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   114484篇
  免费   9767篇
  国内免费   4125篇
耳鼻咽喉   981篇
儿科学   3195篇
妇产科学   1512篇
基础医学   15655篇
口腔科学   2189篇
临床医学   9523篇
内科学   23557篇
皮肤病学   1804篇
神经病学   5677篇
特种医学   3114篇
外国民族医学   17篇
外科学   10648篇
综合类   14935篇
现状与发展   13篇
预防医学   8057篇
眼科学   1140篇
药学   14299篇
  44篇
中国医学   5111篇
肿瘤学   6905篇
  2024年   410篇
  2023年   2426篇
  2022年   4795篇
  2021年   5603篇
  2020年   4842篇
  2019年   4903篇
  2018年   5027篇
  2017年   4553篇
  2016年   4073篇
  2015年   4456篇
  2014年   7175篇
  2013年   7832篇
  2012年   6696篇
  2011年   7691篇
  2010年   6215篇
  2009年   6073篇
  2008年   5761篇
  2007年   5522篇
  2006年   4687篇
  2005年   4012篇
  2004年   3403篇
  2003年   2809篇
  2002年   2198篇
  2001年   1881篇
  2000年   1559篇
  1999年   1406篇
  1998年   1272篇
  1997年   1152篇
  1996年   1001篇
  1995年   1005篇
  1994年   891篇
  1993年   712篇
  1992年   624篇
  1991年   555篇
  1990年   494篇
  1989年   412篇
  1988年   328篇
  1987年   325篇
  1986年   315篇
  1985年   476篇
  1984年   534篇
  1983年   328篇
  1982年   391篇
  1981年   317篇
  1980年   270篇
  1979年   195篇
  1978年   166篇
  1977年   150篇
  1976年   167篇
  1975年   104篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Microinjections of Leu-enkephalin into the dorsal vagal complex induced hypotension and bradycardia. Both naloxone, given at a dose conferring selectivity for μ receptors, and the S antagonist ICI 154,129 prevented the cardiovascular effects of Leu-enkephalin. Naloxone was also found to decrease the gain of the baroreflex. These results suggest that Leu-enkephalin is involved in cardiovascular regulation through activation of δ-, and possibly μ-, opioid receptors in the dorsal vagal complex.  相似文献   
92.
Abstract. Objectives. To define risk factors associated with bacteraemia caused by Staphylococcus aureus or coagulase-negative staphylococci; and to use them to define patients in need of empiric anti-staphylococcal antibiotic treatment. Design, Derivation set: observational, prospective study; validation set: retrospective analysis of a prospectively collected database. Setting. Derivation set: Beilinson Medical Centre, Petah Tiqva, Israel—a 900-bed university hospital. Validation set: St Thomas's Hospital, London, UK—an 800-bed teaching hospital. Subjects. All episodes of bacteraemia detected at Beilinson Medical Centre between March 1988 and September 1990 (derivation set, n = 1410), and at St Thomas's Hospital during 1987–1990 (validation set, n = 1040). Interventions. None. Main outcome measures. Percentage of staphylococcal bacteraemia in groups of patients defined by the models. Results. The following factors were associated with Staphylococcus aureus bacteraemia: focus of infection (whether high or low risk), haemodialysis, intravenous drug abuse and infection acquired in the orthopaedic ward. A logistic model was used to divide the derivation set into three groups with percentages of Staphylococcus aureus bacteraemia of 1.8%, 13.2% and 33.7% (P < 0.0001); and the validation group 2.5%, 18.2% and 53.2% (P < 0.0001). Factors associated with coagulase-negative staphylococcal bacteraemia were: central or peripheral intravenous catheter as the focus of infection, a preterm neonate, the presence of a central intravenous catheter, low temperature, and a low white blood cell count. A second model including those factors was used to divide the derivation set into three groups with percentages of coagulase-negative staphylococcal bacteraemia of 1.9%, 22.8%, and 43% (P < 0.0001). In the validation set, the percentages were 2.9%, 22.4% and 31.0% (P < 0.001). Conclusions. The present study defines groups at high risk for staphylococcal bloodstream infection, in which empiric treatment should include an anti-staphylococcal drug.  相似文献   
93.
评价了PPV系列衍生物的电学性质、非线性光学性质及其应用。  相似文献   
94.
Zusammenfassung Das HELLP-Syndrom (Hemolysis, Elevated Liver enzymes, Low Platelets) tritt als Komplikation einer Schwangerschaftspräeklampsie auf und kann zu ausgedehnten subkapsulären Leberhämatomen führen. Wegen der Rupturgefahr der Hämatome besteht eine lebensbedrohende Notfallsituation für Mutter und Ungeborenes. Anhand von 2 Fallbeispielen wird das interdisziplinäre Vorgehen diskutiert. Mit Diagnosestellung der subkapsulären Leberhämatome sollte die notfallmäßige Entbindung durch Sectio erfolgen. Dann kann die chirurgische Entscheidung für eine konservative, abwartende Therapie mit Intensivüberwachung oder für eine Notfalloperation im Falle einer Leberkapselruptur ohne vermeidbares Risiko getroffen werden.
Subcapsular liver hematoma with HELLP-syndrome — an interdisciplinary urgency
Summary The HELLP-syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets), known as a complication during pregnancy, is associated with preeclampsia and may cause subcapsular liver hematomas. In case of hepatic rupture the lives of mother and unborn are threatened. Therefore, an interdisciplinary diagnostic and therapeutic approach is discussed and compared to two examples. The diagnosis of subcapsular liver hematoma must lead to urgent delivery through Cesarean section. Thereafter, the surgeon may decide between observation on an intensive care unit and urgent operation in case of hepatic rupture, without endangering the unborn.
