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   158149篇
  免费   12636篇
  国内免费   5177篇
耳鼻咽喉   1105篇
儿科学   3001篇
妇产科学   1499篇
基础医学   23836篇
口腔科学   2964篇
临床医学   16018篇
内科学   20602篇
皮肤病学   1503篇
神经病学   8875篇
特种医学   3603篇
外国民族医学   22篇
外科学   13286篇
综合类   25102篇
现状与发展   11篇
一般理论   25篇
预防医学   10921篇
眼科学   4335篇
药学   16651篇
  23篇
中国医学   7948篇
肿瘤学   14632篇
  2024年   338篇
  2023年   1930篇
  2022年   4066篇
  2021年   5564篇
  2020年   4935篇
  2019年   5066篇
  2018年   4961篇
  2017年   4928篇
  2016年   5103篇
  2015年   5155篇
  2014年   8072篇
  2013年   8983篇
  2012年   7562篇
  2011年   8736篇
  2010年   7569篇
  2009年   7471篇
  2008年   7503篇
  2007年   8580篇
  2006年   7900篇
  2005年   7908篇
  2004年   6943篇
  2003年   6136篇
  2002年   4527篇
  2001年   4479篇
  2000年   3679篇
  1999年   3413篇
  1998年   2440篇
  1997年   2138篇
  1996年   2240篇
  1995年   2147篇
  1994年   1900篇
  1993年   1726篇
  1992年   1476篇
  1991年   1289篇
  1990年   1078篇
  1989年   1022篇
  1988年   956篇
  1987年   743篇
  1986年   564篇
  1985年   635篇
  1984年   673篇
  1983年   407篇
  1982年   524篇
  1981年   463篇
  1980年   372篇
  1979年   315篇
  1978年   255篇
  1977年   204篇
  1976年   242篇
  1975年   151篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
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   
112.
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   
113.
114.
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   
115.
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   
116.
James H. Diaz  MD  DrPH 《Pain practice》2004,4(4):295-302
Abstract:   Spontaneous intracranial hypotension (SIH) is a postural headache syndrome unrelated to dural puncture. Because of the increasing failure of epidural blood patch (EBP) to relieve headache in SIH, we retrospectively investigated the epidemiological features and treatment outcomes in 55 cases of SIH. The study population was stratified by age and sex; continuous variables were compared for differences by t -tests; categorical variables were compared by Chi-squared analysis or Fisher exact tests. Significant differences were identified by P values of 0.05 or less. The mean age of the study population was 44 ± 12 years with a female to male ratio of 1.3:1.0. Men presented with subdural hematomas ( P  = 0.001) more often than women. Meningeal enhancement on contrast magnetic resonance imaging (MRI) was the most consistent radiographic finding. Radionuclide cisternography (RC) demonstrated thoracolumbar dural leaks in 16 of 22 patients. EBP failures were more common in patients aged 40 and younger than in older patients ( P  = 0.003). Postural headache from SIH was not uniformly responsive to EBP, and had significant comorbidities, especially in men. The management of postural headache in SIH by other techniques to restore brain position and cerebrospinal fluid dynamics should be investigated.  相似文献   
117.
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   
118.
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   
119.
Zusammenfassung Die Humerusschaftfraktur ist in 10–18% der Fälle durch primäre Radialisparese kompliziert. Sekundäre Radialisläsionen treten iatrogen bei intramedullären Verfahren in 3%, bei Plattenosteosynthesen in 15,5% auf. In der überwiegenden Mehrzahl der Fälle (80%) ist der Radialisschaden rückläufig. Eine Verletzung der A. radialis ist eher selten; sie erfordert ein offenes Vorgehen mit lokaler Revision des Gefäßes und Frakturversorgung mittels Plattenosteosynthese. Die Marknagelosteosynthese ist bei einfachen, komplexen oder pathologischen Schaftfrakturen primär oder als Verfahrenswechsel nach primärer Fixateuranlage indiziert. Während auch ausgewählte Frakturen im Collum chirurgicum mit einem Nagel versorgt werden können, sind Frakturen im distalen Viertel des Humerus ausgeschlossen. Frakturen bei kleinen Kopffragmenten weisen ein erhöhtes Komplikationsrisiko auf. Zur Vermeidung von Läsionen der Rotatorenmanschette stehen wir der anterograden Nagelung noch zurückhaltend gegenüber. Bei differenzierter Indikationsstellung und Nachbehandlung erwies sich die retrograde Marknagelung als ein schonendes Verfahren mit hohem Patientenkomfort und gutem funktionellem Ergebnis.  相似文献   
120.
With the introduction of more potent immunosuppressive agents, rejection has decreased in simultaneous pancreas/kidney transplant (SPK) recipients. However, as a consequence, opportunistic infections have increased. The purpose of this report is to outline the course of SPK patients who developed polyomavirus-associated nephropathy (PVAN). A retrospective review of 146 consecutive SPK recipients from January 1, 1996 to December 31, 2002 was performed. Immunosuppression, rejection and development of PVAN were reviewed. Nine patients were identified. All received induction with either OKT3 or thymoglobulin. Immunosuppression included tacrolimus/cyclosporine, MMF/azathioprine and sirolimus/prednisone. Two patients were treated for kidney rejection prior to the diagnosis of PVAN. Time to diagnosis was an average of 359.3 days post-transplantation. Immunosuppression was decreased but five ultimately lost function. However, none developed pancreatic abnormalities as demonstrated by normal glucose and amylase. Two underwent renal retransplantation after PVAN diagnosis and both have normal kidney function. PVAN was the leading cause of renal loss in SPK patients in the first 2 years after transplantation and is a serious concern for SPK recipients. The pancreas, however, is spared from evidence of infection, and no pancreatic rejection occurred when immunosuppression was decreased.  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