全文获取类型
收费全文 | 5653篇 |
免费 | 396篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 73篇 |
儿科学 | 209篇 |
妇产科学 | 149篇 |
基础医学 | 727篇 |
口腔科学 | 302篇 |
临床医学 | 691篇 |
内科学 | 1005篇 |
皮肤病学 | 94篇 |
神经病学 | 405篇 |
特种医学 | 221篇 |
外国民族医学 | 1篇 |
外科学 | 1011篇 |
综合类 | 85篇 |
一般理论 | 4篇 |
预防医学 | 297篇 |
眼科学 | 128篇 |
药学 | 313篇 |
中国医学 | 7篇 |
肿瘤学 | 349篇 |
出版年
2023年 | 26篇 |
2022年 | 28篇 |
2021年 | 69篇 |
2020年 | 52篇 |
2019年 | 78篇 |
2018年 | 103篇 |
2017年 | 72篇 |
2016年 | 91篇 |
2015年 | 100篇 |
2014年 | 172篇 |
2013年 | 220篇 |
2012年 | 303篇 |
2011年 | 306篇 |
2010年 | 203篇 |
2009年 | 216篇 |
2008年 | 332篇 |
2007年 | 299篇 |
2006年 | 323篇 |
2005年 | 284篇 |
2004年 | 265篇 |
2003年 | 281篇 |
2002年 | 286篇 |
2001年 | 127篇 |
2000年 | 155篇 |
1999年 | 123篇 |
1998年 | 54篇 |
1997年 | 50篇 |
1996年 | 45篇 |
1995年 | 54篇 |
1994年 | 32篇 |
1993年 | 30篇 |
1992年 | 85篇 |
1991年 | 87篇 |
1990年 | 79篇 |
1989年 | 85篇 |
1988年 | 81篇 |
1987年 | 82篇 |
1986年 | 75篇 |
1985年 | 73篇 |
1984年 | 59篇 |
1983年 | 62篇 |
1982年 | 41篇 |
1981年 | 43篇 |
1980年 | 39篇 |
1979年 | 55篇 |
1978年 | 28篇 |
1974年 | 44篇 |
1973年 | 28篇 |
1972年 | 35篇 |
1969年 | 30篇 |
排序方式: 共有6071条查询结果,搜索用时 15 毫秒
31.
32.
Myakov A Nieman L Wicky L Utzinger U Richards-Kortum R Sokolov K 《Journal of biomedical optics》2002,7(3):388-397
We present the design and construction of a fiber optic probe for elastic light scattering spectroscopy in vivo with polarized excitation and polarization sensitive detection. The performance of the fiber probe is evaluated using a suspension of polystyrene spheres placed atop a diffusely scattering substrate, and it demonstrates that the size-dependent characteristics of the scatterers can be extracted in the presence of a highly diffusely scattering background using a linear combination of forward and backward Mie scattering components of the scatterers. Subsequently, Mie theory calculations are performed over a broad range of diagnostically relevant parameters of nuclei-mean diameter, size distribution, and relative refractive index-to understand how the polarized reflectance measurements with the fiber probe can be used to extract morphological information about epithelial tissue. Finally, the feasibility of in vivo measurements with the fiber optic based polarization sensitive light scattering spectroscopy is demonstrated. 相似文献
33.
34.
Survivors of bacterial meningitis frequently suffer from long-term sequelae, particularly from learning and memory deficits. For this reason, spatial memory and learning was studied in a mouse model of ceftriaxone-treated Streptococcus pneumoniae meningitis. Persistent deficits of spatial learning despite normal motor function were observed in mice infected with 10(4) colony-forming units (CFU) in 25 microl of saline into the right forebrain in comparison to mice treated with an equal amount of saline. Survivors of meningitis performed significantly worse in memorizing a hidden platform in a Morris water maze. After 2 weeks, the difference between post-meningitis and control mice diminished. Yet, when the platform was moved after 180 days, learning of the new location was still strongly impaired in mice surviving meningitis. 相似文献
35.
S Gerber D Larget-Piet J M Rozet D Bonneau M Mathieu V Der Kaloustian A Munnich J Kaplan 《Journal of medical genetics》1996,33(1):77-79
Usher syndrome type I (US1) is an autosomal recessive condition in which three different genes have been already localised (USH1A, USH1B, and USH1C on chromosomes 14q32, 11q13, and 11p15 respectively). The genetic heterogeneity of US1 has been confirmed in a previous study by linkage analysis of 20 French pedigrees. Here, we report the genetic exclusion of the three previously reported loci in two large multiplex families of Moroccan and Pakistani origin, suggesting the existence of at least a fourth locus in Usher syndrome type I. 相似文献
36.
