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   1530篇
  免费   118篇
  国内免费   8篇
耳鼻咽喉   11篇
儿科学   78篇
妇产科学   15篇
基础医学   200篇
口腔科学   38篇
临床医学   99篇
内科学   336篇
皮肤病学   62篇
神经病学   66篇
特种医学   116篇
外科学   220篇
综合类   28篇
预防医学   192篇
眼科学   11篇
药学   101篇
中国医学   5篇
肿瘤学   78篇
  2023年   3篇
  2022年   6篇
  2021年   33篇
  2020年   12篇
  2019年   24篇
  2018年   37篇
  2017年   16篇
  2016年   30篇
  2015年   30篇
  2014年   62篇
  2013年   84篇
  2012年   77篇
  2011年   93篇
  2010年   83篇
  2009年   60篇
  2008年   73篇
  2007年   51篇
  2006年   57篇
  2005年   50篇
  2004年   56篇
  2003年   55篇
  2002年   50篇
  2001年   42篇
  2000年   37篇
  1999年   34篇
  1998年   49篇
  1997年   36篇
  1996年   28篇
  1995年   18篇
  1994年   24篇
  1993年   31篇
  1992年   25篇
  1991年   21篇
  1990年   26篇
  1989年   24篇
  1988年   31篇
  1987年   22篇
  1986年   20篇
  1985年   26篇
  1984年   13篇
  1983年   10篇
  1982年   12篇
  1981年   17篇
  1980年   14篇
  1978年   8篇
  1977年   10篇
  1976年   14篇
  1975年   4篇
  1974年   5篇
  1972年   3篇
排序方式: 共有1656条查询结果,搜索用时 12 毫秒
1.
OBJECTIVE: Nocturnal enuresis is a common pediatric problem, the etiology of which is unclear. In recent years, various studies have been published stating that children with nocturnal enuresis exhibit growth and skeletal maturation retardation. METHODS: In this cross-sectional study, we included 27 patients (16 boys, 11 girls) between the ages of 6 and 14 years who had presented with primary nocturnal enuresis (PNE) complaints. We included in the evaluation 19 healthy subjects (12 boys, 7 girls), who were the siblings of the children with PNE, as the control group. RESULTS: The patients in both groups were similar in chronological age, bone age, height and weight, with no significant difference between groups (P>0.05). CONCLUSION: The two groups in our study consisted of the same genetic background. Thus, our results were found to be different from the previous studies. We have concluded that there is no direct relationship between enuresis nocturnal and skeletal maturation.  相似文献   
2.
3.
Heart transplantation (HTx) is a useful therapy for end‐stage Chaga? cardiomyopathy; however, Chagas reactivation remains a mayor complication. Parasitological methods offer poor diagnostic sensitivity, and use of more sensitive tools such as the Polymerase chain reaction (PCR) is usually necessary. In the present study, reactivation incidence and PCR usefulness for early reactivation diagnosis, as well as for treatment response evaluation during follow‐up, were analyzed using Strout parasite detection test, in 10 of 222 consecutive HTx patients suffering Chagas cardiomyopathy. PCR strategies targeted to minicircle sequences (kDNA, detection limit 1 parasite/ 10 mL blood) and miniexon genes (SL‐DNA, 200 parasite/10 mL) were performed to compare parasite burdens between samples. No patients received prophylactic antiprotozoal therapy (benznidazole). Five patients (50%) exhibited clinical reactivation within a mean period of 71.6 days; positive Strout results were observed in most cases presenting clinical manifestations. kDNA‐PCR was positive 38–85 days before reactivation, whereas SLDNA‐PCR became positive only 7–21 days later, revealing post‐HTx parasitic load enhancement present prior to clinical reactivation development. Reactivations were successfully treated with benznidazole and generated negative PCR results. Results observed in this study indicate the value of PCR testing for an early diagnosis of Chagas reactivation as well as for monitoring treatment efficacy.  相似文献   
4.
5.
OBJECTIVES: To assess the appropriateness of using the indices developed by the Study on the Efficacy of Nosocomial Infection Control (SENIC) and the National Nosocomial Infections Surveillance (NNIS) project to determine risk factors for surgical site infection (SSI) in children and, if not appropriate, to explore the factors related to SSI in children so these factors could be used in a risk index for pediatric patients. DESIGN: Cohort study during more than 4 years. SETTING: La Paz University Hospital, a national reference center that serves Health Area 5 of Madrid, Spain, which has approximately 500,000 inhabitants. PATIENTS: Convenience sample consisting of the 3,646 children admitted for surgery who had a postsurgical stay of more than 2 days. RESULTS: A model with 8 predictive factors (degree of surgical contamination; duration of surgery; type of surgery; use of a peripheral venous catheter, central venous catheter, or urinary catheter; number of diagnoses; and SSI exposition time) was created. Its relation to the SSI rate was better than that of the SENIC or NNIS indices. Its sensitivity, specificity, and area under the receiver-operating characteristic curve were higher than that of the SENIC index. CONCLUSIONS: The model that we created seems to be more adequate for predicting SSI and evaluating pediatric patients' intrinsic risk than the SENIC and NNIS indices.  相似文献   
6.
