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   43260篇
  免费   3326篇
  国内免费   571篇
耳鼻咽喉   480篇
儿科学   1172篇
妇产科学   756篇
基础医学   6263篇
口腔科学   752篇
临床医学   3972篇
内科学   9222篇
皮肤病学   957篇
神经病学   3197篇
特种医学   1896篇
外国民族医学   18篇
外科学   5507篇
综合类   1449篇
现状与发展   1篇
一般理论   2篇
预防医学   3256篇
眼科学   895篇
药学   3341篇
  7篇
中国医学   767篇
肿瘤学   3247篇
  2023年   349篇
  2022年   915篇
  2021年   1460篇
  2020年   845篇
  2019年   1097篇
  2018年   1308篇
  2017年   954篇
  2016年   1058篇
  2015年   1310篇
  2014年   1640篇
  2013年   2055篇
  2012年   3061篇
  2011年   2973篇
  2010年   1744篇
  2009年   1489篇
  2008年   2155篇
  2007年   2100篇
  2006年   2032篇
  2005年   1852篇
  2004年   1672篇
  2003年   1606篇
  2002年   1470篇
  2001年   1298篇
  2000年   1273篇
  1999年   1131篇
  1998年   419篇
  1997年   350篇
  1996年   308篇
  1995年   249篇
  1994年   232篇
  1993年   198篇
  1992年   551篇
  1991年   542篇
  1990年   508篇
  1989年   463篇
  1988年   481篇
  1987年   408篇
  1986年   400篇
  1985年   396篇
  1984年   275篇
  1983年   209篇
  1982年   136篇
  1981年   115篇
  1979年   229篇
  1978年   123篇
  1977年   131篇
  1976年   124篇
  1974年   140篇
  1972年   138篇
  1970年   116篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
A retrospective analysis, covering a period of 20 years, of 2049 primo-isolates ofSalmonella typhimurium and 343 primo-isolates ofSalmonella enteritidis was performed at our laboratory. In 1991,S. enteritidis (43.8%) outnumberedS. typhimurium (32.1%) as the most frequently isolated Salmonella. The age group distribution ofS. enteritidis yielded peaks in the under-five and above-60 year age groups, whereasS. typhimurium only peaked in the under-five age group.S. enteritidis appeared to be twice as invasive asS. typhimurium. Both serotypes were more invasive in middle and older age groups than in under-fives.  相似文献   
82.
We compared three different microsurgical vasovasostomy techniques on the rat vas deferens using absorbable and non-absorbable sutures and a fibrin adhesive technique. The best method was an extramucosal technique over a splint using vicryl. The worst results were seen using adhesive.  相似文献   
83.
Human ehrlichiosis is a recently recognized rickettsial disease. It is caused byEhrlichia chaffeensis, an intraleucocytic Gram-negative, obligate intracellular bacterium, grouped within the genusEhrlichiae. Most human cases of ehrlichiosis have been diagnosed in the USA. Two cases have been reported outside of the USA, one in Europe and one in Africa. From 1 January to 30 June 1992, 765 sera from blood donors or other asymptomatic subjects in 8 African countries, including Ivory Coast, Burkina Faso, Mali, Central African Republic, Angola, Zimbabwe, Mozambique and Commores Islands, were tested by indirect immunofluorescence for the presence ofE. chaffeensis antibodies. Positive sera were confirmed by Western immunoblotting. Only two of 765 sera tested were positive. One serum obtained from Burkina Faso had an IgG titer of 1:200 and one from Mozambique had an IgG titer of 1:80. Human ehrlichiosis seems to occur infrequently in Africa, although many more sera from additional African countries need to be evaluated.  相似文献   
84.
