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   157617篇
  免费   12589篇
  国内免费   5138篇
耳鼻咽喉   1093篇
儿科学   2889篇
妇产科学   1488篇
基础医学   23872篇
口腔科学   2983篇
临床医学   16000篇
内科学   20780篇
皮肤病学   1500篇
神经病学   7574篇
特种医学   4796篇
外国民族医学   22篇
外科学   13151篇
综合类   24847篇
现状与发展   11篇
一般理论   25篇
预防医学   10909篇
眼科学   4248篇
药学   16642篇
  16篇
中国医学   7926篇
肿瘤学   14572篇
  2024年   329篇
  2023年   1827篇
  2022年   3923篇
  2021年   5427篇
  2020年   4799篇
  2019年   4947篇
  2018年   4892篇
  2017年   4882篇
  2016年   5047篇
  2015年   5096篇
  2014年   7975篇
  2013年   8926篇
  2012年   7578篇
  2011年   8735篇
  2010年   7617篇
  2009年   7519篇
  2008年   7601篇
  2007年   8677篇
  2006年   7923篇
  2005年   7954篇
  2004年   6954篇
  2003年   6139篇
  2002年   4556篇
  2001年   4513篇
  2000年   3699篇
  1999年   3410篇
  1998年   2430篇
  1997年   2145篇
  1996年   2238篇
  1995年   2140篇
  1994年   1902篇
  1993年   1723篇
  1992年   1475篇
  1991年   1282篇
  1990年   1072篇
  1989年   1004篇
  1988年   950篇
  1987年   729篇
  1986年   556篇
  1985年   635篇
  1984年   669篇
  1983年   415篇
  1982年   519篇
  1981年   446篇
  1980年   384篇
  1979年   320篇
  1978年   261篇
  1977年   210篇
  1976年   247篇
  1975年   150篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The brains of pathogen-free autoimmune MRL/lpr, NZBWF1 and NZB mice were examined for central nervous system (CNS) inflammation in premoribund 8-week-old animals and at ages when active systemic lupus erythematosus (SLE) was present. CNS inflammation was observed only in MRL/lpr mice. Immunohistochemical studies of brains from young MRL/lpr mice found that infiltrates were composed primarily of CD4+ cells. Older MRL/lpr mice (22 and 26 weeks of age) had CD4+ cells predominantly, but CD8+ and B220+ cells were also present. Perivascular leakage of IgG was a prominent and unexpected finding in the MRL/lpr model. Congenic MRL/+ mice with late-onset autoimmunity had no inflammatory cells in brain tissue, and there was no perivascular staining with IgG or albumin. Our findings suggest that MRL/lpr mice are a useful model for studies of lupus-associated CNS inflammatory disease, and perivascular leakage may be a primary mechanism for entry of IgG into the brain.  相似文献   
102.
《Nutrition reviews》1987,45(10):246-248
Increasing dietary 18:2 n-6/18:3 n-3 causes similar relative changes in fatty acid profiles of phosphatidylethanolamine and phosphatidylcholine from rat neural and erythrocyte membranes.  相似文献   
103.
多希紫杉醇联合顺铂治疗晚期非小细胞肺癌疗效观察   总被引:1,自引:0,他引:1  
目的观察和评价多希紫杉醇联合顺铂(DP方案)治疗晚期非小细胞肺癌的疗效和毒性。方法将我科近几年收治的48例晚期非小细胞肺癌患者随机分为治疗组和对照组。治疗组采用多希紫杉醇联合顺铂(DP方案),对照组采用长春瑞滨联合顺铂(NP方案)。2周期化疗后进行疗效、毒性对比研究。结果治疗组和对照组近期有效率分别为45.5%和37.5%,疾病进展时间(TTP)分别为6.3和5.9个月,中位生存期分别为10.1和9.0个月,1年生存率分别为45.8%和39.4%,两组间比较差异均无显著性(P>0.05)。治疗组在恶心呕吐、骨髓抑制等毒性反应发生率方面低于对照组,差异有显著性(P<0.05)。结论多希紫杉醇联合顺铂治疗晚期非小细胞肺癌与NP方案相比较,疗效相似,但毒性反应低于NP组,患者更易耐受,可广泛应用于临床。  相似文献   
104.
白马藏人是一支有待识别的民族。本文以肤纹作聚类分析,结果表明白马藏人与藏族的距离很大,很有可能是一支独立的民族。  相似文献   
105.
