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   9070篇
  免费   446篇
  国内免费   49篇
耳鼻咽喉   83篇
儿科学   228篇
妇产科学   219篇
基础医学   1101篇
口腔科学   218篇
临床医学   540篇
内科学   2006篇
皮肤病学   174篇
神经病学   550篇
特种医学   536篇
外科学   1598篇
综合类   52篇
预防医学   184篇
眼科学   497篇
药学   574篇
中国医学   13篇
肿瘤学   992篇
  2023年   63篇
  2022年   128篇
  2021年   202篇
  2020年   98篇
  2019年   130篇
  2018年   189篇
  2017年   135篇
  2016年   206篇
  2015年   181篇
  2014年   251篇
  2013年   295篇
  2012年   492篇
  2011年   591篇
  2010年   308篇
  2009年   278篇
  2008年   508篇
  2007年   525篇
  2006年   538篇
  2005年   535篇
  2004年   515篇
  2003年   441篇
  2002年   479篇
  2001年   220篇
  2000年   219篇
  1999年   238篇
  1998年   106篇
  1997年   100篇
  1996年   83篇
  1995年   76篇
  1994年   76篇
  1993年   66篇
  1992年   127篇
  1991年   115篇
  1990年   92篇
  1989年   108篇
  1988年   90篇
  1987年   103篇
  1986年   121篇
  1985年   84篇
  1984年   68篇
  1983年   43篇
  1981年   27篇
  1980年   22篇
  1979年   31篇
  1978年   22篇
  1977年   26篇
  1975年   18篇
  1974年   18篇
  1970年   23篇
  1969年   24篇
排序方式: 共有9565条查询结果,搜索用时 218 毫秒
11.
We studied the effects of 15(R)-15-methyl prostaglandin E2 (arbaprostil) on gastric secretion and various acute and chronic gastric lesions produced in rats. Arbaprostil significantly inhibited gastric secretion in 4 hr-pylorus-ligated preparations when given intraduodenally in a dose of 30 or 100 micrograms/kg. The agent, however, significantly stimulated gastric secretion of rats with either a ligated or intact pylorus when given orally in doses of 3-100 micrograms/kg. Orally administered arbaprostil dose-dependently prevented the development of HCI-ethanol-, histamine-, water-immersion stress-, or indomethacin-induced gastric erosions. Intraduodenally administered arbaprostil also dose-dependently prevented the development of aspirin-induced gastric erosions in pylorus-ligated rats. Arbaprostil, given orally in doses of 1-100 micrograms/kg twice daily for 2 weeks, had little or no effect on the healing of acetic acid-induced gastric ulcers. However, oral administration of the agent in a dose of 3 or 10 micrograms/kg twice daily for 4 weeks significantly accelerated the healing of acetic acid-induced gastric ulcers. The increase in doses up to 100 micrograms/kg twice daily for 4 weeks had no effect on ulcer healing. These results indicate that arbaprostil, at either antisecretory or even acid stimulating doses, is effective in preventing the development of acute gastric erosions and in accelerating the healing of chronic gastric ulcers.  相似文献   
12.
目的:分析胃癌大肠转移的X线钡灌肠表现。方法:104例胃癌入院术前检查发现结肠转移或胃癌术后转移入院治疗的病例。分析钡灌肠初次发现大肠转移征象的年龄、发现胃癌原发病变距初次发现大肠转移的间隔时间、转移病变的发生部位和病变造成的X线钡灌肠图像上的肠管变形和粘膜面的改变。结果:104例胃癌结肠转移,男67例,女37例。胃癌术前检查中发现结肠转移者32例,术后发现的大肠转移中,多数转移发生在手术后3年内(占91.3%)。胃癌原发灶的肉眼形态BorrmannⅢ型(28例)和BorrmannⅣ型(65例)者占89.4%,组织学中以低分化腺癌和印戒细胞癌为主要成分者占91.3%。X线钡灌肠检查显示大肠转移的好发部位为横结肠(80),其次为直肠(50)。转移灶可累及多节段肠管,其中横结肠中1/3段(47),横结肠左1/3(44),横结肠右1/3(39)和直肠腹膜返折之上(39)。X线显示肠管单侧变形者227处,双侧变形者96处。黏膜面表现为梳齿状黏膜纹聚集改变253处,颗粒结节状改变23处,外压性改变20处,弥漫性改变62处。结论:胃癌大肠转移的好发部位为横结肠和直肠,结肠黏膜面的梳齿状黏膜纹聚集为胃癌大肠转移的主要X线钡剂灌肠表现。  相似文献   
13.
