全文获取类型
收费全文 | 542780篇 |
免费 | 30223篇 |
国内免费 | 3102篇 |
专业分类
耳鼻咽喉 | 8043篇 |
儿科学 | 14252篇 |
妇产科学 | 14217篇 |
基础医学 | 76411篇 |
口腔科学 | 16314篇 |
临床医学 | 42230篇 |
内科学 | 107860篇 |
皮肤病学 | 13046篇 |
神经病学 | 42325篇 |
特种医学 | 22441篇 |
外国民族医学 | 106篇 |
外科学 | 87571篇 |
综合类 | 10968篇 |
现状与发展 | 1篇 |
一般理论 | 101篇 |
预防医学 | 25183篇 |
眼科学 | 13740篇 |
药学 | 42360篇 |
1篇 | |
中国医学 | 2527篇 |
肿瘤学 | 36408篇 |
出版年
2021年 | 3758篇 |
2019年 | 3922篇 |
2018年 | 7149篇 |
2017年 | 5612篇 |
2016年 | 6568篇 |
2015年 | 7428篇 |
2014年 | 9280篇 |
2013年 | 12456篇 |
2012年 | 17901篇 |
2011年 | 17508篇 |
2010年 | 10581篇 |
2009年 | 9353篇 |
2008年 | 16823篇 |
2007年 | 18416篇 |
2006年 | 18398篇 |
2005年 | 17880篇 |
2004年 | 16986篇 |
2003年 | 16640篇 |
2002年 | 16218篇 |
2001年 | 34076篇 |
2000年 | 34641篇 |
1999年 | 28755篇 |
1998年 | 6669篇 |
1997年 | 5490篇 |
1996年 | 4772篇 |
1995年 | 4248篇 |
1994年 | 3821篇 |
1993年 | 3511篇 |
1992年 | 18337篇 |
1991年 | 17063篇 |
1990年 | 16375篇 |
1989年 | 16037篇 |
1988年 | 14394篇 |
1987年 | 13877篇 |
1986年 | 12787篇 |
1985年 | 11937篇 |
1984年 | 8170篇 |
1983年 | 6608篇 |
1982年 | 3403篇 |
1979年 | 6837篇 |
1978年 | 4347篇 |
1977年 | 3807篇 |
1975年 | 3713篇 |
1974年 | 4165篇 |
1973年 | 3873篇 |
1972年 | 3830篇 |
1971年 | 3758篇 |
1970年 | 3382篇 |
1969年 | 3362篇 |
1968年 | 3036篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
H Nakane Y Okada S Sadoshima M Fujishima 《Stroke; a journal of cerebral circulation》1991,22(2):272-275
A 70-year-old woman developed left hypoglossal nerve palsy, a right hemiparesis sparing the face, and a typical left Wallenberg's syndrome. These symptoms resulted from a lesion in the left half of the medulla oblongata, suggesting Babinski-Nageotte syndrome, a rare cerebrovascular disease. This is the first case of ischemic infarction in the territory of the left vertebral artery and posterior inferior cerebellar artery demonstrated on magnetic resonance imaging. Severe bilateral lesions of the distal vertebral arteries demonstrated on digital subtraction angiography may have contributed to the development of this syndrome. 相似文献
72.
The experimental infection of immunocompetent and immunodeficient athymic mice with an avirulent encephalitogenic Toxoplasma strain (DX strain) was employed to study the ensuing encephalitic process by use of histological and immunocytochemical methods. In the acute phase of the infection Toxoplasma cysts and tachyzoites were accompanied by an infiltrate composed of macrophages, CD4+ and CD8+ T cells. In the chronic stage a granulomatous encephalitis developed. In contrast to immunocompetent NMRI mice, athymic nude NMRI mice died 3 weeks post-infection because of a generalized toxoplasmosis with predominant involvement of the brain. A salient feature of murine Toxoplasma encephalitis was up-regulation of class I and II major histocompatibility complex (MHC) gene products. Class I antigen was widely expressed on microglial cells and astrocytes. Class II antigen was only expressed on microglial cells despite a considerable astrogliosis. Our results indicate a differential expression of MHC-determined antigens on brain cells in acute and chronic murine Toxoplasma encephalitis. 相似文献
73.
