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   1911730篇
  免费   135926篇
  国内免费   4083篇
耳鼻咽喉   25139篇
儿科学   63450篇
妇产科学   53062篇
基础医学   273360篇
口腔科学   54595篇
临床医学   169303篇
内科学   373488篇
皮肤病学   43576篇
神经病学   146675篇
特种医学   72340篇
外国民族医学   281篇
外科学   290815篇
综合类   44860篇
现状与发展   5篇
一般理论   666篇
预防医学   139640篇
眼科学   45683篇
药学   138922篇
  7篇
中国医学   4994篇
肿瘤学   110878篇
  2021年   14353篇
  2019年   15048篇
  2018年   22372篇
  2017年   16988篇
  2016年   18713篇
  2015年   21347篇
  2014年   29425篇
  2013年   43137篇
  2012年   59012篇
  2011年   62077篇
  2010年   37232篇
  2009年   34686篇
  2008年   57655篇
  2007年   61570篇
  2006年   61947篇
  2005年   58957篇
  2004年   56983篇
  2003年   54132篇
  2002年   51969篇
  2001年   100332篇
  2000年   102494篇
  1999年   84532篇
  1998年   21933篇
  1997年   19305篇
  1996年   19243篇
  1995年   18533篇
  1994年   16975篇
  1993年   15659篇
  1992年   63222篇
  1991年   61223篇
  1990年   58874篇
  1989年   56566篇
  1988年   51393篇
  1987年   50045篇
  1986年   47239篇
  1985年   44810篇
  1984年   32905篇
  1983年   27996篇
  1982年   15788篇
  1979年   29005篇
  1978年   20090篇
  1977年   17117篇
  1976年   15858篇
  1975年   16894篇
  1974年   20341篇
  1973年   19688篇
  1972年   18256篇
  1971年   16868篇
  1970年   15779篇
  1969年   14636篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
We report the case of a 38-year-old woman who presented with chronic lower abdominal pain. Her past medical history included a splenectomy due to abdominal trauma. Ultrasound examination revealed four pelvic tumors which, upon laparotomy, were found to be the result of splenosis. Approximately 100 cases of splenosis have been reported but only a minority of them have been published in the gynecological literature. Our case indicates that those involved in pelvic scanning (even of asymptomatic women) and/or treating those complaining of lower abdominal pain or presenting with pelvic tumors should be aware of splenosis as a possible diagnosis.  相似文献   
52.
Although surgical lung resection could improve prognosis in some patients with multidrug-resistant tuberculosis (MDR-TB), there are no reports on the optimal candidates for this surgery. The aim of the present study was to elucidate the prognostic factors for surgery in patients with MDR-TB. Patients who underwent lung resection for the treatment of MDR-TB between March 1993 and December 2004 were included in the present study. Treatment failure was defined as greater than or equal to two of the five cultures recorded in the final 12 months of treatment being positive, any one of the final three cultures being positive, or the patient having died during treatment. The variables that affected treatment outcomes were identified through univariate and multivariate logistic regression analysis. In total, 79 patients with MDR-TB were included in the present study. The treatment outcomes of 22 (27.8%) patients were classified as failure. A body mass index <18.5 kg x m(-2), primary resistance, resistance to ofloxacin and the presence of a cavitary lesion beyond the range of the surgical resection were associated with treatment failure. Low body mass index, primary resistance, resistance to ofloxacin and cavitary lesions beyond the range of resection are possible poor prognostic factors for surgical lung resection in multidrug-resistant tuberculosis patients.  相似文献   
53.
54.
AIM: The intention was to investigate cerebrospinal fluid pressure (CSFP) and volume of cerebrospinal fluid (CSF) drained during and after thoracic- and thoracoabdominal aneurysm repair. The findings were related to the occurrence of postoperative neurologic deficits. METHODS: Twenty-nine patients (12 with thoracic and 17 with thoracoabdominal aortic aneurysm) were operated without shunting or extracorporeal circulation. For monitoring of CSFP an intrathecal catheter was placed in all patients. The volume of CSF withdrawn intraoperatively, on the day of operation as well as on the 1st and 2nd postoperative day was recorded. RESULTS: Twenty-six patients had no postoperative neurologic sequelae. One patient had postoperative paraplegia while 2 had paraparesis. The three patients with neurologic sequelae had higher CSFP intraoperatively than those without neurologic symptoms (P=0.04). Median CSFP during aortic cross-clamping was 19 mmHg and 10 mmHg and the median volumes of CSF drained on the day of operation 210 and 85 mL in the two groups, respectively. There was a significant positive correlation between CSFP and central venous pressure. CONCLUSIONS: A higher intraoperative CSFP was observed in patients with neurologic sequelae following thoracic- and thoracoabdominal aneurysm repair. Further, there was a tendency of higher volumes of CSF drained in this group of patients. Although, the series is too small to allow firm conclusions, it supports the view that CSFP monitoring and drainage is beneficial during thoracic- and thoracoabdominal aneurysm repair.  相似文献   
55.
