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   18696篇
  免费   2432篇
  国内免费   653篇
耳鼻咽喉   165篇
儿科学   55篇
妇产科学   2118篇
基础医学   1867篇
口腔科学   688篇
临床医学   1941篇
内科学   519篇
皮肤病学   69篇
神经病学   775篇
特种医学   549篇
外国民族医学   24篇
外科学   2212篇
综合类   3844篇
现状与发展   8篇
预防医学   1114篇
眼科学   47篇
药学   934篇
  21篇
中国医学   1098篇
肿瘤学   3733篇
  2024年   33篇
  2023年   271篇
  2022年   462篇
  2021年   840篇
  2020年   753篇
  2019年   594篇
  2018年   554篇
  2017年   821篇
  2016年   941篇
  2015年   913篇
  2014年   1633篇
  2013年   1358篇
  2012年   1291篇
  2011年   1456篇
  2010年   1181篇
  2009年   1031篇
  2008年   946篇
  2007年   1008篇
  2006年   898篇
  2005年   686篇
  2004年   556篇
  2003年   550篇
  2002年   430篇
  2001年   382篇
  2000年   231篇
  1999年   200篇
  1998年   209篇
  1997年   175篇
  1996年   185篇
  1995年   138篇
  1994年   137篇
  1993年   97篇
  1992年   94篇
  1991年   80篇
  1990年   76篇
  1989年   68篇
  1988年   70篇
  1987年   47篇
  1986年   57篇
  1985年   56篇
  1984年   55篇
  1983年   42篇
  1982年   49篇
  1981年   27篇
  1980年   29篇
  1979年   15篇
  1978年   17篇
  1977年   11篇
  1976年   9篇
  1972年   5篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
目的对比下颈椎经关节螺钉和Magerl侧块螺钉固定技术神经根(前支和后支)损伤的潜在风险。方法应用经关节螺钉和Magerl侧块螺钉两种固定技术,固定C_(3-7)节段,每种技术使用2具标本和20枚螺钉。使用直径为3.5mm、长度为20mm的螺钉进行过度穿透侧块腹侧皮质固定。仔细解剖颈部的前侧方,观察螺钉与脊神经前、后支的关系。结果下颈椎经关节螺钉固定技术总体神经损伤比例(45%)明显低于Magerl侧块螺钉固定技术(90%),两者差异有显著性意义(P<0.05)。经关节螺钉和Magerl侧块螺钉固定技术引起的神经损伤均最多见于脊神经后支,分别为25%和45%。结论经关节螺钉固定技术神经根损伤的风险低于Magerl侧块螺钉固定技术。  相似文献   
82.
本文应用HPV-PCR技术和DNA杂交技术对76例宫颈鳞癌标本进行了HPV-DNA的研究,发现HPV-DNA存在率为90.79%(69/76),主要类型为HPV16和18。多酶切SouthernBlot杂交证实在宫颈癌中92.56%的HPV-DNA发生变异,说明HPV-DNA的基因变异与其致癌作用密切相关。PCR结果证实HPV-E6片段在宫颈癌组织中常可出现,推测可能是致癌的关键片段之一。因此,检测宫颈癌组织中HPV-DNA的完整性、关键基因片段的存在与否,可能对于病变恶变的预测有一定的意义  相似文献   
83.
高位食管癌切除颈部胃食管重建术的临床应用和初步评价   总被引:1,自引:0,他引:1  
本文报道了我院自1988年至1994年间采用高位食管癌切除颈部胃食管重建术治疗高位食管癌23例的结果,其中男14例,女9例,年龄35-70岁,平均年龄52岁,病变位于颈段者11例,上胸段者12例。2,3,5年生存率分别为62.5%,55.1%,33.3%。同时介绍了手术要点和该术式的优点,并提出了吻合口瘘的预防措施。  相似文献   
84.
