全文获取类型
收费全文 | 1361篇 |
免费 | 74篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 76篇 |
妇产科学 | 21篇 |
基础医学 | 147篇 |
口腔科学 | 93篇 |
临床医学 | 101篇 |
内科学 | 445篇 |
皮肤病学 | 10篇 |
神经病学 | 105篇 |
特种医学 | 57篇 |
外科学 | 99篇 |
综合类 | 39篇 |
预防医学 | 72篇 |
眼科学 | 42篇 |
药学 | 64篇 |
肿瘤学 | 47篇 |
出版年
2021年 | 13篇 |
2020年 | 6篇 |
2019年 | 20篇 |
2018年 | 23篇 |
2017年 | 13篇 |
2016年 | 18篇 |
2015年 | 21篇 |
2014年 | 27篇 |
2013年 | 25篇 |
2012年 | 54篇 |
2011年 | 71篇 |
2010年 | 26篇 |
2009年 | 41篇 |
2008年 | 58篇 |
2007年 | 88篇 |
2006年 | 79篇 |
2005年 | 66篇 |
2004年 | 66篇 |
2003年 | 61篇 |
2002年 | 61篇 |
2001年 | 67篇 |
2000年 | 57篇 |
1999年 | 34篇 |
1998年 | 19篇 |
1997年 | 20篇 |
1996年 | 10篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 30篇 |
1991年 | 24篇 |
1990年 | 24篇 |
1989年 | 31篇 |
1988年 | 27篇 |
1987年 | 26篇 |
1986年 | 36篇 |
1985年 | 19篇 |
1984年 | 16篇 |
1983年 | 8篇 |
1982年 | 18篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 12篇 |
1978年 | 7篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1972年 | 5篇 |
1932年 | 4篇 |
排序方式: 共有1439条查询结果,搜索用时 359 毫秒
61.
In adult populations, elevated blood pressure is related to the development of occlusive atherosclerosis, stroke, and renal disease. The significance of blood pressure levels in childhood, unless extremely elevated, has not been related to disease outcomes. In this study, the risk of high blood pressure in young adult life is evaluated based on the observations of blood pressure and other factors made during the school-aged years. Subjects, 2445 in number, were first observed at ages 7 through 18 years and again between 20 and 30 years. During childhood, measurements of blood pressure, height, and weight were made in alternate years. At adult ages, the same measurements were again made and a health questionnaire was administered. According to the data, adult blood pressure is correlated with childhood blood pressure, body size, and change in ponderosity from childhood to adult life. Adult ponderosity is related to childhood ponderosity, and those who are most obese as adults show the greatest increase in weight for height from their childhood years. These observations suggest that strategies to prevent the acquisition of excess ponderosity during adolescence may be useful in preventing adult hypertension. 相似文献
62.
Pacemaker management for acute onset of heart block in childhood 总被引:3,自引:0,他引:3
L T Mahoney W J Marvin D L Atkins E B Clark R M Lauer 《The Journal of pediatrics》1985,107(2):207-211
Four children aged 2 to 15 years are described who had Stokes-Adams syndrome as the primary cardiac manifestation of complete heart block. All had mild, nonspecific antecedent symptoms without signs of congestive heart failure. Viral neutralizing antibody titers (coxsackievirus B1 and B2) rose significantly in two patients. Electrocardiography demonstrated complete heart block associated with one or more of the following: right bundle branch block, left anterior hemiblock, left bundle branch block, intraventricular conduction delay, and ventricular standstill. In addition, second-degree heart block was seen during the initial or resolving phases of illness. To prevent further life-threatening episodes of Stokes-Adams syndrome, temporary transvenous pacemakers were placed. Two patients with persisting complete heart block required permanent pacemakers. At last examination, the remaining two patients had sinus rhythm and normal conduction. Nonsurgical acquired complete heart block is unusual in childhood, and may be the only manifestation of myocarditis. Extreme bradycardia, which causes syncope, requires immediate temporary cardiac pacing; if the bradycardia persists, a permanent pacemaker should be implanted. 相似文献
63.
Treatment records of patients with primary untreated Stage IIIB carcinoma of the cervix treated at Indiana University Department of Radiation Oncology from November 1964 through January 1979 were reviewed. During this period, 79 patients were treated; 46 received external therapy using cobalt-60, 15 received a 25-MV photon beam, and 18 received a 25-MV photon beam followed by 45 min of 434-MHz microwave hyperthermia producing central tumor core temperatures of 39.5 to 41.5 degrees C. All patients received similar doses of radiation using combination intracavitary radioactive isotopes and external therapy. Patients who received heat therapy in combination with radiation therapy did not have increased acute or chronic complications of normal tissues. Local tumor control was superior when regional heat therapy was given; however, long-term absolute survival rates were not affected as the survival rate at 5 years was not statistically different in any of the three treatment groups. 相似文献
64.
