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   35627篇
  免费   3060篇
  国内免费   1836篇
耳鼻咽喉   578篇
儿科学   508篇
妇产科学   819篇
基础医学   4177篇
口腔科学   564篇
临床医学   4183篇
内科学   6236篇
皮肤病学   813篇
神经病学   1919篇
特种医学   1197篇
外国民族医学   17篇
外科学   3612篇
综合类   4278篇
现状与发展   4篇
一般理论   7篇
预防医学   2333篇
眼科学   795篇
药学   3637篇
  23篇
中国医学   1658篇
肿瘤学   3165篇
  2024年   83篇
  2023年   485篇
  2022年   1150篇
  2021年   1528篇
  2020年   1118篇
  2019年   1167篇
  2018年   1284篇
  2017年   1093篇
  2016年   1045篇
  2015年   1549篇
  2014年   1899篇
  2013年   1891篇
  2012年   2662篇
  2011年   2805篇
  2010年   1792篇
  2009年   1332篇
  2008年   1928篇
  2007年   1835篇
  2006年   1861篇
  2005年   1823篇
  2004年   1330篇
  2003年   1270篇
  2002年   1092篇
  2001年   899篇
  2000年   823篇
  1999年   749篇
  1998年   458篇
  1997年   413篇
  1996年   334篇
  1995年   306篇
  1994年   275篇
  1993年   197篇
  1992年   327篇
  1991年   285篇
  1990年   218篇
  1989年   171篇
  1988年   192篇
  1987年   158篇
  1986年   123篇
  1985年   117篇
  1984年   84篇
  1983年   44篇
  1982年   25篇
  1981年   35篇
  1980年   21篇
  1979年   32篇
  1978年   24篇
  1977年   19篇
  1975年   18篇
  1973年   24篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
Presentation of one case of scrotal hernia in a man of 64 years old patient. Diagnosed by cistography and ultrasound and treated by herniorraphy and posterior transuretral litolaplaxy of a vesical litiasis and RTU of prostate. Postoperative urography showed normal vesical morphology.  相似文献   
104.
The EcoEléctrica Mangrove Planting Project, a five-year voluntary effort, has the purpose of testing a recently developed mangrove planting technique at the EcoEléctrica site in Pe?uelas, Puerto Rico. The goal of the project is to provide empirical validation to promote or improve the technique to be used in recovering mangrove ecosystems in Puerto Rico and United States. The research presented herein analyzed the information collected on the first two years of the project. The proportions of remaining casings and seeds per study zone were compared using the chi-square distribution. Zone 1 had the least pipes lost while Zone 4 had the most (p < 0.05). Forty-three percent of the seeds in Zone 1 remained in the casing, while 26% remained in Zone 2 (p = 0.03). Median growth rates of seeds per study zone showed that Zone 1 had the highest median growth rates. Survival analysis described the survival experience of the seeds, and differences in survival probabilities were compared with the log-rank test. Zone 1 seeds had a better survival experience compared to Zones 2, 3 and 4 (p < 0.0001). Survival probabilities for being free of spots were over 60% during the whole study period. No significant differences were observed in the survival experience with the use-or-no use of casing extensions (p = 0.40), and the use-or-no use of nursed seeds (p = 0.26). Differences in survival probabilities might be attributed to variations in wave energy, depth or substrate conditions. This hypothesis will be evaluated in the second phase of the study.  相似文献   
105.
In order to plan the health services for the elderly population, it is necessary to quantify their health status and their functional capacity. In Puerto Rico, few epidemiological studies have been conducted regarding functional capacity and chronic diseases in the elderly population. One of the difficulties to undertake these studies is the high cost and risks to move this population for clinical exams, in addition to the methodology limitation of self-report in the elderly population. This study shows the use of logistic regression to estimate the prevalence of chronic diseases and functional capacity, when the observed data are not consisted with the planed sampling scheme. Four hundred and eighty-seven elderly persons (65 yr. and over) were interviewed in the municipalities of Canóvanas, Carolina, Loíza and Trujillo Alto in Puerto Rico, using a cross-sectional design. More than half of the elderly had visual problems (IC 95%: 54.8%, 63.8%), arthritis (IC 95%: 52.7%, 61.5%) and hypertension (IC 95%: 47.3%, 56.3%). In the case of hypertension, significant differences (p < 0.05) by sex were observed, where women reported a higher prevalence than men. One of the higher prevalences in the functional capacity status was with urine accidents. More than one-third of the population is estimated to have this problem (IC 95%: 34.7%, 43.4%). One-fourth of the population had limitations with going out for shopping (IC 95%: 23.9%, 31.9%) and using public and private transportation (IC 95%: 19.5%, 26.9%). We conclude that the applied methodology was consistent with the estimation presented in the literature and statistics from the Puerto Rico Health Department. However, it is necessary to continue assessing the design and analytical methodology, in order to undertake consistent and periodic evaluations of the elderly population.  相似文献   
106.
