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   2182300篇
  免费   168707篇
  国内免费   5191篇
耳鼻咽喉   28936篇
儿科学   73603篇
妇产科学   62142篇
基础医学   313340篇
口腔科学   60097篇
临床医学   197629篇
内科学   428372篇
皮肤病学   50498篇
神经病学   177658篇
特种医学   83156篇
外国民族医学   753篇
外科学   325010篇
综合类   51788篇
现状与发展   3篇
一般理论   831篇
预防医学   172845篇
眼科学   49951篇
药学   155195篇
  4篇
中国医学   4863篇
肿瘤学   119524篇
  2019年   17125篇
  2018年   24322篇
  2017年   18686篇
  2016年   21206篇
  2015年   23768篇
  2014年   33305篇
  2013年   50227篇
  2012年   67314篇
  2011年   71523篇
  2010年   42302篇
  2009年   40205篇
  2008年   66440篇
  2007年   70342篇
  2006年   71286篇
  2005年   68845篇
  2004年   66326篇
  2003年   63395篇
  2002年   61255篇
  2001年   105689篇
  2000年   108308篇
  1999年   90245篇
  1998年   25534篇
  1997年   23048篇
  1996年   23087篇
  1995年   22069篇
  1994年   20237篇
  1993年   18943篇
  1992年   69522篇
  1991年   67028篇
  1990年   64991篇
  1989年   62253篇
  1988年   56816篇
  1987年   56333篇
  1986年   52622篇
  1985年   50412篇
  1984年   38215篇
  1983年   32231篇
  1982年   19583篇
  1981年   17482篇
  1979年   34427篇
  1978年   24517篇
  1977年   20517篇
  1976年   19367篇
  1975年   20101篇
  1974年   24368篇
  1973年   23461篇
  1972年   21760篇
  1971年   20032篇
  1970年   18921篇
  1969年   17515篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Summary The authors report 165 cases of thoraco-lumbar lesions with neurological dysfunction. All the patient were operated. They analyze the neurological and mechanical results and indicate the use of different osteosynthesis apparatus according to the type and level of lesions.Harrington's rods seem to give more precise repositioning while Roy Camille's plates give more stability. When the posterior wall of the spinal canal is intact, Kempf's compression rods can be used.Thoraxic spine injuries seem to be an indication for Harrington's rods, while lumbar injuries seem to call for Camille's plates.  相似文献   
992.
993.
Amplification of the graft-versus-host reaction by partial body irradiation   总被引:1,自引:0,他引:1  
An experimental model has been developed for the study of combined effects of partial body irradiation (PBI) and graft-versus-host disease (GVHD) in which irradiation is delivered to the thorax 24 hr prior to induction of GVHD in hybrid mice by the injection of parental lymphoid cells. In mice irradiated to 1000 cGy or exposed to low doses of allogeneic lymphoid cells (20 X 10(6)), survival was 100% at 250 days. In contrast, combination of the two treatments, GVHD and PBI, resulted in a mortality of 83% and a mean survival time of 29 days, indicating synergy between GVHD and PBI. From histological studies of the lung it appeared that about 40% of the deaths occurring after combined GVHD/PBR treatment might be attributable to pneumonia. The cause of death in the remaining mice receiving combined treatment is not known. Mice receiving combined PBI/lymphoid cell treatment develop a characteristic skin lesion that is not seen in nonirradiated mice and is confined to the irradiated area. The effect of preinduction PBR on the timing and severity of GVHD is similar to that which would be produced by an increase in the number of effector cells.  相似文献   
994.
B Lalor  A Freemont  S Carlile 《BONE》1986,7(4):273-276
Transilial crest bone biopsy with quantitative histomorphometry is an important technique for the assessment of metabolic and endocrine bone disease. The surface area of the histologic section suitable for histomorphometric analysis is reduced by the build-up of bone dust and by trabecular fracture, produced by the conventional Bordier bone drill. We describe here a modification of this drill that both allows escape of dust from around the cutting edge of the teeth and greatly reduces bone dust volume and trabecular fracture. In paired samples the new drill was shown to improve significantly the quality of the biopsy specimens.  相似文献   
995.
