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   1884篇
  免费   124篇
  国内免费   13篇
耳鼻咽喉   12篇
儿科学   80篇
妇产科学   28篇
基础医学   308篇
口腔科学   54篇
临床医学   160篇
内科学   424篇
皮肤病学   39篇
神经病学   303篇
特种医学   84篇
外科学   140篇
综合类   3篇
预防医学   116篇
眼科学   19篇
药学   109篇
中国医学   14篇
肿瘤学   128篇
  2024年   7篇
  2023年   22篇
  2022年   52篇
  2021年   76篇
  2020年   45篇
  2019年   56篇
  2018年   57篇
  2017年   71篇
  2016年   66篇
  2015年   82篇
  2014年   96篇
  2013年   102篇
  2012年   165篇
  2011年   169篇
  2010年   93篇
  2009年   71篇
  2008年   113篇
  2007年   97篇
  2006年   115篇
  2005年   76篇
  2004年   71篇
  2003年   74篇
  2002年   63篇
  2001年   11篇
  2000年   10篇
  1999年   17篇
  1998年   15篇
  1997年   17篇
  1996年   14篇
  1995年   10篇
  1994年   10篇
  1993年   6篇
  1992年   7篇
  1991年   2篇
  1990年   6篇
  1989年   6篇
  1988年   3篇
  1986年   3篇
  1984年   4篇
  1983年   3篇
  1982年   5篇
  1981年   3篇
  1980年   2篇
  1979年   4篇
  1978年   5篇
  1977年   3篇
  1974年   4篇
  1971年   3篇
  1969年   2篇
  1966年   2篇
排序方式: 共有2021条查询结果,搜索用时 15 毫秒
61.
62.
63.
The epidemiological status of cystic echinococcosis (CE) in sheep in Sardinia over the 20 years since the last control attempt at the end of the 1980s has been assessed, comparing the results of two surveys carried out in abattoirs in southern Sardinia. In the first, conducted in 1995-1997 (5-7 years after the last control effort), CE prevalence of about 75% was observed in the 1375 sheep sampled, with intensity of 10.0 and mean abundance of 7.5. The most affected organ was the liver, whereas a large percentage of infected animals presented cysts in both the liver and lung. Overall, about 26% of parasitized sheep were found to be heavily infected and 12.15% of infected animals harboured fertile cysts. In the second survey, carried out ten years after the first, during the period 2005-2010 in absence of specific control measures, a total of 1414 sheep were examined. CE prevalence was 65%, 78% in the most rural Oristano province and 58% in the most "urbanised" province of Cagliari. Frequency of sheep infected in both the liver and lung had decreased slightly compared to the first survey, particularly in the Cagliari province, as had intensity and mean abundance, though to a lesser extent in the Oristano province. 14.6% of parasitized sheep were heavily infected, showing a general decline over the 10 years between the two surveys, particularly in the Cagliari area where the figure had more than halved. Conversely, about 14% of infected sheep hosted at least 1 fertile cyst, a slight increase compared to the 1st survey. Finally, the trend of CE transmission in Sardinian sheep according to surveys carried out from 1952 to 2010 has been analysed and the results are discussed in the light of the significant socio-economic and structural transformations that have actually modified the zoonosis scenario on the island.  相似文献   
64.
65.
66.
67.
Background: The role of speckle tracking in the assessment of right atrial (RA) deformation dynamics has not been established yet. The reference ranges of RA longitudinal strain indices were measured by speckle tracking in a population of normal subjects. Methods: In 84 healthy individuals, peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and time to peak longitudinal strain (TPLS) were measured using a six‐segment model for the RA. Strain rate (SR) was also measured starting from the QRS‐wave onset, peak positive (x‐wave), first peak negative (y‐wave), and second negative peak (z‐wave). The time from the QRS onset was measured to each wave peak. Results: Adequate tracking quality was achieved in 64% of segments analyzed. Inter‐ and intraobserver variability coefficients of measurements ranged between 6% and 11%. Global PALS was 49 ± 13%, global TPLS was 363 ± 59 msec, x‐wave was 2.12 ± 0.58 sec?1, y‐wave was ?1.91 ± 0.63 sec?1, and z‐wave was ?2.18 ± 0.78 sec?1. Conclusion: Speckle tracking is a feasible technique for the assessment of longitudinal myocardial RA deformation. Reference ranges of strain indices were reported. (Echocardiography 2012;29:147‐152)  相似文献   
68.
5q14.3 deletions including the MEF2C gene have been identified to date using genomic arrays in patients with severe developmental delay or intellectual disability, stereotypic behavior, epilepsy, cerebral malformations and a facial gestalt not really distinctive though characterized by broad and/or high, bulging forehead, upslanting palpebral fissures, flat nasal root and bridge, small, upturned nose, hypotonic small mouth resulting in cupid bow/tented upper lip. MEF2C mutations have been also identified in patients with overlapping phenotype so that it is considered the gene responsible for the 5q14.3 deletion syndrome. To date, one single duplication including MEF2C has been reported in a patient with intellectual disability but its clinical significance remains uncertain also because of the large size of the imbalance. Here we present two further patients with 5q14.3 duplications including MEF2C. Their phenotype indeed suggest the pathogenic effect of the MEF2C duplication although other duplicated genes also brain expressed might contribute to the clinical features. In none of them a clear-cut syndrome can be identified. A comparison between MEF2C deleted/mutated and duplicated patients is also presented.  相似文献   
69.
70.
We retrospectively analysed 78 patients with relapsed (n?=?38), primary refractory (n?=?34) or untreated (n?=?6) acute myeloid leukaemia (AML) who underwent allogeneic HSCT at our Institution between 2002 and 2011, to verify outcome and to identify factors that can affect long-term outcome. Myeloablative conditioning regimens were used in 48 patients (24 siblings, 24 matched unrelated donor (MUD)), while 30 patients (18 siblings, 12 MUD) received reduced-intensity conditioning. Acute graft versus host disease (GVHD) developed in 37 (47?%) patients, while chronic GVHD occurred in 19 of the 65 evaluable patients (29?%). With a median follow-up time of 5?years, 13 of 78 patients (17?%) are alive and in complete remission (CR), while 64 have died. Cause of death was disease recurrence in 37 patients (58?%), infection in ten patients (16?%) and GVHD in six (9?%). One-year non-relapse mortality was 35?%. In multivariate analysis, performance status ≥80?% WHO and a full-matched donor were associated with a better outcome: these two variables allowed for risk stratification, identifying three groups with significantly different survival after transplant (P?=?0.0001). Considering post-transplant variables, only CR at recovery and development of cGVHD were correlated with a longer survival. Our data confirm the capacity of allogeneic transplant to prolong survival in a significant proportion of extremely high-risk AML 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