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   293109篇
  免费   16970篇
  国内免费   7977篇
耳鼻咽喉   5752篇
儿科学   9128篇
妇产科学   4425篇
基础医学   18486篇
口腔科学   7229篇
临床医学   33735篇
内科学   46537篇
皮肤病学   3698篇
神经病学   13486篇
特种医学   13325篇
外国民族医学   42篇
外科学   57995篇
综合类   29343篇
现状与发展   31篇
一般理论   2篇
预防医学   17285篇
眼科学   8767篇
药学   26681篇
  239篇
中国医学   5312篇
肿瘤学   16558篇
  2024年   492篇
  2023年   3811篇
  2022年   7022篇
  2021年   14078篇
  2020年   9151篇
  2019年   14199篇
  2018年   8930篇
  2017年   7674篇
  2016年   9655篇
  2015年   12565篇
  2014年   23291篇
  2013年   20590篇
  2012年   22980篇
  2011年   19972篇
  2010年   17832篇
  2009年   17270篇
  2008年   15670篇
  2007年   15661篇
  2006年   13302篇
  2005年   9339篇
  2004年   5490篇
  2003年   4638篇
  2002年   3724篇
  2001年   3123篇
  2000年   2804篇
  1999年   2073篇
  1998年   2364篇
  1997年   2188篇
  1996年   1734篇
  1995年   1661篇
  1994年   1563篇
  1993年   1216篇
  1992年   1396篇
  1991年   1263篇
  1990年   1220篇
  1989年   1190篇
  1988年   1114篇
  1987年   1002篇
  1986年   823篇
  1985年   1743篇
  1984年   1886篇
  1983年   1349篇
  1982年   1442篇
  1981年   1415篇
  1980年   1215篇
  1979年   1020篇
  1978年   787篇
  1977年   782篇
  1976年   683篇
  1974年   457篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
82.
目的 探讨电视辅助胸腔镜下解剖性肺切除治疗Ⅰ期肺癌的临床效果。方法 采用回顾性研究方法,选取2015年5月至2017年1月广西医科大学附属肿瘤医院收治的I期肺癌患者84例,按照手术方法不同将患者分为两组:观察组和对照组,每组各42例。观察组患者实施电视辅助胸腔镜下解剖性肺切除术治疗,对照组患者给予传统开胸肺叶切除术治疗。比较两组患者的住院时间、切口长度、术中出血量、手术时间、1年和3年生存情况及生活质量评分(SF-36生活量表)变化。结果 观察组患者的住院时间短于对照组(6. 13±1. 46 vs. 10. 39±2. 41 d),切口长度小于对照组(4. 38±1. 09 vs. 11. 84±3. 25 cm),术中出血量少于对照组(284. 62±54. 21 vs. 397. 57±61. 49 ml),差异均具有统计学意义(P <0. 05);而两组手术时间比较(165. 28±33. 24 vs. 156. 39±30. 92 min),差异无统计学意义(P> 0. 05)。观察组患者的1、3年生存率[97. 62%(41/42)、90. 48%(38/42)]均高于对照组[88. 10%(37/42)、76. 19%(32/42)],但差异无统计学意义(P> 0. 05)。观察组患者的各项生活质量评分[精神健康(75. 42±6. 87 vs 61. 30±4. 15分)、情感职能(81. 38±7. 15 vs. 73. 49±5. 76分)、社会功能(82. 67±5. 78 vs. 75. 42±4. 35分)、一般健康状况(79. 49±6. 17 vs.70. 31±5. 04分)、精力(84. 37±5. 45 vs. 74. 13±6. 07分)、生理职能(86. 52±6. 88 vs. 76. 93±6. 42分)、躯体疼痛(83. 46±7. 49 vs. 74. 33±5. 79分)、生理功能(70. 39±4. 31 vs. 61. 38±3. 56分)]均高于对照组,且差异具有统计学意义(P <0. 05)。结论 与传统开胸肺叶切除术相比,电视辅助胸腔镜下解剖性肺切除治疗I期肺癌手术损伤更小、短期生存率更高,且有助于提高患者术后生活质量水平,这对改善患者预后有重要意义,值得临床推广应用。  相似文献   
83.
The present study aimed at measuring seropositivities for infection by Ascaris suum and Toxocara canis using the excretory/secretory (E/S) antigens from Ascaris suum (AES) and Toxocara canis (TES) within an indigenous population. In addition, quantification of cytokine expressions in peripheral blood cells was determined. A total of 50 Warao indigenous were included; of which 43 were adults and seven children. In adults, 44.1% were seropositive for both parasites; whereas children had only seropositivity to one or the other helminth. For ascariosis, the percentage of AES seropositivity in adults and children was high; 23.3% and 57.1%, respectively. While that for toxocariosis, the percentage of TES seropositivity in adults and children was low; 9.3% and 14.3%, respectively. The percentage of seronegativity was comparable for AES and TES antigens in adults (27.9%) and children (28.6%). When positive sera were analyzed by Western blotting technique using AES antigens; three bands of 97.2, 193.6 and 200.2 kDas were mostly recognized. When the TES antigens were used, nine major bands were mostly identified; 47.4, 52.2, 84.9, 98.2, 119.1, 131.3, 175.6, 184.4 and 193.6 kDas. Stool examinations showed that Blastocystis hominis, Hymenolepis nana and Entamoeba coli were the most commonly observed intestinal parasites. Quantification of cytokines IFN-γ, IL-2, IL-6, TGF-β, TNF-α, IL-10 and IL-4 expressions showed that there was only a significant increased expression of IL-4 in indigenous with TES seropositivity (p < 0.002). Ascaris and Toxocara seropositivity was prevalent among Warao indigenous.  相似文献   
