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   19224篇
  免费   1145篇
  国内免费   149篇
耳鼻咽喉   254篇
儿科学   525篇
妇产科学   668篇
基础医学   2126篇
口腔科学   530篇
临床医学   1572篇
内科学   3784篇
皮肤病学   380篇
神经病学   929篇
特种医学   716篇
外国民族医学   11篇
外科学   3421篇
综合类   353篇
现状与发展   2篇
一般理论   11篇
预防医学   1665篇
眼科学   541篇
药学   1764篇
中国医学   139篇
肿瘤学   1127篇
  2023年   222篇
  2022年   592篇
  2021年   1133篇
  2020年   617篇
  2019年   763篇
  2018年   1030篇
  2017年   600篇
  2016年   636篇
  2015年   645篇
  2014年   911篇
  2013年   1056篇
  2012年   1542篇
  2011年   1693篇
  2010年   958篇
  2009年   696篇
  2008年   981篇
  2007年   992篇
  2006年   911篇
  2005年   864篇
  2004年   753篇
  2003年   692篇
  2002年   618篇
  2001年   157篇
  2000年   120篇
  1999年   108篇
  1998年   86篇
  1997年   77篇
  1996年   73篇
  1995年   70篇
  1994年   63篇
  1993年   55篇
  1992年   60篇
  1991年   65篇
  1990年   64篇
  1989年   51篇
  1988年   52篇
  1987年   52篇
  1986年   41篇
  1985年   43篇
  1984年   43篇
  1983年   42篇
  1982年   37篇
  1981年   29篇
  1980年   25篇
  1978年   16篇
  1977年   14篇
  1976年   17篇
  1974年   13篇
  1973年   23篇
  1966年   13篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
53.
The overlooked, retained double J stent   总被引:2,自引:0,他引:2  
A series of 4 patients with long overlooked, retained ureteral stents is presented to illustrate the variable, unpredictable, and at times, hazardous course of such patients. These cases are cited to re-emphasize the need for careful documentation, observation, and follow-up of patients in whom stents are placed.  相似文献   
54.
This is a retrospective study of patients with first attack of myocardial infarction admitted to Medical College Hospital, Calicut during the years 1969 to 1988. The data analysed were compared to other hospital based studies in India and abroad. A striking increase in the percentage of acute myocardial infarction was observed. There was also an increase in the occurrence of myocardial infarction in the young. A properly designed population based study is warranted.  相似文献   
55.
Following exposure to promastigotes of various Leishmania species, mononuclear cells from non-exposed as well as potentially exposed individuals produced a cytokine response which inhibited intracellular forms of Leishmania aethiopica in a permissive monocytic cell line (THP1). Interferon-gamma (IFN-gamma), was one of the cytokines responsible for this anti-leishmanial effect. IFN-gamma was necessary for inhibition but could not act on its own inhibiting L. aethiopica. Tumor necrosis factor-alpha seemed not to be involved in the anti-L. aethiopica effect. The observed effects were in the absence of endotoxin. The results suggest that the mechanisms of killing of L. aethiopica in human cells may differ from those responsible for inhibition of other Leishmania parasites (such as Leishmania major) in mouse macrophages. Furthermore, that potentially relevant responses to Leishmania antigens may exist in normal individuals.  相似文献   
56.
OBJECTIVE: The purpose of this study was to examine neurophysiological characteristics of dystonia patients using electromyographic soleus H-reflex methods. METHODS: Thirty normal healthy individuals were compared to 27 patients with focal (cervical) or generalized dystonia. Three H-reflex assessment methods were included: the ratio of maximum H-reflex to direct muscle potential (H/M ratio); vibration inhibition (H(v)/H(c) ratio); and H-reflex recovery curves (HRRC). RESULTS: Average H/M ratios between groups were not statistically significant. The average H(v)/H(c) ratio for the generalized dystonia group was significantly greater than the focal dystonia and normal groups. Average values of the HRRC showed the generalized dystonia group had significantly greater disinhibition than the focal dystonia and control groups during the early inhibition phase. The HRRC for the focal dystonia group was greater than normal and more similar to the generalized dystonia group during the late phases of the recovery curve. The average value of the localized late facilitation phase for the focal dystonia group was significantly greater than the control group and less than the generalized dystonia group. No differences were observed between groups for the average localized late inhibition phase of the recovery curve. CONCLUSIONS: Soleus H-reflex measures identified neurophysiologic differences between generalized dystonia, cervical dystonia and normal conditions. SIGNIFICANCE: This methodology enables analysis of the underlying characteristics of dystonic pathologies using soleus H-reflex methods rather than upper extremity H-reflex techniques.  相似文献   
57.