Lipoproteins in the progeny of young men with coronary artery disease: children with increased risk 总被引:2,自引:0,他引:2
The authors studied 173 progeny from 63 families in which the father had angiographically diagnosed coronary artery disease by 50 years of age. To assess the nature of the coronary risk factors in these families, we measured their height and weight to calculate Quetelet index (wt/ht2), BP, fasting plasma cholesterol, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were measured in the affected fathers, their wives, and their progeny. These values were compared with age- and sex-specific values from the Lipid Research Clinic data. Sixty-five percent of the affected fathers and 51% of the progeny had elevated triglyceride, elevated low-density lipoprotein cholesterol, diminished high-density lipoprotein cholesterol, or combinations thereof. The distribution of the lipids and lipoproteins in the children bore a close resemblance to those observed in the affected fathers. A significant number of the mothers had diminished high-density lipoprotein cholesterol, which was attributed to their obesity. Screening the progeny of young coronary artery disease patients is therefore highly productive in identifying young people at excessive risk for future coronary artery disease. Early identification of this young high-risk population offers an opportunity for early initiation of preventive measures. 相似文献
65.
Little is known about the risk of severe illness from respiratory syncytial virus infection in children with bronchopulmonary dysplasia. A prospective study was done of the natural history of respiratory syncytial virus infection in 30 children less than 2 years of age with bronchopulmonary dysplasia who were in a home oxygen program. Surveillance to identify children with acute respiratory symptoms was done by weekly telephone interview. Symptomatic children were examined, oxygen saturation was determined by oximetry, and nasopharyngeal lavage fluid was collected for virus cultures and rapid respiratory syncytial virus antigen tests. During the 4-month study period (December to April), 27 children had one or more acute respiratory illnesses, and respiratory syncytial virus developed in 16/27 (59%). Passive smoking and greater than or equal to four members in the home increased the risk of symptomatic respiratory syncytial virus (P less than .01 and P less than .03, respectively). Of 16 children, 11 (69%) required hospitalization. Of the 11 hospitalized children with respiratory syncytial virus, nine were either still receiving oxygen at home or required oxygen therapy within the previous 3 months v none of five nonhospitalized children (P less than .005). Five of the hospitalized children were greater than 12 months of age and five had respiratory syncytial virus infection previously that had been confirmed by culture results. Hospitalizations were prolonged and complicated. Seven of 11 children were hospitalized for greater than 1 week; four were admitted to the intensive care unit; four were treated with ribavirin aerosol, and two needed mechanical ventilation. There were no deaths.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
66.
67.
68.
69.
In the hippocampal formation of schizophrenics, the detailed morphology of Golgi-impregnated granule cells was examined. These granule cells of the dentate gyrus are interposed between the rostral entorhinal cortex and the hippocampus proper. In these limbic regions significant cytoarchitectural alterations in schizophrenics are reported, giving rise to the concept of a prenatal limbic maldevelopment in schizophrenia. Compared to controls, the frequency of dentate granule cells with basal dendrites was significantly increased in schizophrenics [43% (+/-3)] vs. [22% (+/-2) in the control group]. In epilepsy, dentate granule cells of epileptic patients also develop basal dendrites, which is explained as an adaptive process of plasticity. Similarly, the hippocampal alterations described in schizophrenics could be the sequela of primary entorhinal cytoarchitectural alterations. Since the increase in basal dendrites seems to reflect a process of continuous plasticity, suggesting an increased rate of postnatal granule cell generation, the synthesis of a prenatal limbic maldevelopment with an ongoing process of plasticity might, therefore, supersede the hypothesis of a neurodegeneration in schizophrenia. 相似文献
70.
Lauer P Metzner HJ Zettlmeissl G Li M Smith AG Lathe R Dickneite G 《Thrombosis and haemostasis》2002,88(6):967-974
Blood coagulation factor XIII (FXIII) promotes cross-linking of fibrin during blood coagulation; impaired clot stabilization in human genetic deficiency is associated with marked pathologies of major clinical impact, including bleeding symptoms and deficient wound healing. To investigate the role of FXIII we employed homologous recombination to generate a targeted deletion of the inferred exon 7 of the FXIII-A gene. FXIII transglutaminase activity in plasma was reduced to about 50% in mice heterozygous for the mutant allele, and was abolished in homozygous null mice. Plasma fibrin gamma-dimerization was also indetectable in the homozygous deficient animals, confirming the absence of activatable FXIII. Homozygous mutant mice were fertile, although reproduction was impaired. Bleeding episodes, hematothorax, hematoperitoneum and subcutaneous hemorrhage in mutant mice were associated with reduced survival. Arrest of tail-tip bleeding in FXIII-A deficient mice was markedly and significantly delayed; replacement of mutant mice with human plasma FXIII (Fibrogammin P) restored bleeding time to within the normal range. Thrombelastography (TEG) experiments demonstrated impaired clot stabilization in FXIII-A mutant mice, replacement with human FXIII led to dose-dependent TEG normalization. The mutant mice thus reiterate some key features of the human genetic disorder: they will be valuable in assessing the role of FXIII in other associated pathologies and the development of new therapies. 相似文献