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   247375篇
  免费   6708篇
  国内免费   264篇
耳鼻咽喉   2175篇
儿科学   8595篇
妇产科学   4298篇
基础医学   26018篇
口腔科学   2825篇
临床医学   19706篇
内科学   45651篇
皮肤病学   1456篇
神经病学   23540篇
特种医学   11740篇
外科学   40258篇
综合类   3706篇
现状与发展   1篇
一般理论   60篇
预防医学   24276篇
眼科学   4292篇
药学   14293篇
中国医学   723篇
肿瘤学   20734篇
  2023年   297篇
  2022年   528篇
  2021年   1462篇
  2020年   884篇
  2019年   1398篇
  2018年   23306篇
  2017年   18319篇
  2016年   20653篇
  2015年   2545篇
  2014年   3085篇
  2013年   4091篇
  2012年   11960篇
  2011年   26130篇
  2010年   21536篇
  2009年   14116篇
  2008年   23930篇
  2007年   26372篇
  2006年   5434篇
  2005年   7091篇
  2004年   7860篇
  2003年   8654篇
  2002年   6636篇
  2001年   926篇
  2000年   887篇
  1999年   866篇
  1998年   1110篇
  1997年   969篇
  1996年   771篇
  1995年   744篇
  1994年   692篇
  1993年   614篇
  1992年   497篇
  1991年   490篇
  1990年   488篇
  1989年   458篇
  1988年   428篇
  1987年   389篇
  1986年   365篇
  1985年   391篇
  1984年   470篇
  1983年   446篇
  1982年   619篇
  1981年   570篇
  1980年   567篇
  1979年   313篇
  1978年   319篇
  1977年   331篇
  1976年   257篇
  1974年   260篇
  1973年   258篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
61.
Coronary flow reserve (CFR) has been used toassess coronary microcirculation and epicardial coro-nary stenoses[1— 3 ] . CFR is defined as the ratio ofcoronary flow under maximal coronary vasodilatationto coronary flow under resting conditions[4 ] .Whenthe cross- sectional area of epicardial coronary arteriesis constant,coronary flow velocity (CFV) ratios areequal to volume flow ratios.The most common method used clinically formeasuring CFVR is intracoronary Doppler flow(ICD) analysis re…  相似文献   
62.
In an attempt to identify a cause for the alteration in breathing pattern seen when conventional respiratory apparatus is applied to the face, we have studied the effects of causing the subject to focus attention on breathing by counting breaths in threes for 5 min. We used the respiratory inductance plethysmograph in 18 naive subjects who were unaware that their breathing was being measured. In the control periods, distraction was provided by a recorded story played through head-phones. The experiment was repeated with the rim of a facemask applied to the face. Focusing attention on breathing caused a prolongation of inspiration at a constant mean inspiratory flow, and lengthening of expiration. Tidal volume but not ventilation was increased. The facemask rim caused no significant change. It is concluded that conscious awareness of breathing could account for a major part of the effect of conventional respiratory apparatus.  相似文献   
63.
64.
Stuart Cathcart  BA    Donald Pritchard  PhD 《Headache》1998,38(3):214-221
An exploratory study was conducted examining arousal-related moods and episodic tension-type headache. Twelve subjects meeting International Headache Society criteria for episodic tension-type headache and 12 headache-free controls recorded headache activity and mood eight times daily for 14 consecutive days. Moods were measured using the Activation-Deactivation Adjective Check List, a self-report list that subjectively represents general arousal along two dimensions of Tension and Energy. Headache subjects had higher Tension levels than controls even in the absence of pain, and greater variation in this dimension as well. Within the headache group, Tension during pain-free periods was significantly lower than when experiencing headache, and was correlated with headache activity. The results were taken to support Thayer's (1989) biopsychological model of mood and arousal, and are discussed in terms of the model's heuristic value for general arousal and headache research.  相似文献   
65.
66.
