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   17693篇
  免费   1466篇
  国内免费   931篇
耳鼻咽喉   154篇
儿科学   233篇
妇产科学   337篇
基础医学   2134篇
口腔科学   353篇
临床医学   2304篇
内科学   2754篇
皮肤病学   271篇
神经病学   876篇
特种医学   563篇
外国民族医学   7篇
外科学   1931篇
综合类   2692篇
现状与发展   1篇
一般理论   11篇
预防医学   979篇
眼科学   425篇
药学   1764篇
  8篇
中国医学   697篇
肿瘤学   1596篇
  2024年   62篇
  2023年   275篇
  2022年   631篇
  2021年   747篇
  2020年   555篇
  2019年   548篇
  2018年   597篇
  2017年   491篇
  2016年   450篇
  2015年   749篇
  2014年   916篇
  2013年   930篇
  2012年   1320篇
  2011年   1435篇
  2010年   942篇
  2009年   751篇
  2008年   919篇
  2007年   950篇
  2006年   917篇
  2005年   866篇
  2004年   634篇
  2003年   576篇
  2002年   426篇
  2001年   389篇
  2000年   394篇
  1999年   464篇
  1998年   304篇
  1997年   308篇
  1996年   229篇
  1995年   196篇
  1994年   161篇
  1993年   105篇
  1992年   119篇
  1991年   90篇
  1990年   82篇
  1989年   66篇
  1988年   101篇
  1987年   86篇
  1986年   55篇
  1985年   50篇
  1984年   33篇
  1983年   24篇
  1982年   21篇
  1981年   17篇
  1980年   11篇
  1979年   28篇
  1978年   11篇
  1977年   10篇
  1975年   10篇
  1974年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
ABSTRACT: Klinefelter syndrome occurs in approximately 1 in 1000 males. A 4-year-old boy presented with precocious puberty and an anterior mediastinal mass. Serum alpha-fetoprotein and human chorionic gonadotropin levels were mildly increased. Computed tomography revealed a germ cell tumor (GCT) of the mediastinum. Complete resection of the tumor was performed. Histologic analysis revealed an immature teratoma. Males with Klinefelter syndrome develop GCTs at a rate 50 times higher than unaffected males. This case report calls attention to the need to rule out Klinefelter syndrome in boys who present with precocious puberty and a mediastinal GCT.  相似文献   
3.
Ching-Hao Chang  MD    Yuan-Li Liao  MD    Hong-Shang Hong  MD  Ph  D 《Dermatologic surgery》2003,29(7):775-779
BACKGROUND: Cutaneous metastasis from adenoid cystic carcinoma of the salivary gland is very rare. OBJECTIVE: To present an unusual case of cutaneous metastasis from adenoid cystic carcinoma of the right parotid gland. METHODS: A 63-year-old woman with multiple subcutaneous nodules on the abdomen and a gradually enlarged mass over the right parotid area was examined. A skin biopsy was taken from one of the abdominal nodules. RESULT: Skin biopsy demonstrated the characteristic histopathologic features of metastatic adenoid cystic carcinoma. A subsequent computerized tomography of the head and neck revealed a huge soft tissue mass involving the right parotid gland. Computerized tomography of the chest revealed extensive nodular pleural thickening, and pleural biopsy also showed typical histopathologic features of metastatic adenoid cystic carcinoma. All of these results are consistent with the diagnosis of an adenoid cystic carcinoma of the right parotid gland with disseminated metastases. CONCLUSION: We report a rare case of cutaneous metastasis from adenoid cystic carcinoma of the right parotid gland. The presentation of cutaneous metastasis is often nonspecific and may mimic benign lesions. Subcutaneous nodules that are rapidly developing or eruptive, are rapidly growing and have stony hardness in nature, have pain or tenderness, and have nonhealing ulceration remind us of the possibility of cutaneous metastases. Dermatologists and dermatologic surgeons should keep the diagnosis of cutaneous metastasis in mind and always perform skin biopsy when encountering these lesions.  相似文献   
4.
50只大鼠用乌拉坦麻醉,箭毒制动。通过阻断腹主动脉血流以模拟腰段脊髓的局部缺血和再灌流损伤,玻璃微电极记录L2节段脊髓单位放电(SCUDs),观察缺血再灌流时脊髓神经元对腓神经刺激(PNV),内脏大神经刺激(VLNV)及两者同时刺激(SV)的反应。结果在缺血前所记录的133个自发放电单位中,对3种刺激均产生兴奋(E)、抑制(I)及无反应(NR)3种形式的反应,表明大鼠L2节段脊髓存在躯体、内脏和躯体内脏反应性神经元,并有会聚和阻塞现象。在脊髓缺血再灌流时,神经元对PNV、VLNV、SV也产生E、I、NR3种形式的反应,提示脊髓缺血再灌流时神经元对躯体和内脏传入刺激的反应形式不受影响;但缺血时SCUDs对PNV、VLNV产生反应的单位数减少,这表明脊髓缺血损伤时神经元对躯体和内脏传入刺激的反应性减弱,随着缺血损伤加重,脊髓神经元对躯体内脏信号的整合功能下降  相似文献   
5.
