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   216522篇
  免费   3118篇
  国内免费   227篇
耳鼻咽喉   1666篇
儿科学   7393篇
妇产科学   3461篇
基础医学   21514篇
口腔科学   2945篇
临床医学   15100篇
内科学   40558篇
皮肤病学   1463篇
神经病学   20366篇
特种医学   10836篇
外国民族医学   1篇
外科学   35469篇
综合类   2461篇
现状与发展   1篇
一般理论   7篇
预防医学   19269篇
眼科学   3557篇
药学   12059篇
中国医学   719篇
肿瘤学   21022篇
  2023年   209篇
  2022年   353篇
  2021年   780篇
  2020年   460篇
  2019年   606篇
  2018年   22563篇
  2017年   17875篇
  2016年   20171篇
  2015年   1656篇
  2014年   1836篇
  2013年   2008篇
  2012年   8897篇
  2011年   22925篇
  2010年   20026篇
  2009年   12532篇
  2008年   21256篇
  2007年   23638篇
  2006年   2497篇
  2005年   4126篇
  2004年   5291篇
  2003年   6140篇
  2002年   4354篇
  2001年   1665篇
  2000年   1883篇
  1999年   1521篇
  1998年   799篇
  1997年   671篇
  1996年   523篇
  1995年   471篇
  1994年   466篇
  1993年   385篇
  1992年   1080篇
  1991年   962篇
  1990年   956篇
  1989年   904篇
  1988年   832篇
  1987年   821篇
  1986年   706篇
  1985年   668篇
  1984年   463篇
  1983年   386篇
  1982年   181篇
  1979年   307篇
  1978年   217篇
  1977年   191篇
  1974年   213篇
  1971年   186篇
  1970年   174篇
  1969年   203篇
  1968年   168篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
11.
12.
Advancing nanomedicines from concept to clinic requires integration of new science with traditional pharmaceutical development. The medical and commercial success of nanomedicines is greatly facilitated when those charged with developing nanomedicines are cognizant of the unique opportunities and technical challenges that these products present. These individuals must also be knowledgeable about the processes of clinical and product development, including regulatory considerations, to maximize the odds for successful product registration. This article outlines these topics with a goal to accelerate the combination of academic innovation with collaborative industrial scientists who understand pharmaceutical development and regulatory approval requirements—only together can they realize the full potential of nanomedicines for patients.  相似文献   
13.
14.
While peer support has been investigated in multiple clinical contexts, its application to the postpartum setting is unknown. The aim was to assess acceptability of a postpartum peer support program for women with diabetes. Observational survey-based needs assessment of forty low-income women with diabetes, receiving care at a major medical institution. Mean age and gravidity were 30.7 years and 3.15 ± 1.67 respectively. 45 % expressed interest in a “buddy.” There was no significant difference between groups desiring and not desiring this program. A majority of respondents desired telephone, text messaging, and in-person contacts (79.2, 72.1, 83.8 %), with 72.5 % of patients desiring diabetes-related activities during clinic waiting time. Many women desire a postpartum diabetes reciprocal peer program for support outside of clinician visits. Patients are receptive to educational services during their wait and outside of clinic time, a potentially valuable opportunity to share important health information.  相似文献   
15.
We report a case of a diaphragmatic hernia after a heart transplant operation. A 43-year-old woman, who underwent orthotropic heart transplantation for hypertrophic cadiomyopathy two year earlier, presented with vomiting and epigastric pain. A computed tomography scan showed that the stomach and transverse colon were dislocated in the left thoracic cavity. We diagnosed left diaphragmatic hernia incarceration and performed laparoscopic repair of the diaphragmatic hernia. A 12 × 8 cm diaphragmatic defect was found intraoperatively on the ventrolateral aspect of the left diaphragm, and the stomach with volvulus had herniated into the thorax through the defect. The hernia was considered to be iatrogenic. The diaphragmatic defect was large, and the diaphragm was thinning. We closed the defect by mesh repair. Laparoscopic mesh repair of the diaphragmatic hernia could be performed safely and with minimal invasiveness.  相似文献   
16.
Baloxavir marboxil, a prodrug that is metabolized to baloxavir acid, suppresses viral replication by inhibiting cap-dependent endonuclease. Our aim is to characterize its pharmacokinetics and exposure-response relationships. Population pharmacokinetic analysis of the baloxavir acid was performed using 8310 plasma concentration data points from 1109 subjects. Exposure-response analyses were performed regarding the time to alleviation of symptoms and the reduction in the influenza virus titer. A 2-compartment model with first-order absorption and lag time well described the plasma concentration data for baloxavir acid, and body weight and race were found to be the most important factors influencing the clearance and distribution volume. A dose regimen based on the body weight (40 mg for patients weighing <80 kg and 80 mg for patients weighing ≥80 kg) could provide sufficient exposures for expecting efficacy irrespective of body weight or race; however, the exposures were dependent on the body weight and race. Exposure-response analyses suggested that the reduction in the influenza virus titer was greater in any exposure-based groups in baloxavir marboxil treatment than in the oseltamivir phosphate treatment and placebo groups. In conclusion, the population pharmacokinetic model and exposure-response relationships would be useful for understanding the pharmacokinetic and pharmacodynamic characteristics of baloxavir acid.  相似文献   
17.
18.
Dehydrogenase activity is frequently used to assess the general condition of microorganisms in soil and activated sludge. Many studies have investigated the inhibition of dehydrogenase activity by various compounds, including heavy metal ions. However, the time after which the measurements are carried out is often chosen arbitrarily. Thus, it can be difficult to estimate how the toxic effects of compounds vary during the reaction and when the maximum of the effect would be reached. Hence, the aim of this study was to create simple and useful mathematical model describing changes in dehydrogenase activity during exposure to substances that inactivate enzymes. Our model is based on the Lagergrens pseudo-first-order equation, the rate of chemical reactions, enzyme activity, and inactivation and was created to describe short-term changes in dehydrogenase activity. The main assumption of our model is that toxic substances cause irreversible inactivation of enzyme units. The model is able to predict the maximum direct toxic effect (MDTE) and the time to reach this maximum (TMDTE). In order to validate our model, we present two examples: inactivation of dehydrogenase in microorganisms in soil and activated sludge. The model was applied successfully for cadmium and copper ions. Our results indicate that the predicted MDTE and TMDTE are more appropriate than EC50 and IC50 for toxicity assessments, except for long exposure times.  相似文献   
19.
20.
Contraceptive use is an important strategy for the prevention of unwanted pregnancy and avoidance of induced abortion. Of all the contraception methods, emergency contraceptive (EC) offers the last chance to achieve this. However, few studies have documented the use of EC among young people in Ghana. This study explored knowledge and usage of EC as well as the factors associated with it among University of Cape Coast students. Data were obtained on the knowledge and usage of ECs among University of Cape Coast students in 2013. Logistic regression analysis was used to investigate the association between students’ socio-demographic characteristics and EC knowledge and use. More male students (72 %) than females (59 %) were sexually active. Fifty-seven percent of the respondents had ever heard of EC and 36 % had ever used EC. Although males were more likely to be sexually active, females were more likely to have knowledge of EC use compared to males. The study underscores the need to increase awareness regarding EC among University students in order to offer them the opportunity that EC provides if other forms of contraceptives are missed.  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