全文获取类型
收费全文 | 1249篇 |
免费 | 66篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 11篇 |
妇产科学 | 20篇 |
基础医学 | 184篇 |
口腔科学 | 12篇 |
临床医学 | 109篇 |
内科学 | 233篇 |
皮肤病学 | 45篇 |
神经病学 | 113篇 |
特种医学 | 44篇 |
外科学 | 164篇 |
综合类 | 5篇 |
预防医学 | 123篇 |
眼科学 | 89篇 |
药学 | 80篇 |
中国医学 | 12篇 |
肿瘤学 | 68篇 |
出版年
2024年 | 3篇 |
2023年 | 11篇 |
2022年 | 33篇 |
2021年 | 63篇 |
2020年 | 30篇 |
2019年 | 28篇 |
2018年 | 40篇 |
2017年 | 34篇 |
2016年 | 50篇 |
2015年 | 61篇 |
2014年 | 83篇 |
2013年 | 79篇 |
2012年 | 125篇 |
2011年 | 114篇 |
2010年 | 66篇 |
2009年 | 66篇 |
2008年 | 65篇 |
2007年 | 57篇 |
2006年 | 45篇 |
2005年 | 44篇 |
2004年 | 35篇 |
2003年 | 54篇 |
2002年 | 22篇 |
2001年 | 11篇 |
2000年 | 17篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1966年 | 3篇 |
排序方式: 共有1326条查询结果,搜索用时 500 毫秒
81.
We have earlier reported an increased theta-power value in clozapine (CLO)-treated patients with schizophrenia, nonresponsive to conventional antipsychotics. We also found that the decrease in the production of reactive oxygen species (ROS), induced by CLO, by peripheral blood monocytes (MO) of these patients correlates with clinical improvement. MO share the capability of ROS production with their more mature descendants, microglia of the brain. We hypothesized that the CLO-related changes in peripheral blood MO might be related to a parallel process in microglia and thus be reflected in brain activity. In those 8 patients for whom both QEEG and MO data were available, we explored possible relationships between these parameters. A clear-cut correlation between ROS production (R(2) = 0.929, p < 0.05) for nonstimulated MO, and (R(2) = 0.907, p < 0.001) for stimulated MO and theta-power values in the central frontal electrode (F(z)) was found. It is intriguing to speculate that the EEG slowing is a result of the modulatory action of the activated microglial cells in the central nervous system via production of ROS or cytokines or both. However, this proposition has to be confirmed by future research. 相似文献
82.
Growth hormone-insulin-like growth factor-1 axis,leptin and sleep in anorexia nervosa patients 总被引:1,自引:0,他引:1
Lindberg N Virkkunen M Tani P Appelberg B Rimón R Porkka-Heiskanen T 《Neuropsychobiology》2003,47(2):78-85
The present study characterizes the relationships between severe malnutrition, sleep, growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis, and leptin levels in anorexia nervosa (AN) patients before and after weight gain. Eleven restricting-type anorectic females (mean age = 19.7 years) with severe starvation state [mean body mass index (BMI) = 13.3] were studied using polysomnography and spectral power analysis. The hormone levels were measured in the morning after sleep recording. Eleven normal-weight, age- and gender-matched healthy volunteers without a history of any eating disorder served as controls. After nutritional treatment for about 2 months (65.7 +/- 6.4 days), sleep examinations and blood tests were repeated. At this stage, the study group consisted of 5 patients (mean BMI = 15.6). Higher IGF-1 and leptin levels were associated with longer and deeper sleep among anorectics. The sleep parameters including the percentages of stage 1 sleep and SWS as well as IGF-1 tended to normalize after only limited weight gain. Sleep disturbances in anorectics may be mediated through changes in the levels of the GH-IGF-1 axis hormones, as well as the levels of leptin. 相似文献
83.
We compared the cerebrospinal fluid (CSF) cytology of 30 acutely psychotic patients at the initial phase of their hospital treatment with that of 46 control individuals with no psychiatric disorder or central nervous system (CNS) disease. The cytological profile of May-Grünwald-Giemsa stained CSF cell slides of the patients was significantly different from that of the control population. The most striking finding was a significantly increased frequency of lymphoid cells showing morphological features of activation/stimulation and a decreased proportion of normal small lymphocytes. Many of the cells with aberrant morphology displayed structural details similar to those of the 'P cells' previously described in the blood of schizophrenic patients. The patients' CSF also contained elevated proportions of monocytes/macrophages, some of which were found in 'rosettes' with activated lymphocytes indicating an increased intercellular adhesion. Possible pathogenic mechanisms behind lymphocyte activation and macrophage dominance in the CSF of acutely ill psychotic patients are discussed. 相似文献
84.
