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   15795篇
  免费   724篇
  国内免费   224篇
耳鼻咽喉   225篇
儿科学   344篇
妇产科学   733篇
基础医学   1949篇
口腔科学   274篇
临床医学   1639篇
内科学   3301篇
皮肤病学   385篇
神经病学   956篇
特种医学   495篇
外科学   2347篇
综合类   428篇
现状与发展   2篇
一般理论   3篇
预防医学   773篇
眼科学   302篇
药学   1141篇
  3篇
中国医学   105篇
肿瘤学   1338篇
  2024年   78篇
  2023年   104篇
  2022年   245篇
  2021年   459篇
  2020年   253篇
  2019年   362篇
  2018年   428篇
  2017年   293篇
  2016年   299篇
  2015年   469篇
  2014年   593篇
  2013年   740篇
  2012年   1106篇
  2011年   1096篇
  2010年   716篇
  2009年   583篇
  2008年   879篇
  2007年   923篇
  2006年   812篇
  2005年   827篇
  2004年   702篇
  2003年   580篇
  2002年   542篇
  2001年   479篇
  2000年   416篇
  1999年   358篇
  1998年   139篇
  1997年   114篇
  1996年   98篇
  1995年   72篇
  1994年   70篇
  1993年   55篇
  1992年   183篇
  1991年   176篇
  1990年   151篇
  1989年   123篇
  1988年   112篇
  1987年   125篇
  1986年   100篇
  1985年   86篇
  1984年   76篇
  1983年   60篇
  1980年   38篇
  1979年   58篇
  1978年   49篇
  1977年   43篇
  1976年   39篇
  1975年   38篇
  1974年   47篇
  1972年   59篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
While balloon valvuloplasty has been widely used for the treatment of congenital valvular pulmonary stenosis (PS) in children and adults, its use in elderly patients is less common. An 80-year-old woman with congenital valvular PS received valvuloplasty with double-balloon technique. Right ventricle systolic pressure and pulmonary valve systolic pressure gradient decreased from 95 to 44 mm Hg and from 75 to 35 mm Hg, respectively. Follow-up Doppler echocardiography 2 months later showed further decrease in the transvalvular systolic pressure gradient to 29 mm Hg. The patient had symptomatic relief, and no major complication was noted. Balloon pulmonary valvuloplasty can be an effective treatment for elderly patients with congenital valvular PS.  相似文献   
3.
4.
Background. Medication adherence impacts healthcare utilization. Pharmacy records are useful to establish fill patterns. Objective. Use pharmacy records to establish medication patterns fill patterns for comparison to healthcare utilization. Methods. Pharmacy records of 175 children with persistent asthma were collected and compared to healthcare utilization. Results. Majority of subjects had significant healthcare utilization, low numbers of rescue medications, and poor controller medication fill rates. Those with more rescue medications had more healthcare utilization and more controller medications. Conclusions. Pharmacy fill patterns demonstrate few rescue and/or controller medication fills. Those with more rescue medications reported increased healthcare utilization despite controller medications.  相似文献   
5.
 To monitor the lead hazards in industries and to investigate the prevalence of elevated blood lead levels (BLLs) in lead-exposed workers, a lead surveillance system (PRESS-BLLs) has been established and operated in Taiwan, Republic of China, since July 1993. A cohort of lead-exposed workers who received a periodic annual health examination at 55 accredited hospital laboratories was constructed. A total of 9807 separate BLL measurements were reported to the system in 1994. The mean BLL was 15.8 μg/dl in male workers and 11.6 μg/dl in female workers. The mean BLL of lead-exposed workers was significantly (P<0.05, z-test) higher than that of the general Taiwanese population (8.6 μg/dl for males and 6.7 μg/dl for females). In addition, the BLLs of 983 (10.0%) workers exceeded the regulatory action level (40 μg/dl for males; 30 μg/dl for females). The workplaces and homes of 57% of the workers with elevated BLLs were thoroughly investigated to determine the sources of lead contamination. These actions identified the causes of elevated BLLs and set up strategies to reduce workers’ lead exposure. The establishment of this occupational lead surveillance system represents a method for monitoring of lead hazards from occupational and environmental settings to prevent lead poisoning. The information acquired from the system can help in the setting up of a priority of prevention and the development of control measures. It is also useful for further monitoring of changes in the BLLs of the lead-exposed-worker cohort. The Health Department of Taiwan can use this information to evaluate the effectiveness of current industrial hygiene practice. Subjects with elevated BLLs have been medically treated and placed on long-term follow-up for sequelae. Received: 2 September 1996/Accepted: 29 November 1996  相似文献   
6.
