全文获取类型
收费全文 | 798篇 |
免费 | 46篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 56篇 |
妇产科学 | 23篇 |
基础医学 | 75篇 |
口腔科学 | 8篇 |
临床医学 | 59篇 |
内科学 | 133篇 |
皮肤病学 | 10篇 |
神经病学 | 124篇 |
特种医学 | 160篇 |
外科学 | 56篇 |
综合类 | 11篇 |
一般理论 | 7篇 |
预防医学 | 50篇 |
眼科学 | 4篇 |
药学 | 46篇 |
肿瘤学 | 15篇 |
出版年
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 14篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 20篇 |
2012年 | 18篇 |
2011年 | 19篇 |
2010年 | 14篇 |
2009年 | 18篇 |
2008年 | 14篇 |
2007年 | 18篇 |
2006年 | 25篇 |
2005年 | 22篇 |
2004年 | 25篇 |
2003年 | 18篇 |
2002年 | 26篇 |
2001年 | 23篇 |
2000年 | 11篇 |
1999年 | 12篇 |
1998年 | 20篇 |
1997年 | 26篇 |
1996年 | 26篇 |
1995年 | 14篇 |
1994年 | 27篇 |
1993年 | 15篇 |
1992年 | 32篇 |
1991年 | 20篇 |
1990年 | 29篇 |
1989年 | 36篇 |
1988年 | 36篇 |
1987年 | 16篇 |
1986年 | 28篇 |
1985年 | 28篇 |
1984年 | 33篇 |
1983年 | 16篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 16篇 |
1979年 | 6篇 |
1978年 | 11篇 |
1977年 | 14篇 |
1976年 | 12篇 |
1975年 | 8篇 |
1961年 | 1篇 |
1935年 | 1篇 |
排序方式: 共有852条查询结果,搜索用时 15 毫秒
71.
Familial hemiplegic migraine: a clinical comparison of families linked and unlinked to chromosome 19 总被引:5,自引:0,他引:5
GM Terwindt RA Ophoff J Haan RR Frants MD Ferrari for the DMGRG 《Cephalalgia : an international journal of headache》1996,16(3):153-155
We compared the clinical characteristics of 50 patients from three unrelated families with familial hemiplegic migraine (FHM) linked to chromosome 19, with those of 20 patients from two families with FHM not linked to chromosome 19. We found no significant differences for age at onset, frequency and duration of attacks, duration of the paresis, and occurrence of basilar migraine symptoms. In the linked families, significantly more patients reported unconsciousness during attacks (39%, vs 15%; p<0.05) and provocation of attacks by mild head trauma (70% vs 40%; p< 0.05). In one linked family patients also displayed chronic progressive cerebellar ataxia, whereas in one unlinked family benign infantile convulsions occurred in addition to FHM. Interestingly, so far an association with cerebellar ataxia was only described in chromosome 19-linked families. FHM linked to chromosome 19 and FHM unlinked to chromosome 19 do not differ with respect to clinical features. 相似文献
72.
Central autonomic effects of dermorphin in conscious rats 总被引:1,自引:0,他引:1
G Feuerstein A I Faden 《The Journal of pharmacology and experimental therapeutics》1983,226(1):151-156
Central cardiovascular and respiratory effects of dermorphin were studied in conscious rats. Intracerebroventricular administration (0.1 or 1 nM) of dermorphin increased the systolic and diastolic blood pressure whereas a high dose (50 nM) decreased blood pressure. Dermorphin at 1 nM increased respiratory rate but caused hypoxia, acidosis and hypercapnia; at 50 nM, respiratory rate was suppressed. Both of these doses produced catalepsy. Stimulation of the sympathoadrenomedullary axis at the pressor period elicited by 1 nM dermorphin was evident by high circulating levels of epinephrine and norepinephrine. N-methyl-atropine reversed the severe bradycardia induced by dermorphin and completely prevented this phenomenon if given as pretreatment. Neither blood pressure nor respiratory depression was altered by the muscarinic blocker. Naloxone (1 mg/kg) reversed the respiratory, cardiovascular and sympathetic effects of dermorphin as well as the catalepsy. These data show that dermorphin has central autonomic effects which are naloxone reversible and mediated by both sympathetic and parasympathetic pathways. 相似文献
73.
