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   105231篇
  免费   8777篇
  国内免费   6138篇
耳鼻咽喉   1123篇
儿科学   1554篇
妇产科学   2314篇
基础医学   12452篇
口腔科学   1952篇
临床医学   14095篇
内科学   16654篇
皮肤病学   898篇
神经病学   5692篇
特种医学   3542篇
外国民族医学   43篇
外科学   11301篇
综合类   14909篇
现状与发展   23篇
一般理论   20篇
预防医学   6148篇
眼科学   2868篇
药学   10780篇
  57篇
中国医学   4865篇
肿瘤学   8856篇
  2024年   283篇
  2023年   1523篇
  2022年   3833篇
  2021年   5003篇
  2020年   3547篇
  2019年   3253篇
  2018年   3550篇
  2017年   2939篇
  2016年   2859篇
  2015年   4430篇
  2014年   5657篇
  2013年   5050篇
  2012年   7565篇
  2011年   8290篇
  2010年   4997篇
  2009年   3841篇
  2008年   5301篇
  2007年   5553篇
  2006年   5431篇
  2005年   5713篇
  2004年   3846篇
  2003年   3410篇
  2002年   3032篇
  2001年   2457篇
  2000年   2664篇
  1999年   2719篇
  1998年   1591篇
  1997年   1493篇
  1996年   1319篇
  1995年   1171篇
  1994年   985篇
  1993年   640篇
  1992年   1001篇
  1991年   806篇
  1990年   685篇
  1989年   604篇
  1988年   593篇
  1987年   530篇
  1986年   420篇
  1985年   330篇
  1984年   208篇
  1983年   159篇
  1982年   85篇
  1981年   98篇
  1980年   83篇
  1979年   115篇
  1978年   54篇
  1977年   56篇
  1975年   44篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Nephron preservation has been increasingly prioritized in the treatment of small renal tumors. Radical nephrectomy is now understood as a risk factor for development of chronic kidney disease, which is known to increase the risk of cardiovascular events and all-cause mortality. Indications for nephron-sparing surgery (NSS) have broadened from solitary kidney, bilateral tumors, and hereditary tumor syndromes to essentially all small renal tumors. Laparoscopic NSS has demonstrated excellent cancer control as well as good functional preservation despite the need for warm ischemia. There has been ongoing debate regarding safe parameters for warm ischemia, which are thought to vary with patient factors. Focal ablative therapies have been developed for use in high-risk surgical candidates (eg, radiofrequency ablation, cryoablation) to minimize renal and other treatment-related morbidity. Emphasis on minimally invasive approaches and advances in preventing renal dysfunction and other morbidity after NSS will guide the future of these therapies.  相似文献   
992.
Objective To analyze the effects of dialysis therapy initiation on the prognosis of peritoneal dialysis (PD) patients. Methods PD patients who were newly catheterization and long-term followed-up in Peking University Shenzhen Hospital from January 1, 2012 to March 25, 2019 were retrospectively analyzed. According to the estimate glomerular filtration rate (eGFR) at the time of patients catheterization, the patients were divided into early-dialysis group [eGFR>5.5 ml?min-1?(1.73 m2)-1] and late-dialysis group [eGFR≤5.5 ml?min-1?(1.73 m2)-1]. The endpoint events were transferred to other renal replacement therapy (such as hemodialysis, kidney transplantation) or death. Kaplan-Meier method was used to draw survival curve, and log-rank test was used to compare the difference of survival rate between the two groups. Cox proportional hazard model was used to analyze the influencing factors of all-cause death and technical death in PD patients. Results A total of 342 PD patients were enrolled in this study, and there were 165 cases and 177 cases in the early-dialysis and the late-dialysis group respectively. Compared with the early-dialysis group, the proportion of patients with diabetes and men, and the level of hemoglobin, serum calcium and CO2 binding capacity in the late-dialysis group were lower, while the incidence of hypertension, serum phosphorus, blood uric acid and blood urea nitrogen level were higher in the late-dialysis group (all P<0.05). The median follow-up time was 33(16, 57) months. Kaplan-Meier survival analysis showed that the cumulative survival rate of late-dialysis group was significantly higher than that of early-dialysis group (Log-rank χ2=12.004, P<0.001). After adjusting for gender, age of catheterization, body mass index (BMI), diabetes mellitus and hypertension, the risk ratio of all-cause death in the early-dialysis group was 1.950 times higher than that in the late-dialysis group (HR=1.950, 95%CI 1.019-3.730, P=0.044). Subgroup analysis showed that the timing of dialysis and the risk of end-point events were not affected by BMI, diabetes stratification and other factors (interactive P>0.05), but there was interaction between dialysis time and catheter age (interactive P<0.05). According to the age of catheterization, the risk of all-cause death were higher in the early dialysis group at a young age (≤48 years old) (HR=21.287, 95%CI 2.609-173.665, P=0.004). Conclusions The mortality rate of PD patients is higher in early-dialysis group, which is independent of gender, age, BMI, diabetes and hypertension. The difference is more distinct in low age group.  相似文献   
993.
994.