Induction of neurite outgrowth from superior cervical ganglia (SCG) by rat lymphoid tissues was studied using a tissue culture model. Neonatal rat SCG were cultured with 6–12-week-old rat thymus, spleen, or mesenteric lymph node (MLN) explants in a Martrigel layer, in defined culture medium without exogenous nerve growth factor (NGF). SCG were also co-cultured with neonatal rat heart (as positive control) or spinal cord (SC; as negative control). To determine whether inflammation affects the ability of lymphoid tissues to induce neurite outgrowth, we also examined MLN at various times after infecting rats with Nippostrongylus brasiliensis (Nb-MLN). In one series of experiments, a single lymphoid tissue explant was surrounded by four SCG at a distance of 1 mm. The extent of neurite outgrowth was determinded by counting the number of neurites 0.5 mm away from each ganglion at several time points. Adult thymus and, to a lesser extent, spleen had strong stimulatory effects on neurite outgrowth from SCG after 12 hr or more in culture. For thymus tissue, this was similar to the positive control heart explants. MLN from normal rats had minimal effect on neurite outgrowth; however, Nb-MLN showed a time-dependent enhancement of the neurite outgrowth, maximal at 3 weeks after infection. The relative efficacy of neurite outgrowth induction (heart ≥ thymus ≥ Nb-MLN ≥ spleen ≥ MLN ≥ SC) was confirmed in a second series of experiments where one SCG was surrounded by three different tissue explants. We then examined the role of 2.5S NGF, a well-known trophic factor for sympathetic nerves, in the lymphoid tissue-induced neurite outgrowth. Anti-NGF treatment of co-cultures of SCG and heart almost completely blocked the neurite outgrowth. Anti-NGF also significantly inhibited thymus- and spleen-induced neurite outgrowth, but not as effectively as heart-induced neuritogenesis (93,80, and 77% inhibition at 24 hr; 86,70, and 68% inhibition at 48 hr for heart, thymus, and spleen, respectively). On the other hand, anti-NGF inhibited only 8% of neurite outgrowth induced by 3-week post-infection Nb-MLN at 24 hr, and 41% at 48 hr. These data show that several adult rat lymphoid tissues exert neurotrophic/tropic effects. The predominant growth factor in thymus and spleen is NGF, while Nb-MLN produces factor(s) which is (are) immunologically distinguishable from NGF. These neurotrophic/tropic factors are produced during the reactive lymphoid hyperplasia that forms part of the inflammatory response against the nematode, N. brasiliensis. This suggests the possibility that cytokines produced by lymphocytes or other inflammatory cells may stimulate sympathetic neurite outgrowth in vivo. © 1994 Wiley-Liss, Inc.  相似文献   
85.
颈椎侧块钢板在脊髓型颈椎病治疗中应用   总被引:2,自引:1,他引:1  
目的 对15例脊髓型颈椎病患者行后入路椎管减压、椎板成型术的同时使用颈椎侧块钢板固定,探讨和分析该手术方法的优点和手术治疗效果。方法 从自2000年3月—2002年12月,对15例脊髓型颈椎病患者(术前颈椎MR显示有三个节段颈椎椎间盘水平病变并有黄韧带增厚突入椎管),行颈椎后入路双开门椎板成型术加双侧颈椎侧块钢板固定。按JOA评分法评定患者手术前后恢复情况。结果 本组患者男10例,女5例,随访5个月—1年2个月,平均9个月,术后2—7天(平均3.5天)可戴颈围坐起,颈围外固定时间12周,融合时间3—5个月,(平均为3.5个月),术后JOA评分明显提高,所有病人无术中血管、神经根损伤,无植骨不愈合,无内固定断裂。结论 行颈椎后入路双开门椎板成型术联合应用颈椎侧块钢板固定,从后方扩大椎管容积,对脊髓进行减压,辅助以侧块钢板对减压后的颈椎行即时的稳定的固定,增加后方所植髂骨的融合成功率,大大地减少颈椎术后后突畸形发生和术后卧床并发症的发生率。  相似文献   
86.
颈椎前路钢板在脊髓型颈椎病前路手术中的作用   总被引:10,自引:2,他引:8  
目的 评价内固定在脊髓型颈椎病前路减压中的作用。方法 143例脊髓型颈椎病患者经前路减压后自体髂骨植骨,带锁钢板内固定。获得随访病例132例,随访时间平均20个月,观察术后神经功能恢复情况,植骨融合率,椎间高度及颈椎生理曲度恢复情况。结果 单节段与两节段病变者术后3月均获得骨性愈合,融合率为100%,16例3节段病变者融合体为81.3%,内固定并发症为5/132(3.8%)。术后椎间高度与生理曲度均获得满意重建。JOA记分平均改善率65.8%。结论 在脊髓型颈椎病前路减压手术中应用带锁钢板内固定可有效维持椎间高度和生理曲度,并有助于后路间接减压。  相似文献   
87.
