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   12863篇
  免费   662篇
  国内免费   295篇
耳鼻咽喉   132篇
儿科学   305篇
妇产科学   111篇
基础医学   1011篇
口腔科学   163篇
临床医学   1227篇
内科学   1185篇
皮肤病学   30篇
神经病学   1178篇
特种医学   647篇
外科学   2621篇
综合类   2298篇
预防医学   309篇
眼科学   443篇
药学   824篇
  6篇
中国医学   1236篇
肿瘤学   94篇
  2024年   43篇
  2023年   194篇
  2022年   380篇
  2021年   458篇
  2020年   427篇
  2019年   291篇
  2018年   379篇
  2017年   355篇
  2016年   405篇
  2015年   390篇
  2014年   835篇
  2013年   809篇
  2012年   724篇
  2011年   762篇
  2010年   620篇
  2009年   578篇
  2008年   632篇
  2007年   616篇
  2006年   541篇
  2005年   476篇
  2004年   416篇
  2003年   388篇
  2002年   345篇
  2001年   304篇
  2000年   303篇
  1999年   235篇
  1998年   174篇
  1997年   184篇
  1996年   153篇
  1995年   167篇
  1994年   144篇
  1993年   96篇
  1992年   104篇
  1991年   92篇
  1990年   80篇
  1989年   71篇
  1988年   72篇
  1987年   62篇
  1986年   57篇
  1985年   84篇
  1984年   54篇
  1983年   32篇
  1982年   44篇
  1981年   39篇
  1980年   36篇
  1979年   43篇
  1978年   43篇
  1977年   24篇
  1976年   19篇
  1974年   14篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.

Objectives

The current study investigated the effects of two exercise interventions on cognitive function amongst breast cancer survivors.

Design

Pilot randomised-controlled trial.

Methods

Seventeen female cancer survivors (mean: 62.9 ± 7.8 years) were randomised into three groups: high-intensity interval training (HIIT, n = 6); moderate-intensity continuous training (MOD, n = 5); or wait-list control (CON, n = 6). The HIIT and MOD groups exercised on a cycle ergometer 3 days/week for 12-weeks. Primary outcomes were cognitive function assessments utilising CogState. Secondary outcomes were resting middle cerebral artery blood flow velocity, cerebrovascular reactivity and aerobic fitness (VO2peak). Data were analysed with General Linear Mixed Models and Cohen’s d effect sizes were calculated.

Results

All 17 participants who were randomised were available for follow-up analysis and adherence was similar for HIIT and MOD (78.7 ± 13.2% vs 79.4 ± 12.0%; p = 0.93). Although there were no significant differences in the cognitive and cerebrovascular outcomes, HIIT produced moderate to large positive effects in comparison to MOD and CON for outcomes including episodic memory, working memory, executive function, cerebral blood flow and cerebrovascular reactivity. HIIT significantly increased VO2peak by 19.3% (d = 1.28) and MOD had a non-significant 5.6% (d = 0.72) increase, compared to CON which had a 2.6% decrease.

Conclusions

This study provides preliminary evidence that HIIT may be an effective exercise intervention to improve cognitive performance, cerebrovascular function and aerobic fitness in breast cancer survivors. Considering the sample size is small, these results should be confirmed through larger clinical trials.  相似文献   
2.
Objectives: There is a paucity of reporting on surgical outcomes of isolated posterior cruciate ligament reconstruction (PCLR). We hypothesize that isolated PCL injuries failing nonoperative treatment achieve good outcomes and are able to return to sport following PCLR.

Methods: A retrospective analysis was performed to identify patients with isolated PCL injuries that underwent reconstruction between 2001 and 2014. Patients with multi-ligamentous injury or another concomitant knee pathology were excluded. Medical records were reviewed for demographic, clinical and operative data. Patients were contacted for administration of a telephone-based questionnaire which included the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation form, Lysholm-Tegner scales, Marx activity scale (MAS), return to sport status, and patient satisfaction instruments.

Results: A total of 15 isolated PCL reconstructions in 14 patients with a mean age of 27.5 years (range 17–43) met the study inclusion criteria; mean follow up was 6.3 years (range 1.4–15.2). Pre-operatively, the primary complaint was knee instability in all patients; on physical examination, lack of a firm end point during posterior drawer testing was found in 93% (14/15) of the knees. In total, 12 of 15 knees underwent transtibial, single-bundle PCLR and three of 15 underwent tibial inlay, double bundle PCLR. Graft types included: quadriceps autograft (7/15), Achilles allograft (6/15), and hamstring autograft (2/15). There were no graft failures in our patient cohort. At most recent follow up the mean scores respectively on the IKDC form, Lysholm-Tegner scales and MAS were (standard deviation): 77.3 (16.5), 83.1 (17.9), 6.13 (2.6), and 7.1 (6.0). All fourteen patients were athletes prior to their injury and 79% (11/14) returned to sport and overall patient satisfaction was 9.2/10.