Obesity in youth and middle age and risk of colorectal cancer in men   总被引:5,自引:0,他引:5  
To investigate an association between colon cancer and obesity during early adulthood—a potentially important period in the etiology of this disease—the authors assembled, by computer linkage, a population-based historical cohort of 52,539 men born between 1913 and 1927 residing in Hawaii (USA), for whom weight and height had been recorded in 1942–43 and 1972. Linkage of this cohort to the Hawaii Tumor Registry resulted in the identification of 737 incident cases of colorectal cancer for 1972–86. An average of 3.8 cancer-free controls were matched to each case on month and year of birth and ethnicity of the parents. A case-control analysis in each anatomic subsite of the large bowel revealed that both early and middle-age body mass increased the risk of sigmoid cancer in men in a dose-dependent fashion. The odds ratios (OR) for sigmoid cancer for the highest compared with the lowest tertiles of Quetelet index were: 2.1 (95 percent confidence interval [CI]=1.4–3.2) and 1.7 (CI=1.1–2.5), at ages 15–29 and in prediagnostic years, respectively. These associations were additive and idependent of socioeconomic status. Men who were above the median Quetelet index in 1942 and 1972 had an OR of 2.7 (CI=1.8–4.0), compared with those who were below the median in both periods. This study provides further evidence for an association of obesity with colon cancer in men and suggests that this association is limited to the sigmoid colon and may be related to both early and late events of colon carcinogenesis.The authors are with the Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii. Address correspondence to Dr Le Marchand, Epidemiology Program, Cancer Research Center of Hawaii, 1236 Lauhala Street, Suite 407, Honolulu, HI 96813, USA. This work was supported in part by Public Health Service grant 5-R29-CA44503 and contract NO1-CN-55424 from the National Cancer Institute, National Institutes of Health, Department of Health and Human Services.  相似文献   
85.
We report the case of a child presenting with abdominal Burkitt's lymphoma in whom a relapse presented as orbital and muscle involvement. This clinical feature is extremely rare. Two muscle and one orbital biopsies were necessary to obtain proper diagnosis. A new extension check-up showed bone marrow invasion and normal cerebrospinal fluid. This relapse was successfully treated by conventional chemotherapy and consolidated with high-dose chemotherapy, total body irradiation and autologous bone marrow transplantation. Eighteen months after transplantation, the child may be considered as definitively cured.  相似文献   
86.
87.
In 7 cases of mandibular laterognathia caused by condylar hypertrophy, the authors specify the clinical and teleradiological features in adolescents. They emphasize the inadequacy of lateral teleradiography and of its measurements, and the need for three-dimensional investigation. In adolescents, secondary deformations, either spontaneous or therapeutic, are rare, and the treatment preferred is condylectomy based on the study of casts. The immediate results of this techniques are satisfactory. The long-term consequences on growth and temporomandibular pathology have been studied.  相似文献   
88.
This double blind, placebo-controlled trial was designed to determine whether intervention with a stepped regimen of trimethoprim-sulfamethoxazole (TMP-SMX) and prednisone would prevent high risk children from developing chronic otitis media with effusion (OME) and recurrent acute otitis media. Forty-two children were enrolled, assigned to treatment with active drug or placebo and then examined at 2-week intervals. They received TMP-SMX (or placebo) during the first 2 weeks, TMP-SMX and prednisone (or placebo) during Weeks 3 and 4 for persistent OME and TMP-SMX (or placebo) for Weeks 5 and 6 if OME was still unresolved. After treatment 48% of active drug and 14% of placebo subjects resolved OME bilaterally (P less than 0.05). Active drug subjects also had fewer acute otitis media episodes than placebo subjects while receiving study treatment (P less than 0.01). Although this treatment regimen produced short term OME resolution, long term benefits were not demonstrated.  相似文献   
89.
以15例角膜移植术的护理实践,总结出该手术的护理常规,并对本组病例中发生的并发症的护理进行了讨论,强调护士密切观察病情,有效地处理并嫌下对手术成功的重要性。  相似文献   
90.

Background  

This study compared the prognostic value of exercise single-photon emission computed tomographic (SPECT) thallium imaging with that of treadmill exercise score in medically treated patients with coronary artery disease (CAD)  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