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   1206篇
  免费   85篇
  国内免费   2篇
耳鼻咽喉   10篇
儿科学   80篇
妇产科学   20篇
基础医学   188篇
口腔科学   51篇
临床医学   116篇
内科学   234篇
皮肤病学   43篇
神经病学   66篇
特种医学   22篇
外科学   131篇
综合类   18篇
预防医学   78篇
眼科学   48篇
药学   94篇
中国医学   6篇
肿瘤学   88篇
  2023年   8篇
  2022年   22篇
  2021年   83篇
  2020年   49篇
  2019年   41篇
  2018年   45篇
  2017年   40篇
  2016年   55篇
  2015年   48篇
  2014年   74篇
  2013年   67篇
  2012年   113篇
  2011年   100篇
  2010年   64篇
  2009年   31篇
  2008年   48篇
  2007年   47篇
  2006年   46篇
  2005年   35篇
  2004年   35篇
  2003年   30篇
  2002年   21篇
  2001年   20篇
  2000年   19篇
  1999年   17篇
  1998年   16篇
  1997年   7篇
  1996年   5篇
  1995年   2篇
  1994年   3篇
  1992年   7篇
  1991年   6篇
  1990年   8篇
  1989年   12篇
  1988年   6篇
  1987年   11篇
  1986年   4篇
  1985年   10篇
  1984年   3篇
  1983年   3篇
  1980年   2篇
  1979年   5篇
  1977年   3篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   7篇
  1972年   1篇
  1967年   3篇
  1965年   4篇
排序方式: 共有1293条查询结果,搜索用时 15 毫秒
1.
2.
Between June and September, 1986, an outbreak of measles occurred in Pilkhi Primary Health Centre area (population 56,000) in Tehri Garhwal district, Uttar Pradesh, India. Overall, 1092 cases were identified and 62 died; case-fatality ratio was 5.7%. Illness was restricted primarily to children below 15 years of age; 38% cases were in children under 5 and 58% between 5-14 years of age. To better characterize the outbreak, a survey was conducted in 13 affected villages. The age of the cases ranged from 5 months to 19 years (median = 7.0 years). The age-specific attack rates were 22.4%, 54.5%, 46.2% and 35.3% for children under 1, 1-4, 5-9, 10-14 years of age respectively. In as many as four villages, the attack rate in children below ten was 80% or more. Secondary attack rate among family members was 70%. Overall, 82% of children with measles developed complications which consisted mainly of pneumonia, diarrhoea and dysentery. The age-specific case-fatality ratios in infants and children 1-4 years of age were 23.1% and 11.5% respectively; thereafter the rates tended to decline with increasing age and was higher in females than in males (less than 0.05). Pneumonia which was a complication in 39% of measles cases contributed to 56% of deaths. Traditional beliefs and customs in the area were strong and did not encourage treatment of measles cases. Although a measles vaccination programme has been launched in India since 1985, only 30 districts could be covered during the first year and another 90 during 1986.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
3.
4.

Background  

Sustained use of antiretroviral therapy has been consistently shown to be one of the primary predictors of long-term effectiveness. Switching and discontinuation reflect patient and provider decisions that may limit future treatment options. In this study, we utilize data reported at semi-annual study visits from three prospective cohort studies, the AIDS Link to IntraVenous Exposure (ALIVE), the Women's Interagency HIV Study (WIHS), and the Multicenter AIDS Cohort Study (MACS), to investigate determinants of HAART modification with a particular focus on reported injection drug use (IDU).  相似文献   
5.
A novel modification of conventional video imaging techniques has been developed to determine the velocity of red blood cells (RBCs), which offers compatibility with existing video-based methods for determining blood oxygenation and hemoglobin concentration. Traditional frame-by-frame analysis of video recordings limits the maximum velocity that can be measured for individual cells in vivo to about 2 mm/s. We have extended this range to about 20 mm/s, by electronic shuttering of an intensified charge-coupled device camera to produce multiple images of a single RBC in the same video frame. RBCs were labeled with fluorescein isothiocyanate and the labeled cells (FRBCs) were used as probes to determine RBC velocities in microvessels of the hamster retractor muscle. Velocity was computed as the product of the distance between centroids of two consecutive image positions of a FRBC and the shuttering frequency of the camera intensifier. In vitro calibrations of the system using FRBC and Sephadex beads coated onto a rotating disk yielded an average coefficient of variation of about 6%. Flow conservation studies at bifurcations indicated that the maximum diameter of microvessels below which all the FRBCs in the lumen could be detected was 50 m. The technique was used to estimate mean-FRBC velocity distributions in vessels with diameters ranging from 8 to 50 m. The mean-FRBC velocity profiles were found to be blunter than would be expected for Poiseuille flow. Single FRBCs tracked along an unbranched arteriole exhibited significant temporal variations in velocity. © 1999 Biomedical Engineering Society. PAC99: 8719Tt, 8717Jj, 4279Pw, 8780Tq, 8719Ff, 4230Va, 0705Pj  相似文献   
6.
