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   1210篇
  免费   46篇
  国内免费   4篇
耳鼻咽喉   6篇
儿科学   52篇
妇产科学   12篇
基础医学   220篇
口腔科学   31篇
临床医学   175篇
内科学   172篇
皮肤病学   23篇
神经病学   30篇
特种医学   187篇
外国民族医学   1篇
外科学   120篇
综合类   50篇
预防医学   47篇
眼科学   5篇
药学   80篇
中国医学   4篇
肿瘤学   45篇
  2021年   14篇
  2018年   17篇
  2017年   14篇
  2016年   18篇
  2015年   16篇
  2014年   21篇
  2013年   35篇
  2012年   28篇
  2011年   29篇
  2010年   54篇
  2009年   45篇
  2008年   33篇
  2007年   30篇
  2006年   21篇
  2005年   20篇
  2004年   16篇
  2003年   16篇
  2002年   16篇
  2001年   12篇
  2000年   19篇
  1999年   16篇
  1998年   39篇
  1997年   35篇
  1996年   36篇
  1995年   39篇
  1994年   24篇
  1993年   23篇
  1992年   19篇
  1991年   32篇
  1990年   23篇
  1989年   40篇
  1988年   37篇
  1987年   33篇
  1986年   44篇
  1985年   40篇
  1984年   31篇
  1983年   25篇
  1982年   21篇
  1981年   17篇
  1980年   17篇
  1979年   18篇
  1978年   27篇
  1977年   11篇
  1976年   15篇
  1975年   16篇
  1974年   13篇
  1973年   12篇
  1972年   12篇
  1970年   11篇
  1966年   11篇
排序方式: 共有1260条查询结果,搜索用时 15 毫秒
41.
Bilbey  JH; Muller  NL; Connell  DG; Luoma  AA; Nelems  B 《Radiology》1989,171(2):381-384
Diagnosis of the thoracic outlet syndrome is often difficult, particularly in patients without osseous abnormalities on plain radiographs. The radiographic and computed tomographic (CT) findings were reviewed from 27 patients with thoracic outlet syndrome and 21 normal subjects. The plain radiographs and CT scans were assessed by two independent observers without awareness of the clinical history. Fifteen patients with thoracic outlet syndrome had osseous abnormalities (anomalous cervical ribs; abnormally long, drooping C-7 transverse processes) identifiable on plain radiographs. CT did not provide further diagnostic information in the patients with abnormal radiographs. Eight of 12 patients (66%) with normal plain radiographs had abnormal findings on CT scans, consisting of impingement of the C-7 transverse process on the scalene triangle or anteromedial aspect of the middle scalene muscle. Only two of 21 control patients (9.5%) displayed this CT abnormality (P less than .01). CT may be useful in patients with symptoms suggestive of thoracic outlet syndrome and no osseous abnormalities on plain radiographs.  相似文献   
42.

Purpose

We compared renal function outcomes among patients in the surveillance and intervention arms of the DISSRM registry.

Materials and methods

Patients were grouped into chronic kidney disease stages by estimated glomerular filtration rate range. Cases were considered up staged if a more advanced chronic kidney disease stage was entered during followup. Chronic kidney disease up staging-free survival was compared among groups using Kaplan-Meier analysis and paired comparisons log rank tests. Multivariate Cox regression identified independent predictors of chronic kidney disease up staging-free survival.

