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   11148篇
  免费   370篇
  国内免费   67篇
耳鼻咽喉   49篇
儿科学   400篇
妇产科学   250篇
基础医学   738篇
口腔科学   174篇
临床医学   737篇
内科学   2712篇
皮肤病学   172篇
神经病学   541篇
特种医学   210篇
外科学   1587篇
综合类   804篇
一般理论   5篇
预防医学   1732篇
眼科学   210篇
药学   792篇
  2篇
中国医学   232篇
肿瘤学   238篇
  2023年   101篇
  2022年   201篇
  2021年   313篇
  2020年   304篇
  2019年   748篇
  2018年   642篇
  2017年   384篇
  2016年   205篇
  2015年   222篇
  2014年   441篇
  2013年   447篇
  2012年   383篇
  2011年   419篇
  2010年   331篇
  2009年   318篇
  2008年   308篇
  2007年   297篇
  2006年   244篇
  2005年   176篇
  2004年   106篇
  2003年   120篇
  2002年   87篇
  2001年   93篇
  2000年   92篇
  1999年   60篇
  1998年   54篇
  1997年   43篇
  1996年   41篇
  1995年   38篇
  1994年   39篇
  1993年   41篇
  1992年   27篇
  1991年   28篇
  1989年   17篇
  1988年   22篇
  1987年   19篇
  1986年   17篇
  1985年   285篇
  1984年   483篇
  1983年   401篇
  1982年   400篇
  1981年   340篇
  1980年   316篇
  1979年   390篇
  1978年   283篇
  1977年   195篇
  1976年   283篇
  1975年   249篇
  1974年   255篇
  1973年   243篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
41.
42.
43.
Structural anomalies of mitotic chromosomes from two tumorigenic cell lines of the German cockroach (Blattella germanica) is described. Aberrations, such as unpairable marker chromosomes, double minutes, di- and tricentrics, ring chromosomes, tri- and quadriradials, and chromosome and chromatid gaps and breaks, were observed in varying proportions. This study reports that the double minute chromosomes (DMs) are associated with insect tumor cells, similar to the findings in both murine and human tumor cells.  相似文献   
44.
45.
Severe but atypical osteoarthritic deformities were found in each of 12 femoral heads removed during total hip arthroplasty for Mseleni disease. Although degenerative and regenerative changes were present throughout the cartilage, there was a paucity of eburnation. Histomorphometric analysis of bone at the line of excision indicated that mild osteomalacia was present in four of the 12 specimens. The percentage of the endosteum occupied by osteoid was 9.7 +/- 7.96 (SD) in the patients with Mseleni disease, compared with 5.6 +/- 4.33 in seven African black and 4.1 +/- 2.13 in 13 American white control subjects. The mean thickness of the osteoid seams was not increased. The findings suggest that osteomalacia is not a major pathogenetic factor in Mseleni disease.  相似文献   
46.
Antibodies against pneumococcal polysaccharides were measured by ELISA in Papua New Guinean children with pneumonia aged 0-14 months, in age-matched healthy Papua New Guinean controls and in healthy expatriate children living in Papua New Guinea. At 0-5 months of age, the IgG antibody titres against six of the eight polysaccharides measured were significantly lower in pneumonia patients than in both control groups. Antibody titres in 6-14-month-old Papua New Guinean controls were significantly lower than in control Papua New Guineans aged 0-5 months for five of the eight polysaccharides tested. In the 6-14-months age group the antibody titre was significantly lower in pneumonia patients than in controls for only one polysaccharide. For seven of the eight serotypes tested, antibody levels in expatriate controls did not decline with age. Antibody responses of Papua New Guinean children aged 6-18 months to a 23-valent pneumococcal vaccine were serotype dependent. Fold increases in response to the vaccine were greatest for the IgA isotype. IgG antibody responses were greater than three fold to four of the eight serotypes tested.  相似文献   
47.
中国圆蝇亚科妙蝇属四新种(双翅目:蝇科)   总被引:1,自引:0,他引:1  
在整理采自中国西部成蝇标本中,发现蝇科圆蝇亚科Mydaeinae妙蝇属Myospila Rondani,1856的4新种:春妙蝇Myospilavernatasp.nov.,黑前股妙蝇Myospila ateripraefemurasp.nov.,似净妙蝇Myospil alautoidessp.nov.,峨眉妙蝇Myospilaemeishanensissp.nov。前3种模式标本存中国科学院上海生命科学研究院植物生理生态研究所;后1种模式标本存军事医学科学院微生物流行病研究所医学昆虫标本馆。  相似文献   
48.
Malignancy in patients with constitutional chromosome abnormality is of interest not only because it permits insights into the relationship between chromosome abnormality and cancer, but also because it provides opportunities to address such questions as the clonality and evolution of tumors. We report Ph1-positive chronic myelogenous leukemia (CML) in a 50-year-old mosaic (45,X/46,XX) Turner syndrome patient whose leukemia was restricted to the monosomic cell line. Our extensive cytogenetic studies of this patient demonstrated that non-leukemic normal cells persisted in the marrow and were able to proliferate during a period of temporary suppression of the leukemic clone following aggressive treatment.  相似文献   
49.
A family history study of second-degree relatives of 19 patients with anxiety neurosis (panic disorder) and 19 controls showed a morbidity risk of 9.5% among the former compared with 1.4% among the latter. These risks were approximately half those found among first-degree relatives. Female relatives were at higher risk for anxiety neurosis. The risk for other psychiatric illnesses did not differ between the relatives of anxiety neurosis and controls.  相似文献   
50.
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