全文获取类型
收费全文 | 19884篇 |
免费 | 1872篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 261篇 |
儿科学 | 726篇 |
妇产科学 | 523篇 |
基础医学 | 2962篇 |
口腔科学 | 377篇 |
临床医学 | 2310篇 |
内科学 | 3905篇 |
皮肤病学 | 211篇 |
神经病学 | 1513篇 |
特种医学 | 895篇 |
外国民族医学 | 3篇 |
外科学 | 2472篇 |
综合类 | 512篇 |
一般理论 | 25篇 |
预防医学 | 2075篇 |
眼科学 | 269篇 |
药学 | 1593篇 |
1篇 | |
中国医学 | 5篇 |
肿瘤学 | 1172篇 |
出版年
2021年 | 279篇 |
2019年 | 278篇 |
2018年 | 298篇 |
2017年 | 212篇 |
2016年 | 240篇 |
2015年 | 295篇 |
2014年 | 430篇 |
2013年 | 624篇 |
2012年 | 842篇 |
2011年 | 925篇 |
2010年 | 516篇 |
2009年 | 444篇 |
2008年 | 770篇 |
2007年 | 815篇 |
2006年 | 797篇 |
2005年 | 810篇 |
2004年 | 730篇 |
2003年 | 671篇 |
2002年 | 680篇 |
2001年 | 610篇 |
2000年 | 643篇 |
1999年 | 533篇 |
1998年 | 288篇 |
1997年 | 236篇 |
1996年 | 261篇 |
1995年 | 250篇 |
1994年 | 224篇 |
1993年 | 199篇 |
1992年 | 493篇 |
1991年 | 497篇 |
1990年 | 465篇 |
1989年 | 435篇 |
1988年 | 415篇 |
1987年 | 419篇 |
1986年 | 424篇 |
1985年 | 420篇 |
1984年 | 316篇 |
1983年 | 270篇 |
1982年 | 211篇 |
1981年 | 171篇 |
1980年 | 162篇 |
1979年 | 309篇 |
1978年 | 229篇 |
1977年 | 209篇 |
1976年 | 170篇 |
1975年 | 177篇 |
1974年 | 180篇 |
1973年 | 189篇 |
1972年 | 167篇 |
1971年 | 163篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
M R Ashton A D Postle D E Smith M A Hall 《Archives of disease in childhood. Fetal and neonatal edition》1994,71(2):F114-F117
Objectives - To determine whether dexamethasone `matures' the phosphatidylcholine (PC) composition of broncheoalveolar fluid in infants at high risk of neonatal chronic lung disease (CLD), either by increasing the proportion of dipalmitoylphosphatidylcholine (DPPC), expressed as a percentage of total PC (%DPPC), or by increasing the ratio of DPPC to palmitoyloleoylphosphatidylcholine (DPPC:POPC ratio). 相似文献
33.
P C Chan J Huff J K Haseman J A Quest W Hall 《Japanese journal of cancer research》1992,83(3):258-263
Short-term and long-term carcinogenicity of methyl carbamate (MCB) was evaluated in F344 rats and B6C3F1 mice. In experiments lasting 6, 12, and 18 months, MCB was given in water by gavage to groups of 10 male and 10 female rats at 0 or 400 mg/kg body weight, 5 days per week, and to similar groups of mice at 0 or 1,000 mg/kg. At 6 months, MCB induced atypical mitoses, cytologic alterations, cytomegaly, pigmentation, necrosis, and neoplastic nodules of the liver in rats. At 12 and 18 months, carcinomas of the liver were induced by MCB in 80-90% of male rats and in 60-80% of female rats. None was observed in control rats or in mice. In the 2-year studies, MCB was given to groups of 50 male and 50 female rats at 0, 100, or 200 mg/kg and to similar groups of mice at 0, 500, or 1,000 mg/kg, 5 days/week. Chronic focal inflammation, cytologic alteration, hyperplasia, and neoplastic nodules and carcinomas (200 mg/kg groups only) of the liver were induced by MCB in rats. Liver tumor incidence data for combined experiments in rats were: males--5% in controls, 0% in 100 mg/kg group, 14% in 200 mg/kg group, and 77% in 400 mg/kg group; females--5% in controls, 0% in controls, 0% in 100 mg/kg group, 12% in 200 mg/kg group, and 63% in 400 mg/kg group. MCB was not shown to be carcinogenic in mice. 相似文献
34.
Salmonella arizonae are rarely isolated in the UK. Since 1966 there have been sixty-six isolates from humans of whom 35% gave a recent history of foreign travel. Terrapins and snakes are potential sources of infection. 相似文献
35.
