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   1710篇
  免费   116篇
  国内免费   6篇
耳鼻咽喉   11篇
儿科学   44篇
妇产科学   18篇
基础医学   276篇
口腔科学   31篇
临床医学   179篇
内科学   354篇
皮肤病学   21篇
神经病学   136篇
特种医学   66篇
外科学   206篇
综合类   18篇
一般理论   3篇
预防医学   160篇
眼科学   46篇
药学   97篇
肿瘤学   166篇
  2023年   13篇
  2022年   17篇
  2021年   27篇
  2020年   37篇
  2019年   47篇
  2018年   48篇
  2017年   41篇
  2016年   45篇
  2015年   39篇
  2014年   70篇
  2013年   88篇
  2012年   121篇
  2011年   127篇
  2010年   61篇
  2009年   68篇
  2008年   112篇
  2007年   106篇
  2006年   109篇
  2005年   132篇
  2004年   92篇
  2003年   69篇
  2002年   88篇
  2001年   14篇
  2000年   9篇
  1999年   11篇
  1998年   16篇
  1997年   7篇
  1996年   22篇
  1995年   15篇
  1994年   9篇
  1993年   11篇
  1992年   7篇
  1991年   11篇
  1990年   8篇
  1989年   11篇
  1988年   9篇
  1987年   9篇
  1986年   4篇
  1985年   5篇
  1984年   12篇
  1983年   14篇
  1982年   7篇
  1980年   4篇
  1979年   4篇
  1977年   5篇
  1976年   4篇
  1972年   7篇
  1967年   3篇
  1965年   3篇
  1937年   4篇
排序方式: 共有1832条查询结果,搜索用时 0 毫秒
51.
We present a patient with severe tracheal stenosis resulting from a compression by the innominate artery 6 months after an arterial switch operation in a dextro-transposition of the great arteries. Segmentation and three-dimensional (3D) visualization were derived from a contrast-enhanced dual-source computed tomography and post-processing was performed using a dedicated open-source platform (3D Slicer). Post-processing allowed a comprehensible visualization of the relationship of the innominate artery to the trachea when compared to standard computer tomography reformations. Finally, the surgical approach to move the innominate artery anteriorly in order to relieve the tracheal obstruction was emphasized based on the improved 3D visualization of the actual pathology. An effective aortopexy could be performed and the postoperative result was confirmed by a second 3D visualization. About 3 months of follow-up, the patient is completely asymptomatic. Three-dimensional visualization offers excellent opportunities for diagnosis, treatment planning and follow-up in patients with a vascular-related tracheal stenosis in the context of congenital heart disease.  相似文献   
52.
53.
BACKGROUND: Direct evidence of coronary artery remodeling can be derived only from serial changes in the external elastic membrane (EEM) and plaque area. The aim of the study was to assess the effect of simvastatin on coronary remodeling in serial intravascular ultrasound (IVUS) studies. METHODS: In 39 male patients ECG-triggered transducer pullback IVUS was performed at baseline, after 3 months on a lipid-lowering diet (control period), and after another 12 months of simvastatin 40 mg/day. The lesion site was the image slice with maximum plaque burden at 3 months. RESULTS: Absolute changes in the EEM area correlated significantly with changes in plaque area during the control period [B = 0.966, r = 0.792 (95% CI 0.71-1.22); p < 0.001] and during simvastatin treatment [B = 0.945, r = 0.822 (95% CI 0.73-1.16); p < 0.001], but there was no significant difference in the slope (delta EEM/delta plaque) between the two time intervals. After 12 months of simvastatin, there was a significant reduction in the lesion EEM area of 4.6% (p = 0.006) and in the lesion plaque area of 5.9% (p < 0.001), but there was no change in reference measurements. As a result, the remodeling index was reduced by simvastatin from 1.01 +/- 0.12 to 0.95 +/- 0.09 (p < 0.001). CONCLUSION: Simvastatin decreases the remodeling index by reducing lesion, but not reference plaque and EEM area. However, simvastatin does not affect direct evidence of remodeling (delta EEM/delta plaque) obtained using serial IVUS studies.  相似文献   
54.
Objective: To examine whether mental vulnerability, an enduring personality characteristic, predicts incident hospital-diagnosed ulcer over three decades.

Materials and methods: A population-based cohort study enrolled 3365 subjects with no ulcer history, ages 30–60, in 1982–3. Mental vulnerability, Helicobacter pylori IgG antibodies, socioeconomic status, and sleep duration were determined at baseline; non-steroidal antiinflammatory drug use, smoking, leisure time physical activity, and alcohol consumption both at baseline and in 1993–4. Hospital diagnoses of incident ulcer through 2011 were detected using the Danish National Patient Registry.

