全文获取类型
收费全文 | 15562篇 |
免费 | 1043篇 |
国内免费 | 206篇 |
专业分类
耳鼻咽喉 | 382篇 |
儿科学 | 211篇 |
妇产科学 | 289篇 |
基础医学 | 2685篇 |
口腔科学 | 296篇 |
临床医学 | 1243篇 |
内科学 | 3079篇 |
皮肤病学 | 439篇 |
神经病学 | 1173篇 |
特种医学 | 1070篇 |
外科学 | 2091篇 |
综合类 | 85篇 |
现状与发展 | 3篇 |
一般理论 | 10篇 |
预防医学 | 598篇 |
眼科学 | 426篇 |
药学 | 1258篇 |
中国医学 | 153篇 |
肿瘤学 | 1320篇 |
出版年
2024年 | 10篇 |
2023年 | 91篇 |
2022年 | 272篇 |
2021年 | 664篇 |
2020年 | 268篇 |
2019年 | 441篇 |
2018年 | 526篇 |
2017年 | 412篇 |
2016年 | 613篇 |
2015年 | 875篇 |
2014年 | 956篇 |
2013年 | 1044篇 |
2012年 | 1578篇 |
2011年 | 1423篇 |
2010年 | 844篇 |
2009年 | 716篇 |
2008年 | 895篇 |
2007年 | 925篇 |
2006年 | 775篇 |
2005年 | 625篇 |
2004年 | 520篇 |
2003年 | 470篇 |
2002年 | 382篇 |
2001年 | 295篇 |
2000年 | 242篇 |
1999年 | 179篇 |
1998年 | 87篇 |
1997年 | 71篇 |
1996年 | 51篇 |
1995年 | 46篇 |
1994年 | 43篇 |
1993年 | 34篇 |
1992年 | 39篇 |
1991年 | 43篇 |
1990年 | 42篇 |
1989年 | 51篇 |
1988年 | 35篇 |
1987年 | 36篇 |
1986年 | 21篇 |
1985年 | 20篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 7篇 |
1981年 | 19篇 |
1980年 | 12篇 |
1979年 | 15篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 10篇 |
1975年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 687 毫秒
961.
Restless legs syndrome (RLS) is a common disorder for which agents that enhance dopaminergic activity, including dopamine agonists and levodopa, are the treatment of choice. However, long-term use of dopaminergic drugs can cause unwanted effects such as rebound, tolerance, and augmentation. Bupropion, an inhibitor of dopamine and noradrenalin reuptake, is an antidepressant that modulates dopaminergic systems. The authors report that a low dose of bupropion rapidly and completely ameliorated RLS symptoms in 3 depressed patients within a few days of the initiation of treatment. To their knowledge, this is the first report to show that bupropion may be an effective alternative for treating RLS. Consequently, bupropion may be useful for the treatment of patients with both depression and RLS. 相似文献
962.
Ipsilateral hemiparesis after a supratentorial stroke is rare. However, the role of the reorganization of the unaffected hemisphere in recovery after a stroke is poorly understood. Two patients developed ipsilateral hemiparesis after a left corona radiata infarct. Both of these patients had previously experienced contralateral hemiparesis after a right-sided supratentorial stroke. Functional magnetic resonance imaging demonstrated bilateral motor area activation during paretic left hand movement. This finding suggests that the ipsilateral hemiparesis was caused by a new stroke in the ipsilateral motor system that was functionally reorganized after the previous stroke. 相似文献
963.
Exercise increased BDNF and trkB in the contralateral hemisphere of the ischemic rat brain 总被引:13,自引:0,他引:13
Previous studies have suggested that brain-derived neurotrophic factor (BDNF) and trkB both have a role in plasticity following brain insults and exercise increases BDNF and trkB mRNA levels in the normal brain. We attempted to determine whether treadmill exercise improves motor function following experimental cerebral ischemia, and whether motor outcome is associated with BDNF and trkB expression. We subjected adult male Sprague-Dawley rats to a permanent ischemia, followed by either 12 days of treadmill exercise or non-exercise. In the exercise group, improvements in the motor behavior index were found and BDNF and trkB proteins in contralateral hemisphere were increased. This study suggests that after permanent brain ischemia, exercise improves motor performance and elevates BDNF and trkB proteins in the contralateral hemisphere. 相似文献
964.
In this study, we examined expressional changes of VPAC1 receptor in aged rat brains using an immunohistochemical approach and found that its immunoreactivities are significantly reduced in the cerebral cortex, hippocampal region, and amygdala of aged rats. These results suggest that this reduction could underlie aging-associated memory/learning deficits and several other age-induced functional changes in these areas. However, the functional consequences of these down-regulations require further elucidation. 相似文献
965.
