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   2058697篇
  免费   150307篇
  国内免费   3229篇
耳鼻咽喉   29699篇
儿科学   64352篇
妇产科学   54571篇
基础医学   291696篇
口腔科学   58299篇
临床医学   179241篇
内科学   408098篇
皮肤病学   44309篇
神经病学   160350篇
特种医学   81775篇
外国民族医学   725篇
外科学   324626篇
综合类   42199篇
现状与发展   3篇
一般理论   578篇
预防医学   147437篇
眼科学   46266篇
药学   156036篇
  5篇
中国医学   4339篇
肿瘤学   117629篇
  2018年   20515篇
  2017年   15729篇
  2016年   17406篇
  2015年   19722篇
  2014年   27301篇
  2013年   40848篇
  2012年   56045篇
  2011年   58996篇
  2010年   35250篇
  2009年   33623篇
  2008年   56912篇
  2007年   60501篇
  2006年   61336篇
  2005年   59447篇
  2004年   57900篇
  2003年   55910篇
  2002年   54870篇
  2001年   107794篇
  2000年   111829篇
  1999年   94407篇
  1998年   23988篇
  1997年   21424篇
  1996年   21859篇
  1995年   20561篇
  1994年   19267篇
  1993年   17789篇
  1992年   73401篇
  1991年   71219篇
  1990年   69126篇
  1989年   66581篇
  1988年   61064篇
  1987年   59813篇
  1986年   55774篇
  1985年   53522篇
  1984年   39194篇
  1983年   33051篇
  1982年   18265篇
  1981年   16337篇
  1979年   34927篇
  1978年   23846篇
  1977年   20437篇
  1976年   18426篇
  1975年   20134篇
  1974年   23836篇
  1973年   22749篇
  1972年   21237篇
  1971年   19687篇
  1970年   18651篇
  1969年   17171篇
  1968年   15576篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Background Familial partial lipodystrophy (FPLD) is a monogenic form of diabetes characterised by a dominantly inherited disorder of adipose tissue associated with the loss of subcutaneous fat from the limbs and trunk, with excess fat deposited around the face and neck. The lipodystrophy causes severe insulin resistance, resulting in acanthosis nigricans, diabetes, dyslipidaemia, and increased risk of cardiovascular disease. Preliminary results from animals and man suggest that increasing subcutaneous fat by treatment with thiazolidinediones should improve insulin resistance and the associated features of this syndrome. Case report We report a 24-year-old patient with FPLD caused by a mutation in the LMNA gene (R482W) treated with 12 months of rosiglitazone. Subcutaneous fat increased following rosiglitazone treatment as demonstrated by a 29% generalised increase in skin-fold thickness. Leptin levels increased from 5.8 to 11.2 ng/ml. Compared with treatment on Metformin, there was an increase in insulin sensitivity (HOMA S% 17.2–31.6) but no change in glycaemic control. The lipid profile worsened during the follow-up period. Conclusion This initial case suggests that, for modification of cardiovascular risk factors, there are no clear advantages in treating patients with FPLD with rosiglitazone despite increases in subcutaneous adipose tissue. Larger series will be needed to identify moderate beneficial effects and treatment may be more effective in patients with generalised forms of lipodystrophy.  相似文献   
72.
The clinical outcome and appropriate management for patients showing 'borderline changes' on allograft biopsy after renal transplantation is still controversial. In an attempt to identify predictive factors of clinical outcome of patients with such lesions, we reviewed the clinical course of 91 patients with borderline changes. Multivariate analysis revealed significant and independent effects of histological stage (i + t < or = or > 2) and time to borderline changes (< or = or > 3 months after transplant) on serum creatinine levels at 1 year from borderline changes episodes (respectively, p = 0.04 and p = 0.02) and only a significant effect of time to borderline changes on serum creatinine levels at 2 years (p = 0.005). Renal function at 1 year and 2 years as 5- and 8-year graft survival were not significantly different in the group of patients treated with antirejection therapy (T group, n = 49) compared with the untreated group (UT group, n = 42). This study strongly suggests that borderline changes with histological score (i + t) > 2 and late episodes of borderline changes should be considered to be of poor prognosis.  相似文献   
73.
The purpose of this study is to determine the role of liver biopsy and outcome of patients undergoing donor evaluation for adult-to-adult right hepatic lobe living donor liver transplantation (LDLT). Records of patients presenting for a comprehensive donor evaluation between 1997 and February 2005 were reviewed. Liver biopsy was performed only in patients with risk factors for abnormal histology. Two hundred and sixty patients underwent a comprehensive donor evaluation and 116 of 260 (45%) were suitable for donation, 14 of 260 (5.4%) did not complete evaluation and 130 of 260 (50%) were rejected. Four patients underwent unsuccessful hepatectomy surgery due to discovery of intraoperative abnormalities. Between 1997 and 2001, the acceptance rate of donor candidates (63%) was higher than 2002-2005 (36%), p < 0.0001. Sixty-six of the 150 eligible patients (44%) fulfilled criteria for liver biopsy and 28 of 66 (42%) had an abnormal finding. Less than half of the patients undergoing donor evaluation were suitable donors and the donor acceptance rate has declined over time. A large proportion of the patients undergoing liver biopsy have abnormal findings. Our evaluation process failed to identify 4 of 103 who had aborted donor surgeries.  相似文献   
74.
