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   527篇
  免费   41篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   20篇
妇产科学   25篇
基础医学   88篇
口腔科学   5篇
临床医学   44篇
内科学   128篇
皮肤病学   11篇
神经病学   68篇
特种医学   5篇
外科学   27篇
预防医学   38篇
眼科学   7篇
药学   32篇
中国医学   1篇
肿瘤学   69篇
  2023年   3篇
  2022年   14篇
  2021年   17篇
  2020年   15篇
  2019年   17篇
  2018年   17篇
  2017年   11篇
  2016年   14篇
  2015年   22篇
  2014年   19篇
  2013年   31篇
  2012年   29篇
  2011年   42篇
  2010年   29篇
  2009年   19篇
  2008年   48篇
  2007年   37篇
  2006年   19篇
  2005年   30篇
  2004年   33篇
  2003年   28篇
  2002年   19篇
  2001年   5篇
  2000年   3篇
  1999年   4篇
  1998年   2篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1991年   5篇
  1990年   5篇
  1989年   4篇
  1988年   5篇
  1987年   2篇
  1986年   1篇
  1985年   2篇
  1983年   1篇
  1981年   1篇
  1979年   2篇
  1975年   2篇
  1971年   1篇
排序方式: 共有570条查询结果,搜索用时 15 毫秒
1.
Role of cytokines in radioprotection   总被引:1,自引:0,他引:1  
  相似文献   
2.
OBJECTIVE: To assess the expression of heparanase in the different stages leading to endometrial cancer. METHODS: The 38 examined specimens included adenocarcinoma, hyperplasia, and normal endometrium specimens. Heparanase, estrogen, and progesterone receptor expressions were analyzed immunohistochemically and the intensity was scored. RESULTS: Secretory normal endometrium and simple hyperplasia specimens expressed the lowest mean values of expression (1.00 and 0.63, respectively); the complex hyperplasia specimens and G2 endometrioid adenocarcinoma showed the highest values of expression (2.33 and 2.71, respectively). A linear trend (P=0.005) of heparanase expression was observed when comparing the normal endometrium and simple hyperplasia group with the complex hyperplasia+G1 carcinoma group and the G2+G3 carcinoma group. Evaluation of atrophic and inactive endometrium compared with papillary serous carcinomas yielded no significant differences. We found no significant correlation between heparanase expression and estrogen receptor or progesterone receptor expression. CONCLUSION: Heparanase expression was tightly regulated in endometrial tumorigenesis.  相似文献   
3.
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   
4.
Left ventricular pseudoaneurysm and ventricular septal defect are rare but devastating complications of myocardial infarction. With medical treatment alone, the majority of patients will die from these complications. Until recently, the recommended treatment was surgical closure. These surgeries carried extreme risk due to abnormal hemodynamics, necrotic substrates and the comorbidities of these patients. Recently, trans-catheter closure was shown to be an acceptable alternative to open surgical intervention. 3D echocardiography identifies the location, size, and shape of the defect and can assess, guide, and follow up the closure procedure.  相似文献   
5.
BACKGROUND: Pulse pressure is a derivative of arterial stiffness. We have previously demonstrated ambulatory pulse pressure to be relatively independent from the blood pressure (BP) lowering during sleep, and thus of a neurogenic effect. On the other hand, white coat BP effects are thought to involve neurogenic activation. The aim of this work was to analyze white coat induced variability in pulse pressure. METHODS: Percent clinic-awake differences in systolic BP (SBP) and pulse pressure (white coat effects) were calculated for 688 consecutive subjects (mean age 60 +/- 16 years, 58% female). Of the subjects, 23% had controlled hypertension, 45% uncontrolled hypertension, 8% normotension, and 4% isolated office hypertension; all were referred to our unit for 24 h ambulatory BP monitoring. RESULTS: Pulse pressure highly correlated with SBP (r = 0.82, P <.00001). We found a larger white coat effect on pulse pressure than on SBP (8.3% and 5.2%, respectively, P < or =.0001). This was true in all subgroups except in normotensive subjects. Specifically, the magnitude of the white coat effect on pulse pressure was greater than on SBP in subjects with treated hypertension, untreated hypertension, and isolated office hypertension, and in young hypertensive subjects, older subjects, and those with diabetes. CONCLUSIONS: Although pulse pressure is related to the mechanical properties of large arteries, it is also influenced by the white coat effect, a neurogenic process. Furthermore, in hypertensive but not in normotensive subjects, the white coat effect on pulse pressure is significantly more pronounced than on SBP.  相似文献   
6.