Two pregnancies in a patient with a fixed-rate pacemaker are reported. The first pregnancy was uneventful. The second had no maternal complications either. A moderate tachysystolia was detected during the second period. The newborn was delivered with forceps applied under spinal anesthesia. Newborn infant evolution presented no hazards, but umbilical cord analysis revealed a severe acidosis, in spite of a normal scalp analysis 45 min earlier. Epidural anesthesia is recommended for such patients.  相似文献   
7.
Mortality due to epidural hematoma is virtually restricted to patients who undergo surgery for that condition while in coma. The authors have analyzed the factors influencing the outcome of 64 patients who underwent epidural hematoma evacuation while in coma. These patients represented 41% of the 156 patients operated on for epidural hematoma at their centers after the introduction of computerized tomography (CT). Eighteen patients (28.1%) died, two (3.1%) became severely disabled, and 44 (68.8%) made a functional recovery. The mortality rate for the entire series was 12%, significantly lower than the 30% rate observed when only angiographic studies were available. A significant correlation was found between the final result and the mechanism of injury, the interval between trauma and surgery, the motor score at operation, the hematoma CT density (homogeneous vs. heterogeneous), and the hematoma volume. The patient's age, the course of consciousness before operation (whether there was a lucid interval), and the clot location did not correlate with the final outcome. The mortality rate was significantly higher in patients operated on within 6 hours or between 6 and 12 hours after injury than in those undergoing surgery 12 to 48 hours after injury. Compared with the patients operated on later, the patients undergoing surgery in the early period were, on the average, older and had more rapidly developing symptoms, more pupillary changes, lower motor scores at surgery, larger hematomas, a higher incidence of mixed CT density clots, more severe associated intracranial lesions, and higher postoperative intracranial pressure (ICP). The mechanism of trauma seems to influence the course of consciousness before and after surgery. Passengers injured in traffic accidents had a lower incidence of a lucid interval and longer postoperative coma than patients with low-speed trauma, suggesting more frequent association of diffuse white matter-shearing injury. The duration of postoperative coma correlated with the morbidity rate in survivors. Forty-eight patients (75%) had one or more associated intracranial lesions, and 70% of these required treatment for elevation of ICP after hematoma evacuation. An ICP of over 35 mm Hg strongly correlated with poor outcome; administration of high-dose barbiturates was the only effective means for lowering ICP in nine of 15 patients who developed severe intracranial hypertension after surgery. This study attempts to identify patients at greater risk for presenting postoperative complications and to define a strategy for control CT scanning and ICP monitoring.  相似文献   
8.
J A Diez  M R Pujato  A R Ferreres 《HPB surgery》1990,3(1):5-9; discussion 9-10
In an attempt to rationalize the use of intraperitoneal drainage of the subhepatic space after simple, elective cholecystectomy, a prospective study was designed to compare the post-operative course with and without drainage. There was a higher incidence of postoperative fever of unknown origin and wound infection in the drained group. In the group without drainage the hospital postoperative stay was shorter and there were no complications. The results suggest that routine surgical drainage after uncomplicated cholecystectomy is unnecessary and could be a source of postoperative fever and a higher incidence of wound infection.  相似文献   
9.
Hepatocytes isolated from the liver of rats after a necrotizing dose of thioacetamide (6.6 mmol/kg) were used to study the postnecrotic process of liver regeneration. Flow cytometry analysis revealed populations of dedifferentiated hepatocytes exhibiting physical properties (size and fluorescence emission at 530 nm) similar to those found in fetal (22 days old) liver cells. The percentage of these cells increased progressively from 24 to 48 and 72 hr after thioacetamide administration. In primary cultures of hepatocytes the effects of phorbol 12-myristate 13-acetate, bombesin and insulin were investigated on the 6-phosphofructo 2-kinase/fructose 2,6 bisphosphate system. Bombesin and insulin stimulated 6-phosphofructo 2-kinase activity and fructose 2,6-bisphosphate content both in control and in thioacetamide-treated hepatocytes. However, phorbol 12-myristate 13-acetate stimulated 6-phosphofructo 2-kinase activity and increased fructose 2,6-bisphosphate concentration in thioacetamide-treated liver cells, whereas no similar response was found in hepatocytes from control rats. The response of postnecrotic thioacetamide-treated hepatocytes to phorbol 12-myristate 13-acetate was similar to that obtained from 22-day-old fetal liver cells, which reveals that different methods might control fructose 2,6-bisphosphate content and therefore the mechanisms of glycolysis and gluconeogenesis at this regulatory step. The lack of response to glucagon of glycogen phosphorylase a and 6-phosphofructo 2-kinase from thioacetamide-treated hepatocytes may indicate that the expression of specific enzymes of carbohydrate metabolism undergoes transitions to less-differentiated isoenzymatic forms. Moreover, the isoenzyme pattern of hexokinases elicits a complete disturbance in glucokinase and hexokinases activities.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
10.
Adjuvant arthritis in rats produces alterations in the motor activity circadian rhythm. Specifically arthritic animals show a decrease in the total daily motor activity and an advance in the acrophase of the rhythm. Slight changes are also observed in the power content of the circadian harmonic as well as in the amplitude.  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