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   21166篇
  免费   1434篇
  国内免费   83篇
耳鼻咽喉   144篇
儿科学   668篇
妇产科学   497篇
基础医学   3354篇
口腔科学   400篇
临床医学   2094篇
内科学   4195篇
皮肤病学   460篇
神经病学   2240篇
特种医学   514篇
外科学   1927篇
综合类   118篇
一般理论   27篇
预防医学   2251篇
眼科学   369篇
药学   1242篇
中国医学   38篇
肿瘤学   2145篇
  2023年   189篇
  2022年   342篇
  2021年   639篇
  2020年   423篇
  2019年   606篇
  2018年   685篇
  2017年   530篇
  2016年   607篇
  2015年   694篇
  2014年   842篇
  2013年   1184篇
  2012年   1677篇
  2011年   1666篇
  2010年   947篇
  2009年   841篇
  2008年   1471篇
  2007年   1408篇
  2006年   1286篇
  2005年   1239篇
  2004年   1087篇
  2003年   1111篇
  2002年   965篇
  2001年   132篇
  2000年   82篇
  1999年   120篇
  1998年   182篇
  1997年   152篇
  1996年   122篇
  1995年   123篇
  1994年   103篇
  1993年   100篇
  1992年   55篇
  1991年   67篇
  1990年   50篇
  1989年   46篇
  1988年   26篇
  1987年   43篇
  1986年   45篇
  1985年   54篇
  1984年   54篇
  1983年   46篇
  1982年   70篇
  1981年   53篇
  1980年   45篇
  1979年   37篇
  1978年   34篇
  1976年   30篇
  1975年   26篇
  1974年   33篇
  1973年   28篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
5.
Nonconvulsive Status Epilepticus: High Incidence of Complex Partial Status   总被引:14,自引:6,他引:8  
Nonconvulsive status epilepticus may be subdivided into generalized (absence) status and complex partial status. The latter is regarded as a rarity, whereas the former constitutes the dominant part of the hitherto reported cases. We report 10 consecutive cases of adult patients with nonconvulsive status epilepticus, all documented by ictal electroencephalographic (EEG) recordings. Five had a complex partial status; the origin of the complex partial status appeared to be frontal in four of these patients. Three had recurrent complex partial seizures with incomplete recovery between seizures, and two had more continuous symptoms. One of the latter exhibited neither motor phenomena nor automatisms. The effect of diazepam or clonazepam was immediate in all 10 cases though transient in eight. A lasting control of the status was not achieved in six patients until i.v. phenytoin was added. The difficulties in the differentiation between complex partial status and absence status despite ictal EEG recordings are discussed, illustrated by a case with seizure discharges of a focal onset which rapidly generalized. The study indicates that complex partial status may be more common and the clinical expressions of absence status more variable than hitherto recognized.  相似文献   
6.
To determine whether polymorphisms of platelet surface glycoprotein associated with arterial thrombosis are risk factors for branch retinal vein occlusion. A case-control study in which 69 patients with branch retinal vein occlusion and 147 controls who attended the eye clinic for nonvascular complications participated. DNA was extracted from whole blood and analyzed for genotyping of platelet glycoprotein polymorphisms by polymerase chain reactions and specific restricted enzymes. No relationship was found between the four platelet glycoprotein polymorphisms i.e. GPIa C807T, VNTR and Kozak of glycoprotein Ibalpha, the HPA-1 of glycoprotein IIIa and the occurrence of branch retinal vein occlusion. The HPA-2 polymorphism was found in 18 out 60 (30%) patients with branch retinal vein occlusion in comparison with 27 out 142 (19%) of controls, with an estimated odds ratio of 1.8 (95% confidence interval, 0.91-3.65). The four platelet glycoprotein polymorphisms are not risk factors for branch retinal vein occlusion and therefore it seems unnecessary to screen those patients for it. A larger study is required, however, to determine whether HPA-2 is a novel risk factor for branch retinal vein occlusion.  相似文献   
7.
8.
The effect of 18 months' inhibition of angiotensin-converting enzyme by captopril on the leakage of fluorescein through the blood-retina barrier was examined in a prospective, randomized control study of 20 normotensive insulin-dependent diabetic patients with nephropathy and background retinopathy. After 18 months, 15 patients remained in the study. Fluorescein leakage remained nearly unchanged in the captopril-treated group, being 4.1 ± 4.1 (mean ± SD) × 10–7 cm/s at baseline and 4.2±4.1 × 10–7 cm/s after 18 months' treatment. The permeability increased significantly (P<0.01) from 3.3±2.2 × 10–7 cm/s to 5.6±3.5 × 10–7 cm/s at 18 months in the control group. Arterial blood pressure was nearly constant in both groups throughout the study. The results indicate that angiotensin-converting enzyme inhibition with captopril can arrest or delay a progressive breakdown of the blood-retina barrier in normotensive insulin-dependent diabetic patients with nephropathy and background retinopathy.The authors have no commercial or proprietory interest in the drugs or instruments used in this study  相似文献   
9.
10.
Cardiac resynchronization therapy (CRT) is a treatment option in patients with severe heart failure and left bundle-branch block (LBBB). This study evaluated the effects of 4 and 13 mo of CRT on myocardial oxygen consumption (MVO2) and cardiac efficiency as compared with mild heart failure patients without LBBB. METHODS: Sixteen patients with severe heart failure and LBBB due to idiopathic cardiomyopathy were studied at baseline and after 4 and after 13 mo of therapy. Thirteen patients with mild heart failure without LBBB served as a comparison group. The clearance rate (k2) of 11C-acetate was measured with PET to assess MVO2. Stroke volume was derived from the dynamic PET data according to the Stewart-Hamilton principle and, furthermore, cardiac efficiency using the work metabolic index. RESULTS: After 4 mo of CRT, stroke volume index (SVI) increased by 50% (P = 0.012) and cardiac efficiency increased by 41% (P < 0.001). Global k2 remained unchanged but regional k2 demonstrated a more homogeneous distribution pattern. The parameters showed no significant changes during therapy. Under CRT, cardiac efficiency, SVI, and the distribution pattern of regional k2 did not differ from mild heart failure patients without LBBB. CONCLUSION: CRT improves cardiac efficiency for at least 13 mo, as demonstrated by a higher SVI, whereas MVO2 remains unchanged. Cardiac efficiency, SVI, and the MVO2 distribution pattern reach the level of patients with mild heart failure without LBBB. The unfavorable hemodynamic performance in heart failure with LBBB is effectively restored by long-term CRT to the level of an earlier disease state.  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