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   314篇
  免费   6篇
  国内免费   5篇
耳鼻咽喉   69篇
儿科学   6篇
妇产科学   23篇
基础医学   53篇
口腔科学   3篇
临床医学   14篇
内科学   9篇
皮肤病学   1篇
神经病学   3篇
特种医学   11篇
外科学   66篇
综合类   31篇
预防医学   9篇
眼科学   2篇
药学   11篇
中国医学   5篇
肿瘤学   9篇
  2024年   1篇
  2023年   4篇
  2022年   6篇
  2021年   8篇
  2020年   9篇
  2019年   7篇
  2018年   5篇
  2017年   6篇
  2016年   5篇
  2015年   7篇
  2014年   24篇
  2013年   18篇
  2012年   17篇
  2011年   14篇
  2010年   13篇
  2009年   16篇
  2008年   11篇
  2007年   19篇
  2006年   13篇
  2005年   7篇
  2004年   14篇
  2003年   10篇
  2002年   4篇
  2001年   6篇
  2000年   14篇
  1999年   13篇
  1998年   6篇
  1997年   7篇
  1996年   8篇
  1995年   5篇
  1994年   4篇
  1993年   1篇
  1992年   2篇
  1991年   3篇
  1989年   2篇
  1988年   2篇
  1987年   3篇
  1986年   2篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   3篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
排序方式: 共有325条查询结果,搜索用时 828 毫秒
31.
Summary The influence of simple opening of the round window (RW) membrane and the effect of aspiration of perilymph on the electrophysiological characteristics of the cochlea was tested in guinea pigs by measurement of the compound action potentials. We found that perforations of the RW membrane failed to lead to either shortterm or long-term damage in cochlear function. There was only a slight spontaneous escape of perilymph but without measurable functional loss. Additional aspiration of perilymph led to entry of air into the basal turn and to an immediate loss of function of the cochlea. This regressed within 4 weeks in the middle- and low-frequency ranges. Measurable long-term damage persisted only in the high-frequency ranges. We attribute contradictory results of other authors to methodological errors which we avoided by a specific selection of healthy animals and the development of standardized operation, recording and measurement procedures.  相似文献   
32.
目的 探讨四点荷包缝合方法修复较小圆形皮肤组织缺损的效果。方法 在3只家猪的胸背部做直径3cm的圆形皮肤软组织缺损,共18处创口,分别予以不同的缝合方法,直接关闭创口,观察创面愈合情况。结果 四点荷包缝合法和四边梭形切除加四点荷包缝合法两组缝合创面平整美观,不需要切除较多的边缘正常组织,效果优于其他方法,结论 四点荷包缝合方法是一种较好的关闭圆形病灶的缝合方法。  相似文献   
33.
We have studied the effects of vinblastine sulfate (VBL) and colchicine (COL) on male rat in vivo and in vitro meiosis. A novel methodology based on isolating a segment of seminiferous tubules containing meiotically dividing spermatocytes was applied. During meiotic divisions at stage XIV of rat spermatogenesis, both chemicals induced only low frequencies of micronu-clei (MN), 0.8–3.2 MN/1,000 spermatids. Fluorescence in situ hybridization experiments in mice with the mouse centromere-specific y-sat-ellite DNA probe showed that 50.7% of VBL-induced MN and 56.6% of COL-induced MN were centromere positive, indicating that the MN induced by both chemicals contained detached chromosomes. The inhibition of cell proliferation was determined by counting the number of cells arrested at metaphase during the first meiotic (MI) or the second meiotic (MII) division. VBL was found to be a potent inducer of cell death while COL was not. The direct effects of VBL and COL on the meiotic spindles were evaluated using immunohistochemistry with anti-a-tubulin and confocal microscopy. In the control animals a significant difference was observed between the mean length of metaphase spindles of MI and MII Both were dramatically decreased 6 hr after treatment with 2.0 mg/kg of VBL and 0.8 mg/kg of COL, respectively. At 18 hr after COL injection the spindles had about the same length as in the controls. However, the VBL-induced shortening was even more evident at 18 hr for both Ml and Mll. The possible reasons for observed differences between the two chemicals and between meiosis and mitosis are discussed. © 1995 Wiley-Liss, Inc.  相似文献   
34.
低剂量147Pm内照射对精子DNA链修复的刺激效应   总被引:1,自引:0,他引:1       下载免费PDF全文
作者设计用碱性淋洗技术探讨了小鼠受低剂量147Pm内污染时对精子DNA链修复的刺激效应。动物预先在睾丸内注入3H-TdR,用以标记精子DNA,从标记到采集精子的时间固定为36天,正好为BALB/c小白鼠雄性生殖细胞的一个发育周期.从摄入147Pm到采集精子的时间则固定在12天,因这时小白鼠精子DNA链断裂的洗脱量最大,待精子被溶胞液溶破后,加入淋洗液,调节蠕动泵流量定时收集标本,用液闪装置测量膜上标本和膜下各收集标本的放射性活度,从而判断各标本中DNA的量。研究结果发现,当机体内污染低剂量147Pm在0.185kBq/g时,此时的膜上DNA存留率呈现升高,显著高于相应对照组,表明低剂量裂片147Pm内照射对精子DNA链修复的刺激效应。  相似文献   
35.