Noroviruses (NoVs) are a leading cause of viral gastroenteritis in humans. In the present study, the association between NoV susceptibility and the ABO histo-blood group was studied during 2 outbreaks of acute gastroenteritis in military units in Israel caused by genogroup II (GII) NoVs. The findings demonstrate that, unlike for genogroup I of NoV, there is no association between the ABO histo-blood group and clinical infection with GII NoVs. This is the largest study to test the association between NoVs, proven clinical infection with GII, and the ABO histo-blood group.  相似文献   
7.
In a survey that was conducted during the year 2011, a local strain of Aphid lethal paralysis virus (ALPV) was identified and isolated from a wild population of Aphis nerii aphids living on Nerium oleander plants located in northern Israel. The new strain was tentatively named (ALPV-An). RNA extracted from the viral particles allowed the amplification and determination of the complete genome sequence. The virus genome is comprised of 9835 nucleotides. In a BLAST search analysis, the ALPV-An sequence showed 89 % nucleotide sequence identity with the whole genome of a South African ALPV and 96 and 94 % amino acid sequence identity with the ORF1 and ORF2 of that strain, respectively. In preliminary experiments, spray-applied, purified ALPV virions were highly pathogenic to the green peach aphid Myzus persicae; 95 % mortality was recorded 4 days post-infection. These preliminary results demonstrate the potential of ALPV for use as a biologic agent for some aphid control. Surprisingly, no visible ALPV pathogenic effects, such as morphological changes or paralysis, were observed in the A. nerii aphids infected with ALPV-An. The absence of clear ALPV symptoms in A. nerii led to the formulation of two hypotheses, which were partially examined in this study. The first hypothesis suggest that A. nerii is resistant or tolerant of ALPV, while the second hypothesis propose that ALPV-An may be a mild strain of ALPV. Currently, our results is in favor with the first hypothesis since ALPV-An is cryptic in A. nerii aphids and can be lethal for M. persicae aphids.  相似文献   
8.
BACKGROUND: Several reports have suggested that early chest tube drainage (CTD) may not be necessary in the treatment of severe pleural empyema (PE) in pediatric patients if appropriate antibiotic therapy and supportive care are provided. OBJECTIVES: A prospective open study to compare the short-term course of two treatment protocols of severe PE in pediatric patients. STUDY DESIGN: One group of 32 patients was treated with early insertion of a chest tube for CTD, and a second group of 35 patients was treated by a repeated ultrasound-guided needle thoracocentesis (RUSGT). The severity of the empyema was assessed by chest radiograph, the amount of fluid drained, the number of days the patient had experienced a fever, and the duration of antibiotic treatment. RESULTS: No significant differences were found between the two groups (RUSGT vs CTD) in all of the following measurements: mean (plus minus SD) duration of a temperature > or = 39 degreesC, 6.2 +/- 2.4 vs 6.5 +/- 1.8 days, respectively; mean duration of a temperature > or = 38 degreesC, 9 +/- 3.9 vs 8.2 +/- 4.5 days, respectively; fluid drained, 35.1 + 23.8 vs 30 +/- 28.2 mL/kg, respectively; duration of antibiotic treatment, 30 +/- 13.2 vs 30.2 +/- 7.3 days, respectively; and length of hospitalization and home IV treatment, 22 +/- 7.6 vs 24.2 +/- 7.5 days, respectively. A failure to respond to treatment occurred in three patients in the RUSGT-treated group and in five patients in the CTD-treated group. The failure to respond occurred in the RUSGT-treated group only in those patients with very large empyemas that caused mediastinal deviation. CONCLUSION: The treatment of PE by RUSGT is as efficacious as CTD, unless PE causes mediastinal deviation.  相似文献   
9.
Neta  R; Williams  D; Selzer  F; Abrams  J 《Blood》1993,81(2):324-327
Survival after irradiation with LD100/30 (radiation dose lethal to 100% of mice in 30 days) is based on recovery of impaired hematopoietic function. Our previous studies using antibodies to interleukin-1 receptor (IL-1R), tumor necrosis factor (TNF), and IL-6 demonstrated that endogenous production of these three cytokines is required for untreated mice as well as mice protected with lipopolysaccharide (LPS), IL-1, or TNF to survive lethal irradiation. In this report we show that anti-c-kit ligand/steel factor (SIF) antibody similarly abrogates LPS- and IL-1-induced radioprotection. Furthermore, administration of this antibody to unmanipulated mice increased LD50/30 radiation lethality from 50% to 100%. Such an effect was not obtained using anti-IL-3, anti- IL-4, or anti-granulocyte-macrophage colony-stimulating factor antibody. Thus, like IL-1, TNF, and IL-6, SIF is required for survival from lethal irradiation.  相似文献   
10.
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