes simplex virus (HSV) infection in tissue culture results in host cell destruction. Latent HSV infection in vivo occurs in neurons of peripheral sensory ganglia (PSG) and it therefore can not take place in neurons in which the virus has completed a lytic replication cycle similar to that present in vitro. Our hypothesis, based on experimental data and observations in humans, suggests that establishment of latent infection and reactivation of HSV-1 does not involve neuronal cell loss. Latency is established in neurons in which the virus does not replicate and is determined, in part, by the tissue levels of a herpes transactivating protein (Vmw65) that is a component of the viral tegument. We also suggest that reactivation of latent infection does not involve destruction of neurons and is due to replication of virus at the peripheral mucocutaneous tissues to where virus or viral DNA have been transported from the nervous tissue. Alternatively, reactivation is initiated in the PSG using a replication cycle which does not involve irreversible damage to neurons. This model explains the lack of damage to neurons which continue to serve as permanent reservoirs of latent virus for the entire life of the host.  相似文献   
77.
以病人选择医生为契机 全力推进人事分配制度改革   总被引:1,自引:0,他引:1  
介绍了邯郸市中心医院在病人选医生中,努力完善制度,提高素质,深化内容,并以此为突破口,建立了灵活、高效的人事分配制度.用较为低廉的医疗费用,为人民群众提供了较好的医疗服务.  相似文献   
78.
The effect of interleukin-1 on iron metabolism in rats was evaluated. Plasma iron decreased from 184 +/- 16 micrograms/dl (mean +/- SE) to 24 +/- 12 at 6 hours after interleukin-1 intramuscular administration in non-fasting rats and 109 +/- 6 micrograms/dl to 12 +/- 1 micrograms/dl in fasting rats, which was significantly lower than in control rats. Ferrokinetic studies showed a more rapid disappearance rate and lower iron turnover in interleukin-1-injected rats. The release of iron from the mononuclear phagocyte system to plasma was studied at 3 h after interleukin-1 administration. Although the percent of radioactivity in plasma of the total injected dose was 3.2 +/- 0.6% in interleukin-1, which was significantly lower than in the control rats (5.4 +/- 0.6%) at 9 h after intravenous injection of 59Fe chondroitin ferrous sulfate, there was no difference between the amount of 59Fe released from the mononuclear phagocyte system over the first 9 h in interleukin-1 and control rats. These data appear to imply that iron release is unimpaired but that, for some reason, there is an enhanced rate of clearance of the 59Fe once it has been released from the mononuclear phagocyte system into the plasma.  相似文献   
79.
It has been demonstrated that total parenteral nutrition (TPN) modulates the function of the hepatic reticuloendothelial system (RES). The objective of this study was to evaluate the impact of two different TPN lipid emulsions on the recovery of allograft RES function after orthotopic liver transplantation (OLTx). In a prospective, double-blind study, OLTx patients were randomly assigned to two treatment groups. Group I ( n=13) received a TPN regimen that included long-chain triglycerides (LCT). Group II ( n=9) received a TPN regimen that included a fat emulsion consisting of both medium-chain triglycerides (MCT) and LCT. At baseline, i.e., on days 2 or 3 after OLTx ( t1), before lipids for TPN were started, hepatic RES function was determined using the human serum albumin millimicrosphere technique (K-value, 1/min). A second measurement ( t2) was obtained after 7 days of TPN, including one of the study's two fat emulsions. The mean (+/- SD) K-value (1/min) was 0.48+/-0.16 in the LCT group and 0.55+/-0.28 in the MCT/LCT group at t1, and it improved to 0.62+/-0.21 in the LCT group and to 0.86+/-0.32 in the MCT/LCT group at t2. RES function recovery was significantly better in the MCT/LCT group ( P< or = 0.05). MCT/LCT emulsion appears to be the TPN fat emulsion of choice after OLTx as it seems to have less impact on hepatic RES recovery.  相似文献   
80.
植物抗体及其应用   总被引:1,自引:1,他引:0  
20世纪80年代末科学家将抗体基因转入烟草表达,标志着植物抗体的诞生.人类既可以以植物为生物反应器异源表达和生产具有药用及商业价值的蛋白质;也可用抗体在植物体中进行免疫调节,以研究植物生理代谢机制,或增加植物抵抗病虫害的能力.本文旨对植物抗体的优越性、表达生产及其在医药学、植物抗病及代谢等领域的进展进行综述和讨论.  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