85.
86.
87.
88.
J W Ha B K Lee H J Kim W B Pyun K H Byun S J Rim N Chung 《Journal of the American Society of Echocardiography》2001,14(11):1100-1106
Mitral stenosis (MS) and mitral regurgitation (MR) are the most frequent conditions that cause a dilation and dysfunction of the left atrial appendage (LAA). Despite similarly dilated LAA in patients with MS and MR, the incidence of LAA thrombi and the risk of thromboembolism is different between these patients. The purpose of this study was to characterize the filling pattern of LAA by using intravenous administration of perfluorocarbon-exposed dextrose albumin (PESDA) during transesophageal echocardiographic examination in patients with MS and MR. Twenty-four patients with moderate to severe MS, 12 patients with severe MR, and a control group including 30 patients with conditions other than mitral valve disease underwent transesophageal echocardiographic examination with an intravenous bolus injection of PESDA. LAA emptying and filling velocities and maximal and minimal areas of LAA and LAA ejection fraction were measured. Digital gray-scale intensity (GSI) of the left atrial (LA) and LAA cavity after PESDA injection was measured by off-line analysis. Compared with control patients, patients with MS or MR had larger maximal and minimal areas of LAA and reduced LAA ejection fraction. LAA peak emptying flow velocity was significantly lower in patients with MS compared with those of MR or control patients. LAA peak filling velocity was significantly lower in patients with MS compared with that of control patients. However, there was no significant difference of LAA peak filling velocity between the patients with MS and MR. There was no significant difference of GSI ratio of LAA and LA between patients with MR and control patients; however, GSI ratio of LAA and LA was significantly lower in patients with MS compared with that of MR. The incidence of LAA spontaneous echo contrast and LAA thrombi in patients with MS was significantly higher than that of the patients with MR and control subjects (P <.005). Despite similarly dilated LAA area and depressed contractile function of LAA in patients with MS and MR compared with control patients, profoundly impaired LAA filling with resultant flow stasis was demonstrated by contrast echocardiography in patients with MS. These findings may explain the higher incidence of LAA spontaneous echo contrast and thrombus in patients with MS. 相似文献
89.
Howard Leong-Poi MD Elizabeth Le MD Se-Joong Rim MD Tadamichi Sakuma MD Sanjiv Kaul MD Kevin Wei MD 《Journal of the American Society of Echocardiography》2001,14(12):1173-1182
Although regional myocardial perfusion can be currently quantified with myocardial contrast echocardiography (MCE) by using intermittent harmonic imaging (IHI), the method is tedious and time-consuming in the clinical setting. We hypothesized that regional myocardial perfusion can be quantified and the severity of coronary stenosis determined during hyperemia with MCE using real-time imaging (RTI) where microbubbles are not destroyed. Six open-chest dogs were studied during maximal hyperemia induced by adenosine in the absence or presence of coronary stenoses varying from mild to severe. Myocardial blood flow (MBF) was measured at each stage by using radiolabeled microspheres. MCE was performed using both IHI and RTI. Data for the latter were acquired in both end-systole and end-diastole. No differences were found between myocardial flow velocity (MFV) derived from IHI and RTI when end-systolic frames were used for the latter. MFV was consistently higher for RTI (P <.01) when end-diastolic frames were used. A linear relation was noted between MFV and radiolabeled microsphere-derived MBF ratios from the stenosed and the normal beds when end-systolic frames were used for RTI (r = 0.78, P <.001), whereas no relation was found when end-diastolic frames were used (r = 0.08, P =.78). The scatter for assessing MBF (A.beta) was minimal for IHI and RTI (9%-10%) with end-systolic frames, whereas that for RTI with end-diastolic frames was large (30%). Furthermore the correlation with radiolabeled microsphere-derived MBF was significantly (P <.01) weaker with RTI when end-diastolic frames were used (r = 0.53) than when end-systolic frames (r = 0.94) or IHI was used (r = 0.99). Data acquisition for IHI was 10 minutes, whereas it was 8 seconds for RTI. Thus, RTI can be used to quantify regional myocardial perfusion and stenosis severity during MCE. Only end-systolic frames, however, provide accurate data. RTI offers a rapid and easy means of assessing regional myocardial perfusion with MCE. 相似文献
90.