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   1696篇
  免费   96篇
  国内免费   12篇
耳鼻咽喉   79篇
儿科学   78篇
妇产科学   24篇
基础医学   123篇
口腔科学   46篇
临床医学   226篇
内科学   401篇
皮肤病学   23篇
神经病学   98篇
特种医学   248篇
外科学   155篇
综合类   62篇
预防医学   115篇
眼科学   21篇
药学   54篇
中国医学   9篇
肿瘤学   42篇
  2021年   9篇
  2020年   6篇
  2019年   16篇
  2018年   23篇
  2017年   19篇
  2016年   14篇
  2015年   26篇
  2014年   52篇
  2013年   91篇
  2012年   96篇
  2011年   65篇
  2010年   53篇
  2009年   72篇
  2008年   69篇
  2007年   78篇
  2006年   54篇
  2005年   58篇
  2004年   47篇
  2003年   44篇
  2002年   55篇
  2001年   41篇
  2000年   46篇
  1999年   37篇
  1998年   82篇
  1997年   53篇
  1996年   65篇
  1995年   48篇
  1994年   55篇
  1993年   46篇
  1992年   20篇
  1991年   23篇
  1990年   21篇
  1989年   42篇
  1988年   32篇
  1987年   28篇
  1986年   20篇
  1985年   19篇
  1984年   19篇
  1983年   15篇
  1982年   15篇
  1981年   21篇
  1980年   16篇
  1979年   10篇
  1978年   11篇
  1977年   17篇
  1976年   10篇
  1975年   11篇
  1974年   4篇
  1973年   4篇
  1969年   4篇
排序方式: 共有1804条查询结果,搜索用时 15 毫秒
11.
Induction of neuronal death by alpha-synuclein   总被引:9,自引:0,他引:9  
The molecular and cellular mechanisms underlying neuronal loss in neurodegenerative diseases are unclear. It is generally thought that aggregation of mutated, abnormally modified or abnormally folded proteins leads to the accumulation of extracellular, intracellular or intranuclear deposits that severely compromise cell physiology, leading to the death of the affected neurons. However, there is growing evidence that neuronal apoptosis in the absence of obvious pathological deposits could have a serious impact on the pathogenesis of neurodegenerative diseases. alpha-Synuclein has been implicated in aetiology and pathogenesis of certain neurodegenerative diseases, although the precise role of this protein in neurodegeneration is uncertain. The normal functions of alpha-synuclein and other members of the synuclein family in the development and function of the nervous system also remain elusive. Here we show that overexpression of wild-type and mutant forms of alpha-synuclein in cultured neurons, but not the closely related persyn (gamma-synuclein), causes apoptosis. These findings suggest that abnormalities of alpha-synuclein metabolism could lead to the neuronal loss occurring in certain forms of neurodegeneration before the formation of characteristic pathological lesions.  相似文献   
12.
Self-injection of household insecticide into the upper extremity in 5 patients is reported. All patients had mental problems, such as depression, substance abuse, or both. Four of the 5 cases were suicide attempts. Household insecticides can be divided into 3 categories based on the main chemical component. The hydrocarbon vehicle used in these insecticides, however, is poorly cleared by the local tissues and is responsible for fever, leukocytosis, and liquifaction necrosis. The focus for the hand surgeon is recognition and early and frequently repeated debridement. Psychiatric treatment and hand therapy are required.  相似文献   
13.
OBJECTIVES: To determine the spectrum of N and G genotypes of respiratory syncytial virus (RSV) causing respiratory tract infection and whether particular genotypes are associated with severity of infection. PATIENTS AND METHODS: Nasopharyngeal aspirates (NPAs) were obtained from 114 infants with acute respiratory tract infection due to RSV over two seasons. Viral mRNA was extracted from NPAs or cultured virus, reverse transcribed, and the cDNA amplified by the polymerase chain reaction using primers directed to parts of the N and G gene respectively. Amplicons were separately digested with four different restriction endonucleases for each gene. The fragments were separated by agarose gel, electrophoresis, and the electrophoretic patterns used to assign the various genotypes. Disease severity was assessed as very mild (upper respiratory tract signs only), mild (coryza and signs of lower respiratory tract infection), moderate (requiring nasogastric or intravenous fluids), and severe (requiring oxygen or ventilation). RESULTS: Five of the six known N genotypes were detected, but NP4 and NP2 were found most frequently. There was no association between N genotype and disease severity. Six G (SHL) genotypes were detected. Significantly (p = 0.04) more of the infants infected with the SHL2 genotype had severe or moderate disease. CONCLUSIONS: During the seasonal peaks of RSV respiratory tract infection at least 10 different RSV genotypes cocirculated. While there is no association between N genotypes and disease severity, infection with the SHL2 G genotype appears to result in moderate to severe disease.  相似文献   
14.
15.
16.
随着器官移植体液免疫理论的发展与抗体检测技术的进步,抗体介导的排斥反应(AMR)已逐渐被认识和引起关注。其治疗难度大、逆转率较低,已成为导致移植物失功的重要原因。本文较为系统地介绍了AMR的免疫机制、诊断与防治进展,以及供者特异性抗体的检测技术和临床意义,从而提出供者特异性抗体是引起移植物排斥反应特别是慢性排斥反应的主要原因,移植受者需常规监测抗体以利及时干预和治疗。  相似文献   
17.
