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   128693篇
  免费   9940篇
  国内免费   3598篇
耳鼻咽喉   1008篇
儿科学   2560篇
妇产科学   1875篇
基础医学   7592篇
口腔科学   2910篇
临床医学   15487篇
内科学   19220篇
皮肤病学   2339篇
神经病学   6665篇
特种医学   4183篇
外国民族医学   39篇
外科学   12657篇
综合类   18407篇
现状与发展   23篇
一般理论   2篇
预防医学   6068篇
眼科学   2083篇
药学   10347篇
  75篇
中国医学   11037篇
肿瘤学   17654篇
  2024年   300篇
  2023年   2328篇
  2022年   4233篇
  2021年   5719篇
  2020年   5395篇
  2019年   4928篇
  2018年   4639篇
  2017年   5036篇
  2016年   5269篇
  2015年   5033篇
  2014年   9172篇
  2013年   11587篇
  2012年   7548篇
  2011年   7983篇
  2010年   6562篇
  2009年   6037篇
  2008年   5938篇
  2007年   6351篇
  2006年   5671篇
  2005年   5016篇
  2004年   4076篇
  2003年   3690篇
  2002年   3020篇
  2001年   2674篇
  2000年   2223篇
  1999年   1739篇
  1998年   1441篇
  1997年   1214篇
  1996年   1000篇
  1995年   902篇
  1994年   721篇
  1993年   553篇
  1992年   493篇
  1991年   457篇
  1990年   388篇
  1989年   339篇
  1988年   332篇
  1987年   281篇
  1986年   222篇
  1985年   291篇
  1984年   265篇
  1983年   189篇
  1982年   191篇
  1981年   177篇
  1980年   148篇
  1979年   143篇
  1978年   82篇
  1977年   57篇
  1976年   59篇
  1975年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
目的 了解射频消融灶大小与功率及时间的关系、超声与大体病理测值的关系、消融灶与周围组织的关系。方法 新鲜牛肝 3只和牛肾 2只 ,消融灶分两组 :距肝表面 1cm和 4cm ;同时将肾脏置于肝表面 ,用不同的功率和时间实验。结果  10min时 ,2 0W ,40W ,6 0W ,80W的消融灶病理测值分别为 4.1cm ,3.8cm ,3.0cm ,3.3cm ,超声测值分别为 4.5cm ,4.0cm ,4.5cm ,4.0cm。 2 0min时 ,消融灶病理测值分别为 3.0cm ,4.1cm ,2 .8cm ,3.5cm ,超声测值分别为 4.3cm ,4.2cm ,3.4cm ,3.8cm。 30min时 ,消融灶病理测值分别为 3.5cm ,2 .9cm ,3.5cm ,3.4cm ,超声测值分别为 4.5cm ,4.0cm ,3.6cm ,4.1cm。超声和大体解剖测值相比 ,P <0 .0 1。消融灶和周围组织间有0 .3~ 0 .5cm的浅红色移行区。结论 射频消融灶的大小不随功率和时间的增加而增加 ,超声比大体病理测值大 ,两者差别有极显著性意义。消融病灶和周围组织间有移行区。浅表面的消融病灶对临近组织有损伤作用  相似文献   
992.
目的 :评价氯沙坦、福辛普利、氨氯地平对自发性高血压大鼠 (SHR)心肌细胞凋亡及左室重构的效应。方法 :将 40只 16周龄SHR随机分为氯沙坦治疗组 (SHR -L)、福辛普利治疗组 (SHR -F)、氨氯地平治疗组 (SHR -A)及空白对照组 (SHR -C)。采用末端脱氧核糖核苷酸转移酶介导dUTP缺口末端标记、放免及病理检查方法对SHR治疗 8周、16周心肌细胞凋亡指数 (APOI)、血浆和组织血管紧张素II(PAngII,MAngII)及左室重构指标检测。结果 :①各治疗组治疗 8周、16周收缩压均明显下降 ,组间差异无显著性 ;各治疗组左室重量 (LVW)、左室重量指数 (LVMI)均有显著性改善 ,SHR -F组治疗 16周较其他两组LVMI显著减低。②仅SHR -F组治疗 8周APOI显著性下降 ,治疗 16周各治疗组APOI均有显著下降 ,尤以SHR -F组下降明显。③SHR -L组治疗 8周及 16周PAngII,MAngII显著增加。SHR -F组治疗 8周MAngII显著下降 ,治疗 16周SHR -F ,SHR -A两组MAngII均明显下降 ,且前组较后组下降显著 ,但对PAngII无明显影响。结论 :3药物均能有效逆转心脏肥厚及抗心肌细胞凋亡 ,其中以福辛普利显著。上述作用可能是拮抗心肌组织肾素 -血管紧张素 -醛固酮系统的效应。  相似文献   
993.
在我国历史上的明末清初时期,文人结社和戏曲都很繁盛,并且出现了二者的融合。由于以往的研究者大多将文人结社视为一种纯政治或文学运动.因此对于结社活动的娱乐性关注不够。本文即由此入手,描述了这一时期内结社过程中的演剧活动,阐述二者结合的必然性,进而揭示它们对明清戏曲繁荣的推动作用。  相似文献   
994.
目的 观察急性冠状动脉综合征患者血沉 (ESR)和C -反应蛋白 (CRP)阳性率 ,推断炎症反应在急性冠脉事件中的作用 ,及抗炎治疗对其影响。方法 测定 5 8例急性冠脉综合征患者的ESR和CRP阳性率 ,并与对照组进行比较。再分为抗炎组 ,非抗炎组 ,于治疗 1周后复查ESR和CRP ,进行治疗前后比较。结果 急性冠脉综合征患者ESR和CRP阳性率明显增高 ,抗炎后下降较明显。结论 作为炎症标记物 ,ESR值、CRP阳性率可作为预测因子 ,抗炎治疗在急性冠脉事件中可能是有益的  相似文献   
995.
