全文获取类型
收费全文 | 16679篇 |
免费 | 763篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 264篇 |
儿科学 | 232篇 |
妇产科学 | 151篇 |
基础医学 | 1894篇 |
口腔科学 | 392篇 |
临床医学 | 1050篇 |
内科学 | 4225篇 |
皮肤病学 | 284篇 |
神经病学 | 1824篇 |
特种医学 | 610篇 |
外科学 | 2489篇 |
综合类 | 86篇 |
预防医学 | 707篇 |
眼科学 | 401篇 |
药学 | 1175篇 |
中国医学 | 36篇 |
肿瘤学 | 1701篇 |
出版年
2023年 | 74篇 |
2022年 | 154篇 |
2021年 | 262篇 |
2020年 | 138篇 |
2019年 | 177篇 |
2018年 | 233篇 |
2017年 | 176篇 |
2016年 | 226篇 |
2015年 | 234篇 |
2014年 | 316篇 |
2013年 | 422篇 |
2012年 | 686篇 |
2011年 | 793篇 |
2010年 | 406篇 |
2009年 | 387篇 |
2008年 | 735篇 |
2007年 | 753篇 |
2006年 | 804篇 |
2005年 | 834篇 |
2004年 | 779篇 |
2003年 | 741篇 |
2002年 | 754篇 |
2001年 | 719篇 |
2000年 | 775篇 |
1999年 | 630篇 |
1998年 | 225篇 |
1997年 | 204篇 |
1996年 | 185篇 |
1995年 | 143篇 |
1994年 | 115篇 |
1993年 | 119篇 |
1992年 | 387篇 |
1991年 | 370篇 |
1990年 | 328篇 |
1989年 | 371篇 |
1988年 | 343篇 |
1987年 | 293篇 |
1986年 | 265篇 |
1985年 | 268篇 |
1984年 | 199篇 |
1983年 | 163篇 |
1982年 | 81篇 |
1979年 | 132篇 |
1978年 | 97篇 |
1977年 | 73篇 |
1974年 | 84篇 |
1973年 | 82篇 |
1972年 | 81篇 |
1971年 | 77篇 |
1969年 | 77篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Tiina Paunio Yoshihide Sunada Sari Kiuru Hideo Makishita Shu-Ichi Ikeda Jean Weissenbach Jorma Palo Leena Peltonen 《Human mutation》1995,6(1):60-65
Familial amyloidosis, Finnish type (FAF) (gelsolin-related amyloidosis) is an autosomal dominant form of systemic amyloidosis characterized by corneal lattice dystrophy and peripheral polyneuropathy. The accumulating protein in FAF consists of fragments of gelsolin, an actin-modulating protein. The gelsolin mutation G654A has been found in both Finnish and Japanese patients. To study the origin of the gelsolin mutation in these patients we performed haplotype analysis in 10 Finnish and 2 Japanese FAF families. Poymorphic DNA markers GSN, D9S103, AFMa061xd9, and AFMa139xb9 revealed a uniform disease haplotype in all the disease-associated chromosomes of the Finnish FAF families, which was different from the one observed in the Japanese families. The present results and the previously detected gelsolin mutation G654T in Czech and Danish FAF patients suggest that nucle otide 654 may represent a mutation hot spot in the gelsolin gene. The DNA markers studied here will be useful in future genealogical analyses of FAF. © 1995 Wiley-Liss, Inc. 相似文献
82.
The effect of bile duct ligation on enzyme activities in the subfractions of the rat liver plasma membrane was investigated. Two subfractions were isolated from the rat liver plasma membrane by homogenization and subsequent centrifugation in a discontinuous sucrose gradient. The light subfraction contained fragments of the bile canalicular surface and the heavy fraction contained fragments of the sinusoidal and lateral surfaces of the hepatocyte. Bile duct ligation decreased NaK ATPase and Mg-ATPase activity in the light subfraction, whereas it had no significant effect on these enzyme activities in the heavy fraction. Leucyl-β-naphthylamidase activity was reduced and alkaline phosphatase activity was increased in both subfractions. These facts suggested that ligation of the bile duct led to loss of the secretory polarity of the liver cell. The in vitro effects of some bile acids on the membranebound enzymes in the light subfraction were investigated, and a possible involvement of chenodeoxycholic acid in the alteration of enzyme activities in the bile canalicular membrane was suggested. 相似文献
83.
Sato E Miyazawa T Nishimura Y Ikeda Y Kawakami K Mochizuki M Yokoyama N Maeda K Fujita K Kohmoto M Takahashi E Mikami T 《Archives of virology》2001,146(2):379-387
Summary. We have previously reported the construction of a recombinant feline herpesvirus type 1 (FHV-1), designated C7301ddlTK-gag, expressing the Gag precursor protein of feline immunodeficiency virus (FIV). In this study, we report the construction
of a further recombinant FHV-1 (ddlTK(gBp)-gag) which carries an FHV-1 gB promoter sequence upstream of the FIV gag gene of C7301ddlTK-gag. Strong expression of the FIV Gag protein by ddlTK(gBp)-gag was confirmed by immunoblot analyses and enzyme-linked immunosorbent assays. Although C7301ddlTK-gag and ddlTK(gBp)-gag failed to induce anti-FIV Gag antibodies in cats, we confirmed the infectivity and stability of these recombinants
in cats.
Received January 14, 2000 Accepted August 4, 2000 相似文献
84.
85.