14.
15.
16.
Diagnosis and treatment of thoracic outlet syndrome   总被引:2,自引:0,他引:2  
Patients who develop symptoms of thoracic outlet syndrome (TOS) have a predisposing anatomic abnormality. In most patients with TOS, the symptoms are caused by entrapment of the brachial plexus and they do not arise from compression of the subclavian artery, as was previously thought. The tests advocated for diagnosing this common syndrome (i.e., evaluating the positional compression of the artery when the arms are raised, the neck is turned, or the shoulders are braced) cannot accurately diagnose this syndrome. There are two reasons for this. The symptoms of TOS are not related to the compression of the artery in the outlet in 98% of patients, and 75% of normal individuals without symptoms show diminished radial pulse on various provocation tests. We employed four timed provocation tests (minute tests) to diagnose TOS: the timed Morley test, timed Wright test, timed Eden test, and elevated arm stress exercise, all of which are very sensitive. In normal individuals without symptoms, 20% experience transitional symptoms such as slight pain and tiredness, on these tests indicating a subclinical state. TOS is treated by keeping the thoracic outlet wide, this being done either conservatively or surgically. In 1993 and 1994, we conservatively treated 418 of 422 patients with TOS by means of active exercise, a brace, and by block therapy. These measures did not reduce the symptoms in 23 of these patients, so surgical treatment was indicated. In the remaining 4 of the 422 patients, conservative treatment was not indicated and surgery was performed directly. All the patients showed significant clinical improvement of varying degree. Presented at the 69th Annual Meeting of the Japanese Orthopaedic Association, Tokyo, April 12, 1996  相似文献   
17.
Changes in the distribution of hyaluronic acid in the developing human retina were investigated histochemically with alcian blue staining and theStreptomyces hyaluronidase digestion method using 56 human embryos and fetuses ranging from 5 to 41 weeks of gestational age. Hyaluronic acid was first detected in the inner layer of the retina at 12 weeks. The site of accumulation extended towards the outer layer by 20 weeks. At the neonatal stage, longitudinal fibers, possibly the processes of Müller cells, were proved to contain hyaluronic acid. These findings suggest that Müller cells produce hyaluronic acid transiently from 12 weeks’ gestation to the neonatal stage.  相似文献   
18.
19.
20.
Since the prevalence and clinical characteristics of young-onset hypertension are still to be elucidated, we performed targeted-screening at an annual university health check-up for two consecutive years. Out of 16,464 subjects in 2003 and 17,032 in 2004 that were aged less than 30 years, 22 and 26 students (all males) exhibited high blood pressure (BP), respectively, on three occasions during casual BP measurements at the Tohoku University Health Center (systolic and diastolic BP of 140 and/or 90 mmHg or greater, respectively). These students were asked to measure their BP at home, and 9 subjects in total were diagnosed as having essential hypertension (EH). The remaining students were diagnosed as having white coat hypertension (WCH). In 8 out of 9 EH students, their father and/or mother had also been treated with antihypertensive medication. Adjustment by attendance ratio for each BP measurement suggested that the incidence of EH was around 0.1% and that of hypertension (EH and WCH) was around 0.5% in university students aged less than 25 years, since most of the subjects and hypertensive students were between 18 and 24 years old. Body mass index of the EH, which was more than 25 kg/m2 (overweight), was significantly higher than that with WCH. In conclusion, the combination of repeated casual BP measurements and home BP effectively identified young-onset EH. The clinical parameters indicated that male gender, genetic background, and excessive weight were risk factors for young-onset hypertension.  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