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   580篇
  免费   44篇
  国内免费   3篇
儿科学   33篇
妇产科学   27篇
基础医学   106篇
口腔科学   5篇
临床医学   46篇
内科学   155篇
皮肤病学   5篇
神经病学   103篇
特种医学   9篇
外科学   29篇
预防医学   54篇
眼科学   16篇
药学   28篇
肿瘤学   11篇
  2024年   3篇
  2023年   9篇
  2022年   11篇
  2021年   22篇
  2020年   11篇
  2019年   18篇
  2018年   24篇
  2017年   22篇
  2016年   19篇
  2015年   19篇
  2014年   16篇
  2013年   29篇
  2012年   48篇
  2011年   40篇
  2010年   20篇
  2009年   27篇
  2008年   40篇
  2007年   36篇
  2006年   37篇
  2005年   30篇
  2004年   24篇
  2003年   30篇
  2002年   30篇
  2001年   4篇
  2000年   1篇
  1999年   5篇
  1998年   7篇
  1997年   5篇
  1996年   4篇
  1995年   2篇
  1994年   1篇
  1993年   5篇
  1992年   2篇
  1991年   2篇
  1990年   2篇
  1989年   6篇
  1988年   2篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1984年   2篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
  1976年   1篇
  1975年   1篇
  1971年   1篇
排序方式: 共有627条查询结果,搜索用时 46 毫秒
1.
2.
3.
Trio exome sequencing is a powerful tool in the molecular investigation of monogenic disorders and provides an incremental diagnostic yield over proband‐only sequencing, mainly due to the rapid identification of de novo disease‐causing variants. However, heterozygous variants inherited from unaffected parents may be inadvertently dismissed, although multiple explanations are available for such scenarios including mosaicism in the parent, incomplete penetrance, imprinting, or skewed X‐inactivation. We report three probands, in which a pathogenic or likely pathogenic variant was identified upon exome sequencing, yet was inherited from an unaffected parent. Segregation of the variants (in NOTCH1, PHF6, and SOX10) in the grandparent generation revealed that the variant was de novo in each case. Additionally, one proband had skewed X‐inactivation. We discuss the possible genetic mechanism in each case, and urge caution in data interpretation of exome sequencing data. We illustrate the utility of expanding segregation studies to the grandparent generation and demonstrate the impact on exome interpretation strategies, by showing that objective genotype data can overcome subjective parental report of lack of symptoms.  相似文献   
4.
Purpose: Our purpose was to measure changes in semen quality and quantity in young healthy sperm donors in Jerusalem over time. Methods: A retrospective analysis of semen parameters over 15 years using linear regression analysis, in a single sperm bank in a tertiary university center. Study population consisted of 188 young, healthy medical students, aged 20 to 30 years, who donated sperm samples for Artificial insemination between 1980 and 1995. Results: There were no statistically significant changes in semen concentration and motility during the study period. The mean semen volume increased by 0.1 ml (5.1%) per year (P < 0.0001), with a concomitant mean rise of 5.8 × 106 (7.7%) per year in total motile sperm count. The percentage normal morphology decreased by a mean of 1.04% per year during the entire period (P < 0.0001). Conclusions: During the past 15 years, there has been an increase in total motile sperm count, secondary to an increase in semen volume, and a decline in normal morphology that are independent of the age and the duration of abstinence in fertile men.  相似文献   
5.
Purpose: Maternal thyroid gland dysfunction may adversely affect pregnancy outcome. We aimed to examine the association between subclinical thyroid dysfunction, both hypothyroidism and hyperthyroidism, to adverse pregnancy outcome.

Materials and methods: Retrospective cohort study of all women with an available first trimester thyroid function testing and known pregnancy outcome, categorized to subclinical hypothyroidism, or hyperthyroidism and evaluated for complication during gestation and delivery.

Results: Four thousand five hundred and four women were included in the final analysis – 3231 were euthyroid, 73 (1.6%) were categorized as subclinical hyperthyroidism and 1200 (26.6%) had subclinical hypothyroidism. Low thyroid-stimulating hormone (TSH) levels, i.e. subclinical hyperthyroidism, correlates with higher rates of placental abruption and extremely low birth weight, below 1500?g. Also, the risk for preterm delivery prior to 34 gestational weeks is higher among women with subclinical hypothyroidism, with greater risk among those with a higher TSH level. (OR 1.81, 95% CI 1.0–3.28 for TSH 2.5–4.0 mIU/L and OR 2.33, 95% CI 1.11–4.42 for those with TSH?>?4 4.0 mIU/L).

