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   2065篇
  免费   138篇
  国内免费   45篇
耳鼻咽喉   16篇
儿科学   95篇
妇产科学   26篇
基础医学   150篇
口腔科学   42篇
临床医学   292篇
内科学   328篇
皮肤病学   44篇
神经病学   62篇
特种医学   288篇
外科学   292篇
综合类   205篇
预防医学   142篇
眼科学   17篇
药学   127篇
  2篇
中国医学   32篇
肿瘤学   88篇
  2022年   30篇
  2021年   32篇
  2020年   30篇
  2018年   22篇
  2017年   24篇
  2016年   19篇
  2015年   33篇
  2014年   48篇
  2013年   74篇
  2012年   78篇
  2011年   85篇
  2010年   93篇
  2009年   108篇
  2008年   67篇
  2007年   80篇
  2006年   81篇
  2005年   53篇
  2004年   53篇
  2003年   51篇
  2002年   48篇
  2001年   37篇
  2000年   27篇
  1999年   28篇
  1998年   82篇
  1997年   74篇
  1996年   72篇
  1995年   67篇
  1994年   41篇
  1993年   51篇
  1991年   19篇
  1990年   15篇
  1989年   30篇
  1988年   42篇
  1987年   41篇
  1986年   30篇
  1985年   34篇
  1984年   20篇
  1983年   24篇
  1982年   16篇
  1980年   16篇
  1977年   17篇
  1976年   14篇
  1963年   17篇
  1960年   14篇
  1959年   22篇
  1958年   29篇
  1957年   19篇
  1956年   30篇
  1955年   42篇
  1954年   35篇
排序方式: 共有2248条查询结果,搜索用时 31 毫秒
71.
Nyberg  DA; Filly  RA; Filho  DL; Laing  FC; Mahony  BS 《Radiology》1986,158(2):393-396
Simultaneous sonography and quantitative serum human chorionic gonadotropin (HCG) levels from 126 women with threatened abortion were compared. Of 56 women with normal outcome, 39 (70%) had a gestation sac greater than or equal to 5 mm in mean sac diameter, and in each case the HCG level was 1,800 milli-international units (mIU/ml) or greater. The serum HCG levels strongly correlated with the gestation sac sizes to a mean sac diameter of 25 mm. Of 70 abnormal pregnancies, 31 demonstrated a gestation sac. Of these, 20 women (65%) had disproportionately low HCG levels relative to sac size, including 12 in whom the HCG level was less than 1,800 mIU/ml. One woman with an early molar pregnancy had a disproportionately elevated HCG level. Correlation of sonograms with a simultaneous measurement of serum HCG level is a useful method for evaluating threatened spontaneous abortion. A disproportionately low HCG level relative to gestation sac size is evidence for an abnormal pregnancy.  相似文献   
72.
Clark  DA; Dessypris  EN; Jenkins  DE Jr; Krantz  SB 《Blood》1984,64(5):1000-1005
We have investigated the hemolytic mechanisms in a patient with acquired immune hemolytic anemia whose red cells appeared to be coated with IgA alone. The clinical course was similar to that of patients with hemolytic anemia mediated by warm-reacting IgG antibody. Splenic sequestration of red cells was demonstrated, and marked reduction of hemolysis occurred after corticosteroid therapy. Antibody was eluted from the patient's red cells and used to sensitize normal red cells in vitro. These sensitized red cells were not lysed by fresh autologous serum, nor did they fix detectable amounts of C3. However, red cells sensitized by eluted antibody were lysed by normal human peripheral blood monocytes in a system designed to demonstrate antibody-dependent cell-mediated cytotoxicity. Monocyte-mediated hemolysis of sensitized red cells was inhibited by the addition of low concentrations of normal serum IgA to the system, but not by IgG. The ability of the eluate to induce monocyte-mediated hemolysis was abolished by its adsorption on Sepharose-bound anti-IgA, but not by preincubation with Sepharose-bound anti-IgG. In addition, normal human monocytes were demonstrated to ingest eluate-sensitized red cells. These data demonstrate an in vitro interaction of IgA-sensitized red cells with leukocytes and suggest a possible mechanism for the patient's hemolysis.  相似文献   
73.
目的 探讨Lafora病的临床、病理特点及诊断方法.方法 总结分析5例经腋窝皮肤活体组织检查确诊的Lafora病患者的临床和组织病理学特点.5例患者都进行了腋窝皮肤活体组织检查,常规行HE、糖原(PAS)和阿辛蓝-糖原(AB-PAS)染色.结果 5例患者中4例青少年发病,1例成年起病.所有患者均表现为进行性加重的强直阵挛发作、肌阵挛和智能损害,可早期出现性格改变,构音障碍和行走不稳.腋窝皮肤活体组织检查发现Lafora包涵体存在于大、小汗腺的肌上皮细胞和导管细胞内.结论 经皮肤活体组织检查发现PAS阳性圆形或卵圆形包涵体,结合Lafora病典型的临床表现可以确诊该病;皮肤活体组织检查的部位可选择腋窝或腋窝以外的部位.  相似文献   
74.
The kidneys in paroxysmal nocturnal hemoglobinuria   总被引:6,自引:0,他引:6  
Long-term study of 21 PNH patients revealed an unexpectedly high incidence of functional and anatomic renal abnormalities. Most patients demonstrated varying degrees of hematuria and proteinuria distinct from hemoglobinuria. Evaluation of renal function revealed hyposthenuria, abnormal tubular function, and declining creatinine clearance. Radiologically these patients had enlarged kidneys, cortical infarcts, cortical thinning, and papillary necrosis which were confirmed by autopsy studies. Hypertension developed in eight patients. Urinary tract infection was uncommon. The renal findings bear striking similarity to those of sickle cell anemia. Contrary to the usual opinion, out studies clearly showed evidence of widespread renal pathology in PNH most likely due to repeated microvascular thrombosis similar to the venous thrombosis involving other organs in this disorder.  相似文献   
75.
目的分析5例脊髓延髓肌萎缩症患者的临床特征,以便临床医生对该病的认识。方法收集基因确诊的5例脊髓延髓肌萎缩症患者的临床资料,分析其临床特点及血清性激素、各生化指标水平、脑脊液及肌电图特点。结果脊髓延髓肌萎缩症患者青年发病,病情进展缓慢。神经系统表现为以肢体近端和延髓部受累为主的瘫痪。舌肌受累较早,运动功能损害较轻。血清睾酮(969.3±234.9ng/dl)、雌二醇(57.1±5.3pg/ml)水平增高,男性乳腺发育出现在病史较长的患者。三核苷酸(CAG)重复序列数目43~51(平均47.2±3.6pg/ml)。患者的肌酸激酶(CK,481.8±264.8 IU/L)均增高,脑脊液检查均正常。肌电图为广泛神经源性损害。结论脊髓延髓肌萎缩症患者的早期症状不典型,易误诊,临床特征为青年起病,缓慢加重,以肢体近端无力为主的瘫痪。  相似文献   
76.
77.
78.

