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   2358034篇
  免费   181275篇
  国内免费   3776篇
耳鼻咽喉   32389篇
儿科学   72667篇
妇产科学   64753篇
基础医学   334457篇
口腔科学   70774篇
临床医学   208319篇
内科学   458641篇
皮肤病学   49795篇
神经病学   188211篇
特种医学   93882篇
外国民族医学   541篇
外科学   366759篇
综合类   54334篇
现状与发展   3篇
一般理论   804篇
预防医学   175711篇
眼科学   54405篇
药学   180045篇
  7篇
中国医学   4738篇
肿瘤学   131850篇
  2018年   22465篇
  2016年   19479篇
  2015年   22478篇
  2014年   31035篇
  2013年   46698篇
  2012年   63708篇
  2011年   66879篇
  2010年   39476篇
  2009年   37636篇
  2008年   64296篇
  2007年   67870篇
  2006年   69031篇
  2005年   67001篇
  2004年   65547篇
  2003年   62823篇
  2002年   61433篇
  2001年   116311篇
  2000年   120513篇
  1999年   101829篇
  1998年   26520篇
  1997年   23895篇
  1996年   23892篇
  1995年   23004篇
  1994年   21453篇
  1993年   20080篇
  1992年   82109篇
  1991年   79355篇
  1990年   77338篇
  1989年   75024篇
  1988年   69239篇
  1987年   68033篇
  1986年   64348篇
  1985年   62220篇
  1984年   45713篇
  1983年   39217篇
  1982年   22241篇
  1981年   19747篇
  1980年   18376篇
  1979年   42701篇
  1978年   29291篇
  1977年   24917篇
  1976年   22882篇
  1975年   24554篇
  1974年   29874篇
  1973年   28631篇
  1972年   26591篇
  1971年   25040篇
  1970年   23367篇
  1969年   21957篇
  1968年   20014篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
921.
Intracranial pathology is a common and important complication in extremely low birth weight babies. Lenticulostriate vasculopathy (LSV) is an abnormal finding on cranial ultrasounds of sick babies and has been associated with congenital infection, chromosomal aberration and twin-to-twin transfusion. We describe a previously unreported situation of LSV being detected in both donor and recipient twin. This pair of monochorionic, diamniotic twins was admitted to the Neonatal Intensive Care Unit at 28 weeks of gestation. The mother underwent an emergency caesarean section because ultrasound and Doppler studies showed stage III twin-to-twin transfusion syndrome. The first twin weighed 998 g and second twin weighed 600 g. The first twin had an uneventful stay, whereas the second twin needed prolonged continuous positive airway pressure and indomethacin for patent ductus arteriosus. Both of them developed LSV. The clinical significance of this condition on the neuro-developmental outcome of a neonate has not yet been fully determined.  相似文献   
922.
BACKGROUND: In allergic conditions, the degree of skin test reactivity does not always correlate with the severity of clinical symptoms. Additional factors may contribute to the reported symptom severity. OBJECTIVES: To investigate the association between the magnitude of the skin prick test (SPT) response and the reported symptom severity in patients with allergic rhinitis and the possible modifying role of psychological factors. METHODS: One hundred four patients with allergic rhinitis and 23 with non-allergic rhinitis, classified according to their SPT response to 19 aeroallergens, were asked to rate the severity of five symptoms and to indicate whether their symptoms intensified on exposure to five common aeroallergens. They also completed a psychological questionnaire. Results Reported symptom severity of allergic rhinitis did not correlate with weal size for any of the aeroallergens tested or with the number of positive responses on SPT. It was not related to patient age, sex, or education. The reported symptoms severity correlated positively (0.29, P < 0.01) with reported symptom intensification on exposure to allergens. Moreover, both outcomes were positively associated with the psychological factors of hypochondriasis (0.20, P < 0.05 and 0.18, P < 0.05, respectively), and somatic awareness (0.24, P < 0.05 and 0.33, P < 0.01, respectively), but not with neuroticism. CONCLUSIONS: The severity of symptoms experienced by patients with allergic rhinitis is apparently not related to the magnitude of SPT response, but rather to psychological factors of hypochondriasis and somatic awareness. Physicians should be aware of the contribution of psychological factors to patient perceptions of the intensity of symptoms and of the intensification of symptoms on their exposure to allergens.  相似文献   
923.
924.
925.
926.
BACKGROUND CONTEXT: Osteoporosis is a major cause of morbidity in worldwide elderly populations. Patients may become susceptible to vertebral compression fractures (VCFs) from low-impact situations. For patients who have failed conventional, palliative medical therapy, kyphoplasty not only reduces pain associated with vertebral fractures, but also offers a minimally invasive procedure with the potential to address fracture reduction and spinal sagittal alignment. Kyphoplasty involves expanding an inflatable balloon tamp to create a cavity within a vertebral body before cement deposition. PURPOSE: To evaluate the safety and efficacy of kyphoplasty to reduce and fix painful osteoporotic VCFs. STUDY DESIGN/SETTING: A retrospective, single-arm cohort study of consecutive kyphoplasty patients treated at a single center. PATIENT SAMPLE: Three hundred sixty VCFs were treated during 254 kyphoplasty procedures on 222 osteoporotic patients (mean age, 76 years [range, 28-98]; 28% male and 72% female). OUTCOME MEASURES: Patient-reported pain ratings were examined. Cement extravasation was monitored by intraoperative fluoroscopy and on postoperative radiographs. Anterior and midline vertebral height were assessed from standing, lateral radiographs obtained preoperatively and postoperatively. The number of patients who returned with symptomatic, new fractures was monitored. Perioperative complications were recorded. Mean follow-up occurred 21 months after kyphoplasty (range, 6 months through 36 months). RESULTS: Immediate pain relief was reported by 89% of patients by the first follow-up visit. One patient experienced postoperative pain as a result of radiculopathy related to bone filler leakage into the foramen. The remaining patients had persistent pain and were diagnosed with either a new fracture or underlying degenerative disc disease. Greater than or equal to 20% restoration of lost vertebral height (anterior) was observed in 63% of fractures with an overall mean restoration of 30%, and > or = 20% restoration of lost vertebral height (midline) was detected in 69% of fractures with an overall mean restoration of 50%. In this cohort, 12% (30/254) of the patients required additional kyphoplasty procedures to treat 36 symptomatic, new adjacent and remote fractures. No device-related complications occurred. CONCLUSIONS: Kyphoplasty is a safe and effective, minimally invasive procedure for relief of pain associated with VCF. In our series we also demonstrated some restoration of vertebral height and partial correction of sagittal alignment.  相似文献   
927.
928.
The use of N-acetylcysteine has increased in the prevention of radiographic contrast induced nephrotoxicity. Many nurses need to be aware of the proper administration and action of this prophylactic agent. This article discusses the research behind the use of N-acetylcysteine and the protocol for administration to prevent radiographic contrast-induced nephrotoxicity.  相似文献   
929.
930.
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