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   498篇
  免费   26篇
耳鼻咽喉   7篇
儿科学   44篇
妇产科学   2篇
基础医学   36篇
口腔科学   6篇
临床医学   34篇
内科学   127篇
皮肤病学   20篇
神经病学   42篇
特种医学   1篇
外科学   75篇
综合类   5篇
预防医学   12篇
眼科学   9篇
药学   56篇
中国医学   3篇
肿瘤学   45篇
  2021年   6篇
  2017年   3篇
  2016年   10篇
  2015年   11篇
  2014年   6篇
  2013年   10篇
  2012年   8篇
  2011年   3篇
  2010年   16篇
  2009年   12篇
  2008年   2篇
  2007年   9篇
  2006年   24篇
  2005年   8篇
  2004年   10篇
  2003年   12篇
  2002年   13篇
  2001年   4篇
  2000年   3篇
  1999年   8篇
  1998年   28篇
  1997年   35篇
  1996年   18篇
  1995年   31篇
  1994年   14篇
  1993年   12篇
  1992年   10篇
  1991年   10篇
  1990年   7篇
  1989年   4篇
  1988年   7篇
  1987年   9篇
  1986年   10篇
  1985年   8篇
  1984年   5篇
  1983年   4篇
  1982年   4篇
  1981年   5篇
  1980年   5篇
  1979年   2篇
  1978年   2篇
  1977年   5篇
  1975年   2篇
  1964年   3篇
  1959年   6篇
  1958年   16篇
  1957年   21篇
  1956年   12篇
  1955年   21篇
  1954年   23篇
排序方式: 共有524条查询结果,搜索用时 15 毫秒
21.
Hypertension is a major problem of patients with chronic renal failure or renal transplant recipients. To clarify the characteristics of blood pressure, heart rate, and circadian rhythms of these patients we used an ambulatory blood pressure monitor (ABPM) for 24 h monitoring and analyzed the data by the cosinor method. In eight chronic renal failure patients without dialysis the midline estimating statistic of rhythm (MESOR) of diastolic blood pressure was higher than in controls, but the MESOR of systolic blood pressure was not. Of 11 patients on dialysis some had hypertension and some had hypotension. In 14 renal transplant recipients, especially those with chronic graft rejection, the MESOR of systolic and diastolic pressures were higher than controls, and the increase of blood pressure MESOR had a significant correlation with the elevation of serum creatinine levels. Circadian rhythms of blood pressure were frequently absent in the patients on dialysis, but circadian rhythms of heart rate were not. The use of an ABPM is a non-invasive method to monitor patients and allowed us to know changes of blood pressure and heart rate in the daytime as well as during the night. For the control of hypertension in chronic renal failure, monitoring with an ABPM seems to provide invaluable information.  相似文献   
22.
To observe the secular trend of a proportion of Kawasaki disease patients with cardiac sequelae in Japan, we analyzed patients with Kawasaki disease reported to nationwide surveys of the disease during 10.5 years from July 1982 to December 1992. Of 69 382 patients reported to the surveys, 10 596 (15.3%) were reported to have cardiac sequelae such as dilatation or stenosis of coronary arteries, myocardial infarction or valvar lesions, 1 month or more after onset. The percentage of cardiac sequelae was particularly high in males, infants younger than 1 year and children older than 5 years of age. The overall prevalence declined steadily over the observed period. However, the percentage for children older than 5 years of age did not decrease, whether treated with intravenous gamma globulin or untreated. As a consequence of the increased number of patients treated with intravenous gamma globulin, the proportion of Kawasaki disease patients with cardiac sequelae decreased annually. However, the proportion of children older than 5 years of age did not decrease.  相似文献   
23.
