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   544篇
  免费   42篇
耳鼻咽喉   2篇
儿科学   43篇
妇产科学   15篇
基础医学   60篇
口腔科学   11篇
临床医学   57篇
内科学   105篇
皮肤病学   28篇
神经病学   19篇
特种医学   83篇
外科学   81篇
综合类   22篇
预防医学   11篇
眼科学   7篇
药学   23篇
中国医学   1篇
肿瘤学   18篇
  2021年   2篇
  2019年   2篇
  2017年   6篇
  2016年   5篇
  2015年   7篇
  2014年   13篇
  2013年   24篇
  2012年   4篇
  2011年   6篇
  2010年   24篇
  2009年   26篇
  2008年   15篇
  2007年   12篇
  2006年   14篇
  2005年   15篇
  2004年   7篇
  2003年   14篇
  2002年   13篇
  2001年   4篇
  2000年   5篇
  1999年   7篇
  1998年   20篇
  1997年   42篇
  1996年   30篇
  1995年   20篇
  1994年   23篇
  1993年   21篇
  1992年   12篇
  1991年   8篇
  1990年   15篇
  1989年   32篇
  1988年   23篇
  1987年   17篇
  1986年   18篇
  1985年   16篇
  1984年   6篇
  1982年   2篇
  1981年   4篇
  1980年   6篇
  1979年   2篇
  1978年   8篇
  1977年   11篇
  1976年   5篇
  1975年   7篇
  1974年   3篇
  1972年   1篇
  1963年   1篇
  1956年   1篇
  1955年   1篇
  1932年   1篇
排序方式: 共有586条查询结果,搜索用时 15 毫秒
31.
Germ-line mutations in the BRCA1 tumour suppressor gene contribute to familial breast tumour formation, but there is no evidence for direct mutation of the BRCA1 gene in the sporadic form of the disease. In contrast, decreased expression of the BRCA1 gene has been shown to be common in sporadic tumours, and the magnitude of the decrease correlates with disease progression. BRCA1 expression is also tightly regulated during normal breast development. Determining how these developmental regulators of BRCA1 expression are co-opted during breast tumourigenesis could lead to a better understanding of sporadic breast cancer aetiology and the generation of novel therapeutic strategies aimed at preventing sporadic breast tumour progression.  相似文献   
32.
Caloric restriction (CR) has been observed to retard aging processes and extend the maximum life span in rodents. In an effort to evaluate the effect of this nutritional intervention on physiologic variables in higher species, several nonhuman primate trials are ongoing. In particular, a study evaluating the independent effect of CR on the extent of atherosclerosis was initiated in 1993 in 32 adult cynomolgus monkeys. Therefore, the trial was designed to achieve identical cholesterol intake after animals were randomized to a control group or a calorie-restricted group (30% reduction from baseline caloric intake). The animals were routinely evaluated for glycated proteins, plasma insulin and glucose levels, insulin sensitivity, and specific measures for abdominal fat distribution by CT scans over a 4-year interval. The results from 4 years of intervention demonstrate that CR improves cardiovascular risk factors (such as visceral fat accumulation) and improves insulin sensitivity. In contrast to other primate studies with normolipidemic animals, CR had no independent effects on plasma lipid levels and composition in the presence of equivalent amounts of dietary cholesterol intake. Preliminary analysis of atherosclerotic lesion extent in the abdominal aorta has failed to demonstrate differences between control animals and CR animals. Follow- up studies are being conducted to determine the effect of CR on atherosclerosis extent in coronary and carotid arteries.   相似文献   
33.
Percutaneous drainage access: a simplified coaxial technique   总被引:1,自引:0,他引:1  
We describe an access technique that we have used in 150 nephrostomy and biliary drainage procedures and for access to some abscesses and viscera. The system provides safe coaxial access with a 22-gauge removable hub needle, which then acts as a guide wire and is replaced by an 18-gauge cannula. A major advantage is that only one guide wire is used (0.038-inch) for the entire drainage procedure. No significant complications have occurred to date with this method.  相似文献   
34.
35.
36.
37.
The effect of chronic subarachnoid bupivacaine infusion in dogs   总被引:4,自引:0,他引:4  
A functional and histologic examination of the effect of the continuous intrathecal administration of bupivacaine was made in five dogs. After a partial laminectomy at L5, a silicone rubber catheter was inserted into the subarachnoid space and advanced 10 cm cranially. A model 400 Infusaid pump, used for drug delivery, was placed in a subcutaneous pocket between the 13th rib and iliac crest. Drug infusions were individually adjusted and maintained at a concentration such that the animal just exhibited slight gait impairment. Daily bupivacaine doses ranged from 5.7-11.1 mg. Infusions were maintained for a period of 3-16 weeks. Light microscopic examination of spinal cord and roots revealed no abnormalities. A focal mononuclear cell infiltration of the leptomeninges was seen in two drug animals, as well as one catheter control animal. One of the 16-week animals had a residual limp upon drug removal. While we were not able to quantitatively assess the degree of sensory motor dissociation, the results of this study suggest that chronic intrathecal bupivacaine infusion through an implantable pump system may be a short-term alternative to intrathecal morphine in the control of cancer pain.  相似文献   
38.
A prospective evaluation of color flow mapping and real-time ultrasound was performed to determine if pseudoaneurysms could be distinguished from other causes of masses surrounding vascular grafts of the lower extremities. Twelve palpable pulsatile masses were imaged. Diagnoses were confirmed at angiography (n = 11), computed tomography (n = 7), aspiration biopsy (n = 5), and operative intervention (n = 6). A swirling pattern of blood flow was seen in six of seven cases of pseudoaneurysm. Lack of flow signals was noted in four of the five collections representing hematoma (n = 2) or infection (n = 2). The seventh case was later shown to be an infected, thrombosed pseudoaneurysm. The single false-positive diagnosis was made early in the series when the flow signals detected were due to transmitted arterial pulsations. The authors conclude that color Doppler flow imaging is useful in the differential diagnosis of pulsatile masses associated with prosthetic grafts. Prosthetic graft pseudoaneurysms have a specific appearance of swirling blood flow arising from a wide neck and are distinguishable from traumatic or iatrogenic pseudoaneurysms of the native vascular tree.  相似文献   
39.
Background Previous reports have shown an association between psoriasis and the metabolic syndrome, but there are only a few studies on the association between psoriasis and diabetes. Objectives To study the association between psoriasis and diabetes. Methods A cross‐sectional study was performed utilizing the database of Clalit Health Services (CHS). Patients who were diagnosed with psoriasis were compared with CHS enrolees without psoriasis regarding the prevalence of diabetes. Patients with diabetes were identified using the CHS chronic diseases registry. Chi‐squared tests were used to compare categorical parameters. Logistic regression models were used for multivariate analyses. Results The study included 16 851 patients with psoriasis and 74 987 subjects without psoriasis (control patients). The proportion of diabetes was significantly higher in patients above 35 years (P < 0.05). The age‐adjusted proportion of diabetes was significantly higher in psoriasis patients as compared to the control group [odds ratio (OR), 1.38, P < 0.05] and was similar in men and women (OR, 1.32, 1.45, respectively). A multivariate logistic regression model showed that psoriasis was significantly associated with diabetes, independently of age and gender (OR, 1.58, P < 0.001). Conclusions Our study supports previous reports of an association between psoriasis and diabetes. Dermatologists taking care of patients with psoriasis should be aware of this association and advise the patients to reduce additional risk factors such as smoking, hypertension or dyslipidemia.  相似文献   
40.
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