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   116597篇
  免费   9670篇
  国内免费   5149篇
耳鼻咽喉   448篇
儿科学   2761篇
妇产科学   1226篇
基础医学   23067篇
口腔科学   1117篇
临床医学   8925篇
内科学   29791篇
皮肤病学   1668篇
神经病学   3866篇
特种医学   1837篇
外国民族医学   12篇
外科学   5941篇
综合类   16221篇
现状与发展   31篇
预防医学   12112篇
眼科学   855篇
药学   11336篇
  28篇
中国医学   4523篇
肿瘤学   5651篇
  2024年   137篇
  2023年   1274篇
  2022年   2419篇
  2021年   4279篇
  2020年   3689篇
  2019年   3817篇
  2018年   3720篇
  2017年   3705篇
  2016年   4246篇
  2015年   4751篇
  2014年   7248篇
  2013年   7768篇
  2012年   7270篇
  2011年   7991篇
  2010年   6561篇
  2009年   6143篇
  2008年   6060篇
  2007年   6052篇
  2006年   5531篇
  2005年   4794篇
  2004年   4090篇
  2003年   3574篇
  2002年   2879篇
  2001年   2671篇
  2000年   2159篇
  1999年   1902篇
  1998年   1738篇
  1997年   1567篇
  1996年   1332篇
  1995年   1355篇
  1994年   1215篇
  1993年   977篇
  1992年   828篇
  1991年   675篇
  1990年   592篇
  1989年   535篇
  1988年   496篇
  1987年   385篇
  1986年   324篇
  1985年   742篇
  1984年   655篇
  1983年   509篇
  1982年   508篇
  1981年   428篇
  1980年   361篇
  1979年   330篇
  1978年   275篇
  1977年   203篇
  1976年   211篇
  1975年   164篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.

Background

The ZOE-50 (NCT01165177) and ZOE-70 (NCT01165229) phase 3 clinical trials showed that the adjuvanted recombinant zoster vaccine (RZV) was ≥90% efficacious in preventing herpes zoster in adults. Here we present a comprehensive overview of the safety data from these studies.

Methods

Adults aged ≥50 (ZOE-50) and ≥70 (ZOE-70) years were randomly vaccinated with RZV or placebo. Safety analyses were performed on the pooled total vaccinated cohort, consisting of participants receiving at least one dose of RZV or placebo. Solicited and unsolicited adverse events (AEs) were collected for 7 and 30?days after each vaccination, respectively. Serious AEs (SAEs) were collected from the first vaccination until 12?months post-last dose. Fatal AEs, vaccination-related SAEs, and potential immune-mediated diseases (pIMDs) were collected during the entire study period.

Results

Safety was evaluated in 14,645 RZV and 14,660 placebo recipients. More RZV than placebo recipients reported unsolicited AEs (50.5% versus 32.0%); the difference was driven by transient injection site and solicited systemic reactions that were generally seen in the first week post-vaccination. The occurrence of overall SAEs (RZV: 10.1%; Placebo: 10.4%), fatal AEs (RZV: 4.3%; Placebo: 4.6%), and pIMDs (RZV: 1.2%; Placebo: 1.4%) was balanced between groups. The occurrence of possible exacerbations of pIMDs was rare and similar between groups. Overall, except for the expected local and systemic symptoms, the safety results were comparable between the RZV and Placebo groups irrespective of participant age, gender, or race.