Red cell loss following orthopedic surgery: the case against postoperative blood salvage 总被引:3,自引:0,他引:3
J Umlas ; RR Foster ; SA Dalal ; SM O'Leary ; L Garcia ; MS Kruskall 《Transfusion》1994,34(5):402-406
BACKGROUND: Expensive devices have been developed for the collection and transfusion of blood salvaged after hip or knee arthroplasty. STUDY DESIGN AND METHODS: The volume of salvaged red cells was measured for the first 6 hours after operation. This volume was compared to total red cell loss during hospitalization and to the volume of allogeneic red cells transfused. RESULTS: Mean postoperative red cell loss in 31 patients following hip replacement was 55 +/− 29 mL and that in 20 patients following knee replacement was 121 +/− 50 mL. The 6-hour wound drainage represented 8.7 and 16.8 percent of overall red cell loss during hospitalization for hip and knee replacement, respectively. The transfusion of postoperatively salvaged red cells would have supplanted transfusion of less than one-third of a unit of allogenic blood after hip replacement and two-thirds of a unit after knee replacement. Only three patients (5.9%) lost red cell volume in the drainage equivalent to or in excess of 1 unit of red cells (180 mL). The volume of red cells salvaged postoperatively bore no relationship to perioperative red cell losses as a whole. CONCLUSION: The relatively small red cell loss in the postoperative period in most arthroplasty patients does not appear to justify the routine use of this technique for the recovery of autologous blood. 相似文献
74.
BACKGROUND: Staphylococcal aureus bacteremia (SAB) is a major problem in adult patients with a significant mortality. Less is known about SAB in children. The present study was designed to review a 5-year experience with SAB in a children's hospital. METHODS: We conducted a retrospective chart review from 2000-2004. RESULTS: Thirty-six children experienced 42 episodes of SAB and ranged in age from 1 week to 16.7 years with a mean age of 30.5 months. Thirty-two (89%) of the 36 children had preexisting medical conditions. Thirty-six (86%) of 42 episodes of SAB were due to hospital-acquired infections, and 22 (61%) of these 36 episodes occurred in premature infants in the neonatal intensive care unit. Only 3 episodes (7%) of endocarditis were identified, and 2 were community-acquired infections. Fourteen (39%) episodes of SAB were due to methicillin-resistant strains. There were only 3 (8%) deaths, and all were unrelated to SAB. CONCLUSION: SAB occurred most often as a hospital-acquired infection in the neonatal intensive care unit, and methicillin-resistant Staphylococcal aureus accounted for one third of the episodes. Complications such as endocarditis or other metastatic infections and death because of SAB were infrequent. 相似文献
75.
76.
Anne Drapkin Lyerly Margaret Olivia Little Ruth R. Faden 《American journal of public health》2009,99(10):1742-1745
With a $3 billion investment by the federal government, the National Children''s Study (NCS) recently began recruitment. The NCS is a golden—and potentially missed—opportunity to study one of the most underrepresented populations in clinical research: pregnant women.As the nation''s largest-ever study of children''s health, the NCS will examine the effects of the environment on children from before birth to 21 years of age, with participants sampled primarily through women during pregnancy. Thus the NCS presents a rare opportunity to study the health of women during and after pregnancy, in addition to the health of their children.On both moral and policy grounds, we make the case for inclusion of women''s health outcomes in the NCS.THE YEAR 2009 MARKS AN important threshold for the advancement of children''s health. After nearly a decade of careful planning, recruitment has begun for the pilot phase of the National Children''s Study (NCS), the largest longitudinal study of children''s health ever conducted in the United States. Authorized by Congress in 2000 and led by a consortium of federal agencies, including the National Institutes of Child Health and Development, the National Institute of Environmental Health Sciences, the Centers for Disease Control and Prevention, and the US Environmental Protection Agency, the NCS will examine the effects of environmental influences on more than 100000 children, with data collected from before birth to 21 years of age. At a cost of more than $3 billion, the study aims to gather research findings that will critically inform the “basis of child health guidance, interventions, and policy for generations to come.”1Although the potential benefits are enormous, the NCS may also be one of the largest missed opportunities for health advancement in recent history: the opportunity to prospectively and systematically study the health of women during and following pregnancy, as well as the babies they bear. 相似文献
77.
