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   1713篇
  免费   124篇
  国内免费   7篇
耳鼻咽喉   10篇
儿科学   92篇
妇产科学   61篇
基础医学   191篇
口腔科学   49篇
临床医学   229篇
内科学   289篇
皮肤病学   31篇
神经病学   66篇
特种医学   146篇
外科学   172篇
综合类   90篇
一般理论   4篇
预防医学   173篇
眼科学   24篇
药学   88篇
  1篇
中国医学   19篇
肿瘤学   109篇
  2022年   13篇
  2021年   38篇
  2020年   18篇
  2019年   32篇
  2018年   42篇
  2017年   27篇
  2016年   20篇
  2015年   52篇
  2014年   55篇
  2013年   58篇
  2012年   78篇
  2011年   89篇
  2010年   63篇
  2009年   54篇
  2008年   68篇
  2007年   77篇
  2006年   46篇
  2005年   44篇
  2004年   47篇
  2003年   53篇
  2002年   31篇
  2001年   30篇
  2000年   27篇
  1999年   22篇
  1998年   33篇
  1997年   29篇
  1996年   37篇
  1995年   30篇
  1994年   30篇
  1993年   23篇
  1992年   27篇
  1991年   39篇
  1990年   30篇
  1989年   39篇
  1988年   46篇
  1987年   33篇
  1986年   37篇
  1985年   29篇
  1984年   36篇
  1983年   31篇
  1982年   16篇
  1981年   15篇
  1980年   17篇
  1979年   23篇
  1978年   18篇
  1977年   15篇
  1976年   16篇
  1975年   14篇
  1974年   10篇
  1972年   15篇
排序方式: 共有1844条查询结果,搜索用时 0 毫秒
111.
beta-Propiolactone-treated (BPL-T) homologous serum albumin caused anaphylaxis in guinea pigs with a frequency and severity equal to that of guinea pigs inoculated with human albumin. Untreated guinea pig serum albumin did not cause any reactions in these animals. Some recipients of current rabies vaccine produced in human diploid cells available in the USA develop systemic allergic reactions, usually following booster immunization. The BPL-T human albumin component of the vaccines was believed to be the cause of the complications. Our studies support this conclusion.  相似文献   
112.
113.
Physical activity patterns and their relation with coronary heart disease risk factors are described for a representative sample of 863 Dutch men, 65-84 years old, who participated in the 1985 survey of the Zutphen cohort of the Seven Countries Study. Cross-sectional results revealed a median total of reported physical activity of about 1 hour and 20 minutes per day; only 5.8% reported no physical activity. The percentage of participation and total weekly time spent in physical activity decreased as age increased; the decrease was less pronounced for walking, bicycling, gardening, and doing odd jobs than for sports, hobbies, and work. Statistically significant mean differences were found among quartiles of total weekly physical activity for both total cholesterol and high-density lipoprotein cholesterol (HDL cholesterol); however, only the differences for HDL cholesterol remained significant (p = 0.045) after adjusting for potential confounders. Statistically significant regression coefficients (p less than 0.05) were found for the independent association between walking and total cholesterol and between gardening and total cholesterol, HDL cholesterol, and systolic blood pressure, after adjusting for confounders. Total weekly physical activity and specific activities, e.g., gardening and walking, demonstrated generally favorable associations with cholesterol and systolic blood pressure.  相似文献   
114.
PBL在病原生物与免疫学教学中的实践   总被引:2,自引:0,他引:2  
目的探讨病原生物与免疫学教学中开展PBL教学的效果。方法对照组采用传统的教学方法,实验组采用PBL教学方法,通过问卷调查、考试成绩综合分析教学改革效果。结果实验班绝大多数学生接受并欢迎PBL教学模式,并在自学能力、理解能力、分析解决问题能力等方面得到明显的提高。结论PBL教学方法优于传统的教学方法,能有效提高病原生物与免疫学教学质量。  相似文献   
115.
