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   6959篇
  免费   372篇
  国内免费   28篇
耳鼻咽喉   44篇
儿科学   179篇
妇产科学   99篇
基础医学   1026篇
口腔科学   254篇
临床医学   445篇
内科学   1532篇
皮肤病学   217篇
神经病学   911篇
特种医学   172篇
外科学   571篇
综合类   30篇
现状与发展   1篇
预防医学   362篇
眼科学   274篇
药学   593篇
中国医学   16篇
肿瘤学   633篇
  2024年   8篇
  2023年   54篇
  2022年   117篇
  2021年   174篇
  2020年   106篇
  2019年   145篇
  2018年   150篇
  2017年   130篇
  2016年   180篇
  2015年   178篇
  2014年   226篇
  2013年   270篇
  2012年   479篇
  2011年   575篇
  2010年   310篇
  2009年   228篇
  2008年   465篇
  2007年   480篇
  2006年   470篇
  2005年   468篇
  2004年   468篇
  2003年   432篇
  2002年   415篇
  2001年   50篇
  2000年   49篇
  1999年   63篇
  1998年   75篇
  1997年   50篇
  1996年   58篇
  1995年   42篇
  1994年   35篇
  1993年   33篇
  1992年   39篇
  1991年   40篇
  1990年   33篇
  1989年   27篇
  1988年   29篇
  1987年   22篇
  1986年   13篇
  1985年   22篇
  1984年   20篇
  1983年   11篇
  1982年   17篇
  1981年   11篇
  1980年   18篇
  1978年   8篇
  1977年   7篇
  1974年   6篇
  1970年   6篇
  1966年   9篇
排序方式: 共有7359条查询结果,搜索用时 0 毫秒
91.
92.
93.
94.
95.
Cardiac hypertrophy and left ventricular hypertrophy are known to be substantially controlled by genetic factors. As an experimental model, we undertook genome-wide screens for cardiac mass in F2 populations bred from the stroke-prone spontaneously hypertensive rats (SHRSP) and normal spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) of a Japanese colony. Two F2 cohorts were independently produced: F2(SHRSP x WKY) (110 male and 110 female rats) and F2(SHR x WKY) (151 male rats). The ratio of heart weight to body weight (Hw/Bw) was evaluated at 12 months of age in F2(SHRSP x WKY) after salt-loading for 7 months, and at around 15 weeks of age in F2(SHR x WKY) who had been fed a normal rat chow diet. Subsequent to an initial screen with 251 markers in F2(SHRSP x WKY) male progeny, 170 and 161 markers were selected and characterized in F2(SHRSP x WKY) female progeny and F2(SHR x WKY) male progeny, respectively. Markers from four chromosomal regions showed suggestive or significant linkage to Hw/Bw. The strongest and the most consistent linkage was found in the vicinity of D3Mgh16 on rat chromosome (RNO) 3 (a maximal log of the odds score reached 4.0 to 6.6 across the F2 populations studied). In the other three regions on RNO6, RNO10 and RNO13, the degree of linkage was more prominent in either males or females. These data provide solid evidence for a "principal" RNO3 quantitative trait loci regulating Hw/Bw in SHRSP and SHR, and also suggest the possible presence of sexual dimorphism in regard to genetic susceptibility for cardiac hypertrophy.  相似文献   
96.
Mesangial expansion and glomerular basement membrane (GBM) thickening did not correlate with urinary albumin excretion (UAE) in type 2 diabetic patients in our previous studies; therefore, it was necessary to elucidate more detailed ultrastructural changes in the early stages of diabetic nephropathy (DN) in type 2 diabetic patients. The quick-freezing and deep-etching (QF–DE) method allows us to examine three-dimensional ultrastructures of human renal glomeruli in vivo at high resolution. The QF–DE method was applied to six type 2 diabetic patients without definable renal diseases other than DN. Four patients were normoalbuminuric (NA) and the other two were microalbuminuria (MA). Three control specimens were the normal parts from nephrectomies due to renal cell carcinomas. Electron microscopic morphometric analyses provided quantitative glomerular structural changes. Replica membranes were prepared by the QF–DE method, and diameters of mesh structures at the GBM and mesangial matrix (MM) were measured on electron micrographs as previously described. By the QF–DE method, both the GBM middle layer and MM were composed of polygonal meshwork structures. The mesh pores of the GBM and MM were more enlarged and irregular in shape in NA diabetic patients than those of the controls, and these ultrastructural changes became more obvious in MA patients. The mesh diameters of the GBM and MM in the diabetic patients were also larger than those of the controls. Such a mesh diameter of the GBM was well correlated with the amount of UAE, while the mesh diameter of MM showed a slight correlation with UAE. Although there were small number of subjects in the present study, the detailed ultrastructural changes in NA and MA type 2 diabetic patients, which had not been disclosed by conventional electron microscopy, were revealed by the QF–DE method. Increased mesh diameters of GBM might be related with the increase of UAE.  相似文献   
97.
BACKGROUND/AIMS: The presence of antibodies to the 210-kDa glycoprotein of the nuclear pore complex (gp210) is highly indicative of primary biliary cirrhosis (PBC). However, the significance of anti-gp210 antibody titers for monitoring PBC remains unresolved. METHODS: We used an ELISA with a gp210 C-terminal peptide as an antigen to assess serum antibody titers in 71 patients with PBC. RESULTS: Patients were classified into three groups: Group A in whom anti-gp210 titers were sustained at a high level, Group B in whom anti-gp210 status changed from positive to negative under ursodeoxycholic acid (UDCA) therapy, Group C in whom anti-gp210 antibodies were negative at the time of diagnosis. The rate of progression to end-stage hepatic failure was significantly higher in group A (60%) as compared to groups B (0%) and C (4.2%). The sustained antibody response to gp210 was closely associated with the severity of interface hepatitis. The significance of anti-gp210 antibody was confirmed by National Hospital Organization Study Group for Liver Disease in Japan. CONCLUSIONS: The serial quantitation of serum anti-gp210-C-terminal peptide antibodies is useful for monitoring the effect of UDCA and for the early identification of patients at high risk for end-stage hepatic failure.  相似文献   
98.
99.
Severe hepatitis with an indistinct etiology manifested in a 16-year-old boy who had no particular history. The histological features of the liver and clinical course of the patient were similar to those of patients with autoimmune hepatitis characterized by interface hepatitis and severe lobular inflammation of the liver and recurrent exacerbations of hepatitis. We administered intravenous glycyrrhizin preparation daily or three times a week combined with the oral administration of ursodeoxycholic acid daily throughout the term after the initial onset of disease for the control of disease activity. The normalization of the concentration of alanine aminotransferase in serum was achieved in response to the therapy during the course. The serum concentration of immunoglobulins of the patient gradually decreased from the onset of the disease to an unacceptable level without globulin preparation during the following period of 17 months. Immunological tests revealed impairment of immunoglobulin production bythe B cell population of the patient, which led to the diagnosis of the patient as common variable immunodeficiency (CVID). The patient, with improved liver histology after 27 months from the onset of disease, benefited from the current combination therapy without severe infection through the avoidance of overimmunosuppression. CVID is defined as a heterogeneous syndrome characterized by various degrees of hypogammaglobulinemia without any specific predisposing causes, frequently associated with autoimmunity. Diagnostic criteria and therapeutic options of persistent hepatitis with CVID are to be established, as discussed in the current report.  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