目的探讨原发性脑室出血的临床表现、脑CT征象及其与治疗的关系;方法回顾性分析28例经CT证实原发性脑室出血病人的临床表现及CT征象;结果多有头痛、呕吐等脑膜刺激征表现,无脑局灶受损体征,脑CT均示原发脑室出血;结论原发性脑室出血的诊断依靠脑CT,Ⅰ型脑室出血宜行侧脑室外引流术,预后较差,Ⅱ、Ⅵ型可行腰穿脑脊液置换术.预后较好。  相似文献   
107.
Growth of vascularized composite mandibular allografts in young rabbits   总被引:2,自引:0,他引:2  
Forty-one hemimandible allografts were transplanted in young rabbits immunosuppressed with cyclosporine. The majority of the grafts demonstrated normal wound healing, and growth of hair, bone, and teeth. The mandibular body and the premolars showed significant growth in length. The allografted mandibles functioned sufficiently that the rabbits took oral nourishment soon after surgery. Long-term survival was limited by a toxic "wasting syndrome" specific for rabbits under treatment with cyclosporine.  相似文献   
108.
The geographical distribution of liver cell tancer in China is very uneven. The areas of high frequenCY arc rcstrieted to the coastal zones in :fiangsu Province and southwards of this area and the Guangxi Autonomous Region. The data are mainly collected from LI counties (Qidong, Haimen, Nantong and Rudang) of Jiangsu Province. For many years the bortler 1incs of the high rate areas have remained un- changed. The method of study employed is primarily comparing the environmental factors of adiacent areas with significantly different rates of liver cell cancer, comparing the liver cancer death rates of same area inhabitants using different kinds of drinking water and ob- serving changes in Iiver cancer incidence in vil- 1agers befom and after changing the fype of drinking water. Inhabitauts who drink stagnant and highly polluted ditch water usually incur a higher pre- valence rate while those who drink weii water seldom contract liver cancer. In a sample study, more than 80,000 inhabitants, who were survey- ed twice in 1973 and in 1078 showed a reductiou of approximately 2{JTo in liver cancer incidence in the 5 year interval between surveys, while the propartion of ditch watcr drinkers was re- duced from 79T" in the first survey t0 5;IW,o in the seeand, a reduction of approximately 3270. If all the inhabitants ceased drinking ditch ivater the menace of liver cancer could be wipcd out in Qidong county. It seems that neither hepatitis nor aflatoxin can be considercd as an important causative Factor of liver cell cancer iu China.  相似文献   
109.
This study reports that quiescent herpes simplex virus (HSV) type 1 genomes, persisting in long-term infected nerve growth factor (NGF) differentiated PC12 cells, were not stimulated by superinfection with a HSV-1. We have previously shown that HSV-1 can establish long term, quiescent infections in NGF differentiated PC12 cells. To determine if virion associated factors or virus induced gene products could trans-activate the quiescent viral genomes, long term infected PC12 cell cultures were superinfected at a high moi (moi of 20) with a recombinant HSV 17alpha47/lacZ that contains the lacZ gene within the alpha 47 locus. Progeny virus and gene expression from the resident 'quiescent' viral genomes were not detected following superinfection with recombinant 17alpha47/lacZ. The failure to stimulate the quiescent genome appears to be related to the inability of the super infecting virus to induce any gene expression from its own genome following entry into the long term NGF treated PC12 cells. Interestingly, both primary and superinfecting viruses could be stimulated from the quiescently infected cultures following cocultivation with inducer cells. These data suggest that (i) HSV genomes in quiescently infected PC12 cells are unable to be stimulated by incoming virion associated factors and (ii) NGF differentiated PC12 cells maintained in tissue culture for longer than 3 weeks became completely refractory to viral gene expression. The possibilities that these results are reflective of populations of neural cells, in vivo in mouse central nervous system, which are completely refractory to virus gene expression, yet accommodating to the maintenance of viral genomes and thus favor 'latency', are discussed.  相似文献   
110.
Foreign bodies in a mobile tongue are rarely presented to the laryngologist, because such bodies are commonly lodged superficially and are easily removed by the patients themselves or by general practitioners. Thus, it is rare that a foreign body totally embedded in the mobile part of the tongue presents as an enlarged tongue mass. We have described a 64-year-old female with a 3-month history of an enlarged mass in the anterior right tongue. Physical examination showed a mass located in the anterior right tongue, with intact mucosa and normal color. A benign tongue neoplasm was considered first. However, a fish bone totally embedded in the mobile tongue with granuloma formation was encountered during the incisional biopsy operation. Complete removal of the foreign body with granuloma was achieved under local anesthesia. There was no neuromuscular or neurosensory deficit of the tongue in the follow-up period of 2 years. Although an embedded foreign body in the mobile tongue is a rare condition, it should be considered in the work-up of a patient with an enlarged tongue mass, with or without a history of swallowing a foreign body.  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