Cytokines (IL-1 alpha and IL-2) and soluble interleukin 2 receptors (sIL-2r) were evaluated in patients with rheumatoid arthritis (RA) and controls. In RA, serum sIL-2r and IL-1 alpha were increased, and sIL-2r were significantly higher in synovial fluid than in serum. Serum levels of sIL-1r but not IL-1 alpha were increased in patients with acute infections, suggesting additional discriminatory specificity for IL-1 alpha. Both tender and swollen joint scores were higher for patients with RA with serum sIL-2r levels greater than or equal to 700 U/ml. Quantitation of immune mediators may be useful in the clinical assessment of RA in addition to their implication regarding the pathogenesis of the disease. 相似文献
36.
Students in grades 1 through 6 were assessed on 11 ocular functions. A multivariate correlation was made between these ocular functions and the students' reading ability, as measured on the Stanford Achievement Test. There were no significant multivariate correlations between the ocular functions and the students' reading ability. It was concluded that for students with small heterophorias and no significant refractive errors, a relationship did not exist between ocular functions and reading ability. 相似文献
37.
Clinical evaluation of technetium-99m infecton for the localisation of bacterial infection 总被引:4,自引:3,他引:1
K. E. Britton S. Vinjamuri A. V. Hall K. Solanki Q. H. Siraj J. Bomanji S. Das 《European journal of nuclear medicine and molecular imaging》1997,24(5):553-556
The aim of the study was to distinguish infection from inflammation in patients with suspected infection using technetium-99m Infecton. Ninety-nine patients (102 studies) referred for infection evaluation underwent imaging with 400 MBq99mTc-Infecton at 1 and 4 h. Most patients had appropriate microbiological tests and about half (56) had radiolabelled white cell scans as well. No adverse effects were noted in any patient. The clinical efficacy of99mTc-Infecton depended in part on whether imaging was undertaken during intibiotic therapy for infection or not. In consultation with the microbiologist, 5–14 days of appropriate and successful antibiotic therapy was considered adequate to classify some results as true-negatives. The figures for sensitivity and specificity of99mTc-Infecton for active or unsuccessfully treated infection were 83% and 91% respectively. It is concluded that99mTc-Infecton imaging contributed to the differential diagnosis of inflammation. It is being used as the first imaging modality when bacterial infection is suspected. 相似文献
38.
The aetiopathogenesis of haemorrhagic shock encephalopathy syndrome (HSES) remains unclear and after concern that a novel environmental agent was the cause, the British Paediatric Association and the Public Health Laboratory Service Communicable Disease Surveillance Centre in 1983 initiated surveillance of this condition in the British Isles. After 1986 cases were ascertained via the British Paediatric Surveillance Unit 'active' reporting scheme; this report presents the findings for 1985-8. Sixty five patients were reported, of whom 52 satisfied the criteria for inclusion. Of those whose outcome was known, 24 (46%) died, 18 had severe neurological damage, and six survived apparently intact. Epidemiological features of note were: the median age of 15 weeks (range 3-140); statistically significant clustering of admission times suggesting a peak onset period at night; lack of geographic clusters, of secular trends and, except for a slight excess in winter months, of seasonality. Clinical and pathological features followed a highly consistent pattern, suggesting that HSES is an individual clinical entity distinguishable from conditions with similar presentations, such as septicaemia and Reye's syndrome. There was no microbiological or epidemiological evidence to support the emergence of a novel environmental agent. Many of the features of HSES were, however, the same as those described in heat stroke and we suggest that the two conditions are the same even though there is usually no history of overt overheating. 相似文献
39.
40.
An attempt was made to develop a model of chronic renal disease in the rat through repeated administration of a nephrotoxin specific for proximal tubular epithelium. Mercuric chloride was administered by subcutaneous injection in gradually increasing amounts over a period of 21 weeks. The dose ranged from 1.125 mg/kg once a week to 2.0 mg/kg twice a week. Measured parameters of renal function include plasma urea nitrogen, plasma creatinine, 24-hour urine output volume, and 24-hour urinary protein excretion. When compared to their own pretreatment values and those of the age/weight-matched control animals, the mercuric chloride-treated rats exhibited no significant abnormalities in these parameters of kidney function with the exception of a mild proteinuria at 21 weeks. Light microscopic examination of the kidneys of the mercury-treated rats revealed mild tubular, interstitial, and glomerular lesions which were significantly worse than those in the kidneys of the controls. This study demonstrates the ability of the kidney to sustain a considerable degree of resistance to inorganic mercury toxicity when exposure is continuous over a prolonged period of time. It also demonstrates the inability of commonly measured clinical laboratory parameters of kidney function to identify the effects of chronic mercuric chloride toxicity in the rat. 相似文献