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   7601篇
  免费   740篇
  国内免费   21篇
耳鼻咽喉   29篇
儿科学   229篇
妇产科学   179篇
基础医学   1082篇
口腔科学   207篇
临床医学   801篇
内科学   1345篇
皮肤病学   76篇
神经病学   637篇
特种医学   148篇
外科学   1395篇
综合类   161篇
现状与发展   1篇
一般理论   1篇
预防医学   927篇
眼科学   253篇
药学   406篇
中国医学   3篇
肿瘤学   482篇
  2022年   69篇
  2021年   141篇
  2020年   87篇
  2019年   149篇
  2018年   162篇
  2017年   121篇
  2016年   103篇
  2015年   148篇
  2014年   164篇
  2013年   259篇
  2012年   418篇
  2011年   446篇
  2010年   254篇
  2009年   206篇
  2008年   337篇
  2007年   359篇
  2006年   340篇
  2005年   353篇
  2004年   306篇
  2003年   276篇
  2002年   287篇
  2001年   191篇
  2000年   223篇
  1999年   182篇
  1998年   81篇
  1997年   71篇
  1996年   60篇
  1995年   66篇
  1994年   61篇
  1993年   49篇
  1992年   144篇
  1991年   147篇
  1990年   141篇
  1989年   134篇
  1988年   153篇
  1987年   122篇
  1986年   130篇
  1985年   109篇
  1984年   106篇
  1983年   87篇
  1981年   52篇
  1980年   62篇
  1979年   91篇
  1978年   63篇
  1977年   52篇
  1976年   54篇
  1973年   51篇
  1972年   53篇
  1971年   55篇
  1966年   46篇
排序方式: 共有8362条查询结果,搜索用时 15 毫秒
51.
This paper describes the establishment of faculties of medical library and information science in four of the national medical universities in the People's Republic of China. These faculties were established in the mid-1980s, and each is fully integrated into its university. Students receive three years of non-clinical medical training followed by two years of training in library and information science. The first students to follow this five-year curriculum will graduate in 1992.  相似文献   
52.
53.
54.
High turnover rates among hospital nurses demand rigorous and valid processes of research to determine the reasons motivating such attrition. In most hospitals, the exit interview often provides the only relevant data. The case study reported here examines the relative effectiveness of exit interviews and an employee attitude survey in generating data that are useful in managing nurse retention. The conclusion reached is that the attitude survey generates more data and higher-quality data. Further, the study shows that the use of open-ended questions can provide useful information and probably should be the starting point in developing or supplementing an attitude survey for nurses. Recommendations for improving the usefulness and validity of nurse attitude surveys and exit interviews in managing nurse retention are provided.  相似文献   
55.
The construct of transformation has been presented in many research studies as the epitome of living with a chronic illness. Because it has been inadequately defined, however, many other concepts (e.g., hope, meaning, control) are used in ways that suggest considerable overlap and correspondence with transformation. This article represents an attempt to explicate the structures and processes of transformation as they were revealed in a qualitative inquiry into the experience of individuals with Type I diabetes. In the accounts constructed with participants in this study, the process of personal transformation was significant in the attainment of healthy outcomes. The authors describe this transformation and examine its relationship to control and to the valued outcomes of intensified sense of self, meaning, and mastery.  相似文献   
56.
The influence of operative technique on the formation of incomplete cement mantles in the sagittal plane has been rarely considered in the literature. In this article, we discuss the influence of the anatomy of the proximal femur on the formation of incomplete cement mantles and discuss how their incidence can be reduced by correct component positioning.  相似文献   
57.
OBJECTIVES: Factors accelerating cerebral degenerative changes represent potentially modifiable risks for cognitive decline. Putative risk factors accelerating subtle cognitive decline and dementia were correlated with repeated measures of cerebral atrophy, CT densitometry, perfusions and cognitive testing among neurologically and cognitively normative ageing volunteers. METHODS: Two hundred and twenty-four normative subjects at increased risk for cognitive decline were admitted to the study. Mean entry age was 59. 5+/-15.8 years. Mean follow-up is 4.3+/-3.1 years. At follow-up, 22 developed subtle cognitive decline (deltaCCSE>/=-3), 19 became demented, eight with vascular type (VAD) and 11 with Alzheimer's type (DAT) and 183 remain cognitively unchanged. Standardized questionnaires, medical, neuropsychological, neurological and blood work examinations were obtained. Cerebral atrophy, tissue densities and perfusions were measured by xenon-enhanced CT. RESULTS: After age 60, cerebral atrophy, ventricular enlargement, polio- and leuko-araiosis geometrically increased as perfusions declined. Risk factors accelerating perfusional decline, cerebral atrophy, polio-araiosis and leuko-araiosis (thinning of grey-white matter densities) were: transient ischaemic attacks (TIAs), hypertension, smoking, hyperlipidemia, male gender. At age 71.5+/-11.9, subtle cognitive decline began, accelerated by TIAs, hypertension and heart disease. Leuko-araiosis began before cognitive decline. TIAs, hypertension and hyperlipidemia correlated with VAD. Excessive cortical perfusional decreases and cerebral atrophy correlated with cognitive decline. Family history of neurodegenerative disease correlated with DAT. CONCLUSION: TIAs, hypertension, hyperlipidemia, smoking and male gender accelerate cerebral degenerative changes, cognitive decline and dementia.  相似文献   
58.
