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   22800篇
  免费   2120篇
  国内免费   662篇
耳鼻咽喉   309篇
儿科学   588篇
妇产科学   447篇
基础医学   1774篇
口腔科学   227篇
临床医学   2604篇
内科学   4653篇
皮肤病学   287篇
神经病学   2098篇
特种医学   453篇
外国民族医学   3篇
外科学   4408篇
综合类   2639篇
现状与发展   1篇
预防医学   1029篇
眼科学   461篇
药学   2138篇
  10篇
中国医学   871篇
肿瘤学   582篇
  2024年   101篇
  2023年   543篇
  2022年   905篇
  2021年   1385篇
  2020年   1151篇
  2019年   1036篇
  2018年   1014篇
  2017年   1020篇
  2016年   1021篇
  2015年   980篇
  2014年   1619篇
  2013年   1798篇
  2012年   1177篇
  2011年   1312篇
  2010年   1061篇
  2009年   1105篇
  2008年   1075篇
  2007年   955篇
  2006年   1015篇
  2005年   846篇
  2004年   708篇
  2003年   632篇
  2002年   454篇
  2001年   431篇
  2000年   314篇
  1999年   258篇
  1998年   173篇
  1997年   175篇
  1996年   169篇
  1995年   128篇
  1994年   128篇
  1993年   83篇
  1992年   101篇
  1991年   78篇
  1990年   66篇
  1989年   62篇
  1988年   62篇
  1987年   44篇
  1986年   50篇
  1985年   52篇
  1984年   55篇
  1983年   41篇
  1982年   52篇
  1981年   34篇
  1980年   38篇
  1979年   20篇
  1978年   19篇
  1977年   11篇
  1976年   10篇
  1975年   5篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Sympathetic skin response (SSR) and R–R interval variation (RRIV) were studied in 36 chronic, nondiabetic uremics to compare with their nerve conduction studies (NCS) and clinical dysautonomia. Abnormal SSR was noted in 5 (13.9%) patients, abnormal RRIV in 14 (38.9%), and abnormal NCS in 26 (72.2%). The patients were classified into three groups: group (GP) 1: “normal,” n = 21 (58.3%), normal RRIV and SSR; GP 2: “isolated parasympathetic dysfunction,” n = 10 (27.8%), abnormal RRIV and normal SSR; and GP 3: “sympathetic sudomotor dysfunction,” n = 5 (13.9%), abnormal SSR. A significant difference in age was found among the three groups (GP 3 > GP 2 > GP 1; P < 0.0001, ANOVA). After controlling the age factor, we still noted a tendency toward increasing NCS disturbances (distal latency and nerve conduction velocity of peroneal nerve; P < 0.05, multiple regression analysis) and frequencies of clinical autonomic symptoms (postural dizziness and impotence; P < 0.05, Mantel–Hanszel test) from GP 1 to GP 3. Patients with abnormal SSR (GP 3) displayed significantly higher frequencies of postural dizziness and impotence, indicating the relationship between an absence of SSR and clinical dysautonomia. © 1994 John Wiley & Sons, Inc.  相似文献   
62.
儿童感觉统合失调及其影响因素的调查分析   总被引:17,自引:1,他引:16  
目的 研究儿童感觉统合失调与学习障碍及环境因素的关系。方法 采用感觉统合评定量表和学习障碍(PRS)筛查量表,分别对755名学龄儿童进行检测、分析。结果 感觉统合严重失调率为13.25%;感觉统合正常与失调儿童的学习障碍有统计学差异(P<0.005);其中在LD儿童中感觉统合失调率占63.51%;感觉统合失调与母孕期的情绪、是否足月顺产、出生后的喂养方式、居住环境、孩子1岁内有无高热、家长对孩子的态度及期待等因素有关(P<0.05)。结论 儿童感觉统合失调与环境因素、学习障碍有一定的关系。  相似文献   
63.
64.
BACKGROUND: Patients with diabetes mellitus have a high incidence of coronary heart disease and congestive heart failure (CHF). Thiazolidinediones (TZD) are a new class of pharmacological agents for the treatment of Type 2 diabetes mellitus, which have many beneficial cardiovascular effects. Peripheral oedema and weight gain have been reported in 4.8% of subjects on TZDs alone, with a higher incidence noted in those receiving combination insulin therapy (up to 15%), but there is limited data on the occurrence of CHF. METHODS AND RESULTS: In this paper, we report on six cases of TZD-induced fluid retention with symptoms and signs of peripheral oedema and/or CHF that occurred in subjects attending our diabetic clinic. The predominant finding in all cases was of diastolic dysfunction. All subjects were obese and hypertensive, with 5/6 having the additional risk factor of LVH, 5/6 subjects had microvascular complications, whilst 3/6 were also on insulin therapy. CONCLUSION: We suggest that obese, hypertensive diabetics may benefit from echocardiographic screening prior to commencement of TZDs, as these agents may exacerbate underlying undiagnosed left ventricular diastolic dysfunction.  相似文献   
65.