7.
Trichothiodystrophy, non‐photosensitive type 4 (TTD4), is a rare genetic disorder with an autosomal recessive mode of inheritance. It is characterized by coarse and brittle hair, anomalies of the tissues derived from the neuro‐ectoderm (skin, hair, and nails) and intellectual disability. We herein report two male siblings aged 13 and 16 years with TTD4 and a known homozygous pathogenic variant, c.229del [p.(Arg77Glyfs*76)] in exon 1 of MPLKIP (NM_138701.3). We herein highlight the clinical and molecular findings of the first reported case of TTD4 in probands of Indian ethnicity.  相似文献   
8.
Based on experiments on fresh cadaveric and accidentally amputated 8 upper limbs of children, study of ulnae for presence and absence of non articular strip on the trochlear notch, measurements of carrying angle, length of forearm bones, pronation-supination, height and weight in 2250 infants, children and adults of various age groups and clinical observations on 800 cases of injuries around elbow many new facts have been observed about the development of the carrying angle and its significance in the etiopathogenesis of various types of fractures seen around the elbow. The carrying angle develops in response to pronation of the forearm and is dependent on length of the forearm bones. Lesser the length of forearm bones greater is the carrying angle. So the carrying angle is more in shorter persons as compared to taller persons. It is abduction at the shoulder and not the carrying angle which keeps the swinging upper limbs away from the side of the pelvis during walking. Carrying angle is not a secondary sex character. The type of fracture a child sustains after fall on outstretched hand is also determined by the value of the carrying angle. A new type of fracture hitherto undescribed in the literature, T-Y fracture of the distal humeral epiphysis is also reported.  相似文献   
9.
Khare V  Singh SM  Sodhi A 《Natural immunity》1998,16(5-6):215-227
The present investigation was carried out to study the effect of tumor growth on the spleen of an aged host. Dalton's lymphoma (DL), a spontaneous T cell lymphoma, was grown in mice of different age groups classified as young, adult or old on the basis of their reproductive status. Splenocytes obtained from normal and tumor-bearing young, adult and old mice were checked for an in vitro blastogenic response to concanavalin A (Con A), colony-forming ability and apoptosis. There was an enhanced apoptosis of splenocytes and a concomitant inhibition of splenocyte blastogenesis and their responsiveness to the mitogenic stimulus of Con A in aged mice. The counts of granulocyte macrophage- and macrophage-colony forming units were significantly enhanced in the spleen of tumor-bearing adult mice. It is proposed that the DL-growth-dependent increase in the size of the spleen in adult mice is due to an increased blastogenesis of splenocytes, which, however, may not be applicable in the case of old tumor-bearing mice. The role of splenic macrophages in the regulation of the functions of the spleen by macrophage-derived NO is shown.  相似文献   
10.
The objective of the present study was to examine the effects of a confluence of demographic, socioeconomic, housing, and environmental factors that systematically contribute to heat-related morbidity in Maricopa County, Arizona, from theoretical, empirical, and spatial perspectives. The present study utilized ordinary least squares (OLS) regression and multiscale geographically weighted regression (MGWR) to analyze health data, U.S. census data, and remotely sensed data. The results suggested that the MGWR model showed a significant improvement in goodness of fit over the OLS regression model, which implies that spatial heterogeneity is an essential factor that influences the relationship between these factors. Populations of people aged 65+, Hispanic people, disabled people, people who do not own vehicles, and housing occupancy rate have much stronger local effects than other variables. These findings can be used to inform and educate local residents, communities, stakeholders, city managers, and urban planners in their ongoing and extensive efforts to mitigate the negative impacts of extreme heat on human health in Maricopa County.  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