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   48590篇
  免费   2421篇
  国内免费   1170篇
耳鼻咽喉   264篇
儿科学   1477篇
妇产科学   246篇
基础医学   2454篇
口腔科学   92篇
临床医学   7266篇
内科学   9253篇
皮肤病学   253篇
神经病学   2208篇
特种医学   1483篇
外科学   4984篇
综合类   9718篇
预防医学   2939篇
眼科学   234篇
药学   5548篇
  48篇
中国医学   2233篇
肿瘤学   1481篇
  2024年   70篇
  2023年   617篇
  2022年   1499篇
  2021年   1981篇
  2020年   1751篇
  2019年   1398篇
  2018年   1438篇
  2017年   1565篇
  2016年   1814篇
  2015年   1724篇
  2014年   4200篇
  2013年   3870篇
  2012年   3527篇
  2011年   3615篇
  2010年   2807篇
  2009年   2455篇
  2008年   2356篇
  2007年   2376篇
  2006年   2119篇
  2005年   1729篇
  2004年   1396篇
  2003年   1126篇
  2002年   832篇
  2001年   804篇
  2000年   662篇
  1999年   585篇
  1998年   472篇
  1997年   443篇
  1996年   376篇
  1995年   324篇
  1994年   305篇
  1993年   210篇
  1992年   194篇
  1991年   185篇
  1990年   178篇
  1989年   144篇
  1988年   135篇
  1987年   102篇
  1986年   90篇
  1985年   121篇
  1984年   105篇
  1983年   50篇
  1982年   79篇
  1981年   72篇
  1980年   64篇
  1979年   51篇
  1978年   41篇
  1977年   34篇
  1976年   22篇
  1975年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Otitis media is a common pediatric problem. It is well established that over half of infants and children with acute otitis media may have spontaneous recovery. Since it is difficult to predict the course (self-limited versus serious disease) all the children with acute suppurative otitis media need to be treated with antibiotics. Amoxicillin is still the initial antibiotic of choice. There are several alternate antibiotics available with activity against beta-lactamase positive bacteria. These agents have no advantage over amoxicillin in infections due to penicillin resistant pneumococci. Recent use of beta-lactam antibiotics and/or attendance in a day care where there is frequent use of antibiotics are predisposing factors for penicillin resistant pneumococcal infection. In such cases after tympanocentesis, higher dose of amoxicillin, clindamycin or intramuscular ceftriaxone should be considered. Secretory otitis media does not need to be treated with antibiotics unless the patient is in high risk group. Prophylactic use of antibiotics should be actively discouraged. Influenza and pneumococcal vaccination (2 years or older) should be encouraged in children with recurrent episodes of acute otitis media. Breast feeding should be encouraged.  相似文献   
72.
It has been proposed that -blocker therapy reverses metabolic and cardiovascular disorders in acute theophylline poisoning. We present a case of acute theophylline overdose treated with esmolol under haemodynamic control. Haemodynamic monitoring was useful in determining the appropriate duration of administration of esmolol and in deciding on treatment with fluids.  相似文献   
73.
Growth impairment and growth hormone (GH) deficiency have been reported in children treated for acute lymphoblastic leukaemia (ALL). We have studied growth and GH secretion in a group of 50 patients, affected by ALL, during a 2- to 5-year period after diagnosis, and in 12 long-term-survivors. We observed a significant decrease in growth velocity during the 1st year (in particular during the first 6 months) of therapy and a catch-up growth after the end of therapy. Longterm survivors did not exhibit a significant reduction of height standard deviation score (SDS), as compared to height SDS at diagnosis. None of the patients showed GH deficiency. Our data indicate that chemotherapy significantly affects growth of patients treated for ALL, whereas radiotherapy-at the doses used in this study-does not induce GH deficiency, at least not within 9 years after diagnosis.  相似文献   
74.
Total radiation dose often can be increased without subsequent increases in the severity of tissue injury by using reduced doses per fraction. The flexure dose, df, is defined as the largest fractional dose for which further fractionation produces no significant change in the total dose required to reach a specified effect level. Thus, df is clinically relevant in that it represents the limit of effective dose fractionation. For those tissues in which injury reflects depletion of a critical proportion of target cells, the flexure dose is a measure of the extent of the initial, nearly linear portion of the dose-survival curve. More generally, the flexure dose is a measure of the extent of the initial, nearly linear portion of a dose-response curve in organized tissue, whatever its relationship to clonogenic target cells might be. Several quantitative expressions for df are derived. The characteristic common to these is that each defines the flexure dose as a multiple of the ratio alpha/beta of the parameters of the linear-quadratic model of cell survival or dose response, where the multiple is a measure of experimental or statistical resolution. These multiples tend to fall within a limited range, thereby defining the "region of flexure" via the inequality 0.05 (alpha/beta) less than or equal to df less than or equal to 0.15 (alpha/beta). Estimates of the region of flexure are presented for a variety of normal and neoplastic tissues.  相似文献   
75.
