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   1007篇
  免费   55篇
  国内免费   17篇
耳鼻咽喉   2篇
儿科学   23篇
妇产科学   18篇
基础医学   116篇
口腔科学   5篇
临床医学   80篇
内科学   242篇
皮肤病学   3篇
神经病学   56篇
特种医学   92篇
外科学   141篇
综合类   6篇
预防医学   27篇
眼科学   4篇
药学   92篇
  2篇
中国医学   2篇
肿瘤学   168篇
  2023年   2篇
  2022年   10篇
  2021年   21篇
  2020年   16篇
  2019年   15篇
  2018年   20篇
  2017年   13篇
  2016年   14篇
  2015年   25篇
  2014年   34篇
  2013年   33篇
  2012年   37篇
  2011年   33篇
  2010年   31篇
  2009年   26篇
  2008年   33篇
  2007年   49篇
  2006年   45篇
  2005年   49篇
  2004年   38篇
  2003年   34篇
  2002年   27篇
  2001年   25篇
  2000年   40篇
  1999年   29篇
  1998年   34篇
  1997年   38篇
  1996年   26篇
  1995年   17篇
  1994年   30篇
  1993年   15篇
  1992年   14篇
  1991年   14篇
  1990年   19篇
  1989年   21篇
  1988年   19篇
  1987年   15篇
  1986年   15篇
  1985年   18篇
  1984年   15篇
  1983年   9篇
  1982年   8篇
  1981年   11篇
  1980年   8篇
  1978年   6篇
  1977年   4篇
  1976年   5篇
  1975年   7篇
  1973年   2篇
  1968年   2篇
排序方式: 共有1079条查询结果,搜索用时 15 毫秒
31.
OBJECTIVE: To evaluate radiotherapy dose and length of treatment in the control of early stage nasopharyngeal carcinoma (NPC) treated with a combination of external radiotherapy and brachytherapy, MATERIALS & METHODS: We reviewed the records of 133 patients with early stage nasopharyngeal carcinoma (stage I or II, AJC/UICC staging system) who received definitive radiotherapy in Chang Gung Memorial Hospital from 1979 to 1991. The median follow-up time was 7.1 years with a minimum of 2 years. All patients were treated with megavoltage external radiotherapy to the nasopharynx area (63-72 Gy) followed by high dose rate intracavitary brachytherapy (5-16.5 Gy in one to three fractions, spaced 1-2 weeks apart). The median total dose and time of irradiation was 75 Gy (69.8-81.4 Gy) and 11.6 weeks (7.8-20 weeks) respectively. Survival analysis was used to examine the effect of several variables on prognosis. RESULTS: The 5-year rates were 86.4% for local control, 84.7% for disease free survival, 88.5% for actuarial survival and 84.2% for overall survival. The treatment group (combination of time and dose of irradiation) was the most important prognostic factor according to Cox's proportional hazard model. Patients receiving radiation at a total dose of < or = 75 Gy completed in < 12 weeks showed the best prognosis. CONCLUSION: Treatment time and total treatment dose are both important factors in treating early stage NPC. Decreasing the total radiation time to < 12 weeks and not exceeding a radiation dose of 75 Gy gave the best results.   相似文献   
32.
We examined the relationship between a functional polymorphism (667C-- >T, ala-->val) of the methylenetetrahydrofolate reductase gene (MTHFR) and the risk of colorectal adenomas in the prospective Nurses' Health Study. Among 257 incident polyp cases and 713 controls, the MTHFR val/val polymorphism [relative risk (RR) = 1.35, 95% confidence interval (CI) 0.84-2.17] was not significantly associated with risk of adenomas. This lack of association was observed for both small (RR = 1.36, 95% CI 0.76-2.45) and large (RR = 1.32, 95% CI 0.66-2.66) adenomas. Furthermore, there was no significant interaction between this polymorphism and consumption of either folate, methionine or alcohol. We also examined the relationship of a newly identified polymorphism (asp919gly) of the methionine synthase gene (MS) with the risk of colorectal adenomas in the same population. The MS gly/gly polymorphism was also not significantly associated with risk of colorectal adenomas (RR = 0.66, 95% CI 0.26-1.70). These results, which need to be confirmed in other studies, suggest that the MTHFR val/val polymorphism, which has been previously inversely associated with risk of colorectal cancer, plays a role only in a late stage (adenoma-- >carcinoma) of colorectal tumorigenesis, and/or may protect against malignant transformation in the subset of benign adenomas, which may progress to malignancy.   相似文献   
33.
