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   19491篇
  免费   1111篇
  国内免费   151篇
耳鼻咽喉   254篇
儿科学   526篇
妇产科学   668篇
基础医学   2136篇
口腔科学   536篇
临床医学   1611篇
内科学   3883篇
皮肤病学   380篇
神经病学   932篇
特种医学   726篇
外国民族医学   11篇
外科学   3431篇
综合类   355篇
现状与发展   2篇
一般理论   11篇
预防医学   1685篇
眼科学   548篇
药学   1776篇
中国医学   139篇
肿瘤学   1143篇
  2024年   18篇
  2023年   254篇
  2022年   787篇
  2021年   1134篇
  2020年   617篇
  2019年   763篇
  2018年   1030篇
  2017年   600篇
  2016年   636篇
  2015年   645篇
  2014年   911篇
  2013年   1056篇
  2012年   1542篇
  2011年   1693篇
  2010年   958篇
  2009年   696篇
  2008年   981篇
  2007年   992篇
  2006年   911篇
  2005年   864篇
  2004年   753篇
  2003年   692篇
  2002年   618篇
  2001年   157篇
  2000年   120篇
  1999年   108篇
  1998年   86篇
  1997年   77篇
  1996年   73篇
  1995年   70篇
  1994年   63篇
  1993年   55篇
  1992年   60篇
  1991年   65篇
  1990年   64篇
  1989年   51篇
  1988年   52篇
  1987年   52篇
  1986年   41篇
  1985年   43篇
  1984年   43篇
  1983年   42篇
  1982年   37篇
  1981年   29篇
  1980年   25篇
  1978年   16篇
  1977年   14篇
  1976年   17篇
  1973年   23篇
  1966年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The outcome of patients with acute renal failure (ARF)due to acute tubular necrosis (ATN) was evaluated inthis study. Two hundred and twenty-two patients witha mean age of 55.l ± 17.7 years (range 19–97years; male 153, female 69) who developed ATN in theperiod from July 1991 through January 1997 werestudied. Patients were divided into four groupsaccording to their APACHE II scores at the time of thediagnosis of ATN. Group I included patients with anAPACHE II score of 14 or less (n = 70), Group II with ascore of 15–18 (n = 52), Group III with a score of 19–23(n = 58), and group IV with a score of 24 or above(n = 42). The mean APACHE II score for each of the fourstudy groups was 11 ± 0.4, 16 ± 0.2, 20 ±0.2, and 29 ± 0.7, respectively. Patient survivalwas evaluated by the Kaplan-Meier analysis withcensorship at 12 months. Survival rates at 180 dayswere 67%, 47%, 39%, and zero%, for group I through IV respectively, χ2 = 27.99, p < 0.0001,with a median survival of >365, 120, 31, and 11days, for groups I through IV, respectively. For patients with oliguria (n = 88) survival at 180days was 23% vs. 58% for patients without oliguria(n = 134), p < 0.0001, median survival 13 vs. 364 d.Six months survival of those who required dialysis(n = 79) was 25% vs. 58% for those whom dialysis wasnot needed (n = 143), p = 0.001, median survival 15 vs.364 d, respectively. In patients with sepsis (n = 58),6 months survival was 35% vs. 50% for those withoutsepsis (n = 164), p = 0.013, median survival 14 vs. 169 d. In patients who required mechanical ventilation(n = 72), 6 months survival was 17% vs. 62% for those whodid not need respiratory support (n = 150), p = 0.0001,median survival 13 vs. > 365 d, respectively. Finally, 6 months survival in patients with one(kidney only), two, three, and four organ failure was76, 30, 11, and zero percent, respectively, p = 0.0001,median survival > 365, 16, 11, and 12 days,respectively. We conclude that the use of the APACHE II score forthe stratification of the severity of illness could beof clinical utility in predicting mortality inpatients with ATN. Other predictors of poor prognosisinclude the need for dialysis, the presence ofoliguria, the need for mechanical ventilation, thepresence of sepsis, and the number of failed organs. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
102.
We retrospectively analyzed the prognostic significance of mixed chimerism and associated clinical parameters in 80 patients following unmanipulated allogenic stem cell transplantation. Chimerism studies were performed on marrow aspirates using fluorescent in situ hybridization and variable number tandem repeats techniques at day +30, day +90 and +12 months. The median overall survival (OS) was 24 months (range, 1-56 months). Mixed chimerism was found in 23, 28 and 14% of patients at day +30 (1 month), +90 (3 months), and +12 months, respectively. Day +30 chimerism studies failed to provide any prognostic information. Day +90 mixed chimeras (MC) had significantly higher relapse rates compared to day +90 complete chimeras (CC) at 6 months (P=0.03) and 18 months when compared to MC (P=0.03) following transplant. The median OS in day +90 MC and day+90 CC were, respectively (95% CI, 2-35 months), compared to 47 months (95% CI, 20-74 months) (P=0.02). In conclusion, chimerism studies on day +30 could be reserved for patients who fail to demonstrate engraftment. Day +90 MC had higher relapse rates and lower OS, and therefore may be considered for novel therapies and future studies.  相似文献   
103.
