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   476篇
  免费   21篇
耳鼻咽喉   21篇
儿科学   13篇
妇产科学   32篇
基础医学   47篇
口腔科学   16篇
临床医学   23篇
内科学   77篇
皮肤病学   6篇
神经病学   30篇
特种医学   17篇
外科学   132篇
综合类   3篇
预防医学   10篇
眼科学   11篇
药学   12篇
肿瘤学   47篇
  2023年   4篇
  2022年   8篇
  2021年   24篇
  2020年   15篇
  2019年   21篇
  2018年   17篇
  2017年   13篇
  2016年   18篇
  2015年   22篇
  2014年   23篇
  2013年   27篇
  2012年   38篇
  2011年   27篇
  2010年   6篇
  2009年   15篇
  2008年   33篇
  2007年   26篇
  2006年   31篇
  2005年   45篇
  2004年   25篇
  2003年   20篇
  2002年   10篇
  2001年   4篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1997年   3篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1992年   3篇
  1991年   6篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
排序方式: 共有497条查询结果,搜索用时 15 毫秒
101.
AIMS AND BACKGROUND: We assessed the therapeutic results and tolerability of postoperative chemoradiotherapy with either oral UFT or 5-fluorouracil for carcinoma of the stomach. METHODS AND STUDY DESIGN: Forty-six patients treated with chemoradiotherapy following total or subtotal gastrectomy for gastric carcinoma formed the cohort evaluated. The group included 39 males and 7 females whose ages ranged from 21 to 74 years (median, 53 years). In all patients, surgical therapy was the initial approach with a curative intent. The types of operations performed were total gastrectomy in 11 or subtotal gastrectomy in 35 patients. Radiotherapy began from 14 to 161 days after surgery (median, 55 days). Twenty patients received concomitant oral UFT (200 mg/m2), and 26 patients were given 5-fluorouracil (425 mg/m2, iv bolus) concurrently with irradiation consisting of one or two cycles, usually as a 3-day bolus at the start and last 3 days of irradiation therapy for radiosensitizing purposes. The patients were treated using either cobalt-60 or 6 MV photons, and irradiation doses delivered to the tumor bed and regional lymphatics ranged from 40 to 50 Gy (median, 46 Gy). RESULTS: Median follow-up for the entire group was 24 months (range, 2-67). The 2-year overall survival of the entire group of patients was 64%. The 2-year overall survival rates for 5-fluorouracil and oral UFT groups were 72% and 66%, respectively (P = 0.3). Treatment-related factors were reviewed to identify any impact on survival. Analyses included type of surgery and dissection, fraction size, the total dose of irradiation and the type of chemotherapy. A significant detrimental effect in survival in the patients treated with D2 dissection compared to the patients treated with D1 dissection was noted (P = 0.01). Overall grade II-III toxicity of oral UFT was significantly lower than 5-FU (4 patients vs 14 patients, P = 0.03). CONCLUSIONS: Concomitant use of oral UFT with radiation seems to be more tolerable and an equally effective regimen in the treatment of locally advanced gastric cancer compared with 5-fluorouracil. D2 dissection was found to have detrimental effects on survival in this cohort.  相似文献   
102.

Purpose

Vanished twin (VT) has been associated with poor perinatal outcomes. Our research aimed to investigate the outcomes of pregnancies with vanished twin and its possible association with methylenetetrahydrofolate reductase (MTHFR) polymorphisms.

Methods

This study consisted of 30 of 38 VT pregnancies (group 1, VT group), 109 singletons (group 2), 70 spontaneous twins (group 3), and 101 in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) twins (group 4).

Results

Most patients in group 1 (28/30) were tested for MTHFR genes (C677T or A1298C polymorphisms). Eight of the 38 pregnancies with VT (21.1%) resulted in miscarriage. The prevalence of “2 or more pregnancy losses” in the “obstetric history” in group 1 was higher (23.3%) than those in the other groups (p?=?0.007, χ2?=?17.8). The allelic frequencies of MTHFR 677 and MTHFR 1298 in group 1 were 0.268 and 0.429, respectively (higher than those in healthy population). The median birthweights in groups 1, 2, 3, and 4 were 2940, 3200, 2300, and 2095 g, respectively. The prevalence of respiratory distress syndrome was significantly higher in the IVF/ICSI twin pregnancy group (p?<?0.001, χ2?=?21.2). Early pregnancy loss and the presence of “2 or more miscarriages” in the obstetric history of pregnancies with VT were more frequent.