Background: S9788 is a triazineaminopiperidine derivative capable of reversing multidrug resistance (MDR) in vitro. In preclinical models S9788 was several fold more potent MDR inhibitor than verapamil or cyclosporine. At P-glycoprotein (Pgp) blocking concentrations, S9788 appeared to have only very little toxicity.Patients and methods: In a two step phase I trial we treated 39 patients with refractory cancer with S9788 and bolus doxorubicin. The steps differed mainly in the S9788 infusion duration; in the first part 23 patients received the MDR-reversing drug S9788 over 30 minutes, in the second step of the study 16 patients were administered S9788 over 150 minutes. The doses of S9788 were escalated in cohorts of three patients up to a dose level (DL) of 96 mg/m2 on the 30 minutes infusion, and to 144 mg/m2 on the 150 minutes infusion. The pharmacokinetics of S9788 were determined.Results: With the 30-minute infusion schedule symptomatic cardiac arrhythmia were found to be dose limiting. In all patients at the highest DL transient cardiac repolarization prolongation with a long QT-interval on ECG was demonstrated. With the 150-minute administration schedule, S9788 could be escalated up to 144 mg/m2 without subjective toxicity. However, transient QT prolongation was present in all patients. A third degree AV-block and a QT increase of about 40% occurred at the highest DL. Asymptomatic torsade de pointe (DL 96 mg/m2) was demonstrated on Holter recording in one patient. Theses repolarization disturbances with QT increase were considered dose limiting toxicity and the trial was closed. No arrhythmia related death was noted. Pharmacokinetics were similar with both infusion schedules with a mean alpha half life of 11.3 and 13.2 minutes, for the 30-minute and 150-minute infusion, and a terminal half life of 13.5 and 15 hours, respectively. QTc prolongation duration appeared to be dose-dependent.Conclusions: With the tested infusion schedules, cardiac toxicity, in particular AV-blocks and QT prolongation, leading to ventricular arrhythmia and torsade de pointe, are the dose limiting toxicities of S9788. Our experience together with the observation of asymptomatic torsade de pointe in two other phase I trials of S9788 infused over six hours precluded the further clinical development of S9788.  相似文献   
34.
STUDY OBJECTIVE: The objective of this retrospective study was to report the long-term results of distal revascularization at the ankle in patients with critical ischemia. PATIENTS AND METHODS: From January 1989 to November 1999, 50 inframalleolar bypasses were performed in 49 patients (35 males and 14 females with a mean age of 75 years [range: 51 to 95 years]). Twenty-five patients (50%) were diabetics. All patients presented with critical ischemia of the lower limb. Distal anastomosis was performed at the retromalleolar posterior tibial artery in 28 cases (56%), pedal artery in 20 cases (40%) and distal fibular artery in two cases (4%). Bypasses were performed using a greater saphenous vein (n = 38), a cryopreserved arterial allograft (n = 9), or a PTFE graft (n = 2). A composite graft with greater saphenous vein and arterial allograft was performed in two cases. RESULTS: There were two early postoperative deaths. One patient presented a blow-out of the distal anastomosis that required bypass ligation and subsequent leg amputation. Early thrombosis of the graft occurred in four cases, leading to major amputation in three cases. No patients were lost to follow-up and mean follow-up was 26.7 months (range: 1 to 86 months). Graft thrombosis occurred in 15 patients and led to amputation in 6 cases. Bypass graft patency rate was 72% and 61% at 1 year and 3 years, respectively, yielding a 80% limb salvage rate at 3 years. The 3-year actuarial survival rate was 53%. CONCLUSION: Inframalleolar bypasses are a valuable tool in patients with critical ischemia. The lower limb salvage rate is satisfactory in this elderly population. Based on this experience, angiography with good run-off and, when necessary, a surgical approach to verify patency of the arteries at the ankle should always be performed before undertaking a major amputation.  相似文献   
35.
36.
37.
We analyzed the magnetic resonance studies of the knee in 80 subjects, 45 men and 35 women with a mean age of 38.9 years, who showed no pathological condition of the joint. Using an imaging visualization software, the sagittal longitudinal axis of the tibia was identified. The angle between this axis and a line tangent to the bone profile of the tibial plateau (bone slope) and to the superior border of the menisci (meniscal slope) were calculated. Thickness of anterior and posterior portion of menisci and underlying cartilage were also measured. The bone slope averaged 8° and 7.7° on the medial and lateral sides, respectively. The mean meniscal slope was 4.1° and 3.3° on the medial and lateral sides, respectively, with a significant difference compared with the bone slope. Menisci and underlying cartilage were significantly thicker in their posterior than their anterior portion (7.6 and 5.2 mm, respectively, in the medial compartment; 8.6 and 5.2 mm, respectively, in the lateral compartment). The presence of cartilage and menisci implies a significant decrease in the posterior tibial slope. In the lateral compartment, the greater the bone slope, the larger the difference between bone and meniscal slope, which means that a marked posterior tilt of the lateral tibial plateau is decreased by the cartilage and meniscus. These findings should be taken into account in planning surgical procedures which affect the slope of the articular tibial surface. Clin. Anat. 26:883–892, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
38.