Among the various types of membrane molecules involved in cell-cell interactions in the nervous system, we have focused in this review upon membrane proteins belonging to the immunoglobulin superfamily (IgSF). IgSF molecules are distinctive in that: (1) a large percentage of known neural adhesion molecules belongs to the IgSF; (2) they are homologous in structure (Ig domain), yet exhibit large variation of function in cell-cell interactions. The structure of IgSF molecules is briefly summarized in Section II, and each member of the IgSF which has been found in the nervous system is reviewed in Section III. In Section IV, we have discussed possible properties of yet-unknown nervous system IgSF molecules, on the assumption that nervous system IgSF molecules thus far discovered comprise only a small portion of those existing. Discussion is based upon an analogy with the immune system and upon knowledge of cell-cell interactions in the development of the nervous system. Our principal aims in this review are to summarize knowledge of neural IgSF molecules and to discuss the possibility that some IgSF molecules may encode in their structures instructions for recognizing, or for being recognized by, target neural cells. Further growth of knowledge of IgSF molecules may yield insights into the patterns of cell-cell interactions underlying the formation of neuronal circuits during development. 相似文献
86.
Preparation of monoclonal antibody to hepatocellular membranes and its application to induction of liver cell membrane damage 总被引:1,自引:0,他引:1
Monoclonal antibody (MoAb) to rat liver plasma membranes was prepared by hybridization of mouse immune lymphocytes with mouse myeloma cells, and was identified by the immunodiffusion method in a fraction of IgM secreted from the hybridoma thus obtained. In indirect immunofluorescence tests, specific fluorescence was detected only on the surface of rat hepatocytes, but neither on the cells from other organs of the rat nor on the hepatocytes of other species of animals, suggesting that the antibody may be organ- and species-specific. When the primary culture rat hepatocytes, labelled with isotopic chromium (51Cr), were treated with the MoAb together with complement, a specific release of 51Cr from the cells was found shortly after treatment, accompanied with bubbling of the cell membranes, and a significant release of 51Cr was observed at an MoAb concentration of 15 micrograms/ml or more. Without complement, or with inactivated complement, these reactions were not observed. These facts suggest strongly that the cell surface of the hepatocytes was damaged by the MoAb in the presence of complement. 相似文献
87.
An immunohistochemical analysis of the cat central nervous system revealed that a monoclonal antibody which recognizes a soluble cytosolic protein, R2D5, bound two regions in a prominent spatial gradient. In the medial and lateral superior olivary nuclei of the brainstem, R2D5 immunoreactivity appeared as a gradient across a population of topographically ordered principal neurons. The spatial gradient corresponded to the tonotopic organization in the superior olivary nuclei: i.e., R2D5 immunoreactivity tended to occur more frequently and intensely in low-frequency neurons than in high-frequency neurons. Granule cells in the hippocampal dentate gyrus also had a pronounced spatial gradient in R2D5 immunoreactivity expression, and this gradient corresponded to the septotemporal axis of the hippocampus. Granule cells of the temporal (ventral) portions of the hippocampus were labeled intensely with R2D5 antibody, while those located in progressively more septal (dorsal) portions had gradually less immunoreactivity. These results suggest that in both the superior olivary nuclei and the hippocampal dentate gyrus, neurons differ in intrinsic properties by their position along specific axes. They suggest also that the hippocampus has an intrinsic functional organization related to the spatial gradient along its septotemporal axis. 相似文献
88.
Histologic transformation in the course of non-Hodgkin's lymphoma (NHL) has been reported to occur in 18 to 30% of the cases. Less favorable prognosis in cases with initial low grade malignancy followed by emergence of high grade malignancy has been previously described. In the previous literature, the histologic transformation has been examined mostly in nodal NHL. In the present study, histologic transformation in the course was investigated on 20 cases with early extranodal NHL. All these 20 cases were diffuse lymphomas, and were composed of 7 cases with low grade malignancy and 13 cases with high grade malignancy. Histologic transformation was not observed in any of these cases. These findings indicate that the frequency of histologic transformation is much lower in extranodal NHL than in nodal NHL. The prognostic significance of these findings is also discussed. 相似文献
89.
M Murakami Y Seo T Matsumoto O Ichikawa A Ikeda H Watari 《The Japanese journal of physiology》1986,36(6):1267-1274
The present study was undertaken to measure tissue contents of Na, Li, and Cl non-invasively in the isolated perfused organ by nuclear magnetic resonance (NMR) using a broadband tunable probe. The NMR signals of 23Na, 7Li, and 35Cl from the isolated perfused rat mandibular gland were collected continuously and each spectrum was obtained for every 15 or 20 s. The Na concentration in the perfusate was varied by replacement with Li, and the resulting changes were monitored by measuring the signal intensities of the electrolytes. The time constant for Na exchange was slower following complete removal of extracellular Na than following its half replacement, suggesting that the Na extrusion by Na+/K+ ATPase was reduced by lowering the extracellular Na level. The time constant for Li exchange was slower than that for Na exchange. The level of Cl was nearly constant during experiment, except for a very slow increase in Cl, possibly resulting from increasing edema and/or intracellular Li storage. 相似文献
90.
A new HLA-B*78 allele, B*7805, was identified in a healthy Japanese female. The results of her serological HLA class I typing showed an unusual Bw4/Bw6 pattern with strongly positive reactivity to anti-Bw6, i.e. A24, -, B52, -, Bw4, Bw6. In DNA typing, she was typed as A*24, -, B*52, B*78-like, Cw1202, -, (Bw4, Bw6). Cloning and sequencing of exon 2 and exon 3 of her B locus genes revealed a new allele B*7805. The cloned B*7805 differed from B*78021 by three nucleotide substitutions in exon 2 at position 259 (A to G), 261 (C to G) and 272 (A to C), and contained sequences defining Bw6 motif in the region of codon 77 to 83. 相似文献