Introduction

The results of surgical resection and palliative chemotherapy use in hilar cholangiocarcinoma (HC) have been well publicised but the proportion of patients able to undergo these treatments and the comparative outcomes in a population of patients with HC are less well known.

Methods

Patients with HC were identified by review of all patients undergoing percutaneous cholangiography over a nine-year period (2002–2010) in a tertiary facility. The treatment undertaken and outcomes were recorded.

Results

Overall, 68 patients were identified (37 female) with a median age of 70 years. Forty-five (66%) were treated solely by insertion of a metal stent (median survival 4.73 months) and nine (13%) also received palliative chemotherapy (median survival 13.7 months). Persisting jaundice after stent insertion was noted in 18 of 35 patients (51%) tested within one month of death. Fourteen patients (21%) underwent surgical resection (median survival 20.2 months).

Conclusions

Patients undergoing surgical resection had significantly longer survival than those receiving only a palliative stent but not compared with those also receiving palliative chemotherapy, with short-term follow-up. Only a third of patients, however, receive active treatment (surgery or chemotherapy) and improvements in long-term biliary palliation are needed.  相似文献   
79.
80.
目的 研究胃癌增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)表达与腹腔灌洗液端粒酶活性及腹膜转移的相关性,并比较腹腔灌洗液中端粒酶活性和细胞学检测游离癌细胞预测腹膜转移的应用价值。方法 应用免疫组化SP法检测60例胃癌患者胃癌组织中PCNA表达,PCR—TRAP-ELISA法检测腹腔灌洗液中端粒酶活性,同时行腹腔灌洗液脱落细胞学(peritoneal lavage cytology.PLC)检测;并分析其与相关临床病理因素的关系。结果 胃癌患者腹腔灌洗液中端粒酶活性的阳性率为41.7%;与浆膜侵犯、组织学类型、浸润深度、浆膜受累面积及腹膜转移密切相关,并随着浸润深度及浆膜受累面积的增加而升高(P〈0.05)。PLC检测阳性率为25.0%;在伴肉眼可见腹膜转移灶(P1-3)者明显增高,也随着浸润深度及浆膜受累面积的增加而升高。两种方法检测的阳性率总体上差异无统计学意义。但在未分化型癌、pT1、伴肉眼可见腹膜转移灶(P1-3)者端粒酶活性阳性率明显高于PLC。PCNA增殖指数(PI)在腹腔灌洗液端粒酶活性表达阳性者明显高于表达阴性者,伴肉眼可见腹膜转移灶(P1-3)者明显高于无肉眼可见腹膜转移灶(P0)者,浆膜受侵者明显高于浆膜未受侵者(P均〈0.05)。结论 两种方法均适用于胃癌腹腔脱落癌细胞的诊断或腹膜转移的预测,端粒酶活性检测微量癌细胞的灵敏度优于PLC法检测;胃癌端粒酶活性与恶性增殖活性密切相关;胃癌高增殖活性是浆膜受侵及腹膜转移的重要原因。  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