Acute upper gastrointestinal bleeding (UGIB) is a frequent diagnosis prompting hospital admission or complicating another preexisting condition. This report examines the experience of an urban medical center in the utilization of endoscopy and endoscopic hemostasis in the diagnosis and management of UGIB over a four-year period. The first portion of this study examines 562 admissions to a single institution with UGIB. The most common causes of bleeding were acute gastric mucosal lesions (AGML), 24%; esophageal varices (EV), 22%; gastric ulcers, 19%; duodenal ulcers, 14%; Mallory-Weiss tears, 11%; and esophagitis, 3%. Nonoperative treatment was sufficient in the majority of patients (89.5%). Endoscopic therapy was utilized in 144 patients (26%), of whom 12 required a subsequent operation. Fifty-eight patients (10.5%) underwent surgery; however, emergent operations were required in only 2.5% of the patients. Factors correlating with mortality included shock at the time of admission (SBP < 80), transfusion requirements of > 5 U PRBC, and presence of EV (each p < 0.001). The second part of this study examines the effect of thrombogenic sclerotherapy on both short and long-term survival in 101 patients referred with bleeding esophageal varices. Alcoholic cirrhosis was responsible for the majority (88%) of EV, and most patient were Child's C classification (84%). In long-term follow-up, rebleeding was significantly reduced (p = 0.03) in patients compliant with follow-up sclerotherapy. A trend toward decreased mortality was noted in patients compliant with sclerotherapy and in those who avoided further alcohol usage.  相似文献   
24.
BACKGROUND: Recent studies of chronic lung disease (CLD) of newborns emphasize the contribution of antenatal infection. However, the association of Ureaplasma urealyticum infection and CLD has been controversial. The purpose of the present paper was to determine whether U. urealyticum is associated with chorioamnionitis (CAM) and a certain type of CLD. METHODS: One hundred and five infants <32 weeks of gestation who were admitted to the neonatal intensive care unit at Jichi Medical School Hospital, who underwent both histological and microbiological examinations and who survived to discharge were included. CAM was determined by histological examination. Placenta, gastric and tracheal aspirates, and nasopharyngeal swabs were cultured for Mycoplasma and other microorganisms. CLD was defined as oxygen needed at 28 days of age with symptoms of persistent respiratory distress and hazy or emphysematous and fibrous appearance upon X-ray. CLD was further divided into two subtypes according to the presence of antenatal infection. RESULTS: CAM was associated with premature rupture of membrane (odds ratio [OR], 10.19; 95% confidence interval [CI]: 3.10-33.56), placental colonization of U. urealyticum (OR 6.73, 95%CI: 1.89-23.91), neonatal colonization of other microorganisms (OR 7.33, 95%CI: 1.22-44.13) and level of IgM (OR 1.06, 95%CI: 1.01-1.11). Comparisons between CLD and non-CLD patients showed that gestational age (OR 0.43, 95%CI: 0.30-0.61) and white blood cell count (WBC) at birth (OR 1.06, 95%CI: 1.01-1.11) were risk factors for CLD, while gestational age (OR 0.38, 95%CI: 0.23-0.64), neonatal colonization of U. urealyticum (OR 5.98, 95%CI: 1.17-30.6) and WBC (OR 1.08, 95%CI: 1.01-1.15) were independent risk factors for infection-related CLD compared with non-CLD. Within CLD, infection-related CLD was associated with neonatal colonization of U. urealyticum (OR 43.7, 95%CI: 2.84-673.8) and WBC (OR 1.27, 95%CI: 1.07-1.50). CONCLUSIONS: Placental colonization of U. urealyticum was significantly related to CAM; and neonatal colonization of U. urealyticum and leukocytosis at birth were risk factors for infection-related CLD.  相似文献   
25.
This paper evaluates the loss of power of the simple and stratified logrank tests due to heterogeneity of patients in clinical trials and proposes a flexible and efficient method of estimating treatment effects adjusting for prognostic factors. The results of the paper are based on the analyses of survival data from a large clinical trial which includes more than 6000 cancer patients. Major findings from the simulation study on power are: (i) for a heterogeneous sample, such as advanced cancer patients, a simple logrank test can yield misleading results and should not be used; (ii) the stratified logrank test may suffer some power loss when many prognostic factors need to be considered and the number of patients within stratum is small. To address the problems due to heterogeneity, the Cox regression method with a special hazard model is recommended. We illustrate the method using data from a gastric cancer clinical trial. © 1997 by John Wiley & Sons, Ltd.  相似文献   
26.
