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   254087篇
  免费   16454篇
  国内免费   1021篇
耳鼻咽喉   2904篇
儿科学   6569篇
妇产科学   4753篇
基础医学   32084篇
口腔科学   4772篇
临床医学   25760篇
内科学   53272篇
皮肤病学   3582篇
神经病学   25599篇
特种医学   11000篇
外国民族医学   25篇
外科学   39847篇
综合类   2714篇
现状与发展   1篇
一般理论   183篇
预防医学   17958篇
眼科学   6253篇
药学   16744篇
  1篇
中国医学   360篇
肿瘤学   17181篇
  2023年   1377篇
  2022年   2324篇
  2021年   5594篇
  2020年   3205篇
  2019年   5279篇
  2018年   6314篇
  2017年   4660篇
  2016年   5081篇
  2015年   6025篇
  2014年   8730篇
  2013年   11800篇
  2012年   18058篇
  2011年   18770篇
  2010年   10539篇
  2009年   9747篇
  2008年   16605篇
  2007年   17439篇
  2006年   16934篇
  2005年   16796篇
  2004年   15811篇
  2003年   14422篇
  2002年   13854篇
  2001年   2617篇
  2000年   2136篇
  1999年   2615篇
  1998年   3025篇
  1997年   2430篇
  1996年   2113篇
  1995年   1921篇
  1994年   1670篇
  1993年   1616篇
  1992年   1389篇
  1991年   1349篇
  1990年   1191篇
  1989年   1112篇
  1988年   1059篇
  1987年   950篇
  1986年   977篇
  1985年   977篇
  1984年   1147篇
  1983年   965篇
  1982年   1164篇
  1981年   1088篇
  1980年   960篇
  1979年   686篇
  1978年   677篇
  1977年   610篇
  1976年   566篇
  1975年   467篇
  1974年   486篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Loss of function variants in NOTCH1 cause left ventricular outflow tract obstructive defects (LVOTO). However, the risk conferred by rare and noncoding variants in NOTCH1 for LVOTO remains largely uncharacterized. In a cohort of 49 families affected by hypoplastic left heart syndrome, a severe form of LVOTO, we discovered predicted loss of function NOTCH1 variants in 6% of individuals. Rare or low-frequency missense variants were found in 16% of families. To make a quantitative estimate of the genetic risk posed by variants in NOTCH1 for LVOTO, we studied associations of 400 coding and noncoding variants in NOTCH1 in 1,085 cases and 332,788 controls from the UK Biobank. Two rare intronic variants in strong linkage disequilibrium displayed significant association with risk for LVOTO amongst European-ancestry individuals. This result was replicated in an independent analysis of 210 cases and 68,762 controls of non-European and mixed ancestry. In conclusion, carrying rare predicted loss of function variants in NOTCH1 confer significant risk for LVOTO. In addition, the two intronic variants seem to be associated with an increased risk for these defects. Our approach demonstrates the utility of population-based data sets in quantifying the specific risk of individual variants for disease-related phenotypes.  相似文献   
73.
74.
75.

Background

The purpose of this analysis is to describe the differences in cardiac magnetic resonance characteristics between benign and malignant tumors, which would be helpful for surgical planning.

Methods

This was a prospective cohort study of 130 patients who underwent cardiac magnetic resonance imaging for evaluation of a suspected cardiac mass. After excluding thrombi and tumors without definitive diagnosis, 66 tumors were evaluated for morphologic features and tissue composition.

Results

Of the 66 patients, 39 (59.0%) had malignant tumors and 27 (41.0%) had benign tumors. Patients with malignant tumors were younger when compared with those with benign tumors (age 51 years [42.8-60.0] vs 65 years [60.0-71.0] median). Malignant tumors more often demonstrated tumor invasion (69% vs 0% P < .001) and were more often associated with pericardial effusion (41% vs 7.4% P = .004). Presence of first-pass perfusion (100% vs 33% P < .001) and late gadolinium enhancement (100% vs 59.2%, P < .001) were significantly higher in malignant tumors. In logistic regression modeling, tumor invasion (P < .001) and first-pass perfusion (P < .001) were independently associated with malignancy. Furthermore, using classification and regression tree analysis, we developed a decision tree algorithm to help differentiate benign from malignant tumors (diagnostic accuracy ~90%). The algorithm-weighted cost of misclassifying a malignant tumor as benign was twice that of classifying a benign tumor as malignant.

Conclusions

Our study demonstrates that cardiac magnetic resonance imaging is a useful noninvasive method for differentiating malignant from benign cardiac tumors. Tumor size, invasion, and first-pass perfusion were useful imaging characteristics in differentiating benign from malignant tumors.  相似文献   
76.
Der Freie Zahnarzt - Rechtstipp. Für angebliche Behandlungs- und Aufklärungsfehler bleiben die Zivilgerichte auch bei Kostenerstattung zuständig. Eine kuriose, wiewohl wichtige...  相似文献   
77.
78.
Tauchunfälle     
Notfall + Rettungsmedizin - Tauchunfälle sind vergleichsweise selten und stellen (Erst‑)Helfer vor besondere Herausforderungen. Sie müssen schnell und kompetent behandelt werden, da...  相似文献   
79.
The presented case reports on successful treatment with everolimus in a neonate with left ventricular giant rhabdomyoma. The authors used a different dosage regime compared to literature and documented rapid tumor regression by 3D echocardiography.  相似文献   
80.
ObjectivesSevere acute kidney injury (AKI) is a known risk factor for infection and mortality. However, whether stage 1 AKI is a risk factor for infection has not been evaluated in adults. We hypothesized that stage 1 AKI following cardiac surgery would independently associate with infection and mortality.MethodsIn this retrospective propensity score–matched study, we evaluated 1620 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital from 2011 to 2017. Patients who developed stage 1 AKI by Kidney Disease Improving Global Outcomes creatinine criteria within 72 hours of surgery were matched to patients who did not develop AKI. The primary outcome was an infection, defined as a new surgical-site infection, positive blood or urine culture, or development of pneumonia. Secondary outcomes included in-hospital mortality, stroke, and intensive care unit (ICU) and hospital length of stay (LOS).ResultsStage 1 AKI occurred in 293 patients (18.3%). Infection occurred in 20.9% of patients with stage 1 AKI compared with 8.1% in the no-AKI group (P < .001). In propensity-score matched analysis, stage 1 AKI independently associated with increased infection (odds ratio [OR]; 2.24, 95% confidence interval [CI], 1.37-3.17), ICU LOS (OR, 2.38; 95% CI, 1.71–3.31), and hospital LOS (OR, 1.30; 95% CI, 1.17-1.45).ConclusionsStage 1 AKI is independently associated with postoperative infection, ICU LOS, and hospital LOS. Treatment strategies focused on prevention, early recognition, and optimal medical management of AKI may decrease significant postoperative morbidity.  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