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   10028篇
  免费   1104篇
  国内免费   320篇
耳鼻咽喉   102篇
儿科学   183篇
妇产科学   89篇
基础医学   1153篇
口腔科学   213篇
临床医学   1287篇
内科学   1800篇
皮肤病学   193篇
神经病学   541篇
特种医学   395篇
外国民族医学   2篇
外科学   1086篇
综合类   1089篇
现状与发展   2篇
一般理论   4篇
预防医学   759篇
眼科学   231篇
药学   1180篇
  9篇
中国医学   466篇
肿瘤学   668篇
  2024年   28篇
  2023年   140篇
  2022年   366篇
  2021年   531篇
  2020年   360篇
  2019年   377篇
  2018年   389篇
  2017年   357篇
  2016年   325篇
  2015年   423篇
  2014年   544篇
  2013年   630篇
  2012年   852篇
  2011年   764篇
  2010年   552篇
  2009年   417篇
  2008年   538篇
  2007年   538篇
  2006年   472篇
  2005年   432篇
  2004年   382篇
  2003年   380篇
  2002年   296篇
  2001年   193篇
  2000年   184篇
  1999年   121篇
  1998年   77篇
  1997年   57篇
  1996年   47篇
  1995年   50篇
  1994年   38篇
  1993年   27篇
  1992年   50篇
  1991年   73篇
  1990年   50篇
  1989年   39篇
  1988年   42篇
  1987年   37篇
  1986年   25篇
  1985年   18篇
  1984年   22篇
  1983年   15篇
  1982年   11篇
  1980年   16篇
  1979年   19篇
  1978年   13篇
  1975年   8篇
  1974年   13篇
  1973年   19篇
  1969年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Trisomy 8/8q is a common cytogenetic event in myelocytic malignancies, ranging from myelodysplastic syndrome (MDS) to acute myelocytic leukemia (AML) to blastic transformation of chronic myelocytic leukemia. Isochromosome 8q results in the same gene dosage effect. Duplication of i(8q), resulting in pentasomy 8q, has been reported only in two cases of AML. A patient with fibrosing alveolitis on prolonged cyclophosphamide treatment developed therapy-related MDS. Karyotyping, FISH, and CGH analysis showed a duplicated i(8q) among other complex abnormalities. The clinical features of 11 cases of myelocytic leukemia with pentasomy and hexasomy 8/8q were summarized. Compared with trisomy and tetrasomy 8, significant features included reduced median survival (90 days), treatment refractoriness (even with transplantation), monocytic differentiation, trilineage dysplasia, and radiation or toxin exposure. Increasing copy numbers of chromosome 8/8q may therefore be a marker of advanced leukemic evolution, exposure to toxins, underlying myelodysplasia, and an overall poor prognosis.  相似文献   
72.
Dendritic cells (DCs) are important in the regulation of immune responses and it has been proposed that these cells play an important role in asthma; however, their role in food allergy is still largely unknown. Our aim was to study specific immunoglobulin E (IgE) and immunoglobulin G (IgG) responses in naïve recipients following adoptive transfer of myeloid DCs from allergic and control mice. The phenotypic features and lymphokine production of DCs were also investigated. CD11c + /hi B220? DCs isolated from spleen and Peyer's patches (PP) of cow's milk (CM) allergic and control mice were transferred intravenously (i.v.) into naïve syngeneic recipients, and IgE‐ and IgG‐specific responses were evaluated. Experiments were also carried out to determine the levels of interferon‐γ (IFN‐γ) and interleukin (IL)‐4 produced by splenocytes from naïve recipients following the adoptive transfer, and CD40 ligand (CD40L)‐mediated IL‐10 production by DCs from allergic and control mice. DCs isolated from spleen and PP of allergic mice, but not control groups, induced CM‐specific IgG and IgE antibody production in naïve recipients in the absence of previous immunization, but did not modify the T helper 1 (Th1) and T helper 2 (Th2) balance. Furthermore, although no difference was observed in the expression of canonical DC surface markers, PP DCs from allergic mice produced less IL‐10 than DCs from controls. We interpret these data as showing that DCs play a pivotal role in allergen‐specific IgE responses and that a Th2‐skewed response may not be involved in the early phase of allergic responses. The identification of the mechanisms underlying these events may help to design novel strategies of therapeutic intervention in food allergy.  相似文献   
