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   1284篇
  免费   76篇
  国内免费   1篇
耳鼻咽喉   12篇
儿科学   24篇
妇产科学   28篇
基础医学   149篇
口腔科学   20篇
临床医学   102篇
内科学   279篇
皮肤病学   15篇
神经病学   87篇
特种医学   44篇
外科学   217篇
综合类   28篇
预防医学   62篇
眼科学   182篇
药学   46篇
中国医学   2篇
肿瘤学   64篇
  2023年   8篇
  2022年   19篇
  2021年   30篇
  2020年   21篇
  2019年   33篇
  2018年   47篇
  2017年   34篇
  2016年   24篇
  2015年   24篇
  2014年   39篇
  2013年   61篇
  2012年   105篇
  2011年   101篇
  2010年   51篇
  2009年   35篇
  2008年   79篇
  2007年   58篇
  2006年   54篇
  2005年   44篇
  2004年   56篇
  2003年   44篇
  2002年   41篇
  2001年   45篇
  2000年   41篇
  1999年   28篇
  1998年   6篇
  1997年   8篇
  1996年   15篇
  1994年   7篇
  1992年   10篇
  1991年   8篇
  1989年   10篇
  1988年   9篇
  1987年   8篇
  1986年   8篇
  1985年   8篇
  1984年   11篇
  1983年   8篇
  1982年   7篇
  1979年   9篇
  1978年   8篇
  1977年   5篇
  1975年   9篇
  1974年   8篇
  1972年   11篇
  1971年   6篇
  1969年   8篇
  1968年   7篇
  1967年   7篇
  1966年   12篇
排序方式: 共有1361条查询结果,搜索用时 406 毫秒
111.
To determine whether a nonsocial enrichment program affects cardiovascular responses of individually housed male Sprague-Dawley (SD) and spontaneously hypertensive (SH) rats under basal conditions and after potentially stressful procedures, we used radiotelemetry to record heart rate (HR), systolic blood pressure (SBP), and activity in the cage. Enrichment comprised a simulated burrow (Rodent Retreat), then a food foraging item ("rat cannoli") 2 days later, and a paper bag of bedding for shredding (Nestpak) after another 2 days. Data were collected under undisturbed conditions and before and after several acute and chronic manipulations mimicking common husbandry, experimental, and stressful procedures. Enrichment often, but not always, reduced HR and SBP in male rats, suggesting decreased arousal and stress, and the effects depended on the parameter measured, strain of rat, and nature of the procedure to which animals were exposed. In general, HR varied more than SBP; enrichment affected SH rats more than SD rats; effects of enrichment were more consistently observed under undisturbed conditions than after manipulations of the rats; moderate responses to acute husbandry and experimental procedures were affected more than the larger changes produced by very stressful procedures; and responses to social interactions were unaffected by the enrichment program. What accounts for these variable effects of enrichment is unclear, and more studies are required to resolve the mechanisms. Whether this enrichment program should be used in an animal facility depends on several factors, particularly the professional judgment of the research, veterinary, and animal care staffs involved.  相似文献   
112.
Objective : This study describes and compares prevalence trends of markers for hepatitis B (HBV) from 2004 to 2013 and HBV risk factors between Indigenous and non‐Indigenous prison entrants. Methods : A cross‐sectional survey carried out over two weeks in 2004, 2007, 2010 and 2013 in reception prisons in New South Wales, Queensland, Western Australia and Tasmania. Results : The study included 2,223 prison entrants; 544 were Indigenous. Indigenous prison entrants had significantly higher hepatitis B core antibody (anti‐HBc) prevalence than non‐Indigenous prisoners in 2004 (29% vs. 18%, P=0.026), 2007 (40% vs. 15%, P<0.001) and 2010 (21% vs. 16% 2010, P=0.002), and similar anti‐HBc prevalence to non‐Indigenous entrants in 2013 (14% vs. 14%, P=0.888), with a significant decline from 2007 for Indigenous entrants (P=0.717)?. Being more than 30 years old and coming from an area classified as ‘non‐highly accessible’ were associated with anti‐HBc positivity in both populations. For Indigenous prison entrants, first time in prison and survey year was associated with anti‐HBc positivity. For non‐Indigenous participants, a history of injecting drug use and body piercings was associated with anti‐HBc positivity. Conclusion : There are unique risk factors associated with HBV prevalence for both Indigenous and non‐Indigenous prison entrants. Implications for public health : In developing public health programs and policies for HBV, consideration of similarities and differences of associated HBV risk factors between Indigenous and non‐Indigenous offenders is required.  相似文献   
113.
J. L. Swanson    M. Azar    J. Miller    J. J. McCullough 《Transfusion》1974,14(5):470-474
An inbred family (Wald.) with three apparently LW negative members in two generations is described in this report. Studies of the red blood cells of these LW negative family members with a variety of anti-LW reagents establishes that the VW-Wald. category is a weak LW variant. Wald. red blood cells react weakly with the anti-LW of Bige., but are negative with that of VW. An analogy may be made between the LW, ABO, and P systems. LW negative (lwlw) of the Bige. type corresponds to group O or pp. Weak LW positive or VW-Wald. type corresponds to A2 and P2. Normal LW positive corresponds to A1 and P1. The antibody made by lwlw individuals may be comparable to the anti A + A1 of group O and anti P + P1 of pp. The antibody made by weak LW positive or VW type may be comparable to the anti A1 of A2 and anti P1 of P2 individuals. It is suggested that donors and patients now classified as LW negative be characterized as Bige. or VW types until more precise nomenclature is defined.  相似文献   
114.
115.
116.
Amyloidosis is a spectrum of disease characterized by the abnormal deposition of fibril amyloid-related proteins in the extracellular space. The most common types of amyloidosis are AL and AA amyloidosis. Amyloidosis is also classified according to the extent of the deposition as systemic or localized. Respiratory amyloidosis is classified as laryngeal, tracheobronchial or parenchymal amyloidosis. Tracheobronchial amyloidosis is classically known as a rare manifestation of the localized disease. A few cases only of systemic amyloidosis presenting as a tracheobronchial disease have been reported. We here report a 26-year-old man who presented with hemoptysis related to a systemic tracheal primary amyloidosis.  相似文献   
117.
Recent advances in experimental stimulation methods have raised the following important computational question: how can we choose a stimulus that will drive a neuron to output a target spike train with optimal precision, given physiological constraints? Here we adopt an approach based on models that describe how a stimulating agent (such as an injected electrical current or a laser light interacting with caged neurotransmitters or photosensitive ion channels) affects the spiking activity of neurons. Based on these models, we solve the reverse problem of finding the best time-dependent modulation of the input, subject to hardware limitations as well as physiologically inspired safety measures, that causes the neuron to emit a spike train that with highest probability will be close to a target spike train. We adopt fast convex constrained optimization methods to solve this problem. Our methods can potentially be implemented in real time and may also be generalized to the case of many cells, suitable for neural prosthesis applications. With the use of biologically sensible parameters and constraints, our method finds stimulation patterns that generate very precise spike trains in simulated experiments. We also tested the intracellular current injection method on pyramidal cells in mouse cortical slices, quantifying the dependence of spiking reliability and timing precision on constraints imposed on the applied currents.  相似文献   
118.