84.
目的探讨前路椎体次全切除术和后路椎管扩大椎板成形术对脊髓型颈椎病(CSM)合并椎管狭窄症患者术后疗效及颈椎矢状位参数的影响。方法回顾性分析2010年3月—2015年8月收治的147例CSM合并椎管狭窄症患者的临床资料,其中80例行前路椎体次全切除术治疗(A组),67例行后路椎管扩大椎板成形术治疗(B组)。比较2种手术方法治疗前后日本骨科学会(JOA)评分、Cobb角及矢状位垂直距离(SVA)。将2组患者根据T_1倾斜角分别分为高T_1倾斜角(≥25°)亚组和低T_1倾斜角( 25°)亚组,对不同亚组之间的疗效及手术安全性进行比较。结果 2组术后JOA评分和Cobb角均高于术前,差异有统计学意义(P 0.05)。A组术后SVA低于术前,差异有统计学意义(P 0.05),B组术后SVA与术前相比差异无统计学意义(P 0.05)。A组术后JOA评分和Cobb角均高于B组,SVA低于B组,差异均有统计学意义(P 0.05)。A组中,高T_1倾斜角亚组和低T_1倾斜角亚组JOA评分改善效果和后凸畸形发生率比较差异无统计学意义(P 0.05);B组中,低T_1倾斜角亚组JOA评分改善效果和后凸畸形发生率优于高T_1倾斜角亚组,差异均有统计学意义(P 0.05)。结论相较于后路椎管扩大椎板成形术,前路椎体次全切除术治疗CSM合并椎管狭窄症临床疗效更佳,且有助于改善颈椎矢状位平衡;在高T_1倾斜角水平下,应尽可能选择前路椎体次全切除术。  相似文献   
85.
PurposeTo compare morphological imaging features and CT texture histogram parameters between grade 3 pancreatic neuroendocrine tumors (G3-NET) and neuroendocrine carcinomas (NEC).Materials and methodsPatients with pathologically proven G3-NET and NEC, according to the 2017 World Health Organization classification who had CT and MRI examinations between 2006-2017 were retrospectively included. CT and MRI examinations were reviewed by two radiologists in consensus and analyzed with respect to tumor size, enhancement patterns, hemorrhagic content, liver metastases and lymphadenopathies. Texture histogram analysis of tumors was performed on arterial and portal phase CT images. images. Morphological imaging features and CT texture histogram parameters of G3-NETs and NECs were compared.ResultsThirty-seven patients (21 men, 16 women; mean age, 56 ± 13 [SD] years [range: 28-82 years]) with 37 tumors (mean diameter, 60 ± 46 [SD] mm) were included (CT available for all, MRI for 16/37, 43%). Twenty-three patients (23/37; 62%) had NEC and 14 patients (14/37; 38%) had G3-NET. NECs were larger than G3-NETs (mean, 70 ± 51 [SD] mm [range: 18 - 196 mm] vs. 42 ± 24 [SD] mm [range: 8 - 94 mm], respectively; P = 0.039), with more tumor necrosis (75% vs. 33%, respectively; P = 0.030) and lower attenuation on precontrast (30 ± 4 [SD] HU [range: 25-39 HU] vs. 37 ± 6 [SD] [range: 25-45 HU], respectively; P = 0.002) and on portal venous phase CT images (75 ± 18 [SD] HU [range: 43 - 108 HU] vs. 92 ± 19 [SD] HU [range: 46 - 117 HU], respectively; P = 0.014). Hemorrhagic content on MRI was only observed in NEC (P = 0.007). The mean ADC value was lower in NEC ([1.1 ± 0.1 (SD)] × 10−3 mm2/s [range: (0.91 - 1.3) × 10−3 mm2/s] vs. [1.4 ± 0.2 (SD)] × 10−3 mm2/s [range: (1.1 - 1.6) × 10−3 mm2/s]; P = 0.005). CT histogram analysis showed that NEC were more heterogeneous on portal venous phase images (Entropy-0: 4.7 ± 0.2 [SD] [range: 4.2-5.1] vs. 4.5 ± 0.4 [SD] [range: 3.7-4.9]; P = 0.023).ConclusionPancreatic NECs are larger, more frequently hypoattenuating and more heterogeneous with hemorrhagic content than G3-NET on CT and MRI.  相似文献   
86.
PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%.  相似文献   
87.