Conclusions: Isolated PCLR provides good outcomes at mean medium-term follow up with restoration of function, high rate of return to sport and overall patient satisfaction.  相似文献   

3.
4.
Our group have studied a patient affected by a malignant schwannoma in the posterior tibial nerve. Schwannomas are uncommon neoplasms that originate from the Schwann cells of the peripheral nerves: the most common forms are benign. Malignant transformation is rarer. The therapy is surgical and the operation undertaken, if possible, should be the amputation. Alternatively, where amputation is not possible due to the specific localisation or due to patient refusal, the alternative must be the largest and most radical excision possible.  相似文献   
5.
本文报告113例脑前循环系统动脉管其中包括颈内动脉后交通动脉瘤75例.前交通动脉瘤17例,大脑中动脉瘤10例,人脑前动脉-胼周动脉瘤3例,颈内动脉-眼动脉瘤2例,颈内动脉海绵窦段动脉瘤1例.多发动脉瘤5例.共118个动脉瘤在显微镜下直视手术,动脉瘤直接夹闭术108例.孤立或包裹术5例:5例多发动脉瘤行同期手术3例,分期手术2例.术中发生动脉瘤破裂18次.Hunt和HessⅠ~Ⅱ级病人中有例行早期手术.全组术后死亡率为7.9%.着重讨论手术时机.术中动脉瘤破裂处理及多发动脉瘤的治疗.  相似文献   
6.
对13例体外循环病人进行了观察,发现体外循环后TXB2/6-keto-PGF1α显著增高,表明体外循环使血小板受损,而血小板受损是体外循环后失血的主要原因之一。  相似文献   
7.
Acupuncture analgesia (AA) caused by low frequency stimulation of the acupuncture point (AP) was abolished by hypophysectomy and adrenalectomy. Termination of the AA producing pathway from the AP to the pituitary gland was in the medial hypothalamic arcuate nucleus (M-HARN). The origin of the descending pain inhibitory system associated with AA was in the posterior HARN (P-HARN). AA in the hypophysectomized rats, and enhanced neuronal activity in the P-HARN that were abolished during acupuncture stimulation, were both restored by intraperitoneal microinjection of 0.5 mg/kg morphine or 0.1 micrograms beta-endorphin into the P-HARN during acupuncture stimulation. Of the analgesia produced by dopamine or beta-endorphin injected into the P-HARN, that caused by beta-endorphin disappeared after denervation of the M-HARN. The P-HARN neurons that responded to acupuncture stimulation also responded to iontophoretic dopamine, but not to iontophoretic morphine nor ultramicroinjected beta-endorphin. The transmission between the M-HARN and P-HARN may be dopaminergic, and beta-endorphin might presynaptically modulate this transmission. Reduction of sodium ions may have been the reason for abolition of AA after adrenalectomy.  相似文献   
8.
To obtain a new model of chronic portal hypertension in the rat, two classical methods to produce portal hypertension, partial portal vein ligation and the oral administration of thioacetamide (TAA), have been combined. Male Wistar rats were divided into four groups: 1 (control; n?=?10), 2 [triple partial portal vein ligation (TPVL); n?=?9], 3 (TAA; n?=?11), and 4 (TPVL plus TAA; n?=?9). After 3 months, portal pressure, types of portosystemic collateral circulation, laboratory hepatic function tests (aspartate aminotransferase, alanine aminotransferase, bilirubin, alkaline phosphatase, and gamma-glutamyl transpeptidase) and liver histology were studied. The animals belonging to group 2 (TPVL) developed extrahepatic portosystemic collateral circulation, associated with mesenteric venous vasculopathy without hepatic destructurization or portal hypertension. Animals from group 3 (TAA) developed cirrhosis and portal hypertension but not extrahepatic portosystemic collateral circulation, or mesenteric venous vasculopathy. Finally, the animals from group 4 (TPVL?+?TAA) developed cirrhosis, portal hypertension, portosystemic collateral circulation, and mesenteric venous vasculopathy. The association of TPVL and TAA can be used to obtain a model of chronic portal hypertension in the rat that includes all the alterations that patients with hepatic cirrhosis usually have. This could, therefore, prove to be a useful tool to study the pathophysiological mechanisms involved in these alterations.  相似文献   
9.
患者女,48岁。两年前无明显诱因出现轻微进食梗噎感,抬头时加重,未予治疗。近半年,梗噎感加重,并出现胸闷、咳嗽,痰中带血,遂来我院就诊。胸部CT显示:左后纵隔食管后方见一长条形低密度影,密度不均,其上方见环形斑  相似文献   
10.
目的 探讨上胸椎骨折的特点及治疗。方法 15例病人按AO分型,A型2例、B型10例、C型3例。均经后路切开复位、脊髓减压、长节段内固定、取髂骨植骨融合术治疗。结果 随访18-24个月,后路长节段固定随访时无一例失败,完全瘫的患者9例中有1例神经功能改善I级.不完全瘫的5例均有Ⅲ级改善,1例无神经损伤。结论 上胸椎骨折损伤严重,后路长节段固定技术是一种合理的有效治疗方法。  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