Objectives:

To determine the cause of severe, disabling, groin pain.

Methods:

We describe in this case report 2 patients with severe groin pain. Two myoma-like masses were found on the uterus near the right round ligament. Both masses were excised via laparoscopy.

Results:

The pathology report of these 2 cases indicated adenomyosis. Both patients were asymptomatic after the procedure. Adenomyosis usually propagates in the myometrium, and the nodular shape of this pathology is rare. In patients with severe groin pain (menstrual or continuous), the gynecologist should think about both endometriosis of the round ligament and adenomyosis near the round ligament.

Conclusion:

Severe groin pain is rare but disabling. Endometriosis of the external part of the round ligament is described as a cause. In this case report, we explain that nodular adenomyosis can also be a cause.  相似文献   
36.
Radiographs and clinical charts were reviewed in a series of 13 cases of primary neuroectodermal bone tumors, involving 9 males and 4 females, aged from 3 to 32 years (average: 15 years). The average delay between the onset and diagnosis was 5 months. Fever and other systemic symptoms were present in 6 cases; in 4 cases a fracture was the mode of presentation. Seven patients had metastases (4 involving bone) at the time of presentation. Only one patient is still alive after 5 years. In the 10 patients who died as a direct result of the tumor, death occured on average 8 months following diagnosis if metastases were present initially, and 36 months after the diagnosis otherwise. Tumors predominantly involved the leg (7 cases), the pelvis (2 cases), and the humerus (2 cases), the involvement being both diaphyseal and metaphyseal. The radiologic appearance is that of an aggressive, poorly demarcated tumor, with cortical destruction, periosteal reaction and soft tissue invasion. Comparison with Ewing sarcoma shows little radiologic or clinical difference, except for a poorer prognosis in neuroectodermal bone tumors. Both bone tumors may have a similar neuroectodermal origin, with Ewing sarcoma representing the undifferentiated variety.  相似文献   
37.
Chen ST  Lee JC 《Human pathology》2008,39(12):1854-1858
Inflammatory myofibroblastic tumor is an intermediate-grade neoplasm with potential for recurrence and rare metastasis. Rearrangement of the anaplastic lymphoma kinase gene with variable fusion partners and anaplastic lymphoma kinase expression using immunohistochemistry are noted in about half of the tumors. We present a hepatic inflammatory myofibroblastic tumor from a 34-year–old man with an unusual rearrangement between the Ran binding protein 2 and anaplastic lymphoma kinase genes, as well as a peculiar round cell transformation of tumor cells and a unique nuclear membrane expression of anaplastic lymphoma kinase protein. As the fourth reported inflammatory myofibroblastic tumor with this fusion so far, we find that these genetic and morphologic features may be related to a poor clinical outcome. The diagnostic difficulty and other prognostic factors of inflammatory myofibroblastic tumor are also discussed.  相似文献   
38.
39.
40.
Purpose: This study investigated whether K + -rich medium is better than pure NaCl solution or Na + -rich cell culture medium for handling round spermatid nuclei prior to injection into oocytes (ROSNI). Methods: Round spermatids of the mouse were isolated and stored in isotonic NaCl, a cell culture medium (CZB), or a nucleus isolation medium (NIM) before injection into oocytes. The rates of normal fertilization, embryonic development in vitro, and birth of normal offspring after transfer of embryos to foster mothers were determined. Results: In vitro development of ROSNI-produced zygotes to blastocysts was the same when naked spermatid nuclei were exposed briefly to three media. However, a long (60-min) exposure of the nuclei to NA + -rich medium was detrimental. In K + -rich NIM naked spermatid nuclei best retained their ability to participate in normal embryonic development. Conclusion: NIM was better than Na + -rich medium for retaining isolated spermatids competent to participate in normal embryonic development.  相似文献   
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