Conclusions

No safety concerns arose, supporting the favorable benefit-risk profile of RZV.  相似文献   
42.
43.
This study aimed to observe the therapeutic effects of magnesium lithospermate B on acute and chronic colitis induced by dextran sodiumsulfate (DSS) and the role of inflammasome complex (NOD-like receptor protein, NLRP; apoptosis-associated speck-like protein containing, ASC; caspase-1). Establishment of acute and chronic colitis models were by using 5% DSS oral administration in BALB/C male mice. Magnesium lithospermate B (240 mg/kg body weight) was given by subcutaneous injection. Samples were collected for biomarker assay, histological examination, immunohistochemical evaluation and western blot. There was obvious increase in TNF-α level and NLPR3, ASC, and caspase-1 expressions in acute and chronic colitis groups compared with the normal control. Significant decrease of the tumor necrosis factor-α level and the expressions of NLPR3, ASC, and caspase-1 were observed after treatment with magnesium lithospermate B. This study showed that magnesium lithospermate B could be used to treat acute and chronic colitis by inhibiting the activation of the NLRP3/ASC/Caspase-1 pathway.  相似文献   
44.
《Vaccine》2016,34(26):2948-2952
Herpes simplex virus type-1 (HSV-1) and -2 (HSV-2) are highly prevalent global pathogens which commonly cause recurrent oral and genital ulcerations. Less common but more serious complications include meningitis, encephalitis, neonatal infection, and keratitis. HSV-2 infection is a significant driver of the HIV epidemic, increasing the risk of HIV acquisition 3 fold. As current control strategies for genital HSV-2 infection, including antiviral therapy and condom use, are only partially effective, vaccines will be required to reduce infection. Both preventive and therapeutic vaccines for HSV-2 are being pursued and are in various stages of development. We will provide an overview of efforts to develop HSV-2 vaccines, including a discussion of the clinical need for an HSV vaccine, and status of research and development with an emphasis on recent insights from trials of vaccine candidates in clinical testing. In addition, we will touch upon aspects of HSV vaccine development relevant to low and middle income countries.  相似文献   
45.
Serum thromboxane-B2 (TxB2), together with arachidonic acid (AA)-induced platelet aggregation, are, at the moment, the most used tests to identify patients displaying high on-aspirin treatment platelet reactivity (HAPR). Both tests are specific for aspirin action on cyclooxygenase-1. While the correlation between serum TxB2 assay and clinical outcome is established, data are conflicting with regard to aspirin treatment and a possible association with AA-stimulated platelet markers and clinical outcome. To understand such discrepancy, we performed a retrospective study to compare both assays. We collected data from 132 patients receiving a daily dose of aspirin (100?mg/day) and data from 48 patients receiving aspirin on alternate days. All Patients who received a daily dose of aspirin were studied for AA-induced platelet aggregation together with serum TxB2 levels and AA-induced TxB2 formation was also studied in 71 patients out of entire population. Consistent with recommendations in the literature, we defined HAPR by setting a cut-off point at 3.1?ng/ml for serum levels of thromboxane B2 and 20% for AA-induced platelet aggregation. According to this cut-off point, we divided our overall population into two groups: (1) TxB2?<?3.1?ng/ml and (2) TxB2?>?3.1?ng/ml. We found low agreement between such tests to identify patients displaying HAPR. Our results show that AA-induced platelet aggregation >20% identify a smaller number of HAPR patients in comparison with TxB2. A good correlation between serum TxB2 and arachidonic acid-induced TxB2 production was found (r?=?0.76619).  相似文献   
46.
47.
PurposeTo investigate dynamic variables obtained from retrospective computed tomography angiography for ability to predict thoracic endovascular aortic repair (TEVAR) outcomes in patients with complicated type B aortic dissection (cTBAD).Materials and MethodsSeventy-nine patients with cTBAD who received TEVAR from March 2009 to June 2018 were retrospectively enrolled. Relative true lumen area (r-TLA) was computed at the level of tracheal bifurcation every 5% of all R-R intervals. Parameters that reflect the state of intimal motion were evaluated, including difference between maximum and minimum r-TLA (D-TLA) and true lumen collapse. The endpoints comprised early (≤ 30 days) and late (> 30 days) outcomes after intervention.ResultsOverall early mortality rate was 13.9% (11/79), and early adverse events rate was 24.1% (19/79). Patients who received TEVAR within 2 days of symptom onset demonstrated the worst outcomes. A longer time of r-TLA < 25% in 1 cardiac cycle (P = .049) and larger D-TLA (P < .001) were correlated to an increased early death. In addition, D-TLA was an independent predictor of early mortality. Area under the curve of D-TLA was 0.849 (95% confidence interval 0.730–0.967) for predicting early mortality and 0.742 (95% CI 0.611–0.873) for predicting early adverse events. Survival and event-free survival rates during follow-up were decreased in the D-TLA > 21.5% group compared with the D-TLA ≤ 21.5% group (all P < .001).ConclusionsLarger D-TLA is correlated with worse postoperative outcomes and might be a crucial parameter for future risk stratification in patients with cTBAD.  相似文献   
48.
目的:建立鼠巨细胞病毒(MCMV)感染C57BL/6小鼠急性肝炎模型并对其感染特点进行分析及鉴定。方法:将24 只C57BL/6小鼠随机分为阴性对照组(n =12)及病毒感染组(n =12),病毒感染组腹腔注射1.0×106 PFU(200 μL)MCMV悬液,阴性对照组注射等体积小鼠胚胎成纤维细胞(MEF)悬液。于感染后第3天和第7天取外周血分离血清检测谷丙转氨酶(ALT)及谷草转氨酶(AST)。同时进行肝组织病毒分离、组织病理学及MCMV IE和M55基因、细胞因子白细胞介素-6(IL-6)、白细胞介素-1β(IL-1β)、肿瘤坏死因子α(TNF-α)的检测。结果:病毒感染组肝组织匀浆病毒分离均为阳性,肝炎发生率为100%。在感染后第3天即发生肝炎病理改变,病毒感染组血清ALT及AST较阴性对照组明显升高(P <0.01);病毒感染组肝脏HE染色第3天可见局灶性炎性细胞浸润及肝脏点灶状坏死,持续至第7天,Ishak评分较阴性对照组明显升高(P <0.01);在感染后第3天病毒感染组肝组织内可检测到MCMV IE及M55基因,且在感染后第7天仍可测得IE基因;感染后第3天及第7天病毒感染组炎性细胞因子IL-6、TNF-α及IL-1β mRNA表达水平明显升高(P <0.05)。 结论:成功建立MCMV感染C57BL/6小鼠急性动物肝炎模型,其感染表现主要集中在急性感染前期。  相似文献   
49.
We evaluated RNA stability of Ebola virus in EDTA blood and urine samples collected from infected patients and stored in West Africa’s environmental conditions. In blood, RNA was stable for at least 18 days when initial cycle threshold values were <30, but in urine, RNA degradation occurred more quickly.  相似文献   
50.
Although hepatitis E virus (HEV) is the primary cause of enterically transmitted acute hepatitis and jaundice in developing countries, locally acquired HEV infections are increasing in nonendemic countries. As such, HEV is emerging as an underdiagnosed cause of infection. This report describes three clinically variable cases of HEV infection with unusual clinical presentations. These cases highlight the fact that HEV should be considered in the differential diagnosis of patients with unexplained hepatitis (acute or chronic) with or without extrahepatic manifestations. HEV should also be considered in patients with persistently elevated liver enzymes who have not travelled to known HEV-endemic regions. Lack of knowledge among physicians and an absence of standardized diagnostic tests may result in increased morbidity and mortality from HEV infection.  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