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   2652篇
  免费   171篇
  国内免费   78篇
耳鼻咽喉   13篇
儿科学   65篇
妇产科学   83篇
基础医学   265篇
口腔科学   134篇
临床医学   261篇
内科学   784篇
皮肤病学   108篇
神经病学   126篇
特种医学   298篇
外科学   271篇
综合类   38篇
预防医学   189篇
眼科学   38篇
药学   141篇
中国医学   3篇
肿瘤学   84篇
  2023年   19篇
  2022年   14篇
  2021年   27篇
  2020年   22篇
  2019年   48篇
  2018年   47篇
  2017年   43篇
  2016年   48篇
  2015年   56篇
  2014年   67篇
  2013年   106篇
  2012年   106篇
  2011年   110篇
  2010年   81篇
  2009年   101篇
  2008年   103篇
  2007年   122篇
  2006年   82篇
  2005年   79篇
  2004年   70篇
  2003年   78篇
  2002年   55篇
  2001年   75篇
  2000年   77篇
  1999年   63篇
  1998年   103篇
  1997年   87篇
  1996年   64篇
  1995年   58篇
  1994年   51篇
  1993年   58篇
  1992年   61篇
  1991年   49篇
  1990年   60篇
  1989年   74篇
  1988年   61篇
  1987年   54篇
  1986年   46篇
  1985年   45篇
  1984年   28篇
  1983年   30篇
  1982年   28篇
  1981年   23篇
  1980年   20篇
  1979年   27篇
  1978年   20篇
  1977年   29篇
  1976年   26篇
  1975年   24篇
  1971年   9篇
排序方式: 共有2901条查询结果,搜索用时 15 毫秒
1.
2.
We report the case of a patient with a 13-year history of pemphigus vulgaris (PV) treated with immunosuppressive agents, prednisone and mycophenolate mofetil who had developed lesions of Kaposi's sarcoma (KS) on a sole plaque of PV that had been previously treated with intralesional injections of steroids. The lesions were surgically removed and polymerase chain reaction (PCR) demonstrated human herpesvirus-8 (HHV-8) DNA. There were neither recurrences nor later dissemination of KS following gradual decrease of the immunosuppressive therapy. We suggest that the treatment with intralesional steroids may have influenced the local reactivation of a latent infection of the virus, determining the appearance of this localized KS.  相似文献   
3.
Summary Eight patients with malignant gliomas verified on CT scan, received an intravenous injection of 50 mg of Adriamycin R, 24 hours prior to surgical removal of the tumour. Peroperatively, both tumour and surrounding tissue specimens were obtained for determination of the tissue concentrations of Adriamycin and its reduced metabolite Adriamycinol. It was found that Adriamycin could be detected in tumour tissue from all patients. The concentration varied between 0,9 and 4,6 nmol/g tissue. In contrast, Adriamycin could only be detected in surrounding brain tissue from one patient.In anin vitro study a human malignant glioma cell line (U-251 MG) was exposed to various concentrations of Adriamycin for 24 hours. It was found that an intracellular drug concentration above 30 nmol/g cells caused a concentration dependent inhibition of cell growth. Thus, it is likely that the poor effect of Adriamycin on patients with malignant gliomas is due to an ineffective drug accumulation in the tumour tissue.  相似文献   
4.
There is evidence that the distal intestine participates in the regulation of gastric motor and secretory function. It was the aim of this study to examine in greater detail the effects of ileal nutrient exposure on human gastric acid secretion and to investigate potential intermediary mechanisms. Twelve normal subjects were intubated with an oroileal multilumen tube assembly for gastric, duodenal, and ileal perfusion of marker and test solutions, aspiration, and intestinal manometry. We studied ileal effects on gastric acid output in the unstimulated, interdigestive state (during early phase II,N=6), and during endogenous stimulation by intraduodenal essential amino acid perfusion,N=6) and on release of candidate humoral mediators, peptide YY (PYY) and glucagonlike peptide-1 (GLP-1), both known inhibitors of human gastric acid secretion. Compared with ileal saline perfusion, ileal carbohydrate (total caloric load: 60 kcal) decreased interdigestive gastric acid output by 64% (P<0.01), and endogenously stimulated output by 68%, respectively (P<0.005). Under all experimental conditions, ileal carbohydrate increased plasma GLP-1 by 80–100% (allP<0.005). Ileal lipid perfusion had similar inhibitory effects on gastric acid output and stimulatory effects on GLP-1 release as had ileal carbohydrate. By contrast, ileal perfusion with peptone had no or only weak effects on either acid output or plasma GLP-1. Plasma PYY concentrations and suppression of gastric secretion in response to ileal perfusions were not correlated. In humans, both interdigestive and endogenously stimulated gastric acid output are inhibited in response to intraileal carbohydrate or lipids, but not protein, Decreased acid output is associated with release of GLP-1, but not PYY. These findings support the hypothesis that the distal small intestine may participate in the late postprandial inhibitory regulation of gastric secretory function in humans and that GLP-1 may be an intermediary factor.  相似文献   
5.
Neopterin concentrations, reflecting T-cell macrophage activation, were analyzed in serum and cerebrospinal fluid (CSF) obtained from 14 patients with subarachnoid hemorrhage (SAH). Neopterin concentrations were elevated in both the serum and CSF. The increase in neopterin concentrations was most marked in the CSF, rising from Days 1 to 3 through Days 6 to 9; levels were highest in patient suffering from delayed cerebral ischemia. The present data were interpreted as signs of an ongoing T cell activation both systemically and in the CSF compartment following SAH.  相似文献   
6.
1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.  相似文献   
7.
8.
Hypothesis: Pathogenesis of postmenopausal hot flush   总被引:1,自引:0,他引:1  
The pathogenesis of postmenopausal hot flush is still poorly understood. A hypothesis is presented where the perimenopausal decline in circulating estrogen levels may increase central norepinephrine and LH-RH secretion and produce a downward setting of the central thermostat resulting in a hot flush.  相似文献   
9.
10.
SUMMARY A young patient presenting with splenomegaly and hypersplenism was inadvertently found to have selective IgA deficiency. There were no symptoms of immunodeficiency and the patient responded well to splenectomy, with return of blood counts to normal without adverse effects. No other cause for the hypersplenism was found. We postulate selective IgA deficiency as a cause of splenomegaly and hypersplenism.  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