In floating hip injuries, the priority of the steps in fixation has not been well described. We have treated these patients in accordance with the following protocols. In patients with pelvic ring fractures, the external fixation should be performed first, and in patients with acetabular fractures, the femoral fractures should be internally fixated first. The purpose of the present study was to review our experience with these fracture treatments to evaluate our strategy. For 8 years, 31 patients with femoral fractures associated with ipsilateral fractures: 26 unstable pelvic ring fractures and 7 unstable acetabular fractures were surgically treated at our level 1 trauma center. We reviewed the admission, operation, and follow-up records retrospectively and evaluated the order of the fixation and the complications. Two patients with acetabular fractures failed to follow our protocol outlined at the preoperative planning stage. There were no surgical difficulties other than two patients with the hemipelvis dislocated proximally who required traction of the fixated femur. The complications that were thought to be related to our protocol were one fat embolism syndrome and one pubic fracture displacement. One heterotopic ossification seemed to occur due to using a single approach for both fractures. We believe our protocol to be generally effective, however, in patients with acetabular and vertical shear type pelvic ring fractures, the internal or external fixation of the femur should be performed before the internal fixation of the pelvis.  相似文献   
75.
76.
We describe the simple adaptation of a standard fluorescent microscope for illumination using a 'Royal Blue' Luxeon light emitting diode (LED) and demonstrate that this form of illumination is suitable for the detection of auramine O stained Mycobacterium spp. The low cost, low power consumption, safety and reliability of LEDs makes them attractive alternatives to mercury vapour lamps.  相似文献   
77.
78.
OBJECTIVE: Gelastic seizures are a frequent and well established manifestation of the epilepsy associated with hypothalamic hamartomas. The scalp EEG recordings very seldom demonstrate clear spike activity and the information about the ictal epilepsy dynamics is limited. In this work, we try to isolate epileptic rhythms in gelastic seizures and study their generators. METHODS: We extracted rhythmic activity from EEG scalp recordings of gelastic seizures using decomposition in independent components (ICA) in three patients, two with hypothalamic hamartomas and one with no hypothalamic lesion. Time analysis of these rhythms and inverse source analysis was done to recover their foci of origin and temporal dynamics. RESULTS: In the two patients with hypothalamic hamartomas consistent ictal delta (2-3 Hz) rhythms were present, with subcortical generators in both and a superficial one in a single patient. The latter pattern was observed in the patient with no hypothalamic hamartoma visible in MRI. The deep generators activated earlier than the superficial ones, suggesting a consistent sub-cortical origin of the rhythmical activity. CONCLUSIONS: Our data is compatible with early and brief epileptic generators in deep sub-cortical regions and more superficial ones activating later. SIGNIFICANCE: Gelastic seizures express rhythms on scalp EEG compatible with epileptic activity originating in sub-cortical generators and secondarily involving cortical ones.  相似文献   
79.
AIM: The intention was to investigate cerebrospinal fluid pressure (CSFP) and volume of cerebrospinal fluid (CSF) drained during and after thoracic- and thoracoabdominal aneurysm repair. The findings were related to the occurrence of postoperative neurologic deficits. METHODS: Twenty-nine patients (12 with thoracic and 17 with thoracoabdominal aortic aneurysm) were operated without shunting or extracorporeal circulation. For monitoring of CSFP an intrathecal catheter was placed in all patients. The volume of CSF withdrawn intraoperatively, on the day of operation as well as on the 1st and 2nd postoperative day was recorded. RESULTS: Twenty-six patients had no postoperative neurologic sequelae. One patient had postoperative paraplegia while 2 had paraparesis. The three patients with neurologic sequelae had higher CSFP intraoperatively than those without neurologic symptoms (P=0.04). Median CSFP during aortic cross-clamping was 19 mmHg and 10 mmHg and the median volumes of CSF drained on the day of operation 210 and 85 mL in the two groups, respectively. There was a significant positive correlation between CSFP and central venous pressure. CONCLUSIONS: A higher intraoperative CSFP was observed in patients with neurologic sequelae following thoracic- and thoracoabdominal aneurysm repair. Further, there was a tendency of higher volumes of CSF drained in this group of patients. Although, the series is too small to allow firm conclusions, it supports the view that CSFP monitoring and drainage is beneficial during thoracic- and thoracoabdominal aneurysm repair.  相似文献   
80.
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