996.
Socio-medical indicators of health in South Africa   总被引:3,自引:0,他引:3  
Socio-medical indicators developed by WHO for monitoring progress towards Health-for-All have been adapted to reveal, clearly and objectively, the devastating impact of state planning based on an outmoded immoral and unscientific philosophy of race superiority in South Africa on the health of the disenfranchised majority within the context of social and economic discrimination; Health policy indicators confirm that the government is committed to three options (Bantustans, A New Constitution, and A Health Services Facilities Plan) all of which are inconsistent with the attainment of Health-for-All; Social and economic indicators reveal gross disparities between African, Coloured, Indian, and White living and working conditions; Provision of health care indicators show the overwhelming dominance of high technology curative medical care consuming about 97 percent of the health budget with only minor shifts towards community-based comprehensive care; and Health status indicators illustrate the close nexus between privilege, dispossession and disease with Whites falling prey to health problems related to affluence and lifestyle, while Africans, Coloureds, and Indians suffer from disease due to poverty. All four categories of the indicator system reveal discrepancies which exist between Black and White, rich and poor, urban and rural. To achieve the social goal of Health-for-All requires a greater measure of political commitment from the state. We conclude that it is debatable whether a system which maintains race discrimination and exploitation can in fact be adapted to provide Health-for-All.  相似文献   
997.
Since the aminoglycoside antibiotic apramycin was licensed for veterinary use in 1980, all isolates of Escherichia coli and salmonellas received at the Central Veterinary Laboratory have been monitored for resistance to apramycin and the related antibiotic gentamicin. During the period 1982-4, the incidence of resistance in E. coli to apramycin increased from 0.6% in 1982 to 2.6% in 1984. In salmonellas the incidence of resistance to apramycin increased from 0.1% in 1982 to 1.4% in 1984. Resistance to both apramycin and gentamicin was detected in six different salmonella serotypes, although an isolate of Salmonella thompson from poultry was resistant to gentamicin but not apramycin. Most of the cultures were isolated from pigs, although the incidence of apramycin resistance in S. typhimurium (DT 204C) from calves has shown a recent dramatic increase. All the isolates with one exception produced the enzyme aminoglycoside 3-N-acetyltransferase IV (ACC(3)IV). The resistance was transferable by conjugation in most of the strains examined, and the plasmids specifying the resistance have been found to belong to a number of different incompatibility groups. Plasmids from three E. coli strains were compatible with all the reference plasmids and belonged to a previously undescribed group which was investigated further. It is suggested that bacteria from humans should be examined for resistance to apramycin and gentamicin to determine the possibility of the antibiotic-resistance bacteria, and their genes, spreading from animals to humans.  相似文献   
998.
999.
The effects of labeling a person as hypertensive have important implications for hypertension screening. The Hypertension Detection and Follow-up Program (HDFP) provides an opportunity to examine the effects of labeling, treatment, and study assignment on a large group of hypertensives (n = 10,070). Their answers to questions regarding perceived health and general well-being asked at baseline and again one year later were analyzed. There was no significant change in the perceived health status of persons who were unaware of their hypertension at baseline and remained untreated at one year (labeling alone). The effect of labeling plus treatment was associated with a significant decrease in perceived health. The effect of antihypertensive drug therapy on perceived health status was examined in persons who were aware of their hypertension but not on treatment at baseline, and on treatment at one year. The stepped care group (SC) had a significant improvement in their perceived health and a significant decrease in the amount of time spent worrying about their health. The referred care group (RC) had no change. Program assignment effects were studied in individuals aware of their hypertension and on treatment both at baseline and one year later. Both the SC and RC groups had a significant improvement in their perceptions of their health status. The SC group had a significant decrease in time spent worrying about their health, while the RC group showed no change. These reassuring results fail to support the suggestion that labeling persons as hypertensive is necessarily followed by negative psychological consequences.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
1000.
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