The contribution of gluconeogenesis to hepatic glucose production (GP) was quantified after 2H2O ingestion by Bayesian analysis of the position 2 and 5 2H‐NMR signals (H2 and H5) of monoacetone glucose (MAG) derived from urinary acetaminophen glucuronide. Six controls and 10 kidney transplant (KTx) patients with cyclosporine A (CsA) immunosuppressant therapy were studied. Seven KTx patients were lean and euglycemic (BMI = 24.3 ± 1.0 kg/m2; fasting glucose = 4.7 ± 0.1 mM) while three were obese and hyperglycemic (BMI = 30.5 ± 0.7 kg/m2; fasting glucose = 7.1 ± 0.5 mM). For the 16 spectra analyzed, the mean coefficient of variation for the gluconeogenesis contribution was 10% ± 5%. This uncertainty was associated with a mean signal‐to‐noise ratio (SNR) of 79:1 and 45:1 for the MAG H2 and H5 signals, respectively. For control subjects, gluconeogenesis contributed 54% ± 7% of GP as determined by the mean and standard deviation (SD) of individual Bayesian analyses. For the lean/normoglycemic KTx subjects, the gluconeogenic contribution to GP was 62% ± 7% (P = 0.06 vs. controls), while hyperglycemic/obese KTx patients had a gluconeogenic contribution of 68% ± 3% (P < 0.005 vs. controls). These data suggest that in KTx patients, an increased gluconeogenic contribution to GP is strongly associated with obesity and hyperglycemia. Magn Reson Med 60:517–523, 2008. © 2008 Wiley‐Liss, Inc.  相似文献   
116.
OBJECTIVE: To test the hypothesis that preoperative lumbar epidural morphine improves postoperative pain control and ventilatory function after transsternal thymectomy in patients with myasthenia gravis. DESIGN: The study design was randomized, placebo-controlled, and double-blind. SETTING: After surgery, all patients were admitted to the Neuroscience Critical Care Unit for evaluation and treatment. PATIENTS: All patients with myasthenia gravis who presented to the hospital for thymectomy were asked to participate in the study. Twenty patients were randomized to either the placebo or epidural morphine groups. INTERVENTIONS: Patients received either epidural morphine (7 mg in 14 mL of sterile saline) or saline (14 mL) before induction of anesthesia. Supplemental iv opioids were administered intraoperatively, with need determined by the anesthesiologist. MAIN OUTCOME MEASURES: The main outcome measures were indicators of postoperative pain (e.g., Visual Analog Pain Score, requirement for supplemental opioid administration, respiratory rate) and ventilatory function (e.g., forced vital capacity, negative inspiratory pressure). RESULTS: Immediately after surgery, the Visual Analog Pain Score in the placebo group was twice as high as the score in the epidural morphine group (placebo 7.0 +/- 1.3; epidural morphine 3.5 +/- 1.2, p less than or equal to .05). During the first eight postoperative hours, the placebo group required more opioids (0.22 +/- 0.03 vs. 0.12 +/- 0.04 mg/kg morphine equivalents, p less than or equal to .06) than the epidural morphine group. Later, both groups received similar amounts of opioids. Patients receiving epidural morphine had better initial recovery of forced vital capacity (at 8 hrs: 55 +/- 6% [epidural morphine] vs. 34 +/- 5% [placebo] of preoperative value, p less than or equal to .05). Respiratory rate was lower for the first 12 postoperative hours in the epidural morphine group, without a difference in PaCO2. There was no difference between groups for the duration of postoperative intubation or ventilation. CONCLUSIONS: Preoperative lumbar epidural morphine facilitates postoperative analgesia and improves initial postoperative ventilatory performance.  相似文献   
117.
Administration of exogenous lung surfactant to infants with or at risk for respiratory distress syndrome has been demonstrated to improve gas exchange and survival; administration of surfactant to patients with the adult respiratory distress syndrome is currently undergoing clinical evaluation. Although it is currently assumed the optimal effect will occur when administered surfactant is distributed homogeneously throughout the lung, little is known of the influence of variables inherent in the administration procedure on subsequent distribution. To address this question, we studied the effect of the volume size in which the surfactant is suspended for instillation, and demonstrated a marked relationship in the normal rabbit lung between this volume and the subsequent homogeneity of surfactant distribution. In the rabbit lung that was acutely injured by oleic acid, this relationship was not evident. Concentration of administered surfactant was not demonstrated to be of major influence on its distribution after administration. Our results focus attention on the importance of parameters of the administration procedure, and also demonstrate the usefulness of the techniques used for determination of surfactant distribution.  相似文献   
118.
Manipulation and exercise are recommended by chiropractors for treatment and prevention of low back problems. Many patients stop their exercise program with improvement in their symptoms. The success of exercises for the prevention of low back pain is dependent on several factors, one being continued compliance to the program. Only a small percentage of the general population do regular exercise; therefore, it is essential that patients recognize the importance of regular exercise in reducing the recurrence of their low back pain. This case study shows how the use of a gym ball appears to have improved compliance and reduced the incidence of low back pain for one patient with a history of re-occurring low back pain and a poor record of exercise compliance. The question must be asked, is this an case incident or is use of the gym ball an appropriate treatment for low back pain?  相似文献   
119.
120.
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