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   12108篇
  免费   691篇
  国内免费   58篇
耳鼻咽喉   285篇
儿科学   261篇
妇产科学   550篇
基础医学   1614篇
口腔科学   176篇
临床医学   818篇
内科学   3328篇
皮肤病学   267篇
神经病学   1000篇
特种医学   317篇
外科学   1530篇
综合类   93篇
一般理论   1篇
预防医学   840篇
眼科学   183篇
药学   828篇
中国医学   43篇
肿瘤学   723篇
  2023年   74篇
  2022年   305篇
  2021年   468篇
  2020年   197篇
  2019年   324篇
  2018年   360篇
  2017年   262篇
  2016年   305篇
  2015年   313篇
  2014年   456篇
  2013年   641篇
  2012年   819篇
  2011年   888篇
  2010年   503篇
  2009年   453篇
  2008年   711篇
  2007年   771篇
  2006年   776篇
  2005年   768篇
  2004年   692篇
  2003年   657篇
  2002年   530篇
  2001年   157篇
  2000年   195篇
  1999年   195篇
  1998年   77篇
  1997年   81篇
  1996年   62篇
  1995年   49篇
  1994年   40篇
  1993年   44篇
  1992年   82篇
  1991年   69篇
  1990年   81篇
  1989年   61篇
  1988年   44篇
  1987年   47篇
  1986年   48篇
  1985年   45篇
  1984年   33篇
  1983年   25篇
  1982年   13篇
  1981年   11篇
  1980年   10篇
  1979年   11篇
  1978年   12篇
  1977年   11篇
  1976年   9篇
  1975年   11篇
  1971年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Serum selenium levels were determined in 92 healthy subjects [40 men, 52 women; mean age 33.5 +/- 1.6 (s.e.m.) years, range 16-71 years] living in the province of Barcelona, Catalunya, Spain. Only well-nourished individuals with unremarkable clinical history, normal blood chemistry and haematological tests were selected. The subjects were divided into 6 age groups for each sex. Serum samples were analysed using a modification of the standard electrothermal graphite furnace atomic absorption spectrophotometry method to shorten the procedure while maintaining its accuracy. A significant correlation (y = -1.31 + 1.51 x; r = 0.9967, P less than 0.001) was observed between our method and the standard assay method. The mean serum selenium concentration was 60.39 micrograms/l, 95 per cent CI 53.35-67.45 micrograms/l. There were age- but no sex-group differences (P less than 0.001). This result is similar to that found in countries whose low selenium levels have been related to an increased risk of some disease states. Clinical and health implications of this suboptimal selenium status are discussed.  相似文献   
32.
In this article we present the tenth case, according to the literature, of adenocarcinoma occurring at a long standing ileostomy originally performed for ulcerative colitis. Study of this and previous cases demonstrates common factors such as a previous history of ulcerative colitis, a long interval until the appearance of symptoms, together with a similar clinical and pathological characterisation with invasion of neighbouring skin layers close to the ileostomy. Several pathogenic hypotheses are considered. We believe that local excision in oder to obtain the diagnosis is a better option than a sampling biopsy and that surgery should include a wide resection of the abdominal wall and intestine in order to comply with therapeutic criteria in malignant disease.  相似文献   
33.
34.
The aetiology of porphyria cutanea tarda (PCT) has not been elucidated, but the possibility of an autoimmune mechanism has been proposed. We report a case of an unknown clinical combination of PCT with autoimmune hypothyroidism, alopecia universalis and vitiligo with thyroid and parietal cell circulating antibodies. This is highly suggestive of underlying autoimmune damage in this patient.  相似文献   
35.
36.
Myotonic dystrophy is an inherited multi-system disease. Its pathophysiology leading to muscle malfunction and damage is not well understood. 23Na NMR spectroscopy was applied here for an in vivo comparative study of the calf muscles of 7 myotonic dystrophy patients at various stages of the disease and 11 healthy volunteers. Both the total sodium content, expressed as the ratio of the 23Na and 1H water signals, and the fast transverse relaxation time, T21, determined from the triple quantum-filtered spectra, increased in correlation with the severity of the disease. The results demonstrate that 23Na NMR enables the quantitation of myotonic dystrophy progression.  相似文献   
37.
38.
CONTEXT AND OBJECTIVE: Adverse drug reactions are a significant problem in patients on antiretroviral therapy (ART). We determined liver enzyme elevation frequencies in HIV-infected children and adolescents receiving ART, and their association with risk factors. DESIGN AND SETTING: Cross-sectional study, at the Pediatrics Immunodeficiency Division, University Hospital, Universidade Estadual de Campinas. METHODS: Medical records of 152 children and adolescents (54.6% male; median age 7.48 years) were analyzed, with a mean of 2.6 liver enzyme determinations per patient. Clinically, patients were classified in categories N (6), A (29), B (78) and C (39). Serum levels of aspartate aminotransferase and alanine aminotransferase were evaluated. Hepatotoxicity was scored as grade 1 (1.1-4.9 times upper limit of normality, ULN), grade 2 (5.0-9.9 times ULN), grade 3 (10.0-15.0 times ULN) and grade 4 (> 15.0 times ULN). To assess hepatotoxicity risk factors, odds ratios (OR) and adjusted odds ratios (aOR) for age, gender, TCD4+ cell count, viral load and medication usage were calculated. RESULTS: We observed grade 1 hepatotoxicity in 19.7 % (30/152) patients. No cases of grade 2, 3 or 4 were detected. There was a significant association between hepatotoxicity and use of sulfonamides (OR, 3.61; 95% confidence interval (CI), 1.50-8.70; aOR, 3.58; 95% CI, 1.44-8.85) and antituberculous agents (OR, 9.23; 95% CI, 1.60-53.08; aOR, 9.05; 95% CI, 1.48-55.25). No toxicity was associated with ART. CONCLUSIONS: One fifth of patients experienced mild hepatotoxicity, attributed to antituberculous agents and sulfonamides. Our results suggest that ART was well tolerated.  相似文献   
39.
40.
The qualitative and quantitative (q/q) changes of keratinolytic fungi in soil mixtures with added sewage sludge were examined during a preliminary reclamation experiment. Sludge before land application was characterized by the weak growth of keratinolytic fungi. In devastated urban soil, abundant fungal growth was observed. Over a 19‐month reclamation period, decreasing frequency of Chrysosporium concurrent with the enrichment of the mixture with the geophilic dermatophytes Arthroderma quadrifidum and A. uncinatum were clearly seen. The results are discussed with respect to possible ecological factors influencing the occurrence of keratinolytic fungi in the materials examined. The public health risk associated with the application of sewage sludge for reclamation is also discussed.  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