56.
57.
CONTEXT: Although the nonmedical use of stimulant drugs such as cocaine and methamphetamine is increasingly common in many rural areas of the United States, little is known about the health beliefs of people who use these drugs. PURPOSE: This research describes illicit stimulant drug users' views on health and health-related concepts that may affect their utilization of health care services. METHODS: A respondent-driven sampling plan was used to recruit 249 not-in-treatment, nonmedical stimulant drug users who were residing in 3 rural counties in west central Ohio. A structured questionnaire administered by trained interviewers was used to collect information on a range of topics, including current drug use, self-reported health status, perceived need for substance abuse treatment, and beliefs about health and health services. FINDINGS: Participants reported using a wide variety of drugs nonmedically, some by injection. Alcohol and marijuana were the most commonly used drugs in the 30 days prior to the interview. Powder cocaine was used by 72.3% of the sample, crack by 68.3%, and methamphetamine by 29.7%. Fair or poor health status was reported by 41.3% of the participants. Only 20.9% of the sample felt they needed drug abuse treatment. Less than one third of the sample reported that they would feel comfortable talking to a physician about their drug use, and 65.1% said they preferred taking care of their problems without getting professional help. CONCLUSIONS: Stimulant drug users in rural Ohio are involved with a range of substances and hold health beliefs that may impede health services utilization.  相似文献   
58.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  相似文献   
59.
BACKGROUND: The 1997 National Asthma Education and Prevention Program (NAEPP) recommends a severity classification scheme to optimize the use of anti-inflammatory therapy for persistent asthma. Physician documentation of asthma severity is often used as a quality assurance measure. OBJECTIVE: To test the hypothesis that physician documentation of asthma severity is associated with appropriate use of anti-inflammatory therapy. DESIGN/METHODS: Setting: inner-city academic health center. First, we reviewed a consecutive sample of charts of scheduled pediatric patients. Then, we administered a structured parent survey regarding the child's asthma symptoms and current asthma therapy. We used NAEPP guidelines to classify patients' severity of asthma. The main outcome measure was appropriate use of anti-inflammatory therapy. Appropriate therapy was defined as: (1) mild persistent asthmatics using anti-inflammatory therapy, and (2) moderate-severe persistent asthmatics using inhaled steroids. Chart classification of asthma severity was compared with the NAEPP-applied classification. RESULTS: Of 784 charts, 214 (27%) were asthmatic. Of these, 176 (82%) were surveyed. The mean age was 7.4 years; 61% were males. Severity classification was documented in 77% of charts. Chart documentation differed significantly from survey classification for the same patients: (mild intermittent 54% vs. 40%, mild persistent 21% vs. 14%, moderate persistent 24% vs. 36%, severe persistent 1% vs. 10%; all p < .001). Correctly classified patients were more likely to be on appropriate therapy. CONCLUSIONS: Physicians underestimated the severity classification of asthmatic patients. Incorrect classification was associated with inappropriate asthma therapy. These findings have implications for the institution of asthma quality improvement programs.  相似文献   
60.
OBJECTIVE: To assess the effect of glucose control on the rate of growth of fetuses in women with pregestational diabetes mellitus (Types 1 and 2). METHODS: All pregestational diabetic women booked at Mater Mothers' Hospital, Brisbane, Australia, between 1 January 1994 and 31 December 2002, were included. Pregnancies with congenital fetal anomalies, multiple pregnancies, and pregnancies terminated prior to 20 weeks' gestation were excluded. Dating scans were performed before 14 weeks' gestation and serial scans were performed at 18, 24, 28, 32 and 36 weeks. Fetal parameters, including biparietal diameter, femur length and abdominal circumference, were recorded. The daily growth rates for biparietal diameter, femur length, and fetal abdominal area were calculated and compared with those in a low-risk (non-diabetic) population. The growth rates in fetuses of women with satisfactory diabetic control (HbA1c < 6.5%) and unsatisfactory control (HbA1c > or = 6.5%) in the three trimesters were compared. RESULTS: A total of 174 diabetic pregnancies were included and a total of 997 ultrasound scans were performed. The growth rates for fetuses of mothers with diabetes mellitus were significantly higher than for those in the low-risk population. The z-scores for biparietal diameter, femur length, and fetal abdominal area were 0.18, 0.59 and 1.44, respectively. Fetuses of diabetic mothers with high HbA1c in the first trimester had significantly greater fetal abdominal area growth rate than those with normal HbA1c (fetal abdominal area z-score of 1.7 vs. 0.75, P = 0.009). Although the fetal abdominal area z-scores in fetuses of diabetic mothers with high HbA1c in the second or third trimesters were also higher than those with normal HbA1c levels, the differences did not reach statistical significance. Maternal obesity did not influence the fetal growth rate. CONCLUSION: The rate of growth of fetuses of diabetic mothers differs from that of the normal population. Growth acceleration persists until the late third trimester. Moreover, periconceptional glucose control appears to have a significant effect on accelerated growth of the fetal abdominal area.  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