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   1279000篇
  免费   92829篇
  国内免费   1994篇
耳鼻咽喉   18211篇
儿科学   42354篇
妇产科学   37930篇
基础医学   187273篇
口腔科学   35485篇
临床医学   108314篇
内科学   251925篇
皮肤病学   26532篇
神经病学   99287篇
特种医学   50068篇
外国民族医学   366篇
外科学   197969篇
综合类   26531篇
现状与发展   1篇
一般理论   302篇
预防医学   92701篇
眼科学   29064篇
药学   97879篇
  1篇
中国医学   2500篇
肿瘤学   69130篇
  2018年   11881篇
  2015年   11645篇
  2014年   16058篇
  2013年   24438篇
  2012年   33687篇
  2011年   36082篇
  2010年   21284篇
  2009年   20083篇
  2008年   35086篇
  2007年   38060篇
  2006年   38606篇
  2005年   37925篇
  2004年   36502篇
  2003年   35489篇
  2002年   34995篇
  2001年   58142篇
  2000年   59653篇
  1999年   50756篇
  1998年   14260篇
  1997年   12831篇
  1996年   13089篇
  1995年   12357篇
  1994年   11773篇
  1993年   10871篇
  1992年   41019篇
  1991年   40398篇
  1990年   39923篇
  1989年   38746篇
  1988年   36148篇
  1987年   35393篇
  1986年   33769篇
  1985年   32174篇
  1984年   23950篇
  1983年   20848篇
  1982年   12393篇
  1981年   10941篇
  1980年   10213篇
  1979年   22653篇
  1978年   15890篇
  1977年   13734篇
  1976年   12976篇
  1975年   14214篇
  1974年   16690篇
  1973年   16087篇
  1972年   15325篇
  1971年   14234篇
  1970年   13218篇
  1969年   12734篇
  1968年   11979篇
  1967年   10480篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
996.
997.
WT-1 positivity has previously been noted in nonneoplastic endometrial stroma. In this study we examined WT-1 expression in endometrial stromal neoplasms to ascertain whether these tumors are immunoreactive and whether this antibody might be of value in the diagnosis of these lesions. We also stained cases of cellular and highly cellular leiomyomas to investigate whether WT-1 might be of value in distinguishing these from an endometrial stromal neoplasm. We compared WT-1 staining with CD10, desmin, alpha smooth muscle actin, h-caldesmon, and AE1/3, many of these antibodies being commonly used to distinguish between an endometrial stromal and a smooth muscle phenotype. Cases of ESN (n = 5), low grade ESS (n = 14), and cellular or highly cellular leiomyoma (n = 14) were stained with the aforementioned antibodies. Cases were scored on a scale of 0 to 4+, with 4+ cases exhibiting positivity of >50% of cells. Sixteen of 19 endometrial stromal neoplasms were positive with WT-1, most (14 of 16) with 4+ positivity. Staining was nuclear (5 cases), cytoplasmic (5 cases), or combined nuclear and cytoplasmic (6 cases). All endometrial stromal neoplasms exhibited 4+ staining with CD10. Staining for alpha smooth muscle actin was present in most cases (14 of 19) and desmin and h-caldesmon were positive in a smaller number of cases (8 and 2 respectively). There was 4+ positivity with desmin in only 1 case. The 2 cases that were h-caldesmon positive both exhibited 1+ staining (<5% cells positive). Six cases were positive with AE1/3, 1 with 4+ staining. Leiomyomatous neoplasms always exhibited 4+ staining with desmin and alpha smooth muscle actin and in most cases (12 of 14) with h-caldesmon. The other 2 cases exhibited 2+ positivity. Most cases (12 of 14) were positive with WT-1 (7 of 14 with 4+ staining) and CD10 (5 of 14 with 4+ positivity). One case was positive with AE1/3. We conclude that diffuse WT-1 positivity is characteristic of endometrial stromal neoplasms and that this may be of value in diagnosis. However, WT-1 is of limited use in the distinction between an endometrial stromal and a cellular leiomyomatous neoplasm because many of the latter are also positive. This study confirms the value of h-caldesmon in the distinction between an endometrial stromal neoplasm (almost always h-caldesmon negative) and a cellular leiomyomatous neoplasm (h-caldesmon positive). Although CD10 is positive in endometrial stromal neoplasms, the commonly observed immunoreactivity of cellular and highly cellular leiomyomas with this antibody limits its diagnostic usefulness. Desmin is useful as all leiomyomatous neoplasms exhibited diffuse positivity, whereas only a small number of endometrial stromal neoplasms were focally positive and only 1 case exhibited 4+ positivity. Smooth muscle actin is of limited value since most neoplasms studied were positive. The overlapping immunophenotype of endometrial stromal and leiomyomatous neoplasms may reflect the origin of both cell types from a common progenitor within the uterus.  相似文献   
998.
Chronically elevated levels of corticotropin-releasing factor (CRF) in transgenic mice overexpressing CRF in the brain (CRF-OE) appear to be associated with alterations commonly associated with major depressive disorder, as well as with sensorimotor gating deficits commonly associated with schizophrenia. In the present study, we tested the hypothesis that antipsychotics may be effective in normalizing prepulse inhibition (PPI) of acoustic startle in CRF-OE mice, which display impaired sensorimotor gating compared to wild-type (WT) mice. The typical antipsychotic haloperidol and atypical antipsychotic risperidone improved PPI in the CRF-OE mice, but were ineffective in WT mice. The atypical antipsychotic clozapine did not influence PPI in CRF-OE mice, but reduced gating in WT mice. This effect of clozapine in the CRF-OE mice may thus be regarded as a relative improvement, consistent with the observed effect of haloperidol and risperidone. As expected, the anxiolytic, nonantipsychotic chlordiazepoxide was devoid of any effect. All four compounds dose-dependently reduced the acoustic startle response irrespective of genotype. These results indicate that antipsychotic drugs are effective in improving startle gating deficits in the CRF-OE mice. Hence, the CRF-OE mouse model may represent an animal model for certain aspects of psychotic depression, and could be a valuable tool for research addressing the impact of chronically elevated levels of CRF on information processing.  相似文献   
999.
1000.
Abstract – Traumatic dental injuries often occur to the teeth and their supporting tissues and they are the main reasons for emergency visit to a dental clinic. Management of a fracture depends on its position and the extent of root involvement. Horizontal root fractures are not seen frequently and the treatment consists of reduction and long‐term rigid fixation of the coronal segment. The present case demonstrates the successful management of two horizontally fractured maxillary central incisors with a follow‐up period of 9 months.  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