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   159809篇
  免费   10402篇
  国内免费   779篇
耳鼻咽喉   1498篇
儿科学   4134篇
妇产科学   2970篇
基础医学   21570篇
口腔科学   3805篇
临床医学   15315篇
内科学   34161篇
皮肤病学   3101篇
神经病学   15469篇
特种医学   6426篇
外国民族医学   6篇
外科学   23996篇
综合类   1957篇
现状与发展   2篇
一般理论   149篇
预防医学   11411篇
眼科学   3233篇
药学   10860篇
  2篇
中国医学   253篇
肿瘤学   10672篇
  2023年   840篇
  2022年   1280篇
  2021年   2912篇
  2020年   2018篇
  2019年   2881篇
  2018年   3521篇
  2017年   2745篇
  2016年   3139篇
  2015年   3616篇
  2014年   5166篇
  2013年   6992篇
  2012年   10811篇
  2011年   11432篇
  2010年   6520篇
  2009年   6218篇
  2008年   10477篇
  2007年   11168篇
  2006年   10616篇
  2005年   10888篇
  2004年   10245篇
  2003年   9709篇
  2002年   9169篇
  2001年   1734篇
  2000年   1334篇
  1999年   1793篇
  1998年   2183篇
  1997年   1706篇
  1996年   1484篇
  1995年   1343篇
  1994年   1195篇
  1993年   1165篇
  1992年   889篇
  1991年   882篇
  1990年   712篇
  1989年   706篇
  1988年   653篇
  1987年   689篇
  1986年   608篇
  1985年   621篇
  1984年   712篇
  1983年   636篇
  1982年   809篇
  1981年   742篇
  1980年   636篇
  1979年   406篇
  1978年   432篇
  1977年   454篇
  1976年   403篇
  1975年   337篇
  1974年   292篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
OBJECTIVE: The study goal was to critically evaluate 3 popular noninvasive treatments for snoring: an oral spray lubricant applied before bedtime, a nasal strip designed to maintain nasal valve patency, and a head-positioning pillow. STUDY DESIGN: Prospective, randomized blinded clinical trial of 3 popular noninvasive snore aids using objective acoustic snoring analysis and subjective patient and bed-partner questionnaires in 40 snoring patients. A digital recorder allowed snoring analysis with data collected in the home environment over 1 week. RESULTS: There is neither objective nor subjective benefit to the use of tested popular noninvasive snore aids. Palatal snoring, palatal loudness, average loudness of snoring, averaged palatal flutter frequency, and respiratory disturbance index did not significantly change when comparing the 3 snoring aids with no treatment. Subjective comments and complications are reviewed as well. CONCLUSION: This is the first prospective comparison trial of popular noninvasive snoring aids. There is no significant objective or subjective snoring improvement in the anti-snoring aids studied compared with the use of no aid. SIGNIFICANCE: Outcome studies aid in verifying or refuting claims made by popular noninvasive snore aids.  相似文献   
92.
93.

Background  

The telomeric region of mouse chromosome 12 has previously shown frequent allelic loss in murine lymphoma. The Bcl11b gene has been identified and suggested as a candidate tumor suppressor gene within this region. In this study, we aimed to elucidate whether Bcl11b is mutated in lymphomas with allelic loss, and whether the mutations we detected conferred any effect on cell proliferation and apoptosis.  相似文献   
94.
Intramuscular adrenaline is the treatment of choice for food-related anaphylactic reactions. Although auto-injectable adrenaline devices are routinely prescribed for patients at risk of serious reactions, previous studies have shown that only one-third to one and a half of patients or their carers are able to properly use these devices. The aim of this study was to determine which factors are most strongly associated with the effective use of these devices. A 122 children with food allergies who had previously been prescribed EpiPens and were attending a single specialist pediatric allergy center in the UK. were studied prospectively. A 69% of parents were unable to use the EpiPen, did not have it available, or did not know when it should be administered. A prior practical demonstration was associated with a 4-5 fold greater chance that parents would be able to use the device (p < 0.005). Prior consultation with an allergy specialist rather than a general physician, and parents who independently sought additional information from the national self-help allergy organization were also four to six times more likely to be competent with these devices (p < 0.005). The study clearly shows that for EpiPens to be used safely and effectively it is essential to educate the carer at the time the device is prescribed.  相似文献   
95.
96.
97.
98.
Global coronary blood flow and metabolism were measured in seven patients on the first postoperative day following coronary revascularization to test the hypothesis that tracheal extubation produces adverse haemodynamic responses akin to those observed during tracheal intubation. Regional coronary flow and metabolic measurements were made in five of the seven patients. Extubation from a continuous positive airway pressure (CPAP) of 5 cm H2O was associated with a statistically significant rise in cardiac index from 3.44 ± 0.23 L · min-1 · m-2 to 3.73 ± 0.15L·min-1 ·m-2 related to an increase in stroke index, without significant changes in heart rate, mean arterial and pulmonary capillary wedge pressure. Consequently the changes in myocardial oxygen consumption (8.52 ± 0.55 to 8.85 ± 0.93 ml · min-1) and coronary blood flow (172 ± 18 to 179 ± 17 ml·min-1) were less prominent than those reported during intubation, where substantial rises in myocardial oxygen consumption and coronary flow occurred. Two patients experienced cardiac lactate production but there were no changes in systemic or coronary haemodynamics, nor were there clinical or electrocardiographic signs of ischaemia. We conclude that extubation does not appear to be associated with adverse systemic or coronary haemodynamic responses in patients following coronary bypass grafting. However, the revascularized myocardium may remain vulnerable to anaerobic metabolism in the immediate postoperative period. Pour savoir si comme ľintubation, ľextubation de la trachée provoque des perturbations hémodynamiques, on a mesuré le métabolisme et la circulation coronarienne globale chez sept patients, au lendemain ďun pontage aorto-coronarien. On a aussi calculé les valeurs régionales de ces mêmes variables pour cinq ďentre eux. Ľindex cardiaque de 3.44 ± 0.23 L · min-1 · m-2 sous pression positive en respiration spontanée (CPAP) de 5 cm. H2O s’est élevé à 3.73 ± 0.15 L · min-1 · m-2 post-extubation avec une augmentation significative du volume ďéjection. La fréquence cardiaque et les pressions artérielles moyennes et capillaires pulmonaires n’ont pas changé. Ainsi ľaugmentation de la consommation ďoxygène du myocarde de 8.52 ± 0.55 à 8.85 ± 0.93 ml · min-1 et celle du flot coronarien de 172 ± 18 à 179 ± 17 ml · min-1 ont été moindres que celles, importantes, déjà observées lors de ľintubation. On a noté chez deux patients une production de lactate par le myocarde, sans changement de ľhémodynamic systémique et coronarienne non plus que de signe clinique ou électrocardiographique ďischémie. Donc, après un pontage coronarien, ľextubation ne semble pas causer ďeffet néfaste sur les circulations systémique et coronarienne, toutefois, le myocarde revascularisé peut demeurer sensible au métabolisme anaérobique.  相似文献   
99.
100.
Colorectal cancer is one of the best studied of all malignant diseases interms of genetics and/or molecular prognostic factors. These factors, and relationships with prognosis, may have important implications especially in the design of surgical and adjuvant chemo-radiotherapy options. However, the true prognostic significance of all known factors has yet to be realised. We have reviewed the literature with specific focus on the role of molecular markers involved in prognosis and the prediction of response to adjuvant treatment.  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