Malignant melanoma causes significant health problems. The identification of tumour-associated antigens has led to novel approaches to increase T cell mediated anti-tumour immune response. Melan-A/MART-1 has been use as target antigen for several T cell based immunotherapeutic treatments. More recently, the critical role of CD4+ T cells in inducing and maintaining anti-tumour immunity has been increasingly recognized. In order to optimize tumour immunotherapy, greater efforts have been concentrated on the identification of tumour antigens presented by MHC class II molecules to CD4+ T cells. In a publication, Tiwari et al. (2004) [1] have identified by a computational approach the 15-mer amino-acid sequence 101–115 (PPAYEKLSAEQSPPP) of the Melan-A/MART-1 as a good target for a vigorous and safe immunotherapy. Therefore, we have investigated the in vivo anti-tumour activity of this peptide in a murine melanoma model. For the prophylactic treatment, 20 μg or 50 μg peptide was subcutaneously injected in mice once a week during 3 weeks before tumour induction. Treatment with 50 μg peptide significantly affected tumour development. Thus, our preliminary data demonstrate potential in vivo prophylactic activity of the 101–115 peptide-based vaccine to control melanoma growth.  相似文献   
106.
107.
Global self-rated health (SRH) is increasingly a key indicator in the assessment of immigrant health. However, evidence of the impact on SRH of generational status, duration of residence in the US, and socioeconomic status (SES) among immigrants and their offspring is limited and inconsistent. We overcome limitations in existing research on this topic by using a uniquely large and diverse data source, the March Annual Social and Economic Supplement of the Current Population Survey (CPS; 2003–2007) (n = 637,209). As a result, we are able to disaggregate results by race/ethnicity, account for country of origin, and consider the role of multiple dimensions of SES. We find that overall first-generation immigrants in the US have lower odds of poor/fair SRH compared to the third-generation. This association is particularly strong for blacks and Hispanics but not significant for Asians. Among first-generation Asians and Hispanics, longer duration of residence is positively associated with poor/fair SRH. Finally, socioeconomic gradients in SRH tend to be less pronounced among the first-generation (versus the third) and, within the first-generation, among recent arrivals (versus those with longer durations). Our results highlight the importance of explicitly accounting for multiple immigration-related variables and their interactions with race/ethnicity and SES. Otherwise, studies may misestimate SRH differences by race/ethnicity and socioeconomic status. The continued growth of the US immigrant population and the second-generation underscore the need to examine patterns in immigrant health systematically.  相似文献   
108.
十二指肠镜、腹腔镜联合治疗肝外胆管结石   总被引:6,自引:0,他引:6       下载免费PDF全文
目的探讨十二指肠镜联合腹腔镜治疗胆囊结石并胆管结石的临床效果。方法回顾分析7年间106例胆囊结石并胆管结石患者的临床资料。106例均先行内镜下十二指肠乳头切开(EST)取石、鼻胆引流(ENBD)然后行腹腔镜胆囊切除术(LC)。结果EST取石成功101例(95.3%);并发症包括胰腺炎(高淀粉酶血症)11例(10.4%),出血1例,急性胆管炎2例,均经对症处理治愈。全组病例无死亡,均痊愈出院。85例获平均3.1年随访,术后复发胆管结石5例(5.9%),十二指肠乳突部再狭窄1例;另发生胆管癌2例,其他原因死亡2例。结论联合EST和LC治疗肝外胆管结石是一种安全有效的微创手术方法。  相似文献   
109.
Functional dyspepsia (FD) is associated with impaired gastric accommodation and autonomic dysregulation. The aim of this study was to investigate the effects of autonomic manipulation on distension-induced gastric accommodation in subjects with and without FD, using a newly developed gastric barostat paradigm. Twelve healthy subjects (HS) and 18 subjects with FD had four barostat examinations each: no intervention, intravenous atropine (1 mg), vagal stimulation (mental relaxation with deep breathing) and acute stress stimulation (serial subtraction task). Intrabag pressure increased from 1 to 15 mmHg in 5 min (ramp phase), and was maintained at 15 mmHg for 5 min (tonic phase). Volume responses were analysed using predefined parameters. There were no significant group differences in accommodation variables between HS and subjects with FD. The FD group could be subdivided into two distinct subgroups: subgroup 1 (n = 7, 38%) with low maximum volume and accommodation rate, and subgroup 2 with normal accommodation (n = 11). In subgroup 1, but not in subgroup 2 atropine increased maximum volume and accommodation rate substantially. Neither mental stress nor mental relaxation changed any of the accommodation variables. In a subgroup of subjects with FD, impairment of distension-induced gastric accommodation can be improved by cholinergic blockade, but not by acute physiological autonomic manipulation.  相似文献   
110.
目的 :评价原发性肝癌并发门静脉高压症的外科治疗效果。方法 :回顾性分析联合手术治疗原发性肝癌并发门静脉高压症 30例的疗效。结果 :手术死亡 1例 ,严重肺部感染、肝肾综合征及顽固性腹水各 1例。术后 1、3、5年生存率分别为 93.3%、5 3.3%、40 %。随访中共死亡 1 7例 ,死亡原因 :肝癌复发 9例 ,肝功能衰竭 5例 ,上消化道出血 3例。结论 :理性选择联合手术方式治疗原发性肝癌并发门静脉高压症是安全可行的 ,联合行胃冠状静脉栓塞和脾切除术效果良好。  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