Background

Inpatient satisfaction with care is a standard indicator of the quality of care delivered during hospitalization. Total hip and knee replacement (THR/TKR) for osteoarthritis (OA) are among the most successful orthopaedic interventions having a positive impact on health-related quality of life (HRQoL). The aim was to evaluate the effect of satisfaction shortly after hospital discharge on 1-month, 6-month and 1-year Medical Outcomes Study 36-item Short Form (SF-36) scores for OA patients after THR and TKR, controlling for patient characteristics, clinical presentation and preoperative SF-36 scores.

Methods

A multicenter prospective cohort study recruited 231 patients with OA scheduled to receive THR or TKR. Satisfaction was assessed by the Patients Judgment of Hospital Quality (PJHQ) questionnaire and HRQoL by the SF-36 questionnaire. Linear models for repeated measures assessed the relation between satisfaction (scores were dichotomized) and postoperative SF-36 scores.

Results

Of 231 participants, 189 were followed up 12 months after discharge (mean age 69 SD = 8; 42.6% male). The mean length of hospital stay was 13.5 (SD = 4) days. After adjustment for preoperative SF-36 scores, sociodemographic and clinical patient characteristics, satisfied patients (PJHQ score > 70) had higher SF-36 scores 1 year after surgery than did less-satisfied patients. Admission, medical care, and nursing and daily care scores mainly predicted bodily pain, mental health, social functioning, vitality and general health scores of the SF-36.

Conclusion

Besides being a quality-of-care indicator, immediate postoperative patient satisfaction with care may bring a new insight into clinical practice, as a predictor of self-perceived health status after surgery.  相似文献   
119.

Introduction

Graft dysfunction immediately posttransplantation can vary from subtle slowing of the expected decrease in creatinine concentration to frank oliguria requiring dialysis therapy for days to weeks. Risk factors for slow and delayed graft function include prolonged preservation, older donor age, and high plasma renin activity in the recipient. Cyclosporine (CsA) nephrotoxicity is another cause of early kidney allograft dysfunction.

Objective

To evaluate early kidney allograft function in patients who received low-dose CsA therapy for 48 hours before transplant surgery for comparison with that in recipients who received CsA therapy after improvement in allograft function.

Patients and Methods

In a case-control comparative study, 66 kidney recipients were divided into 2 groups on the basis of time of initiation of CsA therapy. In group 1, patients received CsA, 100 mg twice a day, for 48 hours before surgery, and in group 2, patients received CsA therapy after surgery when allograft function had improved (serum creatinine concentration ≤3 mg/dL). Other immunosuppression medications were the same in both groups. Statistical analysis was performed to compare kidney allograft function in the first month posttransplantation.

Results

In group 1 vs group 2, at day 1 posttransplantation, mean (SD) blood urea concentration was 73.72 (31.00) mg/dL vs 87.52 (29.82) mg/dL, serum creatinine concentration was 5.11 (1.83) mg/dL vs 6.42 (3.64) mg/dL, and urine volume in 24 hours was 11,052 (4290) mL vs 9629 (45.30) mL. At the end of the study, blood urea concentration was 49.61 (12.18) mg/dL vs 69.11 (33.76) mg/dL, serum creatinine concentration was 1.22 (0.28) mg/dL vs 1.47 (0.79) mg/dL, and urine volume in 24 hours was 3202 (986) mL vs 3095 (726) mL. No significant difference was noted between the 2 groups for age, sex, and immunosuppression medications.

Conclusion

Low-dose CsA therapy before transplant surgery preserves early allograft function without deleterious effects.  相似文献   
120.
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