OBJECTIVE

To assess, in a retrospective cohort, urinary tract urothelial carcinoma (UT‐UC) in patients with various stages of chronic kidney disease (CKD) and their clinicopathological features, as patients with end‐stage renal disease (ESRD) have a higher incidence of UT‐UC, but the relationship between early stages of CKD and characteristics of UT‐UC are less well known.

PATIENTS AND METHODS

The study included 267 patients with pathologically confirmed UT‐UC from January 1994 to December 2006; all had a physical examination (blood pressure), and measurements of laboratory data (serum creatinine, serum haemoglobin) and pathological data. The glomerular filtration rate (GFR) was calculated using the Modification of Diet in Renal Disease equation. Patients were divided into three groups by individual GFR (mL/min), i.e. >60 (no/mild CKD), 30–60 (CKD stage 3) and <30 (CKD stage 4/5).

RESULTS

The CKD stages included 81 (30.3%) patients with none/mild CKD, 121 (45.3%) with CKD stage 3 and 65 (24.3%) with CKD stage 4/5. There was a significant and parallel increase in the frequency of UT‐UC as CKD severity increased from none/mild CKD to stage 3 (11% vs 55%), and from CKD stage 3 to 4/5 (55% vs 71%; P < 0.05). Pathologically, the frequency of high‐grade and high T stage UT‐UC in patients with CKD stage 3 (90% and 35%, respectively) and CKD stage 4/5 (91% and 29%, respectively) were significantly greater than in the group with none/mild CKD (P < 0.001). Advanced age and more distant metastasis were independent risk factors for patient survival.

