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   434757篇
  免费   25860篇
  国内免费   19151篇
耳鼻咽喉   3407篇
儿科学   9140篇
妇产科学   6386篇
基础医学   46815篇
口腔科学   5986篇
临床医学   48292篇
内科学   68423篇
皮肤病学   3272篇
神经病学   30202篇
特种医学   18689篇
外国民族医学   155篇
外科学   54205篇
综合类   47646篇
现状与发展   62篇
一般理论   21篇
预防医学   34946篇
眼科学   10466篇
药学   36803篇
  229篇
中国医学   16484篇
肿瘤学   38139篇
  2024年   871篇
  2023年   4182篇
  2022年   10855篇
  2021年   13508篇
  2020年   10307篇
  2019年   8925篇
  2018年   30509篇
  2017年   25295篇
  2016年   26838篇
  2015年   13122篇
  2014年   15669篇
  2013年   13790篇
  2012年   25617篇
  2011年   41546篇
  2010年   31175篇
  2009年   21278篇
  2008年   32332篇
  2007年   34868篇
  2006年   14056篇
  2005年   15403篇
  2004年   12578篇
  2003年   13772篇
  2002年   10571篇
  2001年   7346篇
  2000年   7072篇
  1999年   6735篇
  1998年   4276篇
  1997年   4213篇
  1996年   3239篇
  1995年   3026篇
  1994年   2512篇
  1993年   1600篇
  1992年   2108篇
  1991年   1829篇
  1990年   1548篇
  1989年   1281篇
  1988年   1147篇
  1987年   1008篇
  1986年   806篇
  1985年   616篇
  1984年   374篇
  1983年   281篇
  1982年   182篇
  1981年   157篇
  1980年   157篇
  1979年   149篇
  1975年   62篇
  1974年   75篇
  1938年   64篇
  1932年   57篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
201.
202.
203.
Abstract Objective: To define the diagnostic accuracy of clinical examination in patients with impaired consciousness or endotracheal intubation to detect pelvic ring fractures and to identify those with severe bleeding. Methods: Included in this prospective data collection with retrolective data analysis were a consecutive series of blunt trauma victims with either a Glasgow Coma Scale ≤ 13 or tracheal intubation. Clinical examination comprised testing for stability of the iliac wings. Results: From 784 subjects (injury severity score 23.3 ± 17.4) 93 patients (11.9%) were found to have a pelvic ring fracture. Clinical instability of the pelvic ring was found in 42 patients. There was only one false positive. Fifty-two fractures could not be identified by clinical examination, including nine fractures (17%) that required surgical fracture stabilization (sensitivity of clinical examination 44.1%). Seventeen fractures (18.3%) were associated with a blood loss larger than 20% of circulating blood volume. Sixteen of those were identified by clinical instability of the pelvic ring (sensitivity 94.1%, specificity 97.0%, positive predictive value 38.1%, negative predictive value 99.9%). Conclusions: Clinical examination for stability of the pelvis in this selected group of patients missed a significant number of pelvic ring fractures including fractures that require surgical stabilization. The finding of a clinically unstable identifies most of the patients with the pelvic ring fracture being a major source of bleeding. A stable pelvis makes pelvic ring fracture as being the source of bleeding quite unlikely.  相似文献   
204.
目的 初步建立阴道粘膜上皮细胞体外培养方法,为阴道粘膜上皮研究提供实验模型.方法 取雌性新西兰大白兔阴道粘膜组织小块,胶原酶Ⅳ和胰蛋白酶联合消化分离法收集上皮细胞,接种于角朊细胞无血清培养液中静置培养、传代.动态观察细胞生长增殖情况,扫描和透射电镜观察超微结构,流式细胞仪测定细胞增殖周期,并进行免疫组织化学鉴定.结果 体外培养的阴道粘膜上皮细胞为二倍体细胞,增殖状态良好,细胞间可见桥粒连接,免疫组化角蛋白染色阳性.细胞的超微结构和免疫组化染色均具有上皮细胞特征.结论 在本实验条件下,体外培养的阴道粘膜上皮细胞具有较好的增殖能力,可作为阴道粘膜上皮研究的理想实验模型.  相似文献   
205.
Erratum     
  相似文献   
206.
目的:建立乳腺非典型增生病动物模型,探讨非典型增生与血管生成的关系。方法:采用灌服二甲基苯蒽+颈部枷具方法复制大鼠肝郁血瘀型乳腺非典型增生动物模型,并给予中药乳复汤治疗。常规染色观察大鼠乳腺组织病理组织形态.免疫组化方法检测MVD、VEGF和bFGF的表达。结果:病证模型组乳腺非典型增生率90%.较单纯造模组高.P=0.0415;中药乳复汤治疗组非典型增生率较病证模型组低.P=0.0459;随着一般增生到非典型增生程度加重,MVD计数增多,VEGF、bFGF的表达升高,P〈0.05。结论:病证结合造模更适合中医动物实验要求,中药乳复汤具有抑制血管生成作用。  相似文献   
207.
The authors reviewed the radiographic manifestations of 17 cases of parosteal osteosarcoma, with pathologic correlation in 15. There were two types of parosteal osteosarcoma radiologically. The majority of cases were type I with uniformly dense masses which had regular borders. They often adhered to the cortex and showed no evidence of soft-tissue invasion which correlated with low-grade pathologic malignancy and a relatively benign clinical course. Type II involved the bone, soft-tissue and the medullary cavity. These lesions were poorly differentiated and frequently accompanied by metastatic lesions.
  相似文献   
208.
肝癌基础及临床研究的若干进展   总被引:1,自引:0,他引:1  
  相似文献   
209.
This paper is a summary of our observations on 105 cases of infantile spasms. The age of onset was around six months after birth, but the patients came for treatment mainly about one year after onset. Fever of unknown cause, asphyxia, birth injury, infection of the central nervous system, tuberous sclerosis, phenylketonuria and recent immunization etc. were complained. Clinically, it is characterized by head nodding, mental retardation, myoclonic jerks and various neurologic deficits. EEG findings showed classical or modified arrythmia or other epileptiform patterns. About one third of 22 cases examined had abnormal brain stem auditory evoked potentials. Among 42 patients who underwent CT scanning before ACTH treatment, 18 were normal and 7 abnormal; during ACTH treatment 3 normal and 4 abnormal; after completion of treatment, 4 normal and 6 abnormal, suggesting no further atrophy of the brain. Examination of trace elements of the hair by particle-induced X-ray emission (PIXE) method in 23 patients revealed a significant difference in lead, calcium and zinc contents between patients and 101 controls, but no statistical difference in iron and copper contents between the two groups. Sodium valproate, prednisone and ACTH appear to be effective in the treatment of infantile spasms. Eight patients fully recovered, and they can go to school without difficulty. Many patients derived various degrees of improvement to the satisfaction of their parents. Two patients were still amented and often attacked by myoclonus. The effects, side effects of these drugs, and the possible pathogenesis were discussed.
  相似文献   
210.

Background  

Reports on childhood cancer survivors estimated cumulative probability of developing secondary neoplasms vary from 3,3% to 25% at 25 years from diagnosis, and the risk of developing another cancer to several times greater than in the general population.  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