Conclusions: Subclinical hypothyroidism is associated with an increased risk for preterm delivery prior to 34 gestational weeks. Additionally, subclinical hyperthyroidism may also have a role in adverse pregnancy outcome – low birth weight and placental abruption – although this needs to be further explored.  相似文献   
6.
STUDY OBJECTIVE: To evaluate the efficacy of intraperitoneal nebulization of ropivacaine on pain relief during and after gynecologic laparoscopic procedures including a review of the literature. DESIGN: Double-blinded, randomized, controlled, clinical trial (Canadian Task Force classification I). SETTING: University hospital ambulatory gynecoendoscopic department. PATIENTS: Forty patients (20 patients in each arm) undergoing elective gynecologic same-day outpatient laparoscopic surgery including unilateral/bilateral salpingo-oophorectomy or unilateral/bilateral ovarian cystectomy. INTERVENTIONS: The study group received 10 mL of 1% ropivacaine and the control group received 10 mL of sterile water by intraperitoneal nebulization. During surgery, vital signs were recorded and summarized. Postoperatively patients were followed up for 24 hours including visual analog scale scores and analgesic use. MEASUREMENTS AND MAIN RESULTS: No significant differences existed between the groups during surgery and at the recovery department in terms of arterial blood pressure (p = .42) or heart rate (p = .60). Regarding postoperative analgesia, no difference existed between the groups in terms of morphine consumption (p = .52) or other analgesics (p = .53). No significant difference existed between the groups in postoperative visual analog scale scores including visceral, abdominal wall, and shoulder pain during rest and during cough at the different time frames (30, 60, and 120 minutes and 6 and 24 hours after surgery). CONCLUSION: Our study is the first to examine the effects of intraperitoneal nebulization of ropivacaine throughout laparoscopic gynecologic procedures on patients undergoing general anesthesia. Nebulization of 100 mg of ropivacaine under our specific regimen of anesthesia does not improve patients' outcome in terms of intraoperative and postoperative pain along with consumption of analgesics. Further research with other regimens is required.  相似文献   
7.
DNA methyltransferase 3a (DNMT3a) is an important part of the epigenetic machinery that stabilizes patterns of activated T cell responses. We hypothesized that donor T cell DNMT3a regulates alloreactivity after allogeneic blood and marrow transplantation (allo-BMT). T cell conditional Dnmt3a KO mice were used as donors in allo-BMT models. Mice receiving allo-BMT from KO donors developed severe acute graft-versus-host disease (aGVHD), with increases in inflammatory cytokine levels and organ histopathology scores. KO T cells migrated and proliferated in secondary lymphoid organs earlier and demonstrated an advantage in trafficking to the small intestine. Donor T cell subsets were purified after BMT for whole-genome bisulfite sequencing (WGBS) and RNA-Seq. KO T cells had global methylation similar to that of WT cells, with distinct, localized areas of hypomethylation. Using a highly sensitive computational method, we produced a comprehensive profile of the altered epigenome landscape. Hypomethylation corresponded with changes in gene expression in several pathways of T cell signaling and differentiation. Additionally, Dnmt3a-KO T cells resulted in superior graft-versus-tumor activity. Our findings demonstrate a critical role for DNMT3a in regulating T cell alloreactivity and reveal pathways that control T cell tolerance. These results also provide a platform for deciphering clinical data that associate donor DNMT3a mutations with increased GVHD, decreased relapse, and improved survival.  相似文献   
8.
BackgroundAdvanced heart failure (HF) patients usually poorly tolerate guideline‐directed HF medical therapy (GDMT) and suffer high rates of morbidity and mortality. The use of continuous inotropes in the outpatient settings is hampered by previous data showing excess morbidity. We aimed to assess the safety and efficacy of repetitive, intermittent, short‐term intravenous milrinone therapy in advanced HF patients with an intention to introduce and up‐titrate GDMT and improve functional class.HypothesisRepetitive, intermittent milrinone therapy may assist with the stabilization of advanced HF patients.MethodsAdvanced HF patients treated with beta‐blockers and implanted with defibrillators were initiated with repetitive, intermittent short‐term intravenous milrinone therapy at our HF outpatient unit. Patients were prospectively followed with defibrillator interrogation, functional class assessment, B‐natriuretic peptide (BNP) levels, and echocardiography parameters.ResultsThe cohort included 24 patients with a mean 330 ± 240 days of milrinone therapy exposure. Mean age was 73 ± 6 years with male predominance (96%). Following milrinone therapy, median BNP levels decreased significantly (882 [286−3768] to 631 [278−1378] pg/ml, p = .017) with a significant reduction in the number of patients with New York Heart Association (NYHA) Class III and IV (p = .012, 0.013) and an increase in number of patients on GDMT. Importantly, the number of total sustained ventricular tachycardia events and HF hospitalizations did not change.ConclusionsIn this small cohort of advanced HF, repetitive, intermittent, short‐term milrinone therapy was found to be safe and potentially efficacious.  相似文献   
9.
Despite the growing evidence regarding the effectiveness of cognitive–behavioral interventions in reducing occupational stress, very few studies have examined its effectiveness among nurses. This study investigated the impact of a cognitive–behavioral (CB) course on the nurses' well-being. The study compared the sense of coherence (SOC), perceived stress (PSS), and mood states of 20 nurses who had participated in the CB course to that of 16 control participants using a pre–post test design. At baseline (t1), no significant differences were found between the two groups in SOC, PSS, and mood states. The effects within each group controlling for t1 were examined by analysis of covariance. At t2, a significant increase in SOC and the mood state of vigor and a significant decrease in PSS and fatigue were found only among participants in the CB course. The results are discussed in relation to the conceptual framework of stress and coping theory.  相似文献   
10.
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