全文获取类型
收费全文 | 5155篇 |
免费 | 436篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 82篇 |
儿科学 | 130篇 |
妇产科学 | 107篇 |
基础医学 | 549篇 |
口腔科学 | 244篇 |
临床医学 | 558篇 |
内科学 | 1060篇 |
皮肤病学 | 104篇 |
神经病学 | 337篇 |
特种医学 | 404篇 |
外国民族医学 | 1篇 |
外科学 | 748篇 |
综合类 | 123篇 |
一般理论 | 4篇 |
预防医学 | 344篇 |
眼科学 | 106篇 |
药学 | 231篇 |
1篇 | |
中国医学 | 5篇 |
肿瘤学 | 471篇 |
出版年
2018年 | 55篇 |
2016年 | 50篇 |
2015年 | 51篇 |
2014年 | 71篇 |
2013年 | 106篇 |
2012年 | 157篇 |
2011年 | 175篇 |
2010年 | 112篇 |
2009年 | 95篇 |
2008年 | 169篇 |
2007年 | 214篇 |
2006年 | 213篇 |
2005年 | 181篇 |
2004年 | 174篇 |
2003年 | 191篇 |
2002年 | 182篇 |
2001年 | 174篇 |
2000年 | 183篇 |
1999年 | 148篇 |
1998年 | 75篇 |
1997年 | 66篇 |
1996年 | 57篇 |
1995年 | 73篇 |
1994年 | 60篇 |
1993年 | 65篇 |
1992年 | 129篇 |
1991年 | 142篇 |
1990年 | 121篇 |
1989年 | 128篇 |
1988年 | 151篇 |
1987年 | 158篇 |
1986年 | 139篇 |
1985年 | 155篇 |
1984年 | 95篇 |
1983年 | 105篇 |
1982年 | 69篇 |
1981年 | 61篇 |
1980年 | 53篇 |
1979年 | 82篇 |
1978年 | 77篇 |
1977年 | 60篇 |
1976年 | 71篇 |
1975年 | 51篇 |
1974年 | 55篇 |
1973年 | 58篇 |
1972年 | 52篇 |
1971年 | 53篇 |
1970年 | 50篇 |
1969年 | 45篇 |
1968年 | 41篇 |
排序方式: 共有5609条查询结果,搜索用时 15 毫秒
1.
2.
We treated 100 consecutive ureteral calculi requiring intervention with a previously described algorithm. There were 16 ureteropelvic junction, and 18 upper, 22 mid and 44 lower ureteral calculi. Treatment was by a stent and extracorporeal shock wave lithotripsy in 10 ureteropelvic junction, 10 upper ureteral and 3 mid ureteral calculi, ureteroscopy and extracorporeal shock wave lithotripsy in 6 upper and 6 mid ureteral calculi, and ureteroscopy alone in 5 ureteropelvic junction, 2 upper and 12 mid ureteral calculi. All 44 lower ureteral calculi were treated successfully by ureteroscopy. Of the 100 patients studied 98 were treated by endourological methods (extracorporeal shock wave lithotripsy or ureteroscopy), while 2 required an operation (1 with a ureteropelvic junction calculus and 1 with a mid ureteral calculus). Over-all, 100 patients required a total of 125 procedures to accomplish successful stone removal. An algorithm is developed in which lower ureteral calculi are treated by ureteroscopy, mid ureteral calculi (large and dense) by stent bypass and extracorporeal shock wave lithotripsy or (lucent and fragile) by ureteroscopy, upper ureteral calculi by stent bypass and extracorporeal shock wave lithotripsy without manipulation, and impacted ureteral stones initially by ureteroscopy and, if necessary, then by extracorporeal shock wave lithotripsy. 相似文献
3.
4.
5.
R Shirane H Shimizu M Kameyama P R Weinstein 《Journal of cerebral blood flow and metabolism》1991,11(6):949-956
A new model of temporary complete cerebral ischemia was developed and tested in 64 rats. With use of microsurgical techniques, both pterygopalatine and external carotid arteries were occluded and the basilar artery was coagulated to reduce potential collateral CBF during ischemia. After this preliminary five-vessel occlusion, temporary global ischemia was induced by occluding the common carotid arteries (CCAs) with microclips. To validate the method, CBF was measured autoradiographically in 24 anatomical regions at death after 5 min of ischemia or after 15 min of ischemia followed by 5 min of reperfusion. Mean arterial blood pressure and arterial blood gases remained stable under controlled endotracheal ventilation and anesthesia (halothane, 70% N2O, and 30% O2) throughout the CBF experiments, except for a 10-15% increase in mean arterial blood pressure for 1-5 min after bilateral CCA occlusion. After the initial five-vessel occlusion, the EEG did not change, and local CBF levels were comparable to those in anesthetized non-surgical controls. When the CCAs were occluded, the EEG flattened rapidly; after 5 min of ischemia, autoradiography showed no detectable blood flow in the forebrain and cerebellum. The local CBF levels measured after 15 min of temporary global ischemia and 5 min of reperfusion demonstrated relatively homogeneous postischemic hyperperfusion; only two of eight rats had several 1- to 3-mm areas of no-reflow. Survival studies showed increasing motor impairment after 10, 15, 30, and 60 min of temporary CCA occlusion. Ischemic neuronal damage was observed histologically in the hippocampus and basal ganglia 24 h after 10 min of temporary ischemia.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
6.
