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   4489篇
  免费   310篇
  国内免费   22篇
耳鼻咽喉   45篇
儿科学   122篇
妇产科学   89篇
基础医学   584篇
口腔科学   118篇
临床医学   372篇
内科学   986篇
皮肤病学   94篇
神经病学   662篇
特种医学   105篇
外科学   802篇
综合类   18篇
预防医学   215篇
眼科学   42篇
药学   207篇
中国医学   3篇
肿瘤学   357篇
  2023年   40篇
  2022年   83篇
  2021年   160篇
  2020年   81篇
  2019年   130篇
  2018年   164篇
  2017年   124篇
  2016年   112篇
  2015年   135篇
  2014年   186篇
  2013年   187篇
  2012年   352篇
  2011年   358篇
  2010年   217篇
  2009年   153篇
  2008年   237篇
  2007年   235篇
  2006年   215篇
  2005年   223篇
  2004年   218篇
  2003年   181篇
  2002年   146篇
  2001年   48篇
  2000年   54篇
  1999年   72篇
  1998年   40篇
  1997年   27篇
  1996年   28篇
  1995年   31篇
  1994年   23篇
  1993年   15篇
  1992年   47篇
  1991年   42篇
  1990年   43篇
  1989年   41篇
  1988年   35篇
  1987年   33篇
  1986年   29篇
  1985年   19篇
  1984年   32篇
  1983年   23篇
  1982年   12篇
  1979年   18篇
  1978年   16篇
  1977年   12篇
  1975年   12篇
  1974年   15篇
  1973年   11篇
  1969年   9篇
  1967年   8篇
排序方式: 共有4821条查询结果,搜索用时 0 毫秒
1.
2.
In this new radioimmunoassay system for determination of amatoxins in urine and plasma, a novel chemical approach is used for antigen and 125I-tracer production, based on a detoxified alpha-amanitin derivative (aldoamanitin). Total assay time, including data processing, is less than 100 min. The lowest detectable concentration is 1 microgram/L for urine, 0.1 microgram/L for plasma. In the clinically significant range, within-run CVs are less than 8%. This new 125I-based assay is a significant improvement over existing 3H technology in terms of speed, precision, and freedom from interference.  相似文献   
3.
Hepatitis is a rare complication of herpes simplex virus (HSV), often leading to acute liver failure (ALF), liver transplantation (LT), and/or death. Our aim was to identify variables associated with either survival or progression (death/LT), based on an analysis of cases in the literature and our institution. A total of 137 cases (132 literature, 5 institutional) of HSV hepatitis were identified. The main features at clinical presentation were fever (98%), coagulopathy (84%), and encephalopathy (80%). Rash was seen in less than half of patients. Most cases (58%) were first diagnosed at autopsy and the diagnosis was suspected clinically prior to tissue confirmation in only 23%. Overall, 74% of cases progressed to death or LT, with 51% in acyclovir-treated patients as compared to 88% in the untreated subjects (P=0.03). Variables on presentation associated with death or need for LT compared to spontaneous survival: male gender, age>40 yr, immunocompromised state, ALT>5,000 U/L, platelet count<75x10(3)/L, coagulopathy, encephalopathy, and absence of antiviral therapy. In conclusion, HSV hepatitis has a high mortality and is often clinically unsuspected. Patients who are male, older, immunocompromised, and/or presenting with significant liver dysfunction are more likely to progress to death and should thus be evaluated for LT early. Based on the frequent delay in HSV diagnosis, low risk-benefit ratio, and significantly improved outcomes, empiric acyclovir therapy for patients presenting with ALF of unknown etiology is recommended until HSV hepatitis is excluded.  相似文献   
4.
5.
6.
The pathophysiological changes in neural activity that characterize multiple system atrophy (MSA) are largely unknown. We recorded the activity of pallidal neurons in 3 patients with clinical and radiological features of MSA who underwent unilateral microelectrode-guided pallidotomy for disabling parkinsonism. Findings in these patients were compared with 4 control patients with a clinical diagnosis of Parkinson's disease (PD). The position, firing rates, and firing patterns of single neurons in the pallidal complex were analyzed in both MSA and PD patients. The mean spontaneous firing rate of neurons in the internal segment of the globus pallidus internus (GPii) was significantly lower in MSA than in PD patients. There were no significant differences between MSA and PD patients, however, in firing rates of neurons in the external globus pallidus (GPe) or in the external segment of GPi (GPie). In addition, no significant differences in firing pattern were found between MSA and PD patients. In conclusion, this study has shown that firing rates of neurons in GPii but not in GPie and GPe are different in MSA patients compared with that in PD patients, a finding that may reflect the poor clinical results of pallidotomy reported in patients with MSA.  相似文献   
7.
8.
OBJECTIVE: To determine the separate and interactive effects of age, phase of the menstrual cycle, menopausal hormone status, body fat mass, and regional fat distribution on glucose tolerance in healthy women. DESIGN: Retrospective study. SETTING: The Baltimore Longitudinal Study of Aging. PATIENTS: Two hundred sixty healthy women aged 22-89 years. MEASUREMENTS: Plasma levels of estradiol and progesterone, body mass index (BMI), waist-to-hip ratio (WHR), and plasma glucose values in the fasting state (FPG) as well as 120 minutes after 40 gm/m2 of oral glucose (G120) were measured for each participant. RESULTS: We found a progressive decline in oral glucose tolerance of 0.4 mM (6.7 mg/dL)/decade at G120) in women from early to late adult years, with no relationship to phase of the menstrual cycle and no abrupt change associated with the menopause. Multiple regression analysis revealed significant, independent effects of BMI and WHR on FPG and G120. The influence of age (P less than 0.01) on G120 was stronger than that of the BMI or WHR (P less than 0.05). There was no significant relationship between the levels of endogenous sex hormones and glucose tolerance after adjustments for age, BMI, and WHR. However, women taking oral contraceptives, but not those receiving postmenopausal replacement therapy, did exhibit mildly elevated G120 values. CONCLUSIONS: Age per se, and to a lesser extent BMI and WHR, but not levels of endogenous sex steroids, contribute to the physiological decline in glucose tolerance in older women.  相似文献   
9.
Aggressive angiomyxoma is a rare tumour that is locally infiltrative but nonmetastasizing. It occurs nearly exclusively in adult women of childbearing age and almost always arises in the perineum and pelvic area. A case of angiomyxoma occurring in a middle-aged, morbidly obese man is reported. The clinical presentation was one of progressing scrotal edema and enlargement with subsequent development of scrotal abscesses, requiring several incisions and drainages as well as oral and intravenous antibiotics. His symptoms and body habitus left him in a significantly debilitated state, prompting him to seek treatment for his conditions. He initially presented for abdominal lipectomy. However, due to the chronic scrotal infections and enlargement, scrotectomy was recommended before any other surgical procedures. A scrotectomy was performed by the urology service. Pathological diagnosis of the excised tumour was an aggressive angiomyxoma. Given the rarity of this tumour, especially in males, the proper diagnosis and treatment of angiomyxoma is still being investigated. With this in mind, the physical signs and symptoms that characterize this condition are presented and treatment options are reviewed.  相似文献   
10.
We present a case of inflammatory bowel disease in which the diagnosis of pylephlebitis was made by ultrasonography. The patient was treated with antibiotics and aspirin and had an uneventful recovery. The sonographic findings are described.  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