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   3034906篇
  免费   253649篇
  国内免费   13402篇
耳鼻咽喉   41442篇
儿科学   95551篇
妇产科学   76040篇
基础医学   495769篇
口腔科学   81296篇
临床医学   273081篇
内科学   523425篇
皮肤病学   85032篇
神经病学   258514篇
特种医学   118458篇
外国民族医学   100篇
外科学   473651篇
综合类   94159篇
现状与发展   23篇
一般理论   2113篇
预防医学   256172篇
眼科学   69436篇
药学   205726篇
  23篇
中国医学   9732篇
肿瘤学   142214篇
  2022年   23009篇
  2021年   54769篇
  2020年   34988篇
  2019年   57877篇
  2018年   70316篇
  2017年   53540篇
  2016年   58897篇
  2015年   73460篇
  2014年   107513篇
  2013年   172464篇
  2012年   80389篇
  2011年   78681篇
  2010年   113696篇
  2009年   118698篇
  2008年   65950篇
  2007年   67551篇
  2006年   78861篇
  2005年   74094篇
  2004年   76420篇
  2003年   67439篇
  2002年   57549篇
  2001年   85189篇
  2000年   77127篇
  1999年   80584篇
  1998年   63062篇
  1997年   61294篇
  1996年   59001篇
  1995年   54531篇
  1994年   48709篇
  1993年   45486篇
  1992年   54370篇
  1991年   52190篇
  1990年   49276篇
  1989年   49447篇
  1988年   45708篇
  1987年   44469篇
  1986年   42275篇
  1985年   42813篇
  1984年   41088篇
  1983年   38189篇
  1982年   38929篇
  1981年   36982篇
  1980年   34966篇
  1979年   32865篇
  1978年   30799篇
  1977年   28627篇
  1976年   26287篇
  1975年   24902篇
  1974年   24654篇
  1973年   23526篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Snoring means obstructive breathing during sleep, and its most exaggerated form is obstructive sleep apnea. Mild snoring may respond to simple self-help remedies. Heavy snoring responds well to the surgical removal or reconstruction of obstructive elements in the hypopharynx, nasopharynx or nasal passages.  相似文献   
992.
The exact location of hemorrhage complicating anticoagulant therapy is sometimes difficult to establish. We present a case in which imaging with 99mTc-labeled red cells had a significant role in the diagnosis of soft-tissue bleeding in a paraplegic patient receiving long-term anticoagulation.  相似文献   
993.
Anorectal function in the solitary rectal ulcer syndrome   总被引:8,自引:6,他引:2  
The anorectal function of nine patients with solitary rectal ulcer syndrome (SRUS) (5 F: 4 M, median age, 27 (range, 19–41 years) and nine control subjects (5 F: 4 M, median age, 47 (35–66)P<0.01) has been investigated by a new technique that radiologically visualizes the anorectum during voiding of a semisolid contrast medium, while simultaneously measuring intrarectal pressure and anal sphincter EMG activity. A degree of rectal prolapse was demonstrated in eight of the SRUS patients; six of these lesions were clinically occult. Abnormal failure of the anal sphincter to relax on voiding was present in seven of the SRUS patients. These abnormalities resulted in the SRUS patients requiring a greater increase in intrarectal pressure (median, 100 cm water) to void than the control subjects (median, 65 cm water,P<0.01). This combination of high intrarectal pressure and rectal prolapse during straining seems to be the cause of SRUS This work was supported by a grant from the Medical Research Council.  相似文献   
994.
BACKGROUND: The role of atopy in the evolution to chronic obstructive disease remains controversial. AIM: We aimed to assess the association between individual sensitization to common allergens and lung function. METHOD: We analysed data from 12,687 subjects aged 20 to 44 years, from 34 centres in 15 countries participating in the European Community Respiratory Health Survey (ECRHS). Participants performed a blood test, lung function test, methacholine challenge, and answered an administered questionnaire. The relationships between specific IgE, FEV1 and FEV1/FVC ratio were assessed for each study centre stratified by sex, followed by random effects meta-analysis. RESULTS: Asthmatics sensitized to house dust mite had a lower FEV1 (-119 mL in women and -112 mL in men) and FEV1/FVC ratio (-1.95%, and -2.48%) than asthmatics without sensitization. Asthmatics sensitized to cat had a lower FEV1 (statistically significant for women only) and a lower FEV1/FVC ratio. Asthmatic women sensitized to grass had a lower FEV1 and a lower ratio, and those sensitized to Cladosporium had a lower FEV1. A weak association was found with sensitization to cat and to Cladosporium among non-asthmatic women, which disappeared after adjusting for BHR. CONCLUSION: We conclude that atopy was related to a lower lung function, which was only apparent among asthmatics. This relationship was explained by specific sensitization to cat and to house dust mite, the latter being homogeneous across areas.  相似文献   
995.
