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   4764篇
  免费   188篇
  国内免费   18篇
耳鼻咽喉   50篇
儿科学   95篇
妇产科学   72篇
基础医学   757篇
口腔科学   82篇
临床医学   253篇
内科学   986篇
皮肤病学   49篇
神经病学   619篇
特种医学   159篇
外科学   776篇
综合类   35篇
预防医学   148篇
眼科学   69篇
药学   329篇
中国医学   10篇
肿瘤学   481篇
  2023年   17篇
  2022年   23篇
  2021年   72篇
  2020年   45篇
  2019年   63篇
  2018年   71篇
  2017年   67篇
  2016年   67篇
  2015年   70篇
  2014年   70篇
  2013年   140篇
  2012年   234篇
  2011年   246篇
  2010年   164篇
  2009年   144篇
  2008年   253篇
  2007年   279篇
  2006年   291篇
  2005年   303篇
  2004年   342篇
  2003年   355篇
  2002年   312篇
  2001年   83篇
  2000年   87篇
  1999年   76篇
  1998年   103篇
  1997年   86篇
  1996年   51篇
  1995年   58篇
  1994年   59篇
  1993年   75篇
  1992年   57篇
  1991年   57篇
  1990年   55篇
  1989年   50篇
  1988年   35篇
  1987年   35篇
  1986年   31篇
  1985年   38篇
  1984年   36篇
  1983年   28篇
  1982年   17篇
  1981年   27篇
  1980年   28篇
  1979年   19篇
  1978年   18篇
  1977年   28篇
  1976年   22篇
  1975年   10篇
  1974年   12篇
排序方式: 共有4970条查询结果,搜索用时 539 毫秒
1.
2.
3.
4.
5.
6.
OBJECTIVES: Lateral biopsies are thought to have a better cancer detection rate compared with standard sextant biopsies. This study aimed to determine whether lateral peripheral zone biopsies in Japanese men who underwent transrectal ultrasound-guided prostate biopsies provided a significantly higher cancer detection rate than sextant biopsies. METHODS: Between 1999 and 2004, data were collected from 461 men who underwent prostate biopsy and had enough data regarding the performance of lateral biopsies for statistical analysis. There were two categories in this study: (i) patients who underwent sextant prostate biopsies; and (ii) patients who underwent sextant biopsies plus lateral biopsies. RESULTS: Prostate cancer was detected in 141 (30.6%) of 461 patients. It was detected in 24 (22.2%) of 108 patients who underwent sextant biopsies and 117 (33.1%) of 353 patients who underwent sextant plus lateral biopsies. Lateral biopsies were not associated with a statistically higher rate of positive biopsy findings; however, we found a significantly higher ratio of patients with positive findings in those with prostate specific antigen (PSA) levels 10 ng/mL (one of 71, 1.4%) among those who had positive cores only in lateral biopsy samples (P < 0.0001). CONCLUSIONS: Lateral biopsies did not show a significantly higher detection ratio of prostate cancer compared to sextant biopsies. However, lateral biopsies were more effective than sextant biopsies in patients with lower PSA levels. Our findings might be useful for the establishment of biopsy strategies to detect prostate cancer, especially in patients with lower PSA levels.  相似文献   
7.
Histamine-type 2 antagonists (H2-blockers) as represented by cimentidine have been shown to adversely affect renal allograft function, particularly when coadministered with cyclosporine, currently a major immunosuppressant. To determine whether or not a newer and more powerful H2-blocker, famotidine, would produce similar adverse effects, we assessed seven cyclosporine-treated renal allograft recipients with regard to changes in their renal function on or off the H2-blocker over a one-week period. Neither the administration nor withdrawal of famotidine (20–40 mg/day) resulted in any significant changes in serum creatine, BUN, urine output or cyclosporine trough levels, suggesting that famotidine can be safely administered as an H2-blocker to cyclosporine-treated renal allograft recipients.  相似文献   
8.
C Minetti  K Tanji  E Bonilla 《Neurology》1992,42(9):1751-1754
Using immunologic techniques, we studied vinculin, a cytoskeletal protein associated with the membrane-skeleton of the muscle fiber. We examined muscle biopsies from five patients with Duchenne muscular dystrophy (DMD), two with Becker's muscular dystrophy (BMD), three normal human muscle samples, and four biopsies from disease control patients. All DMD patients showed patchy and low-intensity immunostain at the sarcolemma of most fibers and, by immunoblot analysis, the content of vinculin was 42 to 61% of control values. There was no significant vinculin deficiency in samples from patients with BMD and other disease controls. The data suggest that vinculin content is reduced only in muscle where dystrophin is absent or sparse.  相似文献   
9.
Axonal pathology is a major cause of neurological disability in multiple sclerosis. Axonal transection begins at disease onset but remains clinically silent because of compensatory brain mechanisms. Noninvasive surrogate markers for axonal injury are therefore essential to monitor cumulative disease burden in vivo. The neuronal compound N-acetylaspartate, as measured by magnetic resonance spectroscopy, is currently the best and most specific noninvasive marker of axonal pathology in multiple sclerosis. The possibility has been raised, however, that N-acetylaspartate is expressed also by oligodendroglial lineage cells. In order to investigate N-acetylaspartate specificity for white matter axons, transected rat optic nerves were analyzed by high-performance liquid chromatography and immunohistochemistry. In transected adult nerves, N-acetylaspartate and N-acetyl aspartylglutamate decreased in concordance with axonal degeneration and were undetectable 24 days posttransection. Nonproliferating oligodendrocyte progenitor cells, oligodendrocytes, and myelin were abundant in these axon-free nerves. At 24 days posttransection, N-acetylaspartate was increased (42%; p = 0.02) in nontransected contralateral nerves. After transection at postnatal day 4, total N-acetylaspartate decreased by 80% (P14; p = 0.002) and 94% (P20; p = 0.003). In these developing axon-free nerves, 25 to 33% of oligodendrocyte progenitor cells were proliferating. These data validate magnetic resonance spectroscopy measurements of N-acetylaspartate as an axon-specific monitor of central nervous system white matter in vivo. In addition, the results indicate that neuronal adaptation can increase N-acetylaspartate levels, and that 5 to 20% of the N-acetylaspartate in developing white matter is synthesized by proliferating oligodendrocyte progenitor cells.  相似文献   
10.
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