Nabiximols (Sativex) is an oromucosal spray, containing delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD), used as treatment for unresponsive spasticity in multiple sclerosis (MS) patients. Sativex is thought to not affect cognition or induce any psychiatric problem at the doses generally used. Nonetheless, it is known that the concomitant use of more than one muscle-relaxant drugs can result in additive neuropsychiatric effects. Herein we describe a case of a woman affected by MS and treated with baclofen and methylprednisolone, who developed important behavioral changes, including suicidal ideation, after 4 weeks of Sativex administration. We are not completely able to state if Sativex alone was responsible for our patient’s psychiatric symptoms, in reason of the concomitant use of the other drugs.In conclusion, physicians should pay more attention when prescribing drugs to MS patients affected by spasticity, including Sativex, since neurobehavioral side effects may emerge especially in predisposed individuals.  相似文献   
39.
Background and aimsPediatric obesity is an important health problem representing a major public health concern worldwide in the last decades. An isolated elevation of Thyroid Stimulating Hormone (TSH) with normal levels of thyroid hormones is frequently found in obese children. It has been named Isolated Hyperthyreotropinemia or Subclinical Hypothyroidism (SCH) and may be considered a consequence of obesity. Evidence exists that SCH is related to impairment of both systolic and diastolic myocardial function in the adult population.The aim of our study is to establish if obesity-related SCH influences myocardial function in children.Methods and resultsWe examined 34 obese children and adolescents with SCH and 60 obese children with normal TSH levels who underwent Doppler echocardiographic to evaluate myocardial function.Global systolic function as assessed by Ejection Fraction (EF) was comparable between groups, however Right Ventricle pressure global systolic function and pressure were significantly reduced in SCH group. Mitral annulus peak systolic (MAPSE) excursion lateral and MAPSE septum resulted significantly reduced in SCH group. Tissue Doppler imaging peak systolic motion (TDI-S) was reduced in SCH group. Diastolic function also showed significant modifications in SCH group.ConclusionThese results suggest possible involvement of cardiac function in obese children with SCH resulting in both abnormal diastolic function and reduced longitudinal systolic function. This new insight into cardiovascular consequences of obesity-related SCH in children could influence clinical approach to such patients by pediatric endocrinologists.  相似文献   
40.
Background: We conducted a meta-analysis to assess the overall risk of cardiac toxicity associated with trastuzumab treatment in elderly breast cancer patients.

Methods: We searched databases from PubMed, EMBASE and Cochrane Central Registry of Controlled Trials to identify relevant studies. Statistical analyses were conducted to calculate the incidence rate, overall hazard ratio (HR) and 95% CIs using a fixed effects model.

Results: A total of 116,342 and 360 elderly patients from five cohort studies and two randomized clinical trials (RCTs) were included for analysis. The pooled incidences of symptomatic congestive heart failure (CHF) and CHF/HF/CM were 6.4% (95% CI 4.1% – 9.4) and 16.4% (95% CI 16.19% – 16.61) in patients with median age of 67.5 years from two RCTs and in patients with median age of 67.5 (60 – 75), 71 (66 – 80+), 74.5 (65 – 89), 75 (66 – 81+) and 79.5 (60 – 99) from five cohort studies, respectively. Trastuzumab was significantly correlated with an increased risk of defined cardiac toxicities in five cohort studies (HR = 1.89, 95% CI 1.72 – 2.07, p < 0.00001) and two RCTs (HR = 3.00, 95% CI 1.71, 5.26, p < 0.00001). Sub-group analysis showed that the anthracycline-based chemotherapy increased the risk of CHF/HF and CM in patients among five cohort studies (HR = 2.16, 95% CI: 1.8 – 1.87, p < 0.00001).

Conclusion: Trastuzumab is likely associated with an increased risk of cardiac toxicity in elderly patients with HER-2-positive breast cancer. Carefully monitoring cardiac function in elderly patients receiving trastuzumab, particularly with concurrent use of anthracycline, is warranted.  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