The final events of Wolfe Tone’s short and stormy life are fairly common knowledge. He was captured on board the French flagshipHoche when the vessel surrendered to a superior British naval force off Lough Swilly on October 10, 1798. Despite his protests that he was entitled to normal prisoner-of-war treatment, he was brought in irons a month later to Dublin. A court martial was hurriedly convened and he was found guilty of treason on Saturday November 10 and condemned to be hanged two days later. According to the generally accepted version of subsequent events he cut his own throat early on the Monday morning. The assistant surgeon of the 5th Dragoon Guards dressed the wound “ — but only with a view to prolong life until the fatal hour of one o’clock”. This surgeon was Benjamin Lentaigne, a Royalist emigre from France. Despite the pleas of John Philpott Curran, a leading advocate of the day, the military authorities refused to allow any consultation with a civil surgeon. Was this just bloody mindedness or was there an even more sinister reason? Two possibilities come to mind. One was that the wound had been so incompetently treated that a consultant would have been forced to make adverse comments, the other that the throat wound was not due to a cutting injury but, to a bullet fired either deliberately or accidently and a knife or razor was then used to try and camouflage the original trauma. In 1812 Lentaigne published a pamphlet in Latin in which he made reference to an unusual neck would stating that “— the bullet passed through his throat...” There is no direct evidence that the victim was Tone, why did the writer not make this clear? It may be he was reluctant to expose the medico-military inefficiency or callousness or to jeopardise his son’s career. Whatever the true facts, the verdict must remain the Scots one of “Not proven”.  相似文献   
67.
This study examined the feasibility of isolating and transferringthe centrosome-containing region of spermatozoa to mature humanoocytes. The findings demonstrate that individual sperm centrosomescan be transferred and are capable of nucleating maternal tubulinto form a well-developed sperm aster in the recipient oocyte.The results are discussed with respect to centrosome functionin early human development and applications in clinical in-vitrofertilization in the treatment of certain forms of male factorinfertility.  相似文献   
68.
Four hundred and twenty-three alcohol dependent subjects were enrolled into a 12-week randomized, double-blind, placebo-controlled study to determine the safety and efficacy of the 5-HT2 receptor antagonist, ritanserin (2.5 mg/day or 5 mg/day), in reducing alcohol intake and craving. All subjects received 1 week of single-blind placebo prior to randomization into the 11-week double-blind phase. Additionally, all subjects received weekly individual sessions of manual-guided cognitive-behavioral therapy. Comparing the single-blind period with endpoint, there was approximately a 23% reduction in drinks/day; 34% fall in the total number of drinking days/week; 22% decrease in drinks/drinking day; and a 37% diminution in alcohol craving for all treatment groups. All treatment groups experienced a beneficial clinical outcome as assessed by the Clinical Global Impression Scale. There was, however, no significant difference between treatment groups on any of these measures of alcohol drinking, craving, or clinical outcome. Subjects were of relatively high social functioning at baseline, and this did not change significantly during treatment. Treatment groups did not differ significantly on either medication compliance or reported adverse events. Ritanserin treatment was associated with a dose-related prolongation of subjects’ QTc interval recording on the electrocardiogram. These results suggest that alcohol dependent subjects can show marked clinical improvement within a structured alcohol treatment program. These findings do not support an important role for ritanserin in the treatment of alcohol dependence. Received: 30 April 1996/Final version: 3 July 1996  相似文献   
69.
The fit and fill of the femoral canal are critical to the success of cementless femoral stems in total hip arthroplasty. It is difficult for conventional stems to provide a good fit and fill for the femora of patients with secondary osteoarthritis. Based on measurements of 100 femora of these patients, we designed two types of Fukui Medical School (FMS) stems with a proximal lateral flare that differed in the medial radius. We compared the fit and fill of the FMS stems with those of four conventional stems, using computer simulation. The mean proximal fit and total fit of the FMS stems were 46% and 53% respectively, a significant improvement compared with the other stems examined. The mean fill of FMS stems was 82% at the lower end of the lesser trochanter and 84% at the upper end of the isthmus, values that were significantly higher than those of the other stems. Since September 1995, we have implanted FMS stems in 15 hips with secondary osteoarthritis. Radiographic evaluations showed that the canal fill of the FMS stems was significantly greater in the proximal femur compared with other stems previously inserted at our department. A summary of this paper was presented at the 9th Symposium on Computer-Assisted Radiology; June 1995, Berlin, and at the 8th International Symposium on Technology in Arthroplasty; September 1995, Puerto Rico.  相似文献   
70.
We prospectively enrolled 160 consecutive patients with inversion trauma of the ankle in a diagnostic protocol that included physical examination within 2 days and at 5 days after trauma, arthrography, stress radiography, and ultrasonography. 135 patients had pathological lateral ligament laxity on the later physical examination or lateral ligament rupture diagnosed on arthrography and they were operated on. 122 of these patients had ligament ruptures.

At clinical follow-up after a minimum of half a year, all of the patients who were not operated on had stable joints without signs of previous ligament ruptures.

Delayed physical examination at 5 days after the injury led to the highest overall sensitivity (96%) and specificity (84%) for the detection of a ligament rupture. Additional diagnostic procedures, at a considerable cost, yielded little additional information.  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