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   167102篇
  免费   6937篇
  国内免费   369篇
耳鼻咽喉   2223篇
儿科学   4884篇
妇产科学   3860篇
基础医学   24080篇
口腔科学   5610篇
临床医学   9566篇
内科学   36965篇
皮肤病学   4601篇
神经病学   13526篇
特种医学   4046篇
外国民族医学   1篇
外科学   19194篇
综合类   781篇
一般理论   24篇
预防医学   20039篇
眼科学   4463篇
药学   13071篇
中国医学   681篇
肿瘤学   6793篇
  2023年   860篇
  2022年   641篇
  2021年   2628篇
  2020年   1487篇
  2019年   2980篇
  2018年   5094篇
  2017年   3184篇
  2016年   3163篇
  2015年   3515篇
  2014年   3911篇
  2013年   5969篇
  2012年   10395篇
  2011年   11009篇
  2010年   5400篇
  2009年   3952篇
  2008年   8926篇
  2007年   9578篇
  2006年   9172篇
  2005年   8755篇
  2004年   8132篇
  2003年   7609篇
  2002年   7229篇
  2001年   4879篇
  2000年   5459篇
  1999年   4165篇
  1998年   727篇
  1992年   2223篇
  1991年   1989篇
  1990年   1976篇
  1989年   1683篇
  1988年   1605篇
  1987年   1502篇
  1986年   1542篇
  1985年   1453篇
  1984年   1039篇
  1983年   892篇
  1979年   1208篇
  1978年   807篇
  1977年   780篇
  1976年   743篇
  1975年   878篇
  1974年   1120篇
  1973年   1166篇
  1972年   1111篇
  1971年   1078篇
  1970年   1007篇
  1969年   1084篇
  1968年   1105篇
  1967年   977篇
  1966年   880篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
151.
152.
The purpose of this study is to determine the importance of two-dimensional echocardiography performed soon after admission to the coronary care unit to provide useful information concerning wall-motion abnormalities, and to detect and characterize left ventricular thrombi. A major goal is to identify a subgroup of patients with acute myocardial infarction who are at risk for systemic embolization; in this subgroup the benefits of anticoagulation treatment would theoretically outweigh the associated risks. We studied 7 consecutive male patients, age range from 32 to 60 years, with acute myocardial infarction. Five patients had antero-septal infarction, 1 anterolateral and another had anterior wall infarction. We performed two-dimensional echocardiography within the first week after admission. All patients had severe apical-wall-motion abnormalities (akinesis or dyskinesis) and left ventricular thrombi. All patients received anticoagulation therapy. Two-dimensional echocardiography, performed one month after the first study, showed that the thrombi had decreased in size in 6 patients and could not be visualized in 1 patient. The noninvasive nature of echocardiography allows serial evaluations of patients with known left ventricular thrombi and permits assessment of the effect of therapy.  相似文献   
153.
We present a case report of a patient suffering from portal and superior mesenteric vein thrombosis secondary to splenectomy. No surgical procedure could be performed due to the extension of thrombus.Local fibrinolysis treatment with urokinase through a percutaneous transhepatic approach was decided upon, and this procedure had a successful patient outcome.  相似文献   
154.
BACKGROUND: Malignant peripheral epineurial tumours are a group of tumours that derive histomorphologically from peripheral nerve sheaths. They occur sporadically, with an incidence of approximately 0.001%, and very rarely require emergency operation. PATIENT AND PROCEDURE: An athletic 19-year-old man presented to an orthopaedic outpatient clinic with lumboischialgia and weakness of the third and fourth left toes. A 12 x 10 x 8-cm paravertebral/retroperitoneal tumour was diagnosed by CT, and the patient was referred to our clinic. For classification, CT-assisted puncture of the tumour was carried out. A haemorrhage into the tumour resulted from the puncture, with consequently lower Hb level and progressive peripheral sensomotoric deficits demanding emergency surgery on a weekend. On this occasion, the tumour was resected together with the L5 and S1 nerve roots through cooperation between the general surgical and neurosurgical departments and was classified as a malignant peripheral epineurial tumour in the rapid stage. Due to the spinal R2 resection, after-loading probes were inserted and the tumour bed was clip-marked. Percutaneous radiotherapy and brachytherapy followed postoperatively. Shortly afterwards, relaparotomy had to be performed due to an adhesive ileus, from which the patient recovered quickly. Chemotherapy was carried out due to a G2 tumour classification. The patient is currently undergoing rehabilitation, during which the peripheral neurological deficits are improving gradually. CONCLUSION: This rare case of a malignant peripheral epineurial tumour with acute symptoms demonstrates the ability of hospitals with maximum care facilities to maintain services even in times of financial cuts in health care services.  相似文献   
155.