Kohut ML Lee W Martin A Arnston B Russell DW Ekkekakis P Yoon KJ Bishop A Cunnick JE 《Brain, behavior, and immunity》2005,19(4):357-366
The primary goal of this study was to determine whether exercise-associated improvements of the immune response to influenza vaccination were mediated by improvements in psychosocial factors in older adults. At baseline, prior to the exercise intervention, older adult participants were immunized with influenza vaccine. Blood samples collected pre-immunization, 1, 4, and 12 weeks post-immunization were analyzed for anti-influenza antibody, whereas influenza-specific cytokine (IFNgamma) was evaluated at 1 week post-immunization. Depression and sense of coherence were measured pre-immunization. Four weeks post-immunization, participants were randomly assigned to either an aerobic exercise group (n=14) or a control group (n=14). After a 10-month exercise intervention, the immunization, blood collections, and psychosocial measures were repeated. At the post-intervention evaluation, exercise participants had improved scores on depression and sense of coherence. Also post-intervention, exercise participants had a greater increase in antibody and IFNgamma production. After controlling for the effect of both psychosocial measures, the exercise treatment remained significant with respect to antibody titer suggesting that the increases in antibody were not mediated by improvement in the psychosocial factors. In contrast, the enhancement of IFNgamma appeared to be mediated at least in part by the psychosocial factors. After controlling for psychosocial factors, exercise treatment was no longer significantly related to the change in IFNgamma. Taken together, our findings may suggest that the mechanism(s) of exercise-induced improvement in immunocompetence involve both physiological and psychological pathways. 相似文献
966.
Inflammatory markers, rather than conventional risk factors, are different between carotid and MCA atherosclerosis 总被引:6,自引:0,他引:6
Bang OY Lee PH Yoon SR Lee MA Joo IS Huh K 《Journal of neurology, neurosurgery, and psychiatry》2005,76(8):1128-1134
BACKGROUND: The apparent differences in risk factors for intra- and extracranial atherosclerosis are unclear and the mechanisms that underlie strokes in patients with intracranial atherosclerosis are not well known. We investigated the conventional vascular risk factors as well as other factors in stroke patients with large artery atherosclerosis. METHODS: Using diffusion weighted imaging (DWI) and vascular and cardiologic studies, we selected patients with acute non-cardioembolic cerebral infarcts within the middle cerebral artery (MCA) territory. Patients were divided into two groups: those with atherosclerotic lesions on the carotid sinus (n = 112) and those with isolated lesions on the proximal MCA (n = 160). Clinical features, risk factors, and DWI patterns were compared between groups. RESULTS: There were no differences in conventional risk factors, but markers for inflammation were significantly higher in patients with carotid atherosclerosis than in those with isolated MCA atherosclerosis (p < 0.01 for both). After adjustments for age/sex and the severity of stroke, an inverse correlation was observed between C-reactive protein levels and MCA atherosclerosis (odds ratio 0.57 per 1 mg/dl increase; 95% confidence interval 0.35 to 0.92; p = 0.02). Internal borderzone infarcts suggestive of haemodynamic causes were the most frequent DWI pattern in patients with MCA occlusion, whereas territorial infarcts suggesting plaque ruptures were most common in those with carotid occlusion. CONCLUSIONS: Our results indicate that inflammatory markers, rather than conventional risk factors, reveal clinical and radiological differences between patients with carotid and MCA atherosclerosis. Plaques associated with MCA atherosclerosis may be more stable than those associated with carotid atherosclerosis. 相似文献
967.
968.
Long-term clinical and histological outcomes in patients with spontaneous hepatitis B surface antigen seroclearance 总被引:7,自引:0,他引:7
Ahn SH Park YN Park JY Chang HY Lee JM Shin JE Han KH Park C Moon YM Chon CY 《Journal of hepatology》2005,42(2):188-194
BACKGROUND/AIMS: During the natural course of hepatitis B virus (HBV) infection, the long-term clinical and histological outcomes following spontaneous hepatitis B surface antigen (HBsAg) seroclearance remain unclear. METHODS: Between 1984 and 2003, 49 (9.5%) out of 432 inactive HBsAg carriers had no detectable level of circulating HBsAg. Fifteen of 49 patients had undergone paired peritoneoscopic liver biopsies. RESULTS: During a mean follow-up period of 19.6 months after HBsAg seroclearance, 5 of 49 (10.2%) patients were noted to have HCC. Liver cirrhosis (P=0.040), a history of perinatal infection (P=0.005) and long-standing duration (at least 30 years) of HBsAg positivity (P=0.002) were associated with a significantly higher risk of developing HCC. Despite HBsAg seroclearance, HBV DNA was detected in the liver tissues from all 15 patients who underwent paired liver biopsies. Necroinflammation was significantly ameliorated (P<0.0001). On the other hand, amelioration of the fibrosis score did not reach a statistically significant level (P=0.072). Interestingly, aggravation of liver fibrosis was evident in 2 patients (13.3%) including one who had rapidly progressed to overt cirrhosis. CONCLUSIONS: In patients with spontaneous HBsAg seroclearance, necroinflammation was markedly improved and liver fibrosis was unchanged or regressed despite occult HBV infection. However, HCC developed in a minority of cases. 相似文献
969.
