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   2095篇
  免费   213篇
  国内免费   21篇
耳鼻咽喉   19篇
儿科学   56篇
妇产科学   50篇
基础医学   320篇
口腔科学   114篇
临床医学   313篇
内科学   379篇
皮肤病学   13篇
神经病学   166篇
特种医学   99篇
外科学   253篇
综合类   46篇
一般理论   1篇
预防医学   210篇
眼科学   21篇
药学   149篇
中国医学   2篇
肿瘤学   118篇
  2021年   29篇
  2020年   23篇
  2019年   32篇
  2018年   43篇
  2017年   26篇
  2015年   29篇
  2014年   56篇
  2013年   69篇
  2012年   98篇
  2011年   100篇
  2010年   67篇
  2009年   59篇
  2008年   75篇
  2007年   83篇
  2006年   64篇
  2005年   75篇
  2004年   64篇
  2003年   70篇
  2002年   68篇
  2001年   68篇
  2000年   64篇
  1999年   47篇
  1998年   28篇
  1997年   28篇
  1996年   33篇
  1995年   20篇
  1994年   24篇
  1992年   38篇
  1991年   44篇
  1990年   48篇
  1989年   49篇
  1988年   46篇
  1987年   32篇
  1986年   48篇
  1985年   37篇
  1984年   32篇
  1983年   36篇
  1982年   22篇
  1981年   24篇
  1980年   27篇
  1979年   34篇
  1978年   26篇
  1977年   27篇
  1976年   30篇
  1975年   27篇
  1974年   24篇
  1973年   24篇
  1972年   30篇
  1971年   17篇
  1970年   18篇
排序方式: 共有2329条查询结果,搜索用时 31 毫秒
1.

Background  

Cerebral arterial gas embolism is a potentially life-threatening event. Intraarterial air can occlude blood flow directly or cause thrombosis. Sclerotherapy is an extremely rare cause of cerebral arterial gas embolism.  相似文献   
2.
3.
4.
This study examines young children's perceptions of work through a specific example. Reception class children at an inner city school were shown pictures of the same figure washing in four different contexts, ranging from housework to paid employment, in order to examine early classifications and conceptual systems relating to the concept of work and to ascertain whether these were gender related. Individual children varied in the complexity of their ideas, but the majority had not yet began to form hierarchical classifications of work which favour paid employment. There was evidence however that some children were beginning to devalue traditional women's work, suggesting that gender stereotypes are still prevalent amongst this age group, despite efforts by the educational system to counter this.  相似文献   
5.
Plantar sensory threshold in the ulcerative foot   总被引:1,自引:0,他引:1  
J A Birke  D S Sims 《Leprosy review》1986,57(3):261-267
  相似文献   
6.
A Sims 《Psychopathology》1991,24(6):369-374
Schneider considered that first rank symptoms always signify schizophrenia. They appear to have in common permeability of the barrier between the individual and his environment, or a loss of ego boundaries. They may be a manifestation of a specific disturbance which may be caused pathologically by a limbic lesion in the dominant hemisphere.  相似文献   
7.
Summary Two individuals with an X-chromosomal deletion were recently found to lack the genes encoding monoamine oxidase type A (MAO-A) and MAO-B. This abnormality was associated with almost total (90%) reductions in the oxidatively deaminated urinary metabolites of the MAO-A substrate, norepinephrine, and with marked (100-fold) increases in an MAO-B substrate, phenylethylamine, confirming systemic functional consequences of the genetic enzyme deficiency. However, urinary concentrations of the deaminated metabolites of dopamine and serotonin (5-HT) were essentially normal. To investigate other deaminating systems besides MAO-A and MAO-B that might produce these metabolites of dopamine and 5-HT, we examined plasma amine oxidase (AO) activity in these two patients and two additional patients with the same X-chromosomal deletion. Normal plasma AO activity was found in all four Norrie disease-deletion patients, in four patients with classic Norrie disease without a chromosomal deletion, and in family members of patients from both groups. Marked plasma amine metabolite abnormalities and essentially absent platelet MAO-B activity were found in all four Norrie disease-deletion patients, but in none of the other subjects in the two comparison groups. These results indicate that plasma AO is encoded by gene(s) independent of those for MAO-A and MAO-B, and raise the possibility that plasma AO, and perhaps the closely related tissue AO, benzylamine oxidase, as well as other atypical AOs or MAOs encoded independently from MAO-A and MAO-B may contribute to the oxidative deamination of dopamine and 5-HT in humans.  相似文献   
8.
We studied blood pressure and natriuretic responses to acute salt loading, and the effect of non-steroidal anti-inflammatory agents on these responses, in five healthy normotensive women aged 65 to 71 years. Five women aged 25 to 31 years acted as controls. Intravenous saline loading, with and without prior ingestion of ibuprofen, was 15 ml/kg/h for 3 h. Baseline blood pressures were higher in the elderly. Saline infusion without ibuprofen raised systolic blood pressure (SBP) by about 25 mmHg in the older group only. Ibuprofen increased baseline SBP in the elderly (129 +/- 6 vs. 116 +/- 5 mmHg, p < 0.05). Saline loading after ibuprofen again raised blood pressure by about 25 mmHg in the elderly only. The elderly group showed markedly increased sodium excretion during saline loading, but this was reduced by ibuprofen. Ibuprofen had no effect on SBP or sodium excretion in controls. Ageing appears to increase susceptibility to salt retention and hypertension from non-steroidal anti-inflammatory agents.   相似文献   
9.
Unfortunately, acute pulmonary embolism is still a far too common occurrence. Fortunately, with prompt recognition, diagnosis, and treatment, mortality can be reduced. This article provides an overview of risk factors, diagnostic studies, and treatment of patients with acute pulmonary embolism in the critical care setting.  相似文献   
10.
Acute thoracic aortic dissection has a high mortality if untreated, so the diagnosis must be rapidly made if mortality is to be lowered significantly. Multiple imaging techniques are often used. This retrospective study from 1988 to 1993 assesses the usefulness in diagnosis of chest X-rays, computed tomography (CT) scanning, aortography, magnetic resonance imaging (MRI), trans-thoracic (TTE) and trans-oesophageal (TOE) echocardiography. Forty-two patients with a final clinical diagnosis of dissection were studied. The diagnosis was confirmed in 16 (13 at surgery and three at autopsy). Three died with dissection given as the only cause for death. Chest X-ray abnormalities were seen in all 19 patients with surgery or death from dissection, with a widened mediastinum and/or dilated aorta being present in 17. In the group of 16 patients with surgery or autopsy proof, CT scans found dissections in 9 of 12 patients studied and correctly classified the type in only five. Aortography was performed in five, with accurate depiction of dissection and type in all. TTE found dissections in three of eight patients imaged by this method. MRI and TOE were performed each on two patients, with accurate depiction of dissection and type in each. Because of the relatively low sensitivity of CT scanning in defining aortic dissections Westmead Hospital is currently assessing the use of TOE as the prime imaging modality prior to surgical intervention.  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