H S Ozaki K Iwahashi M Tsubaki Y Fukui Y Ichikawa Y Takeuchi 《Journal of neuroscience research》1991,28(4):518-524
The presence of cytochrome P-45011 beta in rat brain was studied by immunohistochemistry using polyclonal rabbit antibodies raised against purified bovine adrenocortical P-45011 beta, which is involved in the steroid 11 beta-hydroxylation and glucocorticoid formation. The results showed that cytochrome P-45011 beta immunoreactivity is selectively localized to the tracts of myelinated fibers throughout the brain. The specificity of immunohistochemical stainings with P-45011 beta antibodies was established by control tests including nonimmune rabbit immunoglobulin Gs and P-45011 beta antibodies absorbed with purified antigen. Western immunoblots of homogenates from different brain areas with P-45011 beta antibodies, together with biochemical enzymatic assays for cytochrome P-45011 beta monooxygenase activity in these homogenates, confirmed the selective localization of this enzyme observed with immunohistochemistry. Cytochrome P-45011 beta and 11 beta-hydroxylase activity were detected in a homogenate from the cortical white matter (brain area rich in myelinated fibers) as in that from the rat adrenal, but were not detectable in a homogenate from the cerebral cortex (brain area poor in myelinated fibers). Furthermore, quantitation of the P-45011 beta bands on the immunoblots by the areal density revealed that the cortical white matter contains approximately 1.4 pmol of cytochrome P-45011 beta/mg of tissue protein, the value of which was about one sixth of the corresponding value estimated in the rat adrenal. This relatively high content of cytochrome P-45011 beta was also reflected in a relatively high level of 11 beta-hydroxylase activity measured in a homogenate of this brain area by biochemical enzymatic assays using [4-14C]-11-deoxycorticosterone.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
74.
75.
Although the human tumor clonogenic assay (HTCA) is extremely reliable in determining clinical correlations, it is a complicated process requiring considerable time in order to obtain results. Thus, an experimental study on cytopathologic observation (cytologic assay) and comparative evaluation between it and HTCA were performed in order to establish a more rapid and accurate drug sensitivity test. Materials included Colon 26, a cell line established in our department, malignant effusion and surgical specimens. In carrying out HTCA according to the Hamburger-Salmon method, the cell suspension samples following exposure to anti-tumor agents (MMC, L-PAM, ADM, CDDP) were cultivated in test tubes for 3-8 hours and stained by the Papanicolaou and Giemsa methods. According to Tokita's criteria, when cellular changes showed as nuclear pyknosis and nuclear destruction were found to have increased significantly in comparison with a control group, the cells were judged to be sensitive. Very similar and parallel results were obtained between HTCA and cytologic assay in this study, with a significant correlation. Cytologic assay was proved to be an easy, rapid and accurate method for testing drug sensitivity and its clinical application can be expected in the future. 相似文献
76.
IgG-maleimide peroxidase, Fab'-maleimide peroxidase, polymer and monomer types of Fab'-periodate peroxidase were prepared from an antibody against rat lipoamide dehydrogenase, a component of the pyruvate dehydrogenase complex which is located in mitochondria. They were examined for immunohistochemical staining of the rat kidney. Fab'-maleimide peroxidase was the best for staining mitochondrial protein. IgG-maleimide peroxidase and the monomer type of Fab'-periodate peroxidase had the same intensity of staining. The polymer type of Fab'-periodate peroxidase could not stain the lipoamide dehydrogenase. 相似文献
77.
78.
79.
80.
Carnitine status in Reye and Reye-like syndromes 总被引:4,自引:0,他引:4
Fourteen children with the following Reye and Reye-like syndromes were studied to determine each patient's carnitine status: valproate-induced Reye-like attack, ornithine transcarbamylase deficiency, systemic carnitine deficiency, methylmalonic acidemia, and propionic acidemia. Reduced free carnitine and increased serum and urine acylcarnitine levels were found in all patients except for 2 with Reye syndrome, in whom serum creatinine levels were mildly elevated and serum free carnitine levels were not reduced. The renal free carnitine reabsorption rate was reduced in all cases. The free carnitine content of autopsied liver samples were reduced in 2 Reye syndrome patients, 2 OTC deficiency patients, and in a single systemic carnitine deficiency patient. The observed secondary free carnitine deficiency may be a factor in the pathogenesis of Reye and Reye-like syndromes. 相似文献