Results

A total of 162 patients met the study inclusion criteria, with 68 in the surveillance arm, 65 undergoing partial nephrectomy, 15 undergoing radical nephrectomy, and 14 undergoing cryoablation. Median tumor size was 2.2 cm. Mean estimated glomerular filtration rate change was significantly larger for radical nephrectomy vs. surveillance (?9.2 vs. ?0.5 ml/min/1.73 m2) and for radical vs. partial nephrectomy (?9.2 vs. ?1.9 ml/min/1.73 m2) (P = 0.001). No other groups differed significantly. On Kaplan-Meier analysis, patients undergoing radical nephrectomy had significantly worse chronic kidney disease up staging-free survival vs. those treated with partial nephrectomy (P = 0.029), surveillance (P = 0.007), and cryoablation (P = 0.019). No other groups differed significantly. On multivariate analysis, radical nephrectomy independently predicted poor chronic kidney disease up staging-free survival (odds ratio vs. surveillance 30.6, P = 0.001). Neither partial nephrectomy (P = 0.985) nor cryoablation (P = 0.976) predicted poor chronic kidney disease up staging-free survival relative to surveillance.

Conclusions

Patients in the surveillance arm had superior estimated glomerular filtration rate preservation compared to those in the radical nephrectomy but not the partial nephrectomy arm. In certain patients with small renal masses, surveillance and partial nephrectomy may offer comparable renal functional outcomes. This could be partly attributable to a modest estimated glomerular filtration rate decrease associated with surveillance itself. A thorough understanding of the renal functional impacts of treatment modalities is critical in the management of small renal masses.  相似文献   
43.
44.
Superficial- and deep-tissue heating was measured in five dogs during high-specific-absorption-rate radiofrequency (RF) irradiation to see whether significant temperature changes could be produced by a 1.5-T clinical magnetic resonance imager. The RF power output employed was 6.3 times that required for routine imaging. Temperature probes were placed in both deep and superficial tissues, and temperatures were recorded before, during, and after exposure. In each dog, there was a linear temperature increase of several degrees during RF exposure; the maximal average change was 4.6 degrees C in the urinary bladder. The temperature increase was slightly greater in deep tissues than in superficial tissues. The calculated specific absorption rate, based on the temperature change, averaged 7.9 W/kg for all five dogs. These findings argue for continued caution in the design and operation of imagers capable of high specific absorption rates, particularly when they are used for imaging infants or patients with altered thermoregulatory capability.  相似文献   
45.
46.
47.
48.
Summary. The clinical significance of placental perforation and bloodstained amniotic fluid was studied in a group of 7238 Danish women undergoing mid-trimester amniocentesis for prenatal diagnosis under ultrasound guidance. The risk of spontaneous abortion was significantly increased both in pregnancies where the placenta was perforated and in those with blood-stained amniotic fluid. The risk estimate nearly doubled after placental perforation and more than doubled with a bloody tap. It is concluded that for women at relatively low risk of a fetal genetic abnormality, the indication of the amniocentesis should be reconsidered if a placental perforation is unavoidable.  相似文献   
49.
Ferritin was assayed by immunoradiometrical procedure in peritoneal fluid (26 patients with various ovarian pathologies) and gastric juice (18 patients with stomach cancer and 28 cases of gastric ulcer disease). It was found that diagnostic significance of ferritin measurements in peritoneal fluid in ovarian pathology is compromised by inflammation. Therefore, this marker cannot be used to differentiate between malignant and benign ovarian tumor. Single measurements of ferritin for detecting stomach ulcers were also diagnostically irrelevant since the data for stomach cancer and gastric ulcer exacerbation showed no significant difference.  相似文献   
50.
Moderate and severe malnutrition are endemic in much of the developing world and in association with pockets of deprivation in the developed world. The cost in terms of individual and social development is high. The principles of effective management are clearly documented. A low cost, community based treatment programme for moderately and severely malnourished children under 3 years of age was established at a health centre in rural Jamaica. Children were followed up monthly and defaulters were rigorously recalled. Management consisted of carefully delivered dietary advice, antibiotics, anthelminthics, and vitamin supplements. All children improved and the response of 36 children, who were treated in the first year, showed an accelerated weight gain, with catch-up growth and the maintenance of length gain. There was a significant increase in the weight for age, at 1.9% per month over six months, which exceeds the rate reported with food supplementation programmes and nutrition rehabilitation centres.  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