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   73484篇
  免费   7704篇
  国内免费   5442篇
耳鼻咽喉   557篇
儿科学   802篇
妇产科学   578篇
基础医学   7583篇
口腔科学   1217篇
临床医学   9102篇
内科学   9482篇
皮肤病学   588篇
神经病学   3622篇
特种医学   3002篇
外国民族医学   39篇
外科学   7967篇
综合类   15534篇
现状与发展   14篇
一般理论   16篇
预防医学   5829篇
眼科学   1549篇
药学   8330篇
  79篇
中国医学   4996篇
肿瘤学   5744篇
  2024年   98篇
  2023年   974篇
  2022年   1840篇
  2021年   3058篇
  2020年   2823篇
  2019年   2206篇
  2018年   2393篇
  2017年   2333篇
  2016年   2109篇
  2015年   3495篇
  2014年   4356篇
  2013年   4354篇
  2012年   6396篇
  2011年   7133篇
  2010年   5006篇
  2009年   4223篇
  2008年   4677篇
  2007年   4626篇
  2006年   4357篇
  2005年   3963篇
  2004年   2772篇
  2003年   2457篇
  2002年   2094篇
  2001年   1617篇
  2000年   1444篇
  1999年   1135篇
  1998年   752篇
  1997年   731篇
  1996年   560篇
  1995年   515篇
  1994年   385篇
  1993年   284篇
  1992年   238篇
  1991年   194篇
  1990年   189篇
  1989年   182篇
  1988年   137篇
  1987年   121篇
  1986年   96篇
  1985年   94篇
  1984年   48篇
  1983年   33篇
  1982年   28篇
  1981年   24篇
  1980年   15篇
  1979年   17篇
  1978年   7篇
  1973年   5篇
  1972年   6篇
  1971年   4篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
3.
Information regarding the impact of the coronavirus disease 2019 (COVID-19) pandemic on cervical cancer in mainland China is lacking. We explored its impact on the hospital attendance of patients with primary cervical cancer. We included 1918 patients with primary cervical cancer who initially attended Harbin Medical University Cancer Hospital between January 23, 2019, and January 23, 2021. Attendance decreased by 31%, from 1135 in 2019 to 783 in 2020, mainly from January to June (𝜒2 = 73.362, P < .001). The percentage of patients detected by screening decreased from 12.1% in January-June 2019 to 5.8% in January-June 2020 (𝜒2 = 7.187, P = .007). Patients with stage I accounted for 28.4% in 2020 significantly lower than 36.6% in 2019 (𝜒2 = 14.085, P < .001), and patients with stage III accounted for 27.1% in 2020 significantly higher than 20.5% in 2019 (𝜒2 = 11.145, P < .001). Waiting time for treatment was extended from 8 days (median) in January-June and July-December 2019 to 16 days in January-June (𝜒2 = 74.674, P < .001) and 12 days in July-December 2020 (𝜒2 = 37.916, P < .001). Of the 179 patients who delayed treatment, 164 (91.6%) were for the reasons of the healthcare providers. Compared to 2019, the number of patients in Harbin or non-Harbin in Heilongjiang Province and outside the province decreased, and cross-regional medical treatment has been hindered. The COVID-19 pandemic has negatively impacted cervical cancer patient attendance at the initial phase. These results are solid evidence that a strategy and mechanism for the effective attendance of cervical cancer patients in response to public health emergencies is urgently needed.  相似文献   
4.
5.
6.
The purpose of this study was to investigate the feasibility of two-dimensional (2D) navigated, interleaved multishot echo-planar imaging (EPI) to enhance kidney diffusion-weighted imaging (DWI) in rats at 7.0 T. Fully sampled interleaved four-shot EPI with 2D navigators was tailored for kidney DWI (Sprague–Dawley rats, n = 7) on a 7.0-T small bore preclinical scanner. The image quality of four-shot EPI was compared with T2-weighted rapid acquisition with relaxation enhancement (RARE) (reference) and single-shot EPI (ss-EPI) without and with parallel imaging (PI). The contrast-to-noise ratio (CNR) was examined to assess the image quality for the EPI approaches. The Dice similarity coefficient and the Hausdorff distance were used for evaluation of image distortion. Mean diffusivity (MD) and fractional anisotropy (FA) were calculated for renal cortex and medulla for all DWI approaches. The corticomedullary difference of MD and FA were assessed by Wilcoxon signed-rank test. Four-shot EPI showed the highest CNR among the three EPI variants and lowest geometric distortion versus T2-weighted RARE (mean Dice: 0.77 for ss-EPI without PI, 0.88 for ss-EPI with twofold undersampling, and 0.92 for four-shot EPI). The FA map derived from four-shot EPI clearly identified a highly anisotropic region corresponding to the inner stripe of the outer medulla. Four-shot EPI successfully discerned differences in both MD and FA between renal cortex and medulla. In conclusion, 2D navigated, interleaved multishot EPI facilitates high-quality rat kidney DWI with clearly depicted intralayer and interlayer structure and substantially reduced image distortion. This approach enables the anatomic integrity of DWI-MRI in small rodents and has the potential to benefit the characterization of renal microstructure in preclinical studies.  相似文献   
7.
8.
9.
10.
Sepsis is a life-threatening condition and a global disease burden.Heterogeneous syndrome is defined as severe organ dysfunction caused by a dysregulated host response to infection,with renewed emphasis on the immune pathophysiology.Researchers worldwide constantly update the diagnostic criteria of sepsis and have introduced concepts such as“sepsis-3”“Surviving Sepsis Campaign(SSC)”“Early Goal-Directed Therapy(EGDT)”,the 3-h and 6-h bundles to an hour-1 bundle[1],“limited ventilation”“the best PEEP[2]”,and“Lung Protective-Ventilation”.Despite all efforts of experimental and clinical research during the last three decades,the ability to positively influence the course and outcome of the syndrome remains limited.  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