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   9113篇
  免费   504篇
  国内免费   127篇
耳鼻咽喉   119篇
儿科学   194篇
妇产科学   197篇
基础医学   1051篇
口腔科学   178篇
临床医学   1144篇
内科学   1396篇
皮肤病学   70篇
神经病学   702篇
特种医学   279篇
外科学   752篇
综合类   772篇
现状与发展   1篇
预防医学   1697篇
眼科学   171篇
药学   531篇
  2篇
中国医学   85篇
肿瘤学   403篇
  2024年   18篇
  2023年   143篇
  2022年   250篇
  2021年   332篇
  2020年   324篇
  2019年   296篇
  2018年   277篇
  2017年   293篇
  2016年   299篇
  2015年   307篇
  2014年   554篇
  2013年   814篇
  2012年   481篇
  2011年   534篇
  2010年   400篇
  2009年   453篇
  2008年   466篇
  2007年   459篇
  2006年   348篇
  2005年   314篇
  2004年   273篇
  2003年   210篇
  2002年   194篇
  2001年   157篇
  2000年   133篇
  1999年   126篇
  1998年   118篇
  1997年   99篇
  1996年   76篇
  1995年   82篇
  1994年   74篇
  1993年   74篇
  1992年   65篇
  1991年   52篇
  1990年   48篇
  1989年   45篇
  1988年   35篇
  1987年   34篇
  1986年   57篇
  1985年   63篇
  1984年   57篇
  1983年   28篇
  1982年   48篇
  1981年   31篇
  1980年   41篇
  1979年   31篇
  1978年   25篇
  1977年   24篇
  1976年   17篇
  1974年   14篇
排序方式: 共有9744条查询结果,搜索用时 15 毫秒
11.
The aim of this study was to explore undergraduate and postgraduate dental students' understanding of a good learning experience by using 'reflection on learning' as described by Schon. Four groups of Year 4 BDS students and one group of postgraduate students in dental public health took part in a series of focus group discussions. The responses were grouped into four broad themes (a) active, practical and positive learning; (b) interactive/together learning; (c) personal learning; (d) theory into practice. Six educational models of good learning proposed by the students are described.  相似文献   
12.
Human cartilage link protein exists as three native components, while equine, bovine, and porcine cartilage link protein exist as two and Swarm rat chondrosarcoma link protein exists as only one component. These nonhuman link protein components represent intact protein structures, and there is little evidence for proteolytically modified forms in nonhuman tissues. In human cartilage, the proteolytic production of modified link proteins increases with age, whereas high amounts of such products were not seen in the nonhuman tissues. However, the small amounts of link protein fragments that were observed in the nonhuman cartilages were of a similar size to their human counterparts. On digestion of human proteoglycan aggregate with stromelysin, rapid modification of the link protein components occurred, whereas the aggregates from nonhuman cartilages showed incomplete cleavage of their link protein components. The relative resistance of nonhuman link protein to stromelysin may in part be due to a unique amino acid substitution present near the enzymic cleave site.  相似文献   
13.
瑶族体型的Heath—Carter人体测量法研究   总被引:4,自引:0,他引:4  
的 探讨瑶族成人体型的特点与规律。方法 应用Heath -Carter人体测量法 ,对广西田林县利周乡 2 18例(男 116 ,女 10 2 ) 2 0~ 45岁盘古瑶族成人体型进行活体测量。结果 瑶族平均体型男性为均衡的中胚层体型 ( 1.8-4 .9-2 .2 ) ,女性为偏内胚层的中胚层体型 ( 3 .1-4 .3 -1.9) ;瑶族男性 2 0~ 40岁间各年龄组 ,内因子值和中因子值变化不大 ,外因子值略有减少 ,内、中因子值的最小值及外因子值的最大值均在 40~ 45岁组 ;女性 2 0~ 45岁间各年龄组 ,随着年龄增加 ,外因子值明显增加 ,中、内因子值略有减少 ;瑶族男女间体型各年龄组比较差异均有显著性或高度显著性 ,P<0 .0 5或P <0 .0 1。结论 瑶族与其他群体体型比较 ,体脂少 ,骨骼肌肉较发达 ,身体线性度适中。  相似文献   
14.
Determination of age at death on the basis of aspartic acid racemization in dentin is one of the most reproducible and accurate methods. In Germany, age estimation by this method has so far generally not been applied to living persons, since the extraction of a tooth exclusively for age estimation when it is not medically indicated is regarded as ethically and legally problematic. The development of a biopsy technique applicable to dentin took place against this background. Testing the technique and analysis of dentinal biopsy specimens revealed that the biopsy technique is a low-risk procedure that causes only minor discomfort to the affected person. It is readily practicable and facilitates standardized specimen removal. The relationship between the extent of aspartic acid racemization in dentinal biopsy specimens and age is very close, facilitating age estimation. A prerequisite for accurate results is the performance of biopsies under strictly standardized conditions. If this is guaranteed, age determination on the basis of aspartic acid racemization in dentinal biopsy specimens appears to be superior in precision to most other methods in living persons and can be used for all age groups.  相似文献   
15.