58.
PURPOSE: To determine if there is an association between the timing of surgical intervention for congenital cataract within the first 12 weeks of life and the prevalence of postoperative complications. METHODS: We performed a retrospective review of records from 1990 to 2000 of infants who underwent surgery for congenital cataract within the first 12 weeks of life. Eighty eyes in 55 children were involved with a minimum follow up of 6 months. Bilateral cataracts were present in 25 and monocular cataracts in 30 infants. A limbal approach lensectomy-vitrectomy was performed in all infants. Children with aphakia were rehabilitated with contact lens or glasses. Operative and postoperative complications-including glaucoma, nystagmus, strabismus, retinal detachment, and posterior capsule opacification/secondary membranes-were recorded. Ocular and systemic associations were noted. Statistical analysis was carried out with classification and regression trees (CART). RESULTS: The mean age at the time of surgery was 31.5 +/- 23.3 days (median, 26.5; range, 2 to 84). Mean follow up from the time of surgery was 2.85 +/-1.9 years (median, 2; range, 0.5 to 8). Persistent fetal vasculature (persistent hyperplastic primary vitreous) was present in 14 eyes. One infant with bilateral persistent fetal vasculature had bilateral retinal dysplasia and was excluded from the analysis. Glaucoma developed in 12 infants (22%); nystagmus was present in 18 infants (33%); strabismus developed in 28 infants (52%); and secondary membranes developed in 7 eyes (13%). CART analysis suggests that glaucoma is more prevalent in infants when the surgery was performed between 13.5 and 43 days of life (CART = 0.370); nystagmus when surgery is performed between 48 and 84 days of life (CART = 0.500); strabismus when surgery is performed between 55.5 and 84 days of life (CART = 0.600); and secondary membranes when surgery is performed between 26.5 and 40 days of life (CART = 0.4). CONCLUSIONS: Our data suggest that the first 2 weeks of life comprise the most favorable time for decreasing postoperative complications resulting from surgical intervention for infants presenting with cataracts within the first 12 weeks of life.  相似文献   
59.
Sir, The expansion of haemodialysis includes older patients withcomorbidities, poor quality vessels, unsuitable for transplantationor peritoneal dialysis. Vascular access complications accountfor 20% of hospital admissions [1]. With exhausted sites inupper extremities, unusual sites for arteriovenous grafts formationare used [2]. The  相似文献   
60.
Six cases of bile duct carcinoma were encountered among 1207 patients with ulcerative colitis, a prevalence rate of 0.5%. The relative risk of bile duct carcinoma in patients with ulcerative colitis was 31.3. Colitis was extensive in all six patients with a mean duration of 23.2 years before the diagnosis of carcinoma. The mean age at the diagnosis of carcinoma was 38.5 years. Three patients had undergone colectomy 5–16 years earlier, and in four patients pericholangitis and sclerosing cholangitis preexisted. The tumors, histologically adenocarcinomas, were located in the common bile duct in five patients and in the hepatic duct in one. The mean survival was 11.8 months (one patients is still alive with recurrent carcinoma). Pericholangitis and sclerosing cholangitis is a frequent preexisting lesion in patients with bile duct carcinoma complicating ulcerative colitis and may be considered a premalignant lesion in these patients. Both sclerosing cholangitis and bile duct carcinoma are rare in Crohn's disease.  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