Recovery of a unique bacterial organism in human middle ear fluid and its possible role in chronic otitis media 总被引:1,自引:6,他引:1 下载免费PDF全文
The middle ear fluids of 10 children with persistent otitis media with effusion (OME) were found to contain an unclassified, slow-growing, gram-positive organism. Large gram-positive cocci, often present as diplococci or tetrads, were readily seen in each effusion. Culture of the fluid on a blood agar plate required 2 to 5 days of incubation at 37 degrees C and yielded a slow-growing coccus in pure culture in 70% of cases and in mixed culture in 30% of cases. The organism in question was unique and could be distinguished from aerococci, gemellas, enterococci, and micrococci. It grew in 6.5% saline and on bile esculin agar. It did not grow at 45 degrees C or anaerobically. It was uniformly catalase and hippurate positive. It gave negative reactions with tellurite, tetrazolium, and pyruvate and did not utilize any of the carbohydrates tested. Reactions to bile esculin were variable. The episodes of OME associated with the bacterium in question were asymptomatic, had been present from 1 to 8 months, and occurred in children who had previously experienced OME. The middle ear fluids were typically serous or seromucinous and contained inflammatory cells. The data suggest that the gram-positive coccus is a newly described middle ear pathogen and may be responsible, in part, for persistent middle ear effusion. The characteristically slow growth of the organism in vitro could hinder recovery of the organism from clinical specimens and may therefore have prevented its earlier recognition. 相似文献
78.
79.
In order to determine the prognostic significance of thrombocytosis in idiopathic sideroblastic anemia, the clinical courses of 17 patients were reviewed. Six patients (36%) had thrombocytosis, and none developed acute leukemia. Nine patients (53%) had normal platelet counts, and one developed acute leukemia. Two patients (12%) were thrombocytopenic, and one died of acute leukemia. There was little correlation between survival and platelet count. Sixty-three additional case reports of idiopathic sideroblastic anemia were collected from the literature. Analysis of those patients and the patients in the present study documented transformation to acute leukemia in 5 of 9 (56%) thrombocytopenic patients, 4 of 54 (7.4%) patients with normal platelet counts, and 0 of 17 patients with thrombocytosis (p less than 0.05). Therefore patients with idiopathic sideroblastic anemia and thrombocytosis appear to have a decreased likelihood of leukemic transformation. 相似文献
80.
Hypersensitivity pneumonitis: evaluation with CT 总被引:4,自引:0,他引:4
Thirteen chest radiographs and computed tomographic (CT) scans obtained from 11 patients with hypersensitivity pneumonitis were reviewed. The CT findings were correlated with open lung biopsy findings in seven patients. The two patients with acute hypersensitivity pneumonitis showed air-space opacification on CT scans. An open lung biopsy, done in one of these patients, demonstrated noncaseating granulomas and filling of the air spaces with macrophages. The nine patients with subacute hypersensitivity pneumonitis showed small, rounded opacities and patchy air-space opacification on CT scans. These findings reflected the histologic findings, which consisted of interstitial pneumonitis, cellular bronchiolitis, and small, noncaseating granulomas. The six patients with symptoms for 12 months or longer also showed irregular linear opacities on CT scans, corresponding to areas of fibrosis. CT scans were superior to radiographs in helping to assess the type and extent of abnormalities, and high-resolution CT scans were superior to conventional CT scans. 相似文献