BACKGROUND: The purpose of this study was to examine the diagnostic efficiency of prostate-specific antigen (PSA) and digital rectal examination (DRE) testing when using either 4.0 ng/ml or an age-specific reference range (ASRR) as an abnormal cutoff PSA value. METHODS: Between 1992-1995, 116,073 men, aged 40-79 years, were screened during Prostate Cancer Awareness Week. When using a 4.0-ng/ml cutoff PSA value, 22,014 had either an abnormal PSA, an abnormal DRE, or both. When using an ASRR cutoff PSA value, 17,561 had either an abnormal PSA, an abnormal DRE, or both. The positive predictive value (PPV), sensitivity, and specificity of PSA, DRE, and combined PSA and DRE tests were evaluated. RESULTS: When using a 4.0-ng/ml cutoff PSA value, the PPVs of abnormal PSA alone, abnormal DRE alone, and combined abnormal PSA and DRE tests were 27.7%, 17.7%, and 56.0%, respectively. Sensitivities were 34.9%, 27.1%, and 38.0%, respectively. Specificities were 63.1%, 49.0%, and 87.9%, respectively. When using an ASRR cutoff PSA value, the PPVs of each category were 31.8%, 20.8%, and 63.7%, respectively. Sensitivities were 27.1%, 41.0%, and 31.8%, respectively. Specificities were 75.0%, 32.8%, and 92.2%, respectively. The PPVs of the PSA test were higher than those of the DRE. The PPVs of combined tests were highest when using either a 4.0-ng/ml cutoff PSA value or an ASRR cutoff PSA value (all P < 0.001). When using an ASRR, the PPVs of PSA, DRE, and combined tests were higher than those when using a 4.0-ng/ml without statistical significance (all P > 0.05). Sensitivity of PSA when using an ASRR was lower than when using 4.0 ng/ml. CONCLUSIONS: Significantly higher PPVs indicated that utilizing both a PSA test and a DRE is most effective in screening for the early detection of prostate cancer. Although higher PPVs when using an ASRR cutoff PSA value suggested fewer unnecessary biopsies, lower sensitivities resulted in fewer cancers detected. Thus, we recommend that the combination of a PSA test with a cutoff value of 4.0 ng/ml and a DRE should continue to be utilized in the screening programs.  相似文献   
59.
We reviewed histologically the incidence and pathogenesis of the deposition of calcium pyrophosphate dihydrate (CPPD) crystals in the pseudocapsule, femoral and acetabular membranes and periprosthetic tissue at revision of 789 cases of failed total hip replacement. In 13, periprosthetic tissues were found to have deposits of CPPD crystals in areas of cartilaginous metaplasia; four also showed evidence of localised deposition of amyloid. None of the patients had a history of chondrocalcinosis in the hip or other joints. Cartilaginous metaplasia and other changes in periprosthetic tissues may predispose to the deposition of CPPD and associated localised amyloid.  相似文献   
60.
PURPOSE: Hydroxyapatite (HA) spheres used to replace volume after an enucleation are often wrapped with autologous tissue before orbital implantation. Man-made materials are less expensive and pose no risk for viral transmission. The use of expanded polytetrafluoroethylene (ePTFE) to wrap HA spheres was evaluated. METHODS: The medical records of 2 consecutive patients who underwent uncomplicated implantation of an HA sphere wrapped in ePTFE were reviewed. RESULTS: An unusual reaction to the ePTFE material that was nonresponsive to topical or systemic antibiotic therapy developed in these 2 patients. Eventual wound erosion and bacterial infection of the implant necessitated its removal. CONCLUSIONS: Although well tolerated in other surgeries, ePTFE, when used to wrap HA spheres and placed into the orbit, may cause persistent conjunctival discharge, pyogenic granuloma formation, and eventual wound erosion. Therefore, the use of this material to wrap HA spheres is not recommended.  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