Yoon HJ Choi JY Park YS Kim CO Kim JM Yong DE Lee KW Song YG 《American journal of infection control》2005,33(10):595-601
BACKGROUND: Serratia marcescens is an aerobic gram-negative bacillus belonging to the family Enterobacteriacea. Infections caused by S marcescens may be difficult to treat because of their resistance to a variety of antibiotics, including beta-lactams and aminoglycosides. METHODS: This study aimed to (1) identify the risk factors associated with the development of Serratia marcescens bacteriuria in neurosurgical intensive care units (NSICU); (2) genotype the pathogens to determine the source of infection; (3) compare these results with antibiograms; and (4) determine and implement appropriate control measures. A retrospective case-control study of the epidemiologic data, the surveillance of environmental cultures, and the genotyping of strains using arbitrarily primed polymerase chain reaction (AP-PCR) were performed at a 750-bed, tertiary care teaching hospital. Seventy-four bacteriuria patients were compared with 74 age/sex-matched control patients in the NSICU between March 2002 and March 2004. The factors assessed were patient demographics; duration of hospital stay; duration of indwelling catheter use before and during stay in the NSICU; chronic underlying illnesses (diabetes mellitus, cardiovascular disease, malignancy); other sites of infection; history of trauma; exposure to a nasogastric tube; mechanical ventilation; urinary catheterization; central venous catheterization; surgical drainage; tracheostomy; brain or spine surgery; and receipt of total parenteral nutrition (TPN), antimicrobials (beta-lactams, aminoglycosides, quinolones, carbapenems, vancomycins), or steroids. RESULTS: Patients with S marcescens bacteriuria were more likely to have a longer NSICU stay and other sites of infection. Environmental surveillance showed the handling of urine jugs to be the point source of contamination. Genotyping and antibiograms of 14 patients were the same except for those of 2 patients. CONCLUSION: The patient-related risk factors were identified, and a rapid identification of the organism was made. Heightened surveillance, infection control measures, and empiric therapy led to improved methods for handling urine jugs, which terminated the outbreak. 相似文献
970.
Triad of MR arthrographic findings in patients with cam-type femoroacetabular impingement 总被引:8,自引:0,他引:8
PURPOSE: To retrospectively analyze magnetic resonance (MR) arthrographic findings in patients with clinical cam-type femoroacetabular impingement. MATERIALS AND METHODS: This study was approved by the institutional review board, and informed consent was waived. Study was compliant with the Health Insurance Portability and Accountability Act. Forty-two MR arthrograms obtained in 40 patients with clinical femoroacetabular impingement were analyzed retrospectively by two radiologists. Quantitative analysis by using alpha angle measurement was performed to assess anterosuperior femoral head-neck morphology. Presence of labral tears, articular cartilage lesions, paralabral cysts, os acetabuli, and synovial herniation pits was recorded. Presence of the typical triad of anterosuperior labral tear, anterosuperior cartilage lesion, and abnormal alpha angle was recorded. Surgical comparison was available for 11 patients. RESULTS: At imaging, in 40 patients (22 male, 18 female) with a mean age of 36.5 years, 39 of 42 hips (93%) had an abnormal alpha angle, with a mean angle of 69.7 degrees ; 40 of 42 (95%) had an anterosuperior cartilage abnormality; and 42 of 42 (100%) had an anterosuperior labral tear. Thirty-seven of 42 hips (88%) had the triad. Six had paralabral cysts, 17 had an os acetabuli, and two had synovial herniation pits. Surgical comparison for 11 hips led to confirmation of all labral and cartilage abnormalities seen at imaging. CONCLUSION: MR arthrography demonstrated a triad of abnormal head-neck morphology, anterosuperior cartilage abnormality, and anterosuperior labral abnormality in 37 of 42 patients with cam-type femoroacetabular impingement. 相似文献