角膜溃疡穿孔的修复与修复材料的选择   总被引:2,自引:0,他引:2  
廖世煌  张悦 《眼科研究》1995,13(3):169-170
总结21例用不同材料修复角膜穿孔的病例,修复材料分别为结膜瓣、硅胶板、断层自体皮片和同种异体角膜。结膜瓣遮盖仅2/3保存眼球,愈合后视力差,并发症多;硅胶板可在穿孔大、情况紧急时作暂时封孔保存眼球之用;自体断层皮片术后不久即溶解,角膜移植者7眼中6眼保存了眼球,且有5例植片透明,视力0.1以上。  相似文献   
6.
[目的]研究大豆蛋白对肾损害大鼠钙平衡的影响。[方法]选择3月龄断乳雄性SD大鼠40只.按体质量从小到大排序,采用完全随机化原则分为4组。每组10只。标准饲料对照组:喂食含有14%酪蛋白饲料;大豆蛋白饲料组:喂食含有14%大豆分离蛋白饲料;混合饲料1组:喂食含有7%酪蛋白加7%大豆分离蛋白饲料;混合饲料2组:喂食含有7%酪蛋白加14%大豆分离蛋白饲料。实验期用腺嘌呤灌胃共21d,建立肾损害大鼠模型,各组大鼠喂养相应饲料6周,测饲料消耗量、24h尿蛋白、尿钙、钙表观吸收率、储留钙量。[结果]4组实验大鼠饲料摄入量1d~30d无统计学差异,大豆蛋白饲料组和混合饲料1组实验结束时与另外两组相比,尿钙排泄量低,钙表观吸收率和储留钙量高,差异有统计学意义(P〈0.05)。[结论]蛋白质含量水平在14%条件下,含大豆蛋白的两种饲料对肾损害大鼠钙吸收、钙排泄的影响无统计学差异,有利于促进钙吸收,减少钙排泄。  相似文献   
7.
To investigate the association between pre-walking locomotor strategies and psychomotor developments in children with mental retardation (MR), 50 children with non-specific MR were included in this study. There were 29 boys and 21 girls, 96% of whom had moderate to severe MR. They were followed from 4-53 months to 25-99 months of age, and their follow-up periods ranged from 10 to 48 months (mean 30 months). According to the pre-walking locomotor strategies, these children were categorized into three groups: the crawling group (n = 34) who used crawling or creeping as their main locomotion pattern before independent walking; the shuffling group (n = 9) who used shuffling prior to independent walking; and the direct-walking group (n = 7) who did not have any other locomotor strategies except rolling. In almost all motor developmental milestones, children in the direct-walking group developed earlier than those in the crawling and shuffling groups. Children in the crawling group had more advanced developments than those in the shuffling group. The difference in the mean ratio developmental quotients of the Bayley Mental Scale among the three groups was not significant. The present study showed that crawling may not be a necessary prerequisite for early ambulation or better cognitive function in MR children.  相似文献   
8.
Q Lin  J Liao 《中西医结合杂志》1990,10(2):78-81, 68
344 cases of Heart-Qi Deficiency Syndrome (HQDS) including 19 Kinds of disease were observed to explore the rule of differentiation of symptoms and signs for HQDS. The results showed that the common symptoms of HQDS were weakness, shortness of breath, and palpitation, etc. According to with or without complicated cardiovascular diseases, the patients were divided into two groups: group A with cardiovascular diseases, group B without that. In group A, the symptoms and signs of HQDS were the most frequent and early clinical manifestations, the associated symptoms and signs were blood stasis and attack of water-evil, etc. In group B, in whom often associated with nervous and emotional symptoms such as insomnia, dreamfulness, and amnesia, etc., which was due to the disturbance of emotional activities of heart. In order to avoid diagnostic confusion, the authors suggest that the HQDS patients with cardiovascular diseases would be diagnosed as HQDS; on the other hand, the HQDS patients without cardiovascular diseases would be diagnosed as disturbance of emotional activities of heart.  相似文献   
9.
Summary From 1987 to 1990 the authors treated 20 cases of spondylolisthesis by an improved operative procedure including excision of the medial part of the superior articular processes of the slipped vertebra, excision of the soft tissue between the ununited isthmi, and excision of the ligamentum flavum between the intervertebral space above the slipped segment. In some instances the lower portion of the lamina over the slipped vertebra should be resected. A U-shaped rod was used to hold sublaminar fixation of two segments above and below the slipped vertebra, with the slipped vertebra spared. Utilizing the U-shaped rod as support, bone strips were placed along the lateral and anterior sides of the rod to bridge the gap between the laminae of the displaced vertebra. Other bone grafts were focused on the facet joints. The patients were allowed ambulation early postoperatively. 19 cases could be evaluated at preliminary follow-up. All showed satisfactory results.  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