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   2102篇
  免费   101篇
  国内免费   5篇
耳鼻咽喉   22篇
儿科学   34篇
妇产科学   97篇
基础医学   181篇
口腔科学   21篇
临床医学   166篇
内科学   503篇
皮肤病学   20篇
神经病学   237篇
特种医学   76篇
外国民族医学   1篇
外科学   302篇
综合类   2篇
预防医学   102篇
眼科学   16篇
药学   236篇
中国医学   5篇
肿瘤学   187篇
  2023年   11篇
  2022年   40篇
  2021年   36篇
  2020年   22篇
  2019年   40篇
  2018年   45篇
  2017年   38篇
  2016年   42篇
  2015年   45篇
  2014年   61篇
  2013年   81篇
  2012年   132篇
  2011年   138篇
  2010年   82篇
  2009年   79篇
  2008年   157篇
  2007年   150篇
  2006年   135篇
  2005年   142篇
  2004年   148篇
  2003年   136篇
  2002年   106篇
  2001年   33篇
  2000年   33篇
  1999年   22篇
  1998年   24篇
  1997年   23篇
  1996年   18篇
  1995年   10篇
  1994年   8篇
  1993年   13篇
  1992年   11篇
  1991年   11篇
  1990年   21篇
  1989年   5篇
  1988年   13篇
  1987年   17篇
  1986年   10篇
  1985年   8篇
  1984年   14篇
  1982年   6篇
  1980年   6篇
  1979年   3篇
  1978年   4篇
  1977年   3篇
  1976年   2篇
  1973年   2篇
  1972年   2篇
  1971年   3篇
  1933年   2篇
排序方式: 共有2208条查询结果,搜索用时 15 毫秒
41.
ObjectivesTo compare three-dimensional facial scans obtained by stereophotogrammetry with two different applications for smartphone supporting the TrueDepth system, a structured light technology.Materials and MethodsFacial scans of 40 different subjects were acquired with three different systems. The 3dMDtrio Stereophotogrammetry System (3dMD, Atlanta, Ga) was compared with a smartphone (iPhone Xs; Apple, Cupertino, Calif) equipped with the Bellus3D Face Application (version 1.6.11; Bellus3D Inc, Campbell, Calif) or Capture (version 1.2.5; Standard Cyborg Inc, San Francisco, Calif). Times of image acquisition and elaboration were recorded. The surface-to-surface deviation and the distance between 18 landmarks from 3dMD reference images to those acquired with Bellus3D or Capture were measured.ResultsCapturing and processing times with the smartphone applications were considerably longer than with the 3dMD system. The surface-to-surface deviation analysis between the Bellus3D and 3dMD showed an overlap percentage of 80.01% ± 5.92% and 56.62% ± 7.65% within the ranges of 1 mm and 0.5 mm discrepancy, respectively. Images from Capture showed an overlap percentage of 81.40% ± 9.59% and 56.45% ± 11.62% within the ranges of 1 mm and 0.5 mm, respectively.ConclusionsThe face image acquisition with the 3dMD device is fast and accurate, but bulky and expensive. The new smartphone applications combined with the TrueDepth sensors show promising results. They need more accuracy from the operator and more compliance from the patient because of the increased acquisition time. Their greatest advantages are related to cost and portability.  相似文献   
42.
BackgroundPhysical activity may increase the risk of cardiotoxicity (myocardial ischemia, major arrhythmias) of 5-Fluorouracil, but this risk has never been investigated for its prodrug capecitabine.Patients and MethodsOne hundred and ninety-two consecutive patients undergoing capecitabine chemotherapy from December 1, 2010 through July 31, 2016 were prospectively evaluated. The baseline evaluation included electrocardiography (ECG) and echocardiography (2DE); a follow-up evaluation, including ECG and exercise stress testing (2DE in case of ECG abnormalities), was done after ≥10 days of treatment. Cardiotoxicity was suspected from ischemic ECG changes, new kinetic abnormalities at 2DE, Lown classification ≥2 ventricular arrhythmia, symptomatic arrhythmias, or positive stress test, and confirmed by a negative stress test after capecitabine washout.ResultsCardiotoxicity was diagnosed in 32 patients (16.7%): six at rest and 26 during exercise. All 32 patients had ECG abnormalities: ST-segment changes (24 patients), negative T-waves (2) and/or arrhythmias: ventricular arrhythmias (14 cases), supraventricular tachycardia (2), complete heart block (1). Eight patients had typical symptoms, 6 had atypical symptoms, 1 had syncope, 17 (53%) were asymptomatic. Cardiotoxicity was more common in patients with atypical symptoms during daily life (OR = 15.7) and in those on a therapeutic schedule of 5 days/week (OR = 9.44).ConclusionCapecitabine cardiotoxicity is frequent, and often elicited by physical effort. Oncologists, cardiologists, and general practitioners should be aware of this risk. Active cardiotoxicity surveillance with ECG (and echocardiogram and/or stress testing in suspected cases) during therapy is recommended.Clinical Trials registration numberCRO-2010-17.  相似文献   
43.