CONCLUSION

The aggressiveness of UT‐UC increased with the severity of CKD, and this might have important clinical consequences.  相似文献   
995.
996.
显微椎间盘镜治疗腰椎间盘突出症   总被引:5,自引:3,他引:5  
目的探讨显微内镜腰椎间盘切除术(microendoscopy discectomy,MED)治疗腰椎间盘突出症的疗效. 方法回顾分析MED治疗59例腰椎间盘突出症的临床资料,总结经验教训. 结果 59例随访4~24个月,平均15个月,按Macnab评定标准,优43例,良14例,可1例,差1例,术后出现神经功能障碍,优良率96.6%(57/59). 结论 MED是包容性腰椎间盘突出症的首先治疗方法,严格掌握手术适应证及提高手术技巧是MED成功的关键.  相似文献   
997.
经蓝碟(LapDisc)手助腹腔镜结直肠癌根治术   总被引:2,自引:4,他引:2  
目的 探讨手助腹腔镜结直肠癌根治术的临床效果。方法 应用LapDisc手助腹腔镜技术完成27例结直肠癌根治术。结果 手术全部成功,无一例中转开腹。手术时间90~260min,平均140min。术中出血50~200ml,平均110ml。术后无死亡及吻合口漏等并发症。随访6~23个月,平均8.6月,未见切口种植复发。结论 手助腹腔镜结直肠癌根治具有安全、创伤小、术后恢复快及降低标准腹腔镜手术难度等优点,值得临床推广应用。  相似文献   
998.
经皮内镜下胃造口、空肠造口及十二指肠造口120例临床分析   总被引:40,自引:0,他引:40  
Jiang ZW  Wang ZM  Li JS  Li N  Wu SM  Ding K  Liu BZ  Huang Q  Li Q  Jia YH  Zhou W 《中华外科杂志》2005,43(1):18-20
目的 探讨经皮内镜下胃造口、空肠造口及十二指肠造口的技术操作及适应证。方法2 0 0 1年 5月— 2 0 0 4年 4月间 ,共行 12 0例经皮内镜下胃肠造口 ,其中 75例经皮内镜下胃造口 (PEG) ,4 2例经皮内镜下空肠造口 (PEJ) ,2例经皮内镜下十二指肠造口 (PED) ,1例直接法经皮内镜下空肠造口(DPEJ)。操作均采用经典经腹壁拉出法技术。结果 采用上述方法共行长期肠内营养 88例 ;胃肠减压 2 5例 ;肠内营养联合胆汁回输 5例 ;围手术期应用PEG 2例 ,术前行胃肠减压 ,术后行长期肠内营养。PEG操作时间平均 (9± 4 )min ,PEJ平均 (17± 6 )min ,DPEJ为 2 0min ,2例PED分别为 10和 12min。技术成功率 98 4 % (12 0 / 12 2 )。严重并发症发生率为 0 8% (1/ 12 0 ) ,轻微并发症发生率为 7 5 %(9/ 12 0 )。结论 经皮内镜下胃肠造口操作简便、有效 ,并发症少。  相似文献   
999.
颈动脉外翻内膜剥脱术治疗颈动脉硬化狭窄   总被引:1,自引:0,他引:1  
Liu CJ  Huang D  Wang W  Liu C  Ran F 《中华外科杂志》2005,43(7):409-411
目的观察颈动脉外翻内膜剥脱术治疗颈动脉狭窄的疗效。方法24例颈动脉硬化狭窄患者,其中18例有慢性或一过性脑缺血症状,6例无症状;术前均行彩色超声、数字减影动脉造影(DSA)或CT和MRA扫描检查,颈动脉狭窄程度65%~95%;在颈丛麻醉下行颈动脉外翻内膜剥脱术,手术要点是于颈动脉分叉处斜形切断颈内动脉,外翻颈内动脉剥除有粥样斑块的内膜,同时从颈总动脉切口剥除颈总动脉和颈外动脉增厚的内膜。结果全组无手术死亡,术后随访3~20个月,临床症状均有不同程度改善,一过性脑缺血症状消失,4例仍有轻度慢性脑缺血症状。术后行脑部多普勒超声检查,22例脑部供血有明显改善。结论颈动脉外翻内膜剥脱术是一种安全、有效和合理的手术方式。  相似文献   
1000.
胸腔镜下胸腰段疾病的前路手术及内固定   总被引:2,自引:1,他引:2  
目的回顾胸腔镜下前路减压、植骨内固定治疗胸腰椎骨折、结核和椎间盘突出症的经验,评价胸腔镜技术在脊柱前路手术中的应用价值。方法收集12例接受胸腔镜下前路手术患者的临床资料,分析操作技术、手术时间、出血量以及功能恢复情况。结果胸腰椎骨折8例;结核3例;椎间盘突出症l例。平均手术时间210min,平均出血量600ml,平均住院时间12d。1例结核患者因严重骨质疏松而放弃内固定,仅作病灶清除植骨术。所有患者随访3—10个月,神经功能恢复与普通开胸前路手术近似,骨折复位良好,植骨块和内固定未发现移位,活动基本恢复正常。结论胸腔镜下脊柱前路手术创伤小,并发症及出血量少,术后恢复快,为胸腰椎前路手术提供了一种安全、有效的操作技术。  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