The University of Washington School of Medicine (UWSM) has initiated new efforts to build a regional minority applicant pool and to expand its educational programmes to accommodate students from disadvantaged backgrounds. Specific interventions include: establishment of medical career planner position to coordinate region-wide outreach; pre-entry education; and support activities once enrolled. This study describes specific services and presents sociodemographic and performance data on 56 minority and 280 majority students entering the UWSM between 1981 and 1985. Economic status and educational background of minority students were significantly below that of majority students, several flexible academic policies enabled most students to achieve mastery in courses and to progress through the curriculum. The educational data base utilized in this study, and those at other institutions, can assume important roles in the identification of problem areas in the education of disadvantaged students and in evaluation of the interventions attempted.  相似文献   
16.
研究观察年龄对潘库溴铵药代动力学的影响,选择24例施择期整形外科手术的患者,根据年龄分成三组:1组为5例婴幼儿,年龄0.75-2.95岁;2组为13例儿童,年龄4-14岁;3组为6例病人,年龄16-27岁,静注潘库溴铵100ug/kg后用改良蒌光法测定其血浓度,潘库溴铵的体内过程能用二室开放模型完整描述,年龄愈小,分布容积愈大,血浆清除率愈高,潘库溴铵的血药浓度愈低,V1(中央室分布容积),V2(周边室分布容积),Vdss(稳态分布容积),C1(血浆清除率)和AUC(曲线下面积)在三相间有明显差别,1组的T1/2β和MRT明显比2,3组长,但T1/2α和K21在三组间无明显差别。  相似文献   
17.
Summary: Age has a profound influence on our approach to the convulsive disorders. Age is a variable which is an important determinant for risk factors for epilepsy. Age, as a surrogate of brain maturation, is a determinant of the specific characteristics of the seizure disorder in those with epilepsy, and age-related changes in these manifestations can be identified. Age is a determinant for the occurrence of acute symptomatic seizures in several types of metabolic or central nervous system insults. Age is a determinant for prognosis, whether one considers remission, medication withdrawal in those entering remission, relapse following prolonged remission, or mortality. Last, age per se seems to be a risk factor for epilepsy independent of other factors. This seems particularly true for partial seizures.  相似文献   
18.
Older age is not considered a contraindication for liver transplantation, but age-related morbidity may be a cause of mortality. Survival and the incidence of the main post-transplant complications were assessed in 111 adult liver transplant recipients. They were divided in two groups according to their age (patients younger than 60 years, n=54; patients older than 60 years, n=57) and both groups were compared. Older patients were more frequently transplanted for hepatitis C (p= 0.03) and hepatocellular carcinoma (p= 0.05) and their liver disease was less advanced (Child-Pugh and MELD scores were significantly lower; p=0.004 and p=0.05, respectively). After transplantation, older patients had a significantly lower survival (p=0.02). Higher age was independently associated with mortality (hazard ratio for each 10-year increase: 2.1; 95% confidence interval: 1.1- 4.0; p=0.02). The incidence of de novo neoplasia and nonskin neoplasia were higher in older patients (p=0.02 and p =0.007, respectively). Malignancy was the cause of death in one patient younger than 60 years and in 12 patients older than 60 years (p =0.002). In multivariate analysis, a higher age and smoking were independently associated with a higher risk of dying of de novo neoplasia. In conclusion, older liver transplant recipients have a significantly lower survival than younger patients. Malignancy is responsible for this decreased survival.  相似文献   
19.
目的:探讨幽门螺杆菌(HP)感染与消化性溃疡(PU)及年龄、性别的关系。方法:采用快速尿素酶和组织H-E染色法对119例PU病人进行HP感染检测,其中男性96例、女性23例,以上二种方法测定结果均阳性定为HP感染。然后将这些病例按年龄分为三组,即青年组33例,中年组78例和老年组8例。结果:HP总感染率:胃溃疡78.6%,十二指肠球溃疡63.6%,幽门管溃疡66.7%及复合溃疡62.5%,该结果与以前报道相同。各种溃疡的HP感染率在各年龄组间比较及男、女性别间比较无显著性差异(P均>0.05)。结论:HP感染与PU关系密切,与性别无关,并不与年龄成正比上升。  相似文献   
20.
Effects of gender,age, and heart rate on QT intervals in children   总被引:9,自引:0,他引:9  
The objective of this study was to determine if gender, age, and heart rate affect corrected QT intervals in children. Electrocardiograms were obtained from 781 healthy children 10–18 years of age. Corrected QT intervals were significantly (p < 0.0005) greater for girls than for boys in the entire population and for each age group over 14 years. The corrected QT interval varied inversely with age and directly with heart rate. Hence gender, age, and heart rate should be considered when diagnosing long QT syndrome.  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