AIM:To examine surgical and medical outcomes for patients with cholangiocarcinoma using a populationbased cancer registry.METHODS:Using the California Cancer Registry’s Cancer Surveillance Program,patients with intrahepatic cholangiocarcinoma treated in Los Angeles County from 1988 to 2006 were identified and evaluated for clinical and pathologic factors and therapies received(surgery,radiation,and chemotherapy).The surgical cohort was further categorized into three treatment groups:patients who received adjuvant chemotherapy,adjuvant chemoradiation,or underwent surgery alone(no chemotherapy or radiation administered).Survival was assessed by Kaplan-Meier method;and Cox proportional hazard modeling was used in multivariate analysis.RESULTS:Of 825 patients,60.2% received no treatment.Of the remaining 328 patients,18.5% chemotherapy only,7.4% chemoradiation,and 13.8% underwent surgery.More male patients underwent surgical resection(P = 0.004).Surgical patients were younger than the patients receiving chemotherapy or chemoradiation(P < 0.001).Of the surgical cohort(n = 114),60.5% underwent surgery alone while 39.5% underwent surgery plus adjuvant therapy(chemotherapy n = 20;chemoradiation,n = 21)(P < 0.001).Median survival for all patients in the study was 6.6 mo.Median survival was highest for patients who underwent surgery(23 mo),whereas both chemotherapy(9 mo) and chemoradiation(8 mo) alone were each less effective(P < 0.001).By multivariate analysis,extent of disease,receipt of surgery,and administration of chemotherapy(with/without surgery) were independent predictors of overall survival.CONCLUSION:This study demonstrates that surgery is a critical treatment modality.Multimodality treatment has yet to be standardized,but play a role in optimal therapy for cholangiocarcinoma.  相似文献   
18.
目的探讨金属对金属(金对金)大头径假体微创全髋关节置换术(THA)治疗青中年股骨头坏死Ⅲ、Ⅳ期的临床疗效。方法本组32例(35髋)青中年股骨头缺血性坏死Ⅲ、Ⅳ期患者,年龄24~59岁,平均45岁,术前髋关节Harris评分平均(37.9±7.5)分;以改良后外侧小切口、肌间隙人路、充分保留关节动力性组织结构为特征的金对金大头径微创THA治疗。术中严格采取正确的假体植入技术,术中保留完整的软骨下骨和髋臼横韧带,击入臼杯时一次性安装成功,正确运用万古霉素预防感染。术后口服利伐沙班片抗凝,术后12h开放负压引流及卧床行功能锻炼,术后第2天拔除引流管后扶拐下地部分负重行走,术后2—3周患者即可弃拐完全负重行走。结果本组32例35髋患者均获随访,随访时间为12个月~6年,平均为4年。所有患者切口均一期愈合,无深静脉血栓形成、关节脱位、坐骨神经损伤、髋臼及股骨疲劳骨折、关节疼痛等严重并发症,X线片示髋关节假体位置均良好,无松动、移位、股骨柄下沉、假体周围骨折等表现。末次随访Harris评分由术前平均(37.9±7.5)分,提高至术后平均(92.2±4.6)分,前后比较有统计学意义(t=44.341,P〈0.05)。所有患者末次随访时髋关节功能明显优于术前,均对治疗效果满意,完全恢复正常生活及工作。结论采用金对金大头径微创THA治疗青中年股骨头坏死Ⅲ、Ⅳ期患者,能够明显降低手术风险,缩短卧床时问,迅速恢复髋关节功能,减少手术并发症,取得了满意的近期临床疗效。随着基础和临床研究的不断深入,金对金大头径髋关节假体的长期疗效还需要进一步探讨。  相似文献   
19.
20.
目的 探讨热休克蛋白72肽结合区在肾小管上皮间质转分化(EMT)过程中的作用和可能机制.方法 应用质粒转染方法分别诱导热休克蛋白72(HSP72)野生型、肽结合区缺失型(HSP72-△PBD)和肽结合区(PBD)的表达.用转化生长因子β1(TGF-β1)刺激大鼠肾小管上皮细胞(NRK-52E)48 h,Western印迹和免疫荧光染色检测细胞E-钙黏蛋白(cadherin),α-平滑肌肌动蛋白(SMA),HSP72和Smad3/磷酸化(p)-Smad3蛋白表达.结果 TGF-β1(10 μg/L)刺激NRK-52E细胞48 h后上调α-SMA和下调E-cadherin蛋白表达水平.Western印迹及细胞免疫荧光显示,过表达HSP72和PBD能明显减轻TGF-β1诱导的NRK-52E细胞E-cadherin蛋白表达下调和α-SMA蛋白表达上调,而过表达HSP72-△PBD不能改变上述蛋白的表达.此外,过表达HSP72和PBD显著抑制Smad3的磷酸化.结论 HSP72抑制Smad3活化和EMT的发生可能与PBD的功能有关.  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