7.
8.
Retrolisthesis and lumbar disc herniation: a preoperative assessment of patient function. 总被引:3,自引:0,他引:3
Michael Shen Afshin Razi Jon D Lurie Brett Hanscom Jim Weinstein 《The spine journal》2007,7(4):406-413
BACKGROUND CONTEXT: Retrolisthesis is relatively rare but when present has been associated with increased back pain and impaired back function. Neither the prevalence of this condition in individuals with lumbar disc herniations nor its possible relation to preoperative back pain and dysfunction has been well studied. PURPOSE: The purposes of this study were as follows: (1) to determine the prevalence of retrolisthesis (alone or in combination with other degenerative conditions) in individuals with confirmed L5-S1 disc herniation who later underwent lumbar discectomy; (2) to determine if there is any association between retrolisthesis and degenerative changes within the same vertebral motion segment; and (3) to determine the relation between retrolisthesis (alone or in combination with other degenerative conditions) and preoperative low back pain, physical function, and quality of life. STUDY DESIGN/SETTING: Cross-sectional study. PATIENT SAMPLE: A total of 125 individuals were identified for incorporation into this study. All patients had confirmed L5-S1 disc herniation on magnetic resonance imaging (MRI) and later underwent L5-S1 discectomy. All patients were enrolled in the Spine Patient Outcomes Research Trial (SPORT) study; data were obtained from the multi-institutional database comprised of SPORT patients from across the United States. OUTCOME MEASURES: Retrolisthesis, degenerative change on MRI, and Modic changes. METHODS: MRI scans of the lumbar spine were assessed at spinal level L5-S1 for all 125 patients. Retrolisthesis was defined as posterior subluxation of 8% or more. Disc degeneration was defined as any loss of disc signal on T2 imaging. Modic changes were graded 1 to 3 and collectively classified as vertebral endplate degenerative changes. The presence of facet arthropathy and ligamentum flavum hypertrophy was classified jointly as posterior degenerative changes. RESULTS: The overall incidence of retrolisthesis at L5-S1 in our study was 23.2%. Retrolisthesis combined with posterior degenerative changes, degenerative disc disease, or vertebral endplate changes had incidences of 4.8%, 16%, and 4.8% respectively. The prevalence of retrolisthesis did not vary by sex, age, race, smoking status, or education level when compared with individuals with normal sagittal alignment. However, individuals with retrolisthesis were more likely to be receiving workers' compensation than those without retrolisthesis. Increased age was found to be associated with individuals having vertebral endplate degenerative changes (both alone and in conjunction with retrolisthesis) and degenerative disc disease. Individuals who had retrolisthesis with concomitant vertebral endplate degenerative changes were more often smokers and had no insurance. The presence of retrolisthesis was not associated with an increased incidence of having degenerative disc disease, posterior degenerative changes, or vertebral endplate changes. No statistical significance was found between the presence of retrolisthesis on the degree of patient preoperative low back pain and physical function. Patients with degenerative disc disease were found to have increased leg pain compared with those patients without degenerative disc changes. CONCLUSIONS: We found no significant relationship between retrolisthesis in patients with L5-S1 disc herniation and worse baseline pain or function. It is possible that the contribution of pain or dysfunction related to retrolisthesis was far overshadowed by the presence of symptoms caused by the concomitant disc herniation. It remains to be seen whether retrolisthesis will affect outcome after discectomy in these patients. 相似文献
9.
10.
An ecological approach to public health intervention: Ross River virus in Australia. 总被引:3,自引:2,他引:1
下载免费PDF全文
![点击此处可从《Environmental health perspectives》网站下载免费的PDF全文](/ch/ext_images/free.gif)
P Weinstein 《Environmental health perspectives》1997,105(4):364-366
A detailed look at the ecology of a disease can lead to recommendations for public health interventions that are not otherwise obvious. To illustrate this point, this paper discusses the ecology and control of infection with the Australian arbovirus Ross River virus (RRV). The traditional insecticidal approach to mosquito control is recommended when an outbreak of RRV results from the expansion of an area endemic for the disease to include a population of previously unexposed (nonimmune) people. In contrast, if an outbreak results from the expansion of a non-immune population into an endemic area, an insecticidal approach can lead to an increased incidence of the disease. Education about antimosquito measures is more appropriate in the latter situation; the differing applicability of these intervention strategies is highlighted. Both strategies could be more scientifically applied if endemic areas were clearly defined by modeling ecological variables and if intervention were more closely linked to improved surveillance systems. An ecologically based control strategy must be developed for RRV to manage the disease appropriately when faced with its probable ecological changes brought about by global warming, increased rainfall, and demographic change. Key words: arbovirus, ecology, endemic, epidemic, global change, intervention. 相似文献