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   1073篇
  免费   71篇
  国内免费   1篇
耳鼻咽喉   12篇
儿科学   20篇
妇产科学   33篇
基础医学   131篇
口腔科学   16篇
临床医学   92篇
内科学   264篇
皮肤病学   6篇
神经病学   62篇
特种医学   26篇
外科学   156篇
综合类   25篇
预防医学   59篇
眼科学   168篇
药学   42篇
中国医学   2篇
肿瘤学   31篇
  2023年   8篇
  2022年   17篇
  2021年   25篇
  2020年   20篇
  2019年   27篇
  2018年   45篇
  2017年   33篇
  2016年   21篇
  2015年   22篇
  2014年   29篇
  2013年   43篇
  2012年   66篇
  2011年   68篇
  2010年   45篇
  2009年   31篇
  2008年   59篇
  2007年   55篇
  2006年   48篇
  2005年   40篇
  2004年   50篇
  2003年   38篇
  2002年   37篇
  2001年   40篇
  2000年   36篇
  1999年   25篇
  1998年   6篇
  1997年   7篇
  1996年   15篇
  1994年   6篇
  1992年   9篇
  1991年   8篇
  1989年   9篇
  1988年   8篇
  1987年   6篇
  1986年   8篇
  1985年   8篇
  1984年   11篇
  1983年   8篇
  1982年   7篇
  1979年   7篇
  1978年   4篇
  1977年   4篇
  1975年   9篇
  1974年   9篇
  1972年   11篇
  1971年   4篇
  1969年   8篇
  1968年   6篇
  1967年   5篇
  1966年   10篇
排序方式: 共有1145条查询结果,搜索用时 15 毫秒
11.
Laser in situ keratomileusis for the treatment of myopia   总被引:3,自引:0,他引:3  
  相似文献   
12.
The commonly used vasodilators sodium nitroprusside and nitroglycerine increase the intracranial pressure (ICP). Oxytocin is also a vasodilator although its primary effect is contraction of uterine smooth muscle. We therefore studied the effect of oxytocin on the ICP of cats. Twelve cats were assigned to two equal groups. One group had normal ICP and in the other the ICP was artificially increased by inflating a balloon placed in the extradural space. All of the cats initially received an oxytocin infusion for 15 min. After a period of stabilization, an additional dose of oxytocin was injected as a bolus. Oxytocin administered as an infusion did not change the ICP significantly in any of the cats. Oxytocin administered as a bolus increased the ICP from 27 +/- 4 to 31 +/- 2 mm Hg in the cats with artificially increased ICP. There were no significant changes in the mean blood pressure or heart rate in either group.  相似文献   
13.
IntroductionSexual difficulty has various effects on patients suffering from this condition that can impact on interpersonal and marital relationships. Sexual function may be adversely affected by stress of any kind and emotional disorders. There have been limited studies focusing on the mental health of those suffering from this problem.AimTo determine the relationship between sexual difficulties and mental health in female patients seeking help in psychiatric clinics.MethodsThe study was based on the case–control design methodology in which the case group consisted of 165 outpatients of two psychiatric clinics, who were diagnosed with different mental disorders such as depression, anxiety, phobia, aggression, and somatic complaints (33 subjects for each type of disorder). The 33 subjects in the control group were chosen among the patients’ relatives and visitors who had no history of either seeking psychiatric help or taking psychiatric drugs. The subjects of both case and control groups were selected based on a convenience sampling method. Moreover, the data were collected based on two techniques of “interview” and “questionnaire;” the latter was of three different subcategories, each dealt with demographic characteristics, sexual difficulties, and a Symptom Check-List-90-Revised.Main Outcome MeasureAssessing female sexual difficulties associated with mental health and differences between women with and without psychiatric problems.ResultsThe obtained results indicated that there was a significant difference between the prevalence of sexual difficulties (e.g., sexual desire and orgasm disorders) in the case group and that of the control group. It was also revealed that there was a significant difference between the depressed, aggressive, as well as those with somatic complaints, and their control group counterparts.ConclusionsIn Iran, sexual difficulties seem to be more frequent in those seeking psychiatric help in clinics than in those within the normal population. Azar M, Noohi S, and Shafiee Kandjani AR. Relationship between female sexual difficulties and mental health in patients referred to two public and private settings in Tehran, Iran.  相似文献   
14.
In this report, we describe a national-scale monitoring of the SARS-CoV-2 (SC-2) variant dynamics in Israel, using multiple-time sampling of 13 wastewater treatment plants. We used a combination of inclusive and selective quantitative PCR assays that specifically identify variants A19/A20 or B.1.1.7 and tested each sample for the presence and relative viral RNA load of each variant. We show that between December 2020 and March 2021, a complete shift in the SC-2 variant circulation was observed, where the B.1.1.7 replaced the A19 in all examined test points. We further show that the normalized viral load (NVL) values and the average new cases per week reached a peak in January 2021 and then decreased gradually in almost all test points, in parallel with the progression of the national vaccination campaign, during February–March 2021. This study demonstrates the importance of monitoring SC-2 variant by using a combination of inclusive and selective PCR tests on a national scale through wastewater sampling, which is far more amendable for high-throughput monitoring compared with sequencing. This approach may be useful for real-time dynamics surveillance of current and future variants, such as the Omicron (BA.1, BA.2) and other variants.  相似文献   
15.
16.
With the multiplication of electronic devices in our daily life, there is a need for tailored wideband electromagnetic (EM) absorbers that could be conformed on any type of surface-like antennas for interference attenuation or military vehicles for stealth applications. In this study, a wideband flexible flat electromagnetic absorber compatible with additive manufacturing has been studied in the X-Ku frequency bands. A multilayer structure has been optimized using a genetic algorithm (GA), adapting the restrictions of additive manufacturing and exploiting the EM properties of loaded and non-loaded filaments, of which the elaboration is described. After optimization, a bi-material multilayer absorber with a thickness of 4.1 mm has been designed to provide a reflectivity below −12 dB between 8 and 18 GHz. Finally, the designed multilayer structure was 3D-printed and measured in an anechoic chamber, achieving −11.8 dB between 7 and 18 GHz. Thus, the development of dedicated materials has demonstrated the strong potential of additive technologies for the manufacturing of thin wideband flexible EM absorbers.  相似文献   
17.
Many women suffer from new or worsening anxiety during pregnancy. In this pilot study, we investigated the effect of timing and severity of prenatal state anxiety symptoms on reduced birth weight. We hypothesized that: (1) Women with state anxiety symptoms during mid-gestation would deliver newborns with lower birth weight in comparison to participants with symptoms in early gestation and (2) compared to women with lower anxiety symptoms (< 50th percentile), women with medium-to-high state anxiety symptoms (> 50th percentile) would have lower birth weight offspring. The sample consisted of the first 30 pregnant women who agreed to participate in this pilot study. We assessed anxiety symptoms, using the State-Trait Anxiety Inventory during early and mid-gestation. We obtained birth weight from clinical charts. A hierarchical multiple regression showed that, after controlling for covariates, state anxiety symptoms in mid-gestation were associated with lower infant birth weight [F(9, 7) = 20.30, p<.001]. However, birth weight did not differ as a function of the severity of maternal state anxiety [F(1, 23)=.14, p=.71 and F(1, 24)=1.76, p=.20., respectively]. Clearly, our pilot data need replication. Once statistical significance is established with larger samples, it will be informative to examine the clinical significance of those findings.  相似文献   
18.
19.
20.
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