73.
74.
Since a novel beta-coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in December 2019, there has been a rapid global spread of the virus. Genomic surveillance was conducted on samples isolated from infected individuals to monitor the spread of genetic variants of SARS-CoV-2 in Korea. The Korea Disease Control and Prevention Agency performed whole genome sequencing of SARS-CoV-2 in Korea for 1 year (January 2020 to January 2021). A total of 2,488 SARS-CoV-2 cases were sequenced (including 648 cases from abroad). Initially, the prevalent clades of SARS-CoV-2 were the S and V clades, however, by March 2020, GH clade was the most dominant. Only international travelers were identified as having G or GR clades, and since the first variant 501Y.V1 was identified (from a traveler from the United Kingdom on December 22nd, 2020), a total of 27 variants of 501Y.V1, 501Y.V2, and 484K.V2 have been classified (as of January 25th, 2021). The results in this study indicated that quarantining of travelers entering Korea successfully prevented dissemination of the SARS-CoV-2 variants in Korea.  相似文献   
75.
7岁以下儿童健康状况是反映经济社会发展重要指标之一,一直受到社会关注.为了解芜湖市托幼机构儿童健康状况,提高芜湖市托幼机构卫生保健质量,芜湖市各县区妇幼保健机构每年对辖区内的托幼机构儿童进行1次健康检查,现将2015-2018年芜湖市托幼机构健康检查结果分析如下.  相似文献   
76.
Initial cases of coronavirus disease in Hong Kong were imported from mainland China. A dramatic increase in case numbers was seen in February 2020. Most case-patients had no recent travel history, suggesting the presence of transmission chains in the local community. We collected demographic, clinical, and epidemiologic data from 50 patients, who accounted for 53.8% of total reported case-patients as of February 28, 2020. We performed whole-genome sequencing to determine phylogenetic relationship and transmission dynamics of severe acute respiratory syndrome coronavirus 2 infections. By using phylogenetic analysis, we attributed the community outbreak to 2 lineages; 1 harbored a common mutation, Orf3a-G251V, and accounted for 88.0% of the cases in our study. The estimated time to the most recent common ancestor of local coronavirus disease outbreak was December 24, 2019, with an evolutionary rate of 3.04 × 10−3 substitutions/site/year. The reproduction number was 1.84, indicating ongoing community spread.  相似文献   
77.
目的 :探讨三氧化二砷 (As2 O3 )对人肺癌细胞株 (Spc- A1)诱导凋亡的机制 ,为抗肿瘤药物的筛选和用药方式提供理论依据。方法 :体外培养 Spc- A1细胞株与不同浓度的 As2 O3 进行作用 ,应用 MTT比色法、流式细胞仪技术、电子显微镜技术观察细胞增殖率、细胞周期率、细胞凋亡率及亚细胞水平变化。结果 :As2 O3 能够抑制 Spc- A1细胞的增殖 ,且呈时间剂量依赖性 ,Spc- A1细胞凋亡率与药物浓度和时间呈依赖关系。电镜观察细胞线粒体肿胀、空泡 ,染色质浓缩、核碎裂。结论 :As2 O3 可诱导 Spc- A1细胞凋亡 ,细胞周期延长 ,线粒体变性。  相似文献   
78.
目的:探讨血浆瓦皮素(ET)和心钠素(ANP)在维持性血液透析患者高血压中的作用。方法:尿毒症患者分为维持性血液透析不使用促红细胞生成素(EPO)组、维持性血液透析使用EPO组及尿毒辣症非透析组,以上3组各自分为高血压组和高血压正常组,另设健康对照组。应用放射免疫法检测血浆ET-1和ANP水平。结果:所有尿毒症患者血浆ET-1和ANP水平均高于健康对照组,维持血液透析使用EPO组血浆ET-1和ANP水平高于维持特性血液透不使用EPO组(P<0.05);各组中高血压亚组的血压ET-1水平及ET-1/ANP比值均高于其相应的患者的高血压同 浆ET-1水平井高升以及ET-1和ANP比值的增大有密切关系。  相似文献   
79.
Zhang  Hui  Che  Lin  Wang  Yanfei  Zhou  Haiyan  Gong  Haihong  Man  Xiaofei  Zhao  Qian 《International urology and nephrology》2021,53(10):2107-2116
Background