[目的]探讨伴有上肢局部水肿的颈椎病患者的发病机理和与手术颈椎减压的关系。[方法]总结分析4a来收治的10例伴有上肢局部水肿的颈椎病人,其中脊髓型颈椎病7例,神经根型颈椎病2例,后纵韧带骨化型1例,7例行前路椎体次全切减压植骨内固定,1例行前路椎体次全切+单间隙间盘摘除植骨内固定,2例行后路减压植骨内固定,术后观察患者水肿消退情况。[结果]10例病人上肢局部水肿不同程度消退,前路手术者较后路手术者消退快。[结论]颈椎病患者上肢水肿的发生与颈交感神经受激惹有关,通过前路或后路颈椎管减压,去除颈椎不稳、椎间盘突出、骨赘等交感神经受激惹因素,水肿可逐步消退。  相似文献   
88.
The presence of hypoxic cells is one of the major factors affecting resistance against radiation therapy. In the clinical setting, little information exists as to the relationship between intratumoral oxygen partial pressure (pO(2)) and outcome. This study involved 30 consecutive patients with cervical cancer, who were treated with a combination of external and high-dose rate intracavitary irradiation. The pO(2) was measured before radiation therapy and at 9 Gy, using a needle-type polarographic oxygen electrode. The mean intratumoral pO(2) before radiation therapy was 17.3 +/- 10.8 mm Hg. The 3-year local control rates of patients with pO(2)< or = 20 mm Hg and pO(2) > 20 mm Hg before radiation therapy were 52% and 100%, respectively, representing a significant difference (P= 0.035). At 9 Gy, mean intratumoral pO(2) was 23.6 +/- 9.1 mm Hg, a significant increase compared to the value before radiation therapy (P= 0.006). The 3-year local control rates of tumors with pO(2)< or = 20 mm Hg and pO(2) > 20 mm Hg at 9 Gy were 35% and 93%, respectively, representing a significant difference (P= 0.001). The significantly better local control for oxygenated tumors at 9 Gy as well as before radiation therapy indicated that the oxygen effect and reoxygenation by radiation played an important role in local control in radiation therapy for cervical cancer.  相似文献   
89.
The reliability and applicability of colposcopically directed cervical punch biopsy was assessed in a sample of 170 paired punch and large loop excision of cervical transformation zone (LLETZ) specimens obtained from previously untreated women who had been selected for treatment on the basis of cytology and/or colposcopic findings and in whom the entire cervical transformation zone was visible. A single punch biopsy was taken immediately before the LLETZ, and all the specimens were reviewed by a single pathologist. Nine (5.3%) punch biopsies were inadequate. In terms of whether or not there was cervical intraepithelial neoplasia (CIN), the chance-corrected kappa analysis rated overall agreement as poor (kappa = 0.21, 95% confidence limits 0.02-0.39), whereas in terms of histologic grade, it was fair to moderate (kappa = 0.32, 95% confidence limits 0.23-0.42). Punch biopsy tended to underestimate the disease. The sensitivity and specificity of colposcopically directed punch biopsy for the detection of high-grade CIN was 74% and 91%, respectively, with positive- and negative predictive values of 97% and 48%, respectively. Two microinvasive and two intraepithelial glandular lesions were missed on punch biopsy. Punch biopsy should be avoided when high-grade disease is suspected.  相似文献   
90.
In this study, we evaluated the presence of human papillomavirus (HPV) DNA in organs of the female upper genital tract, using nine hysterectomy and salpingo-oophorectomy specimens affected by HPV-positive invasive cervical carcinomas, to establish if cervical HPV infection can spread to upper tracts of the female genital system. HPV DNA was evaluated by polymerase chain reaction (PCR) in all cervical carcinomas as well as in all tracts of the genital system. Then, these data were compared with the results obtained from PCR study of five other hysterectomy and salpingo-oophorectomy specimens (control cases). The criteria used for selection of the control cases were informed consent of the patients for research at the time of surgery, absence of neoplasms, absence of any anatomic lesion caused by HPV in cervix, and external genitalia. All selected cases were squamous cervical carcinomas. PCR analysis revealed HPV DNA in all cases of cervical carcinoma. The HPV DNA was detected as weak positivity on PCR analysis in other organs of the genital system. However, the distribution of HPV DNA varied in the various cases and in the different tracts of the same hysterectomy and salpingo-oophorectomy specimen. We believe that the HPV DNA, detected as a weakly positive signal, in the upper genital tract of patients who have a cervical squamous carcinoma could be a reflection of a latent HPV infection, as well as a sign of the existence of micrometastases containing HPV DNA, which cannot be detected by conventional histologic techniques.  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