Bühling F Gerber A Häckel C Krüger S Köhnlein T Brömme D Reinhold D Ansorge S Welte T 《American journal of respiratory cell and molecular biology》1999,20(4):612-619
Alveolar and bronchial epithelial cells have been shown to have regulatory functions in the maintenance of lung structure and function. Recent evidence supports the premise that these cells can synthesize a variety of extracellular matrix components in vitro, suggesting an active participation in connective tissue remodeling. Their possible role in extracellular matrix degradation, however, is less clear. This study addresses the question of whether alveolar and bronchial epithelial cells express the highly collagenolytic and elastinolytic cysteine proteinase cathepsin K, which has recently been newly described. We provide evidence that the epithelial cell lines A549 and BEAS-2B are capable of expressing cathepsin K messenger RNA. Furthermore, we show that cathepsin K is expressed in normal bronchial epithelial cells. Western blot analyses of human lung-tissue lysates revealed specific immunoreactivity at molecular weights of 46 and 27 kD, corresponding to the procathepsin and the mature cathepsin K. Immunohistochemical analyses showed a pronounced staining of bronchial epithelial cells and in single alveolar epithelial cells. Using a specific fluorogenic cytochemical assay, the intracellular activity of the enzyme was localized. These findings demonstrate that bronchial and alveolar epithelial cells are capable of expressing cathepsin K, which could be of considerable importance for remodeling processes of the extracellular matrix in the lung. 相似文献
37.
Expression of cytokeratins in normal and diseased livers and in primary liver carcinomas 总被引:10,自引:0,他引:10
Y S Lai S N Thung M A Gerber M L Chen F Schaffner 《Archives of pathology & laboratory medicine》1989,113(2):134-138
Hepatocytes and bile duct epithelium express several types of cytokeratins, the characteristic intermediate-filament proteins of epithelial cells. The cytokeratin antigen expression was studied in normal and diseased livers, intrahepatic cholangiocarcinomas, and hepatocellular carcinomas by immunohistochemical methods using a panel of polyclonal and monoclonal antibodies to cytokeratins. Ten percent formaldehyde solution-fixed, paraffin-embedded sections obtained from ten patients without liver disease, 18 patients without liver disease, 18 patients with different stages of primary biliary cirrhosis, 14 patients with alcoholic hepatitis, ten patients with fatty liver hepatitis secondary to diabetes mellitus or morbid obesity, five patients with hepatocellular carcinomas, and five patients with cholangiocarcinomas were examined. The results suggested that hepatocytes and bile duct epithelium retain their distinct cytokeratin profiles in liver disease, including malignant transformation. Therefore, demonstration of cytokeratins in the liver is useful in establishing the cellular origin of neoplasms and understanding the pathogenesis of liver diseases. 相似文献
38.
K Matsuno T Schaffner H A Gerber C Ruchti M W Hess H Cottier 《Journal of the Reticuloendothelial Society》1983,33(4):263-273
The translocation of Percoll microspheres (mean diameter 20-30 nm) from the intestinal lumen through the epithelial layer to internal organs was examined in suckling mice using transmission electron microscopy. Repeated administration of this material by gavaging for 7 consecutive days resulted in a heavy particle load of vacuolated enterocytes. A limited amount of Percoll was transported to the subepithelial tissue of both the villous mucosa and Peyer's patches where microspheres were found endocytosed, predominantly by macrophages. Even smaller numbers of particles reached mesenteric lymph nodes and, occasionally, milky spots of the omentum. Minor Percoll aggregates were easily found in Kupffer cells of the liver, indicating hematogenous translocation. Small numbers of particles were regularly detected in perivascular macrophages of the thymic cortex, which are in close contact with surrounding lymphocytes. We conclude that the thymic cortex is not totally inaccessible to particulate matter of the intestinal content. 相似文献
39.
Fiber optic probes are a key element for biomedical spectroscopic sensing. We review the use of fiber optic probes for optical spectroscopy, focusing on applications in turbid media, such as tissue. The design of probes for reflectance, polarized reflectance, fluorescence, and Raman spectroscopy is illustrated. We cover universal design principles as well as technologies for beam deflecting and reshaping. 相似文献
40.
Myosin VIIA gene: heterogeneity of the mutations responsible for Usher syndrome type IB 总被引:8,自引:1,他引:8
Levy G; Levi-Acobas F; Blanchard S; Gerber S; Larget-Piet D; Chenal V; Liu XZ; Newton V; Steel KP; Brown SD; Munnich A; Kaplan J; Petit C; Weil D 《Human molecular genetics》1997,6(1):111-116
Usher syndrome is recognized as the most frequent cause of hereditary
deaf-blindness. Usher syndrome type I (USH1), the most severe form of the
disease, is characterized by profound congenital sensorineural deafness,
constant vestibular dysfunction, and retinitis pigmentosa of prepubertal
onset. This form is genetically heterogeneous and five loci (USH1A-E) have
been mapped thusfar. However, only the gene responsible for USH1 B (which
accounts for approximately 75% of USH1 cases) has been characterized. It
encodes a long-tailed unconventional myosin, myosin VIIA, with a predicted
2215 amino acid sequence. Primers covering the complete myosin VIIA coding
sequence as well as the 3' non coding sequence were designed, allowing
direct sequence analysis of each of the 48 coding exons and flanking splice
sites in seven patients affected by USH1. Four novel mutations were thereby
identified. The possibility should now be considered of a sequence-based
prenatal diagnosis in some of the families affected by this very severe
form of Usher syndrome.
相似文献