Implants of defatted, freeze-dried Saos-2 human osteosarcoma cells grown to confluency induce de novo bone formation in athymic mice. These cells are also richly endowed with bone morphogenetic proteins and express mRNA for bone morphogenetic proteins 1, 2, 3, 4, and 6, as well as for transforming growth factor-β1. Our aim was to study whether the ability to induce bone formation is related to the level of expression of bone morphogenetic protein. We studied the osteoinductive abilities and levels of expression of bone morphogenetic protein of Saos-2 cells both during the growth phase and after confluency was reached. Subconfluent cells were at least 70% less effective in their osteoinductive ability than confluent cells. Comparison of bone morphogenetic protein mRNA expression in confluent and subconfluent cells revealed that the latter had lower expression of all the mRNAs studied. The expression of bone morphogenetic protein-1, bone morphogenetic protein-2, and bone morphogenetic protein-6 mRNAs was 2, 3, and 6 to 10-fold lower, respectively, in subconfluent cells. These results suggest that the ability of Saos-2 cells to induce de novo bone formation may be correlated with the relative expression of these proteins; the expression of bone morpho-genetic proteins in Saos-2 cells also may be dependent on the cell cycle.  相似文献   
7.
Propionic acidemia is a rare hereditary disease which is an autosomal recessive disorder. Defect of propionyl CoA carboxylase results in abnormal accumulation of propionate and its metabolites which interfere the pathway of glycine cleavage and the urea cycle. This organic acidemia is characterized by a wide spectrum of clinical and biochemical findings, including recurrent vomiting, difficult feeding, lethargy, hypotonia, metabolic ketoacidosis, hyperglycinemia and hyperammonemia during the acute episodes. We present a male newborn infant who sustained this disorder and was managed successfully with blood exchange transfusion, peritoneal dialysis, supplemented with sodium benzoate and sodium bicarbonate therapy. Urine gas chromatography disclosed significant elevation of propionate and its metabolites which subsided 2 days after peritoneal dialysis. Special designed formula was then given with restriction of protein intake and supplement with sodium benzoate and sodium carbonate. Prenatal genetic counseling is necessary in further pregnancy. Diagnosis can be obtained when propionyl CoA carboxylase activity is low in cultured amniotic fluid cells or chorion villi sample or when there is abnormally high methylcitrate level in amniotic fluid.  相似文献   
8.
Back pain among nurses is a common problem. Prior studies of this problem have been based on cross-sectional or retrospective data. This 18-month prospective study involving nurses newly graduated from nursing school investigated personal, worksite, and training factors associated with future risk of back pain. Each nurse underwent a preliminary interview and periodic follow-ups to identify those with back injuries. Contingency tables and logistic regression analyses demonstrated that prior significant back pain episodes (evidenced by previous job changes because of back pain, frequent medication use, etc.) were associated with increased future risk. Training at nursing school or on the job did not have a protective effect. This pilot study therefore suggests factors useful in placement and counseling of new nurses and indicates the need for further implementation of mechanical lift assist device use. © 1994 Wiley-Liss, Inc.  相似文献   
9.
We present two case studies, one of generalized chorea and one of hemichorea, both after severe hypoglycemia episodes. Both cases showed hyperperfusion in their SPECT scans. The MRI and SPECT findings serve as clues regarding the role of basal ganglion dysfunction associated with chorea.  相似文献   
10.
A new diterpene antitumor antibiotic, myrocin C, has been isolated from the culture filtrate of a soil fungus, Myrothecium verrucaria strain No. 55. The antibiotic was effective against Gram-positive bacteria, fungi and yeasts, and prolonged the life span of mice bearing Ehrlich ascites carcinoma.  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