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   26448篇
  免费   1736篇
  国内免费   84篇
耳鼻咽喉   222篇
儿科学   639篇
妇产科学   448篇
基础医学   3860篇
口腔科学   339篇
临床医学   2465篇
内科学   6445篇
皮肤病学   672篇
神经病学   2238篇
特种医学   793篇
外国民族医学   3篇
外科学   3803篇
综合类   271篇
一般理论   28篇
预防医学   1970篇
眼科学   490篇
药学   1676篇
  1篇
中国医学   56篇
肿瘤学   1849篇
  2022年   134篇
  2021年   335篇
  2020年   226篇
  2019年   359篇
  2018年   426篇
  2017年   290篇
  2016年   356篇
  2015年   414篇
  2014年   628篇
  2013年   948篇
  2012年   1419篇
  2011年   1575篇
  2010年   947篇
  2009年   967篇
  2008年   1501篇
  2007年   1661篇
  2006年   1647篇
  2005年   1753篇
  2004年   1608篇
  2003年   1537篇
  2002年   1518篇
  2001年   408篇
  2000年   339篇
  1999年   400篇
  1998年   376篇
  1997年   337篇
  1996年   296篇
  1995年   280篇
  1994年   257篇
  1993年   230篇
  1992年   316篇
  1991年   299篇
  1990年   277篇
  1989年   259篇
  1988年   234篇
  1987年   227篇
  1986年   243篇
  1985年   228篇
  1984年   220篇
  1983年   201篇
  1982年   224篇
  1981年   232篇
  1980年   185篇
  1979年   141篇
  1978年   133篇
  1977年   138篇
  1976年   113篇
  1975年   111篇
  1974年   102篇
  1973年   94篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
92.
Trahan S  Têtu B  Raymond PE 《Human pathology》2005,36(12):1316-1321
Serous papillary carcinoma is an aggressive tumor. Point mutations in the p53 suppressor gene might explain in part the rapid growth of this malignant tumor and its unfavorable outcome. The aims of this study were to evaluate the behavior of serous papillary carcinoma developing in endometrial polyps and to assess the p53 protein overexpression. Patients included in this study were treated in our institution between 1982 and 2003. All clinical and pathological materials were examined. A p53 protein immunohistochemical analysis was performed on paraffin-embedded tissues. Thirteen serous papillary carcinomas arising from benign polyps of the endometrium were identified. The patients' age averaged 73 years. All patients were treated surgically. After an average follow-up of 22 months, 54% of the patients were dead or alive with disease. Of 10 serous papillary carcinomas, 8 (80%) for which paraffin blocks were available overexpressed the p53 protein. A serous papillary carcinoma arising from benign polyps of the endometrium remains a malignant neoplasia with an unfavorable outcome even if the primary tumor is limited to the polyp. The high rate of protein p53 overexpression suggests that a p53 gene mutation occurs early in the disease and might explain the rapid growth of the tumor.  相似文献   
93.
94.
95.
Cytochrome P450 IID6 is an autoantigen recognized by the sera of children affected with a subtype of autoimmune hepatitis. It was hypothesized that a mutation in the CYP2D6 gene could explain the autoimmune response in these patients. To examine this question, genomic DNA from peripheral lymphocytes (n = 9) and liver (n = 1) of 10 patients with anti-LKM-1 antibody was analysed by Southern blot for genetic association studies between a particular CYP2D6 haplotype and autoimmune hepatitis. In addition, a region of CYP2D6, from the same genomic DNA, was amplified by polymerase chain reaction (PCR) and digested by BstNI, in a search for the most prevalent 29B mutation, described in subjects who do not express the P450 IID6. Total RNA and proteins, prepared from the liver of an anti-LKM-1+ patient, were analysed by Northern and Western (immunoblot) blots respectively. Our results do not reveal any major structural change in the DNA of this patient at the CYP2D6 locus that could explain their autoimmune response. Corroborating this observation, no changes were noted either in P450 IID6 mRNA size or in the corresponding protein. However, these data do not exclude the possibility of subtle changes in the protein due to point mutations in critical regions that might trigger an autoimmune response.  相似文献   
96.
97.
The autopsy of an infant with the 4p- or Wolf-Hirschhorn syndrome revealed visceral abnormalities not previously described, i.e., agenesis of the gallbladder and spleen. The parent's chromosomes were normal.  相似文献   
98.
To study the role of Mycoplasma hominis and T-mycoplasmas (Ureaplasma urealyticum) in chorioamnionitis, we obtained culture from 249 puerperal women and their babies. The placentas were examined histologically. Infants whose placentas showed inflammation (chorioamnionitis) had cultures positive for T-mycoplasmas more frequently (37.5 per cent) than those with normal placentas (19.0 per cent) (P = 0.021). Colonization with M. hominis was found in 16.0 per cent of the babies and was not significantly associated with chorioamnionitis. Material colonization with mycoplasmas was more frequent (73.4 per cent) and was not correlated with placental inflammation. We conclude that a substantial proportion of cases of chorioamnionitis may be caused by prenatal infection with T-mycoplasmas. The fact that these organisms are not highly virulent could explain the frequent finding of inflammed placentas from otherwise normal pregnacies. No adverse clinical effects of the placental lesions or of mycoplasmal colonization could be detected in this small study.  相似文献   
99.
Virus isolation and titration, electrocardiography, enzyme assays and light and electron microscopic studies were undertaken in male turkeys infected with influenza A/turkey/Ontario/7732/66 virus to determine its potential role in the genesis of heart disease. Virus was isolated from the heart initially before a demonstrable viremia and terminally in declining serum viral titer. Virus was isolated from the heart muscle as early as 1 day postinoculation. Highest viral titers were found in the heart at 6 days postinoculation and coincided with maximum elevations of serum glutamic-oxalacetic transaminase and lactic acid dehydrogenase, microscopic lesions in the heart and cardiac arrhythmias. Microscopic lesions in the heart were first detected at 4 days postinoculation and consisted of disseminated areas of necrosis, focal myocarditis, pericarditis and endocarditis. Alterations in myocardial ultrastructure which followed viral infection included fragmentation and dissolution of myofibrils, dilation of the sarcotubular system, increase in membrane vesicle formation in the region of the endoplasmic reticulum, discontinuity of the sarcolemma, proliferation of mitochondrial population, swelling of mitochondria with separation and disruption of the cristae, and the presence of intramitochondrial and perinuclear densities.  相似文献   
100.
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