Treatment of retinitis by cytomegalovirus (CMV) in AIDS patients requires frequent repetitive injections of intravitreal ganciclovir (GCV). This study was undertaken to establish experimentally whether the intravitreal application of liposomally-entrapped GCV could prolong intraocular therapeutic levels when compared with the intravitreal injection of free GCV, and the clinical effectiveness of this approach in AIDS patients. Intraocular concentration of GCV was determined by means of an ELISA test in rabbit vitreous 2, 3, 7, and 14 days after a single intravitreal injection of either different doses of the free drug (0.2–20 mg) or 1 mg of liposomally-entrapped GCV. After 72 h, only the vitreous of rabbits injected with doses of free GCV greater than or equal to 5 mg showed therapeutic levels of the drug; no GCV was detected after 72 h with any of the doses applied. Moreover, the microscopic study revealed GCV-induced damage in retinal structures in the animals injected with a free GCV dose greater than or equal to 15 mg. Intravitreal injection to rabbits of 1 mg of liposomally-encapsulated GCV showed no retinal toxicity at any of the time points studied, and therapeutic levels were detected up to 14 days after injection (4.67 ± 0.39 g/ml). Five AIDS patients suffering CMV retinitis were injected with 0.5 mg of liposomally-entrapped GCV (2 mg of lecithin). Complete remission of the CMV retinitis was observed already at the third injection of 0.5 mg GCV (one per week) and relapse did not occur during the 2–4 month follow-up of the patients. In view of the results presented, it can be concluded that intravitreal injection of liposomally-encapsulated GCV increases the time period required for reinjections in the treatemnt of CMV retinitis.Abbreviations AIDS acquired immunodeficiency syndrome - AZT zidovudine - CMV cytomegalovirus - GCV ganciclovir  相似文献   
76.
From January 1988 to September 1989, seven patients (4 girls and 3 boys, aged 3–12 years) with haemorrhagic fever with renal syndrome (HFRS) were hospitalised at the University Children's Hospital in Belgrade. In four patients the disease appeared as a family outbreak, the others were sporadic cases. In six patients the clinical presentation was suggestive of HFRS, as they had fever with headache, myalgia, sore throat and gastrointestinal illness followed by renal abnormalities. However, severe haemorrhagic syndrome with petechia, haematoma, haematemesis and melaena was present in one patient only. Renal disease presented as nephritic syndrome and/or acute renal failure. Five patients recovered after 2–3 weeks without sequellae, one patient had decreased renal function 17 months after the start of the disease and the remaining patient died. In six patients the diagnosis of HFRS was confirmed serologically by a significant rise in antibody titres against hantaviruses, while in the patient with the fatal and fulminant course of the disease, the diagnosis was established on the basis of epidemiological and autopsy findings. We suggest that children living in endemic areas who develop an ill-defined, febrile and gastrointestinal disease with renal dysfunction should be evaluated for HFRS.  相似文献   
77.
An open study was carried out in 17 acutely ill, newly admitted, floridly psychotic schizophrenic patients to a city hospital in New York. Penfluridol was given on a daily basis up to doses of 120 mg and patients were rated objectively by means of different psychometric evaluations; vital signs were monitored daily as were side effects.The drug was found to be a rapid acting, well-tolerated, and highly effective antipsychotic agent within the population of patients explored and within the dose range used. It was particularly effective in acutely agitated floridly paranoid schizophrenics; a statistically significant impact was achieved by 7 days and usually within 72 h after initiating treatment. The drug appears unique in that (1) its effects are realized without the untoward and usually trouble-some effects of nonspecific sedation attendant upon the use of many other neuroleptic medications, and (2) even within the relatively high doses used it produces no hypotensive effects. It is concluded that this appears to be a unique antipsychotic agent and a potentially important addition to the treatment armamentarium of both acute and chronic schizophrenic individuals.Dr. Klein was a research fellow who has since returned to the University of Munich, West Germany. Dr. Selzer was also a research fellow who is now in private practice  相似文献   
78.
Go T  Imai T 《Neuroradiology》2000,42(9):682-684
We report a case of acute disseminated encephalomyelitis (ADEM) with a residual cystic lesion on MRI. This seemed to be induced by Japanese encephalitis vaccination. Despite complete clinical improvement with high-dose steroid therapy, the cystic lesion has persisted for 3 years on MRI. There have been no previous reports of residual cystic lesions in ADEM. Received: 20 August 1999/Accepted: 11 November 1999  相似文献   
79.
从细胞凋亡及其相关基因蛋白表达方面探讨推拿、针剌治疗急性脑缺血的作用机理。用线栓法制成SD大鼠大脑中动脉阻塞再灌注模型,在阻塞2小时再灌注24小时后,应用TUNEL法和免疫组织化学法检测针刺、推拿治疗后大鼠脑组织细胞凋亡及Bel-2、Bax蛋白表达。结果:推拿、针刺均可减少缺血所致TUNEL阳性表达,提高梗死周边区皮层Bcl-2/Bax的比值。提示推拿、针刺对急性脑缺血的治疗作用可能与其可抑制细胞凋亡有关,从而保护脑神经细胞。  相似文献   
80.
Eleven patients with Yersinia enterocolitica infections were identified in the Upper Valley of New Hampshire and Vermont during October and November of 1995. Three children presented with an appendicitis-like picture. Two underwent appendectomy, one of whom was the outbreak's index case. Both appendectomy patients presented with lower abdominal pain, fever, vomiting, and a right lower quadrant mass associated with leukocytosis. Both had terminal ileitis, and in both, cultures of peritoneal fluid and a mesenteric lymph node grew Y. enterocolitica. Even during an outbreak there is no consistently reliable nonoperative way to separate a sporadic case of appendicitis from one whose appendicitis-like symptoms are due to Yersinia. In addition, a small percentage of Yersinia patients will present with true appendicitis as a complication of their disease. Accepted: 20 January 1997  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