Background  

Esophagojejunostomy (EJS) represents the most difficult steps during totally laparoscopic total gastrectomy (TLTG). Over the past few years, several techniques have been developed. This study aimed to evaluate the feasibility and surgical outcomes of the laparoscopic intracorporeal side-to-side EJS during TLTG used to treat malignant disease of the stomach.  相似文献   
44.
Electrical pulse stimulation has an important effect on skeletal muscle development and maturation. However, the methodology for controlling these stimulation parameters to develop in vitro functional skeletal muscle tissues remains to be established. In this work, we have studied the effect of simulated action potentials on the growth and differentiation of skeletal myoblast cell cultures. A circuit simulating action potentials of 0.15 and 0.3 V/mm, at a frequency of 1 Hz and with a 4‐ms pulse width, is proposed. Results show an important improvement of the growth rate and differentiation of myoblasts at a voltage of 0.15 V/mm. Parameters such as electrodes geometry or type of signals must be considered in the development of in vitro skeletal muscle.  相似文献   
45.
46.
47.
Six-year survival of cirrhosis was assessed in a series of 1155 consecutive patients (751 men, 404 women). Among the men, 33% were alcoholics and 18% were HBsAg positive; corresponding figures for the women were 15% and 6%, respectively. Features of decompensation at first presentation were observed in 63% of the patients. Six-year survival was 54% in compensated and 21% in decompensated patients. No significant differences in survival were found between alcoholics and nonalcoholics. Leading causes of death were liver failure (49%), hepatocellular carcinoma (22%), and bleeding (13%). The prognostic role of 21 variables was evaluated separately in compensated and decompensated patients by the Cox's regression model. The following variables were found to be significant predictors of death risk in compensated patients: male sex, HBsAg positivity, age, prothrombin time prolongation, and esophageal varices. In decompensated disease the significant indicators of death risk were: hepatocellular carcinoma, encephalopathy, hemorrhage, SGOT, esophageal varices, gamma globulins, prothrombin time prolongation, continued abuse of alcohol, HBsAg positivity, gamma glutamyl transpeptidase, and cholinesterase. A simple prognostic index based upon the relative risk coefficient of the significant variables is suggested.Members of the Liver Study Group are: Maria Caltagirone, Gabriella Filippazzo, Giovanni Gatto, Gandolfo Giannuoli, Silvio Margin, Guiseppe Malizia, Lorenzo Maniaci, Maria Pia Marcenó, Alberto Maringhini, Rocco Micciolo, Salvatore Orsini, Fabio Pace, Ugo Palazzo, Linda Pasta, Giuseppina Russo, Rosa Giovanna Simonetti, Mario Spinello, Mario Traina, Mario Valenza, Maria Vinci, Giovanni Vizzini.  相似文献   
48.

Objective

To determine if there is a correlation between self-perception and self- efficacy in the development of learning abilities associated with the care of the critically ill patient in a Clinical Environment of High Fidelity Simulation, as part of the training for nursing students in the field of Life Support.

Method

Quasi-experimental study carried out in academic year 2014-2015 with two groups of Nursing Degree students, and applying pre/post measurement tests. The students were subjected to the same simulation experience, that of a critical patient with a possible progression to cardiac arrest. Simulation training, self-perception, and self-efficacy were used as theoretical framework, as well as the latest recommendations by European Resuscitation Council.

Results

A significant increase in self-perception for the development of competences associated with a critical situation was observed in both groups. As for self-perception and self-efficacy, some variations were found between the groups.

Conclusions

The results found allow us to recommend clinical simulation for the training of students in critically ill patients, since there is a significant increase in the level of self-perception for the development of competences associated with critical care. Likewise, clinical simulation provides a positive link between self-perception and self-confidence in the students.  相似文献   
49.
50.
Studies of animal models suggest that the activation of soluble guanylate cyclase by nitric oxide is altered in liver disease. We studied 77 patients with liver disease and 17 controls, to investigate whether the activation of soluble guanylate cyclase is altered in lymphocytes from patients with liver disease. The basal content of guanosine 3',5'-cyclic monophosphate (cGMP) in lymphocytes was decreased both in patients with liver cirrhosis (by 52%) and in patients with chronic hepatitis (by 62%). Activation of soluble guanylate cyclase by nitric oxide was higher in lymphocytes from patients with cirrhosis (3100+/-1000% of basal) or with hepatitis (5200+/-2500% of basal) than in lymphocytes from controls (1200+/-500% of basal). cGMP in plasma was increased in patients with liver disease. Successful (but not unsuccessful) treatment with interferon of patients with hepatitis due to virus C reversed all the above alterations. Altered modulation of soluble guanylate cyclase by nitric oxide in liver disease may play a role in the hemodynamic alterations found in these patients.  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