  相似文献   
95.
Prediction of outcome from intensive care after gastroenterologic emergency   总被引:1,自引:0,他引:1  
Prognostic factors determining the outcome from intensive care were studied in 952 patients admitted to 25 Finnish ICUs after gastroenterologic emergency. Logistic regression analysis was used to create predictive models based on the APACHE II–system. The models were constructed by using data from a random two–thirds of the study population and validated in the remaining independent one–third together with the original APACHE II–index. The Acute Physiology Score, age, and a pre–existing liver disease were the three most important determinants of outcome. The inclusion of the TISS score describing the intensity of treatment into a model did not enhance the accuracy of the prediction. Our models were better calibrated than the original APACHE II–equation when tested by the goodness–of–fit –statistics. These statistical models may help the clinicians to predict the outcome for an individual patient by providing them information about the relative impacts of predictive factors or about the probability of death. These probabilities should be interpreted cautiously, taking into acount the limitations of statistical methods. This is especially important when assessing the highrisk patients. Their number in our study was too low for accurate outcome prediction.  相似文献   
96.
Fourteen adult patients (mean age 22.5 years, range 18–35) with cystic fibrosis undertook nocturnal nasogastric feeding for a mean period of 14.7 (range 6–18) months consuming an average of 1042 ml of a high energy feed on five nights of each week. Following this protocol all patients gained weight (mean weight gain 5.4 kg, range 2–17). For the group as a whole, lung function remained stable during the period of feeding; however a significant correlation between improvement in lung function and weight gain was demonstrated. Hyperglycaemia during feeding in this adult population was common (9/14, 64%) but was easily controlled with insulin therapy.  相似文献   
97.
目的 :探讨各种肝病患者血清肝纤维化标志的改变 ,甘草酸二胺注射液对肝脏炎症、纤维化指标的作用。方法 :用放免法检测透明质酸 (HA)、层粘蛋白 (LN)、Ⅲ型前胶原多肽 (PCⅢ )。结果 :急性肝炎的三种肝纤指标均升高 (P <0 0 5 )。急黄肝高于急无黄肝 (P <0 0 5 )。慢性肝炎 1 1 2例 ,三项肝纤指标显著高于正常对照 (P <0 0 5 )。慢肝重度显著高于慢肝轻度 (P<0 0 0 1 )。肝硬化的三项肝纤指标又显著高于慢肝 (P <0 0 0 1 ) ,其它肝病的肝纤指标也升高。 2 5例慢肝用甘草酸二胺注射液治疗 2月 ,ALT、AST、GGT显著降低 (P <0 0 1 )。三项肝纤指标中HA降低较显著 (P =0 0 5 ) ,LN和PCⅢ虽有降低 ,但差异不明显 (P =0 4 5 9,P =0 1 92 )。结论 :各种肝病的三项肝纤维化指标均升高 ,以慢肝重度 ,肝硬化升高明显。甘草酸二胺注射液治疗有抗炎及改善肝纤维化的作用  相似文献   
98.
Leukotriene B4 (LTB4) and the protein kinase C activator, 4-beta-phorbol dibutyrate (PDBu), both induced a pronounced and concentration-dependent stimulation of hydrogen peroxide (H2O2) generation by purified guinea pig peritoneal eosinophils in the concentration range 1 nM-1 microM. The LTB4 response was inhibited competitively by the specific LTB4 receptor antagonist, U-75302, with a KB of 25 nM, while the concentration-response curves for both stimuli were shifted rightwards (3.8-fold and 2.8-fold for LTB4 and PDBu, respectively) by the competitive protein kinase C inhibitor, 1-O-hexadecyl-2-O-methylglycerol at a concentration of 300 microM. LTB4 appears, therefore, to induce respiratory burst in eosinophils via a receptor-mediated mechanism involving protein kinase C.  相似文献   
99.
N┐(4┐乙氧苯基)苯甲酰胺类化合物的合成及抗炎、抗变态反应活性研究周玉新1)党永红刘建飞2)徐颖刘百里(沈阳药科大学制药系,沈阳110015)郑文义(东北第六制药厂,沈阳110043)1981年,刘百里等〔1,2〕发现和研制的新药益肤酰胺,经药理实...  相似文献   
100.
脑电双频指数用于门诊无痛内镜检查的临床研究   总被引:6,自引:0,他引:6  
目的 观察脑电双频指数 (BIS)监测对门诊无痛内镜检查病人麻醉过程及恢复的意义。方法  12 0例择期在丙泊酚 芬太尼静脉麻醉下行胃镜检查的门诊病人 ,随机分为BIS监测组 (A组 )与常规监测组 (B组 ) ,每组 6 0例。静脉给予芬太尼 1μg/kg、丙泊酚 0 5mg/kg负荷量后 ,丙泊酚的维持量A组根据BIS值 (4 5~ 6 0 )调节 ,B组仅根据临床体征调节。记录丙泊酚用量、术中反应、胃镜检查时间及留观时间等。结果 两组间一般资料及麻醉前MAP、HR、SpO2 、BIS均无显著性差异(P >0 0 5 )。丙泊酚用量A组明显少于B组 ,留观时间A组显著短于B组 (P <0 0 1)。MAP在麻醉诱导入睡后和插镜时两组均有下降 ,但A组降幅低于B组 (P <0 0 1)。不良反应发生率A组明显少于B组 (P <0 0 1)。结论 BIS监测用于门诊麻醉对预防麻醉药用量不足或逾量 ,减轻血液动力学改变 ,避免术中肢动与知晓有重要意义 ,有利于提高麻醉安全 ,减少并发症。  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