The metallic stent has become the most common device to reduce acute occlusion and late restenosis after balloon angioplasty, but the long-term effects of metallic stents in human coronary arteries are still unknown. To overcome several problems of conventional stenting, there have been many attempts to manufacture stents made of biodegradable materials. Although some studies have noted various degrees of inflammatory responses after biodegradable stent implantation, stents made of poly-1-lactic acid (PLLA) showed high biocompatibility with minimal inflammatory response and neointimal formation in porcine coronary arteries. A clinical study of PLLA self-expanding stent implantation is underway in Japan. The initial and 6-month results are favorable and suggest the feasibility, safety, and efficacy of the PLLA biodegradable stent in humans. However, long-term follow-up with larger numbers of patients will be required to validate the long-term efficacy of PLLA stents.  相似文献   
27.
目的:为进一步研究isoline的代谢和毒理,采用化学方法制备其代谢产物。方法:分别采用水解,氮氧化和脱氢化反应将isoline转化为与代谢和毒理研究相关类型的产物。结果与结论:成功地制备了五个化合物,其中两个为新化合物,其结构经UV,IR.MS和NMR分析得以鉴定。  相似文献   
28.
We report a case with rapidly growing subcutaneous and intra-muscular tumours that were identical histopathologically to a pre-existing left atrial myxoma. No invasion of visceral organs or skeleton was found. This is a very rare case of metastasizing myxoma with wide dissemination and rapid metastastic growth, despite the benign appearance of the original tumour.  相似文献   
29.
Macrolides are effective for inflammatory acne, but there are not many studies on roxithromycin. In this study, patients with acne were surveyed for improvement of their quality of life after treatment with roxithromycin. Patients were orally given roxithromycin 300 mg daily for 2–4 weeks. At the time of pre- and post-treatment, the dermatologists graded the severity of acne symptoms, and the patients answered questionnaires. In 123 half faces of 76 patients, 80 half faces were improved, 42 half faces were not changed, and one half face was deteriorated. The score of "symptom and feeling" and "leisure" in DLQI-J and "emotions" and "symptoms" in Skindex-29-J were significantly decreased after roxithromycin treatment. Roxithromycin has a therapeutic effect on inflammatory acne and leads to improvement of quality of life in the patients.  相似文献   
30.
Summary  Knowledge of the standard value of the occlusal curvature would be helpful when providing oral rehabilitation for patients with or without occlusal derangement. Dentists often use a 4-inch radii arc as the standard based on Monson spherical theory. However, the validity of application of this theory in Japanese has not yet been verified. The objective of this study was to determine the typical shape of the occlusal curvature in Japanese adults and investigate the relative contribution of each factor to the depth of the curvature, as the initial phase, to prove the validity of determination of occlusal curvature. Seventy-nine Japanese adults (42 males and 37 females, aged 18 to 37 years) with intact dental arches were recruited, and the occlusal curvature was estimated by calculating the radius and center position of the approximate sphere. Besides, the relative contribution of gender, age, dental arch length and width, overjet, overbite for the radii was calculated. The median radius of the sphere was 110·6 mm, larger than the 4-inch value advocated by Monson. This indicates the necessity to reconsider the application of the method of occlusal plane analysis in Japanese individuals. Median position of the centre was 64·6 mm anterior to and 68·5 mm above the mid-point between condyles. Relative contribution of overbite for the radii was 10·9%, the highest amongst the factors. Therefore, a typical shape of the occlusal curvature was observed in Japanese subjects. Overbite is considered as one of the principal factors correlated to the depth of the occlusal curvature.  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