PURPOSE: Imatinib mesylate is a tyrosine kinase inhibitor with high affinity for the BCR-ABL fusion protein expressed by the hematopoietic cells in chronic myelogenous leukemia (CML). Some patients with chronic-phase or accelerated-phase CML either relapse after an initial response or are refractory to imatinib, prompting us to evaluate the efficacy of dose increase in such patients. EXPERIMENTAL DESIGN: Twelve chronic-phase patients initially receiving 400 mg/day and 4 patients with accelerated phase initially receiving either 400 mg/day (two patients) or 600 mg/day (two patients) had their dose increased (14 to 800 mg/day and 2 to 600 mg/day) because of progressive disease (usually clonal evolution) or inadequate cytogenetic response after at least 1 year of therapy. RESULTS: Six patients had major cytogenetic responses after dose increase (3 complete and 3 partial). Two others had minor cytogenetic responses. Two patients with clonal evolution transiently lost the additional clonal aberrations. Almost all of the responses occurred within 6 months, and were typically 3-6 months in duration. However, 3 patients have continuing major cytogenetic responses of >18 months duration. Dose increase was well tolerated, with thrombocytopenia, mild leukopenia, and exacerbation of prior edema being the most common adverse events. CONCLUSIONS: Although increasing the dose of imatinib can benefit a subgroup of patients with CML with either an inadequate cytogenetic response or disease progression, our results suggest the majority will not have a sustained meaningful response, and that other options, such as allogeneic stem cell transplant or investigational therapies, also need to be considered at the time of dose increase.  相似文献   
104.
338 women with age ranging from 15 to 69 years in a suburban Sudanese community were randomly selected and studied. Urine sample, high vaginal swabs and blood samples were investigated for bacterial vaginosis, candidiasis, trichomoniasis, gonorrhoea, HIV and syphilis. The sensitivity and specificity of some laboratory tests were evaluated. Bacterial vaginosis was found in 17.2% of the subjects, candidiasis in 10.1%, trichomoniasis in 7.7%, gonorrhoea in 1.2%, HIV in 1.2% and syphilis in 0.9% of the subjects. The sensitivity and specificity of amine test as a criterion for diagnosing bacterial vaginosis was 58.6% and 73.2%, respectively. The respective values of clue cells in wet preparation were 43.1% and 99.6%. The vaginal discharge in women with bacterial vaginosis lacked pus cells unless associated with concurrent infection.  相似文献   
105.
106.
OBJECTIVE: To describe the development and validation of the Barriers to Care Questionnaire (BCQ). METHODS: The 39-item BCQ was developed through review of the literature, focus groups, and cognitive interviews of Spanish- and English-speaking parents of children with chronic health conditions. Barriers to care are conceptualized as a multidimensional construct consisting of pragmatics, health knowledge and beliefs, expectations about care, skills, and marginalization. The BCQ was field tested in 3 samples of children with special health care needs (CSHCN). RESULTS: Response rate for the field test was 77.2%. There were minimal missing data (0.08%), no floor effects, and minimal ceiling effects (3.8%, total scale). Internal consistency reliability (alpha) for the BCQ total scale was.95 and subscale alpha ranged from.75 to.91. The BCQ total scale and subscales correlated in the expected direction with validated measures of primary care characteristics and health-related quality of life. BCQ scores were higher (fewer barriers) for children with a primary care physician and for those who reported no problems getting care or foregone care. CONCLUSION: The BCQ is a feasible, reliable, and valid instrument for measuring barriers to care for CSHCN. Its use may inform efforts to support consumer choice, enhance provider accountability, and spur quality improvement.  相似文献   
107.
Diffuse neurological manifestations of preeclampsia are due to endothelial involvement that lead to ischemia, hemorrhage, or edema. We analyzed clinical and radiological features and the course of brainstem ischemic strokes in a preeclampsia patient. We report a case of severe preeclampsia in a 30-year-old woman who was admitted 10 hr after a vaginal delivery at home. The pregnancy was at 39 wk, with no prenatal care. At her admission, she was conscious, and she had tetraparesia, swinging deep tendon reflex testing, drowsiness, and dysarthria; the BP was at 160/100 mmHg and 4 + proteinuria; magnetic resonance imaging revealed brainstem ischemic stroke. The evolution was favorable with symptomatic treatment. The patient was discharged on the 16th day; 2 months later she had a normal recovery. Brainstem strokes are rare. They are frequently due to hemorrhage; sometimes, they can also be ischemic. Their course is favorable.  相似文献   
108.