白血病病人骨髓抑制期实施防感染措施时机的研究   总被引:5,自引:0,他引:5  
目的 :研究白血病病人在化疗期间 ,不同时间实施预防感染护理的效果。方法 :对照组在化学疗法结束后给予预防感染的护理措施 ,实验组在化学疗法开始前 3~ 7d实施预防性护理措施。观察两组病人感染发生率。结果 :感染发生率实验组明显低于观察组。结论 :在化学疗法开始前实施预防性护理措施有助于降低感染发生率  相似文献   
996.
To compare pulmonary effects, postoperative pain and fatigue, morbidity, patient satisfaction, and cost of different anesthetic techniques for inguinal hernia repair, 50 patients were randomized to local and general anesthesia groups (LA and GA). All patients received the same premedications and the same postoperative analgesic regimen. The standardized postoperative analgesic, intramuscular pyroxicam 20 mg, was given to all patients in the recovery room and an additional 20 mg on the same day was given as requested by each patient. Pulmonary function studies and arterial blood gas analysis were performed 1 h prior to the operation and at the postoperative 8th and 24th hours. All patients underwent Lichtenstein's tension-free hernioplasty. Postoperative pain and fatigue were registered 8 h and 24 h after the operation. A questionnaire was filled out by the patients, and they were asked to give grades for the general comfort of the anesthesia and the surgical procedure (1=worst, 10=best). Postoperative pulmonary function tests were significantly poorer in the GA group both on 8th- and 24th-hour measurements (P<0.05). Patients who underwent LA had significantly lower PCO2 and higher PO2 at the postoperative 8th hour (P<0.05). Mean postoperative pain and fatigue scores revealed a significant difference in favor of local anesthesia at only the 8th hour (P<0.05). There were two complications, one in each group (a hematoma in LA and a urinary retention in GA). Patient satisfaction grades were not different in the two groups. We conclude that LA in inguinal hernia repair does not adversely affect pulmonary functions, patients feel less pain, and patient satisfaction is comparable to that with GA. Electronic Publication  相似文献   
997.
998.
999.
1000.
PURPOSE: Gas embolism is a rare but well documented entity during operative hysteroscopy, with an incidence of 10-50%. Catastrophic outcomes occur at a rate of three in 17,000 procedures. The purpose of this report is to present a non-fatal case of gas embolism probably caused by the gaseous products of combustion. CLINICAL FEATURES: A 50-yr-old woman with a history of menorrhagia was scheduled for hysteroscopy and endometrial ablation and polypectomy. Fifteen minutes into the procedure, with the patient in lithotomy position, 20 degree head down tilt, and breathing spontaneously, a sudden oxygen desaturation occurred from 97% to 87%. The patient's end-tidal carbon dioxide dropped from 46 mmHg to 27 mmHg. The patient's breathing pattern remained normal, respiratory rate remained 11-12 breaths x min(-1) but amplitude of the reservoir bag movement was increased. Cardiovascular variables remained stable. She responded rapidly to 100% oxygen and made an uneventful recovery. Having ruled out other possible causes, we concluded gas embolism was responsible for the fall in oxygen saturation and end-tidal CO(2). CONCLUSION: With all the precautions in place to minimize the likelihood of fluid overload and ambient air embolism occurring, we surmised that products of combustion were the cause of the gas embolism. During endometrial ablation, gaseous products of combustion, mainly carbon dioxide, accumulate. The gases may then contribute to the rise in uterine pressure that occurs as irrigation fluid enters the uterus and this rise in pressure in turn encourages passage of gas into the open venous sinuses.  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