Acute kidney injury (AKI) is a common and serious complication of sepsis. MicroRNA-22-3p (miR-22-3p) has been found to be involved in septic AKI progression. The purpose of this study was to analyze both the serum and urinary expression of miR-22-3p in septic AKI patients, and evaluated the clinical value of miR-22-3p in the diagnosis and prognosis of sepsis-induced AKI.

Methods

Serum and urinary expression of miR-22-3p was examined using qRT-PCR. The risk factors related with septic AKI onset were assessed using logistic analysis. A receiver-operating characteristic (ROC) curve was constructed to evaluate the diagnostic performance of miR-22-3p, and the Kaplan–Meier survival curves and Cox regression analysis were used to evaluate the predictive value of miR-22-3p for the 28-day survival of septic AKI patients.

Results

Both serum and urinary miR-22-3p expression was decreased and negatively correlated with kidney injury biomarkers in septic AKI patients. MiR-22-3p expression was a risk factor for AKI onset and had diagnostic accuracy in septic AKI patients. The expression of both serum and urinary miR-22-3p was lower in patients who died, and served as a prognostic biomarker to predict 28-day survival in septic AKI patients.

Conclusion

Serum and urinary miR-22-3p was reduced in sepsis-induced AKI patients, and served as a biomarker to predict AKI occurrence and 28-day survival in sepsis patients.

  相似文献   
80.
Purpose

To define the clinical and pathological patterns of urinary bladder carcinoma from the University Hospital of Nepal.

Methods

This is a retrospective analytical study. Patients with bladder mass who underwent surgery over 1 year and who had data record were included in the study. Demographic profile, type of surgery, findings on clinical examination, cystoscopy findings, histopathological report, tumor stage, and post-surgery adjuvant therapy were analyzed.

Results

Out of 86 patients who underwent transurethral resection of bladder tumor, 77 patients had biopsy-proven malignant bladder tumor. Urothelial cancer was present in 96.1%. Male were 78.6%. The mean age of diagnosis was 65.5?±?11.8 years. Non-muscle-invasive bladder cancer (NMIBC) was 3.7 times more common than muscle-invasive bladder cancer (MIBC). High-grade tumors (58.6%) were more common than low grade (41.4%). The detrusor muscle was present inthe biopsy specimen of 48 patients (64%). Re-TURBT within 2–6 weeks was considered based on histopathology reports for about half of the patients (45.3%). Upstaging and upgrading of the tumor was present in 5.8 and 5.8% of the patients, respectively. Residual tumor without upstaging and upgrading was present in 23.5%. One patient (1.3%) had Clavien–Dindo grade 1, three (4%) patients had grade 2 and two patients (2.7%) had grade 3b.

Conclusion

In the present study, patients with bladder cancer are younger than reported in other studies. Smokers are strongly predisposed. The histological pattern is similar to the Western and Asian populations. NMIBC and MIBC occur in proportion to that described as in other studies. We had a lower rate of recurrence, upstaging and upgrading. We had a lesser rate of acceptance for radical cystectomy in our 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