Conclusion

The coincidence of VT and MTHFR polymorphisms might play an incidental or factual role in this connection.
  相似文献   
103.
Availability and utilization of computed tomography angiography has been increasing recently. We aimed to assess the effectiveness of low amount of contrast media and low kV value in order to reduce possible side effects of contrast media and to provide optimization of kV value in the evaluation of the carotid artery with multi-detector computed tomography angiography. Forty one patients were randomized into two groups. Contrast media was administered at a dose of 1 ml/kg in group A patients and of 0.5 ml/kg in group B patients. kV value of 120 in group A and 100 in group B were chosen. Bolus tracking technique was used. Attenuation values of certain arterial segments were measured, and values over 200 HU were considered as significant. North American Symptomatic Carotid Endartherectomy Trial criteria were utilized in the evaluation of stenosis. Image quality in arterial segments of all cases was found to be sufficient for diagnosis. Arterial attenuation values were found to be higher in group B than group A. When compared separately in all arterial segments, there was no statistically significant difference between the groups. For stenosis, 615 arterial segments were evaluated. Moderate stenosis in eight segments and severe stenosis in three segments were identified in group A. Occlusion in three segments, severe stenosis in three segments, and moderate stenosis in 25 segments were detected in group B. Better image quality can be obtained, and the amount of contrast media can be reduced using low kV technique in carotid artery multi-detector computed tomography angiography examination.  相似文献   
104.
To compare retrospectively the recurrence rates of TUR alone versus different intravesical chemotherapy modalities in superficial bladder cancer cases, 187 patients with stage Ta and T1 bladder tumours were treated with transurethral resection followed by adjuvant intravesical chemotherapy with mitomycin, BCG or epirubicin or by transurethral resection alone. All patients in this study had historically proven transurethrally resectable primary, category Ta and T1 transitional cell carcinoma (TCC) of the bladder. Group I included transurethral resection alone, and the other groups included intravesical mitomycin-C(Group II), BCG (Group III) and epirubicin (Group IV) therapies after transurethral resection. 146 male and 41 female patients (78% male and 22% female patients) in this study were diagnosed as primary TCC bladder tumours. Only 52 of them were stage Ta and 135 of them were stage T1 bladder tumours. Examining the histological grade of the bladder tumours, 88 (47%) of the patients had grade I, 53 (28%) had grade IIa, 30 (16%) had grade IIb and remaining 16 (9%) had grade III bladder cancers. The recurrence rates were 25% for Group I, 23.8% for Group II, 26.2% for Group III and 22.7% for Group IV. These values were given with disregarding the grade and volume of the bladder tumours. For solitary, less than 3 cm low grade tumours (grade I, IIa) recurrence rates were 16% for Group I, 15.4% for Group II, 17.8% for Group III, 17.2% for Group IV (p> 0.05). As a result of this retrospective study, for patients with low grade, stage Ta and T1 tumours TUR alone may be the best treatment modality. Although intravesical chemotherapy is effective in decreasing short-term incidences of tumour recurrence, it has not decreased long-term incidences of tumour recurrence. The high cost and adverse side effects of intravesical chemotherapy should also be taken into consideration in superficial, single, low grade tumours of bladder. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
105.
106.
Purpose: Neural tube defects (NTDs) are the most common malformations of the central nervous system (CNS). There is continuing research for the identification of risk factors and interventions for prevention of NTDs. The aim of this study was to investigate the maternal second trimester blood levels of selected heavy metals namely, arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), nickel (Ni), and lead (Pb) and their possible relation with the occurrence of NTDs.

Methods: Twenty-one healthy second trimester pregnant women with fetuses affected with NTD (cases) were matched with 21 healthy pregnant women with unaffected fetuses (controls) with respect to age, body mass index (BMI), and gestational age. Maternal blood levels of heavy metals were measured after an overnight fasting period.

Results: No significant differences were observed in terms of maternal blood levels of As, Cd, Hg, and Ni between NTD-affected and unaffected pregnancies. The blood Pb and Mn levels were found to be higher in pregnant women with a fetus affected with NTD when compared with pregnant women with unaffected fetuses (for Pb, in cases 12.3?±?5.5?µg/L, in controls 7.8?±?2.4?µg/L; for Mn in cases 3.6?±?1.4?µg/L, in controls 2.4?±?1.0?µg/L, p?Conclusions: High maternal second trimester blood levels of Pb and Mn during pregnancy are associated with NTDs in the newborn.  相似文献   
107.
108.
Breast cancer is the most common type of malignancy in females. Advances in systemic therapies and radiotherapy (RT) provided long survival rates in breast cancer patients. RT has a major role in the management of breast cancer. During the past 15 years several developments took place in the field of imaging and irradiation techniques, intensity modulated RT, hypofractionation and partial-breast irradiation. Currently, improvements in the RT technology allow us a subsequent decrease in the treatment-related complications such as fibrosis and long-term cardiac toxicity while improving the loco-regional control rates and cosmetic results. Thus, it is crucial that modern radiotherapy techniques should be carried out with maximum care and efficiency. Several randomized trials provided evidence for the feasibility of modern radiotherapy techniques in the management of breast cancer. However, the role of modern radiotherapy techniques in the management of breast cancer will continue to be defined by the mature results of randomized trials. Current review will provide an up-to-date evidence based data on the role of modern radiotherapy techniques in the management of breast cancer.  相似文献   
109.
Family history and hepatitis B virus (HBV) infection have been identified as risk factors for hepatocellular carcinoma. We report hepatocellular carcinoma (HCC) diagnosed at the same time in identical twin brothers. Serological analyses of the patients showed that both were chronically infected with HBV. Molecular analyses of the tumor specimens confirmed loss of heterozygocity of the Rb gene region. Both of the patients were unresponsive to chemotherapy and died within the same month with an interval of I wk. With a review of the current literature, we discuss the role of HBV infection and genetic factors on hepatic carcinogenesis.  相似文献   
110.

Purpose:

This study aimed to evaluate the changes in macular thickness following inferior oblique muscle recession surgery.

Materials and Methods:

Thirty-eight eyes from 21 patients undergoing ocular muscle surgery were included. Patients were grouped into three groups based on the type of surgical intervention: Group I (n = 12), inferior oblique recession surgery alone; Group II (n = 12), inferior oblique plus horizontal muscle surgery; Group III (n = 14), horizontal muscle surgery alone. Each eye was scanned using the optical coherence tomography (OCT) device preoperatively and on the first postoperative day to measure macular thickness.

Results:

Following surgery, a significant increase in foveal thickness occurred in Group I (P < 0.05) and Group II (P < 0.01). In addition, a statistically significant difference was observed between the groups with regard to the increase in foveal thickness (P = 0.016), with significantly lower changes in Group III.

Conclusion:

Our findings suggested that inferior oblique muscle recession surgery is associated with an increase in macular thickness.  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