Examination is a cornerstone in the manual procedures leading to mobilisation/manipulation of the low back. The observer variation of the more specific segmental tests remains to be investigated. Two skilled specialists in manual medicine examined the segmental changes in the lumbar spine. The patients were unknown to the examiners and no information of the case history was given. All test results were recorded by an observer present in the room who ensured that no conversation was allowed during the examination. The primary outcome measures were the kappa values for each test. The matching was defined as acceptable (acc) within two neighbouring levels and perfect (per) on the same level. Intra-observer variation (tested in 33 patients and 10 subjects without low-back pain): The agreement between first and second segmental diagnosis examination was 70% (per) and 82% (per + acc). Kappa values were: segmental diagnosis 0.60 (per) and 0.70 (per + acc), multifidus test 0.51 (per) and 0.60 (per + acc), sideflexion 0.57 (per) and 0.69 (per + acc), and ventral flexion 0.31 (per) and 0.45 (per + acc). Inter-observer variation (tested in 60 patients): The agreement for segmental diagnosis between the examiner A and B was 42% (per) and 75% (per + acc). Kappa values were: segmental diagnosis 0.21 (per) and 0.57 (acc), multifidus test 0.12 (per) and 0.48 (acc), sideflexion 0.22 (per) and 0.45 (acc), and ventralflexion 0.22 (per) and 0.44 (acc). By manual tests, skilled examiners seem to be able to diagnose segmental dysfunctions in the low back. The clinical implication of these dysfunctions remains to be clarified.  相似文献   
66.
Objective To assess the value of detecting sympathetic skin response (SSR) in the diagnosis of autonomic dysfunction in patients with Parkinson disease (PD). Methods SSR measurement was performed in 47 PD patients and 20 healthy control subjects and the results were compared. The SSR was also comparatively analyzed between patients with and those without autonomic dysfimction. Results Compared with the healthy controls, the PD patients showed significantly lowered mean amplitude (2.56±1.47 vs 1.87±0.26, P<0.05) and prolonged latency (1.42±0.29 vs 1.55± 0.18, P<0.05) of the SSR in the upper limbs, with also lowered mean amplitude (0.76±0.39 vs 0.49±0.21, P<0.05) and prolonged latency (2.04±0.27 vs 2.13±0.16, P<0.05) in the lower limbs. Compared with the PD patients without autonomic dysfunction, those having autonomic dysfunction showed significantly lowered mean amplitude (1.89±0.33 vs 1.75±0.21, P<0.05) and prolonged latency (1.53±0.15 vs 1.56±0.17, P<0.05) of SSR in the upper limbs and lowered mean amplitude (0.51±0.17 vs 0.46±0.20,P<0.05) and prolonged latency (2.08±0.24 vs 2.17±0.18, P<0.05) in the lower limbs. Conclusion The results of SSR measurements are consistent with the clinical manifestations of the PD patients. SSR can be of value in the diagnosis of autonomic nerve dysfunction in PD.  相似文献   
67.
用荧光探剂DPH研究家蝇线粒体膜脂流动性   总被引:1,自引:0,他引:1  
本文探讨了用DPH作为荧光探剂,研究家蝇飞翔肌线粒体膜脂流动性的方法。实验表明:DPH确是用来研究家蝇生物膜流动性的有效探剂。同时,初步观察了不同杀虫剂对DPH与线粒体膜结合后荧光强度的影响。其中氯菊酯和倍硫磷、马拉硫磷、敌百虫、氧化乐果,可使DPH探剂与线粒体膜结合后的荧光相对强度增加;而氰戊菊酯、氯氰菊酯,溴氰菊酯及辛硫磷、乙酰甲胺磷,则可使荧光强度减弱。  相似文献   
68.
Abstract: In an experimental dog model of acute biventricular failure, the effects of left ventricular (LV) assist on renal hemodynamics and function were evaluated. After the induction of severe cardiac failure by multiple ligation of the coronary arteries, LV assist with a 40 ml pneumatic pulsatile pump was initiated, and the aortic flow was maintained at control values. The right atrial pressure (RAP) rose to 21.3 mm Hg with the appearance of profound right ventricular (RV) failure. Renal arterial blood flow (RAF) decreased to about 60% of the control value after 2 h of LV assist. The urine volume decreased and renal function deteriorated progressively. RV assist decreased the RAP to 4.8 mm Hg, and the reduced RAF recovered. After 3 h of RV assist, the RAF returned to initial values and the urine volume increased, but renal function did not recover. Advanced biventricular failure with elevated RAP during LV assist reduced renal perfusion and impaired renal function and may be an indication for early RV assist  相似文献   
69.
Summary The plasma and urine concentrations of famotidine, a new, potent H2-receptor antagonist, have been measured in 16 healthy young adults, 8 healthy elderly people and 18 patients with varying degrees of renal dysfunction after intravenous administration.Both the plasma elimination and renal excretion of famotidine were decreased in the elderly volunteers and renal patients. The renal clearance of famotidine averaged 4.43 ml/min/kg (310 ml/min) in normal young volunteers, which exceeded the mean creatinine clearance 1.55 ml/min/kg (109 ml/min), suggesting net secretion is a significant mechanism for elimination of famotidine.The ratio of famotidine renal clearance to creatinine clearance decreased as creatinine clearance decreased; these results suggest that the deterioration in the secretion process was much faster than that in glomerular filtration and are incompatible with the intact nephron hypothesis. Nevertheless, both total body clearance and renal clearance were significantly correlated with creatinine clearance.The apparent half-life was also significantly correlated with creatinine clearance. Since famotidine is essentially free of dose-related adverse effects, dose adjustment in patients with mild renal insufficiency and in elderly people is not required; however, either a prolonged dosing interval or a decrease in daily dose during long-term therapy may be adapted for the patients with severe renal insufficiency to avoid accumulation and the potential undesirable effects.  相似文献   
70.
Lymphocyte beta adrenergic receptor binding using [125I]CNP was determined in patients with panic disorder (N=4) or agoraphobia with panic attacks (N=17) and age- and sex-matched healthy subjects (N=22). The patients showed a significantly lower number of -adrenergic receptor binding sites and a significantly higher affinity of binding than healthy subjects. A past or present history of major depression in the patients did not alter these findings. These results are consistent with a growing body of knowledge implicating noradrenergic dysfunction in the pathophysiology of panic anxiety.  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