Results: Ulcers were diagnosed in 166 subjects, including 83 complicated by bleeding or perforation. Age-, gender-, and socioeconomic status-adjusted associations were significant for mental vulnerability (Hazard Ratio (HR) 2.0, 95% Confidence Interval 1.4–2.8), Helicobacter pylori (HR 1.7, CI 1.2–2.3), smoking (HR 2.0, CI 1.3–3.1), heavy drinking (HR 1.6, CI 1.1–2.4), abstinence (HR 1.6, CI 1.1–2.5), non-steroidal antiinflammatory drugs (HR 2.1, CI 1.5–3.0), and sedentary lifestyle (HR 1.9, CI 1.4–2.7). Adjusted for all behavioral mediators, the HR for mental vulnerability was 1.5 (CI 1.0–2.2, p?=?.04). Mental vulnerability raised risk in Helicobacter pylori seropositive subjects and those exposed to neither Helicobacter pylori nor non-steroidal antiinflammatory drugs; its impact was virtually unchanged when analysis was limited to complicated ulcers.

Conclusions: A vulnerable personality raises risk for hospital-diagnosed peptic ulcer, in part because of an association with health risk behaviors. Its impact is seen in ‘idiopathic’ and Helicobacter pylori-associated ulcers, and in acute surgical cases.  相似文献   
55.
56.
BACKGROUND: Only a few randomized clinical trials have tested the effect on transition rates of intervention programs for patients with sub-threshold psychosis-like symptoms. AIM: To examine whether integrated treatment reduced transition to psychosis for first-contact patients diagnosed with schizotypal disorder. METHODS: Seventy-nine patients were randomized to integrated treatment or standard treatment. Survival analysis with multivariate Cox-regression was used to identify factors determinant for transition to psychotic disorder. RESULTS: In the multivariate model, male gender increased risk for transition to psychotic disorder (relative risk=4.47, (confidence interval 1.30-15.33)), while integrated treatment reduced the risk (relative risk=0.36 (confidence interval 0.16-0.85)). At two-year follow-up, the proportion diagnosed with a psychotic disorder was 25.0% for patients randomized to integrated treatment compared to 48.3% for patients randomized to standard treatment. CONCLUSION: Integrated treatment postponed or inhibited onset of psychosis in significantly more cases than standard treatment.  相似文献   
57.
58.
59.
OBJECTIVE: Andriol Testocaps is a new oral formulation of testosterone undecanoate (TU) for treatment of hypogonadism. As TU is taken up by the intestinal lymphatic system, both the presence and the composition of food influence the absorption. The aim of this study was to investigate the effect of food composition on the pharmacokinetics of oral TU. DESIGN: An open-label, single-centre, four-way crossover study. With a washout period of 6-7 days, 80 mg TU was administered in the morning 5 min after consuming each of four different meals in a randomized order (A: 230 kcal, 0.6 g lipid; B: 220 kcal, 5 g lipid; C: 474 kcal, 19 g lipid; D: 837 kcal, 44 g lipid). PATIENTS: Twenty-four postmenopausal volunteers. MEASUREMENTS: Serial blood samples were collected until 24 h after dosing to determine testosterone and dihydrotestosterone (DHT) by gas chromatography-mass spectroscopy (GC-MS). RESULTS: The bioavailability of testosterone after a low-calorie meal containing 0.6 g lipid or 5 g lipid was relatively low, the area under the concentration-time curve (AUC(0-tlast)) for testosterone being 30.7 and 43.5 nmol h/l, respectively. The bioavailability of testosterone after a meal containing 19 g lipid was considerably higher (AUC(0-tlast) = 146 nmol h/l), whereas increasing the lipid content to 44 g lipid did not further increase the bioavailability of testosterone (AUC(0-tlast) = 154 nmol h/l). CONCLUSION: Approximately 19 g of lipid per meal efficiently increases absorption of testosterone from oral TU. Therefore, coadministration with a normal rather than a fatty meal is sufficient to increase serum testosterone levels when using oral TU.  相似文献   
60.
Nuclear-cytoplasmic partitioning and traffic between cytoplasmic and nuclear compartments are fundamental processes in eukaryotic cells. Nuclear pore complexes mediate transport of proteins, RNAs and ribonucleoprotein particles in and out of the nucleus. Here we present positional cloning of a plant nucleoporin gene, Nup133, essential for a symbiotic signal transduction pathway shared by Rhizobium bacteria and mycorrhizal fungi. Mutation of Nup133 results in a temperature sensitive nodulation deficient phenotype and absence of mycorrhizal colonization. Root nodules developing with reduced frequency at permissive temperatures are ineffective and electron microscopy show that Rhizobium bacteria are not released from infection threads. Measurement of ion fluxes using a calcium-sensitive dye show that Nup133 is required for the Ca2+ spiking normally detectable within minutes after application of purified rhizobial Nod-factor signal molecules to root hairs. Localization of NUP133 in the nuclear envelope of root cells and root hair cells shown with enhanced yellow fluorescent protein fusion proteins suggests a novel role for NUP133 nucleoporins in a rapid nuclear-cytoplasmic communication after host-plant recognition of symbiotic microbes. Our results identify a component of an intriguing signal process requiring interaction at the cell plasma membrane and at intracellular nuclear and plastid organelle-membranes to induce a second messenger.  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