BACKGROUND: Artemisia species pollen represents a major cause of allergy in Central Europe. Variations in the pollen season, the influence of climate variables and the prevalence of pollinosis to it were analyzed in Poznan, in western Poland between 1995 and 2004. METHODS: A Hirst volumetric spore trap was used for atmospheric sampling. Pollination date trend analysis and Spearman correlation tests were performed. Skin prick tests (SPT) and allergen specific immunoglobulin (lg)E antibody measurements were performed in 676 and 524 patients, respectively. RESULTS: The Artemisia species pollen season grew longer due to a clear advance in the starting day and only a slightly earlier end point; the peak day also came slightly earlier. Rainfall in the first fortnight of July highly influenced pollen season severity. Temperature was directly correlated with daily Artemisia species pollen levels; relative humidity was inversely correlated. Twelve percent of patients had a positive SPT reaction to Artemisia species. Their symptoms were rhinitis and conjunctivitis (15%), atopic dermatitis (15%), chronic urticaria (14.3%), bronchial asthma (2.4%), and facial and disseminated dermatitis (1.3%). Elevated specific IgE concentrations were detected in the sera of 10.1% of patients. CONCLUSIONS: Artemisia species pollen is an important cause of pollinosis in western Poland. Pollen season intensity is highly influenced by rainfall in the previous weeks. Trends towards earlier season starts and longer duration, possibly caused by climate change, may have an impact on the allergic population.  相似文献   
156.
OBJECTIVE: To study the effect of seasons on the health-related quality of life (HRQL) of asthmatic children. METHODS: Four groups of asthmatic children 7 to 14 years old were recruited by pediatricians during each season of the year. Their HRQL was assessed by means of the Paediatric Asthma Quality of Life Questionnaire (PAQLQ). Other factors surveyed were asthma severity, atopy, medical treatment, immunotherapy, obesity, parental smoking, and anti-allergic measures. RESULTS: The mean (SD) overall PAQLQ score was highest in summer at 6.2 (1.0) and lowest in autumn at 5.5 (1.2). The same trend was found for domains in summer and autumn, respectively: symptoms, 6.2 (1.0) vs 5.4 (1.4); emotions, 6.5 (0.8) vs 6.0 (1.0); and activities, 5.9 (1.4) vs. 5.0 (1.5). Factors such as male gender (odds ratio [OR], 0.60; 95% confidence interval [CI], 0.41-0.87), being on immunotherapy (OR, 0.59; 95% CI, 0.38-0.92), living in an urban environment (OR, 0.56; 0.33-0.93), and residing on the northern coast of Spain along the Bay of Biscay (OR, 0.56; 0.36-0.89) were independent protective factors against having a total PAQLQ score in the lower tertile. Conversely, being recruited in a primary care setting (OR, 1.55; 1.01-2.38) and having more severe asthma were risks for being in the lower tertile. CONCLUSIONS: Irrespective of the severity of the disease, season has a significant influence on the HRQL of asthmatic children.  相似文献   
157.
PTH fragments consisting of the C-terminal portion of the molecule may have biologic effects and may modify the actions of PTH. Evidence for the presence of a C-terminal PTH receptor further supports a biologic role for such fragments. Because C-PTH fragments accumulate in patients with renal insufficiency, it is possible that they may contribute to renal bone disease. The precise role of circulating C-PTH fragments in the pathogenesis, diagnosis, and management of renal osteodystrophy, however, remains to be determined. Future studies of the biologic effects and regulation of these fragments may lead to better understanding of skeletal biology and may also improve our approach to the diagnosis and treatment of renal bone disease.  相似文献   
158.
Coronary angioplasty is known to mediate an inflammatory response. Recently, we have characterized the transient systemic inflammatory response after coronary stent implantation in patients with unstable angina by measuring different soluble protein markers. In the present study we have characterized the expression of various cellular activation markers in neutrophils, monocytes and lymphocytes from the same group of patients. Peripheral blood samples were taken before and 24 h, 48 h and 7 days after successful coronary stenting in 58 patients. Cell surface markers (CD11b/CD18 and CD38) were analyzed by flow cytometry to determine the activation of neutrophils, monocytes and T lymphocytes. We found that coronary angioplasty with stent implantation produces an increase in the cell surface expression of CD11b/CD18 in neutrophils and CD38 in monocytes, following a similar time-course with a peak after 24 h, returning to basal levels after 48 h and a second peak after 7 days. However, T lymphocytes were not found to be activated. These results suggest that coronary stent implantation induces a different pattern inducing soluble and cellular inflammation markers, and therefore, they should be taken into account in patients undergoing stent implantation to study clinical correlations.  相似文献   
159.
160.
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