BACKGROUND: Osteopenia of prematurity is a known source for morbidity in preterm infants. Premature infants have shown favorable outcomes in response to massage and physical activity. Whether such intervention can stimulate bone formation or decrease bone resorption is yet to be determined. OBJECTIVE: To test the hypothesis that massage combined with physical activity can stimulate bone formation and ameliorate bone resorption in premature infants. DESIGN/METHODS: A prospective double-blinded randomized trial was conducted at the Neonatal Intensive Care Unit of Ain Shams University in Cairo, Egypt. Thirty preterm infants (28 to 35 weeks' gestation) were randomly assigned to either control group (Group I, n=15) or intervention group (Group II, n=15). Infants in the intervention group received a daily protocol of combined massage and physical activity. Serum type I collagen C-terminal propeptide (PICP) and urinary pyridinoline crosslinks of collagen (Pyd) were used as indices for bone formation and resorption, respectively. PICP and Pyd were measured at enrollment and at discharge for all subjects. t-Test, ANOVA and linear regression analysis were used for statistical analyses. RESULTS: There was no difference between groups I and II in gestational age (32.1+/-1.8 vs 31.5+/-1.4 weeks) or birth weight (1.429+/-0.148 vs 1.467+/-0.132 g). In the control group, serum PICP decreased over time from 82.3+/-8.5 to 68.78+/-14.6 (p<0.01), while urinary Pyd increased from 447.7+/-282.8 to 744.9+/-373.6 (p<0.01) indicating decreased bone formation and increased bone resorption, respectively. In the intervention group, serum PICP increased over time from 62.5+/-13.8 to 73.84+/-12.9 (p<0.01). Urinary Pyd also increased over time from 445.7+/-266.5 to 716.8+/-301.8 (p<0.01). In a linear regression model including gestational age and intervention, serum PICP increased significantly in the intervention group (regression coefficient 18.8+/-4.6, p=0.0001) while urinary Pyd did not differ between groups (regression coefficient=5.6+/-114.3, p=0.961). CONCLUSIONS: A combined massage and physical activity protocol improved bone formation (PICP) but did not affect bone resorption (Pyd). Pyd increased over time in both groups, possibly due to continuous bone resorption and Ca mobilization.  相似文献   
109.
A prospective observational study was designed to evaluate the effect of the different techniques of hysterectomy on urinary and sexual function. One hundred and eighty-seven women aged 29-73 years and admitted for hysterectomy for various indications were recruited to the study. Women presenting primarily with major uterine prolapse and those requiring radical hysterectomy were excluded. Patients underwent one of four different techniques of hysterectomy: total abdominal, vaginal, laparoscopic or subtotal. All patients completed a standardised questionnaire addressing urinary and sexual symptoms and underwent urodynamic testing using the Lectromed 6000 System (Lectromed, Letchworth, Herts, UK) before and 6 months after surgery. Out of 187 women, 184 (98.4%) had completed data. Seventy-three patients (39%) had a total abdominal hysterectomy, 62 (34%) had vaginal, 38 (21%) had laparoscopic and 11 (6%) had subtotal hysterectomy. At 6 months after surgery, urinary symptoms occurred less frequently (P<0.01) and urodynamic studies remained unchanged. Moreover, patients reported significantly lower rates of stress incontinence (P=0.005), urgency (P=0.03) and deep dyspareunia (P<0.001) than before the operation, regardless of the hysterectomy technique used. The route of hysterectomy did not influence the outcome of surgery. We conclude that simple hysterectomy, whether performed abdominally, vaginally or laparoscopically, does not adversely affect urinary or sexual function at 6 months after surgery.  相似文献   
110.
Hepatocellular carcinoma (HCC) is the most frequent primitive cancer of the liver. It mostly develops on cirrhotic livers. Orthotopic liver transplantation is the only treatment that definitively addresses both the metachronous occurrence risk of HCC and the underlying disease. Under Milan criteria, i.e. less than 3 nodules of 3 cm max in diameter, or 1 nodule of 5 cm maximum, OLT has been shown effective and provides with survival rates almost equal to those obtained with HCC free cirrhotic patients. In Rennes, 195 patients with early HCC on cirrhotic livers have been transplanted from January 1995 to June 2005. Global and disease free 8 years patient survival rates were 73 and 70%, respectively. These results were significantly altered when the recipient was female, the cirrhosis due to C virus and the patient of B blood group. Despite these excellent results, the principal limit to the application of transplantation for HCC remains the long period of time patients have to wait for a graft. During this period of time, growth of the tumour may drop the patient out of Milan criteria and subsequently from the waiting list. The role of chemoembolisation, liver resection and thermal ablation while the patient is waiting for a graft remains debatable.  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