996.
BackgroundDuctal prostate adenocarcinoma (DAC) is a rare, aggressive, histologic variant of prostate cancer that is treated with conventional therapies, similar to high-risk prostate adenocarcinoma (PAC).ObjectiveTo assess the outcomes of men undergoing definitive therapy for DAC or high-risk PAC and to explore the effects of androgen deprivation therapy (ADT) in improving the outcomes of DAC.Design, setting, and participantsA single-center retrospective review of all patients with cT1–4/N0–1 DAC from 2005 to 2018 was performed. Those undergoing radical prostatectomy (RP) or radiotherapy (RTx) for DAC were compared with cohorts of high-risk PAC patients.Outcome measurements and statistical analysisMetastasis-free survival (MFS) and overall survival (OS) rates were analyzed using Kaplan-Meier and Cox regression models.Results and limitationsA total of 228 men with DAC were identified; 163 underwent RP, 34 underwent RTx, and 31 had neoadjuvant therapy prior to RP. In this study, 163 DAC patients and 155 PAC patients undergoing RP were compared. Similarly, 34 DAC patients and 74 PAC patients undergoing RTx were compared. DAC patients undergoing RP or RTx had worse 5-yr MFS (75% vs 95% and 62% vs 93%, respectively, p < 0.001) and 5-yr OS (88% vs 97% and 82% vs 100%, respectively, p < 0.05) compared with PAC patients. In the 76 men who received adjuvant/salvage ADT after RP, DAC also had worse MFS and OS than PAC (p < 0.01). A genomic analysis revealed that 10/11 (91%) DACs treated with ADT had intrinsic upregulation of androgen-resistant pathways. Further, none of the DAC patients (0/15) who received only neoadjuvant ADT prior to RP had any pathologic downgrading. The retrospective nature was a limitation.ConclusionsMen undergoing RP or RTx for DAC had worse outcomes than PAC patients, regardless of the treatment modality. Upregulation of several intrinsic resistance pathways in DAC rendered ADT less effective. Further evaluation of the underlying biology of DAC with clinical trials is needed.Patient summaryThis study demonstrated worse outcomes among patients with ductal adenocarcinoma of the prostate than among high-grade prostate adenocarcinoma patients, regardless of the treatment modality.  相似文献   
997.
Radiotherapy (or radiation therapy) uses ionizing radiation to selectively kill cancer cells, especially for solid tumours. Like surgery, it is meant to be a ‘local’ treatment, although its beneficial systemic effects are being discovered. It is most commonly used in addition to surgery (adjuvant, e.g. breast), but its role in the neoadjuvant setting in combination with chemotherapy for some cancers (e.g. rectum) is also established. In early stages of cancer, it can be the definitive treatment, avoiding surgery and enabling organ preservation (e.g. larynx), while in late stages, it can provide excellent palliation (e.g. bone metastasis). Radiotherapy can be delivered at various energy levels (kiloVolts, megaVolts), with various subatomic particles (e.g. electrons, protons, and high-energy electromagnetic radiation). The traditional bulky equipment (e.g. linear accelerator) needs to be housed in an underground bunker and uses complex imaging to improve precision and avoid radiation to normal tissues. Fractionated regimens spanning several days reduce individual doses. Modern techniques using mobile devices (e.g. TARGIT-IORT) can deliver radiotherapy during surgery with the highest precision and immediacy.  相似文献   
998.
Introduction and objectiveMost prostate cancers are classified as acinar adenocarcinoma. Intraductal carcinoma of the prostate (IDC-P) is a distinct histologic entity that is believed to represent retrograde spread of invasive acinar adenocarcinoma into prostatic ducts and acini.We have analyzed the impact of IDC-P in hormonal naïve and castration resistant metastatic prostate cancer patients.Patients and methodsWe retrospectively evaluated 118 metastatic castration resistant prostate cancer (mCRPC) patients who were initially diagnosed with distant metastases from May 2010 to September 2018. Group 1 patients included 81 metastatic PCa patients with acinar adenocarcinoma and Group 2 included 37 metastatic PCa patients with IDC-P.ResultsMean age at presentation was 76 years (IQR 73.4-78.7) in group 1 and 74 years (68.5-80.6) in group 2. Mean PSA at diagnosis was 619 ng/mL (IQR 85-1113) and 868 ng/mL (IQR 186-1922), respectively. Time to castration resistance was 24.7 months (IQR 16.7-32.7) in group 1 and 10.2 months (IQR 4.2-16.2) in group 2 (p = 0.007). Time to progression in CPRC patients was: 10.6 months (IQR 5.6-15.6) and at 6.2 months (3.2-9.2), respectively (p = 0.05). Overall survival was 57.9 months in group 1(CI 95% 56.4-59.5) and 38 months (CI 95% 19.9-48.06) in group 2 (p = 0.001). In the multivariate analysis, adenocarcinoma subtype was statistically significant p 0.014, CI 95% (HR 0.058, 0.006-0.56).ConclusionsIDC-P seems to be a subtype of prostate cancer that is associated with a shorter response to hormonal treatment when compared to acinar adenocarcinoma in metastatic patients. New drugs in CRPC scenario as abiraterone and enzalutamide also obtained less response in IDC-P patients. In daily clinical practice it might be interesting to take into account that patients with IDC-P may present shorter responses to first and second line hormonal treatments.  相似文献   
999.
1000.
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