Objective

The “Centre Hospitalier Francois Dunan” is located on an isolated island and ensures patients care in hemodialysis thanks to telemedicine support. Many research studies have demonstrated the importance of hemodialysis fluids composition to reduce morbidity in patients on chronic hemodialysis. The aim of this study was to identify the risks inherent in the production of dialysis fluids in a particular context, in order to set up an improvement action plan to improve risk control on the production of dialysis fluids.

Methods

The risk analysis was conducted with the FMECA methodology (Failure Mode, Effects and Criticality Analysis) by a multi professional work group. Three types of risk have been reviewed: technical risks that may impact the production of hemodialysis fluids, health risks linked with chemical composition and health risks due to microbiological contamination of hemodialysis fluids.

Results

The work group, in close cooperation with the expert staff of the dialysis center providing telemedicine assistance, has developed an action plan in order to improve the control of the main risks brought to light by the risk analysis.

Conclusion

The exhaustive analysis of the risks and their prioritisation have permitted to establish a relevant action plan in this improving quality of dialysis fluids approach. The risk control of dialysis fluids is necessary for the security of dialysis sessions for patients, even more when these sessions are realized by telemedicine in Saint-Pierre-et-Miquelon.  相似文献   
88.
目的 探讨腹腔镜下子宫双侧动脉阻断术联合清宫术治疗剖宫产瘢痕妊娠疗效及对内分泌的影响.方法 选择2011年1月至2015年12月剖宫产瘢痕妊娠患者57例,其中A组32例患者给予超声引导下清宫术治疗,B组25例患者给予腹腔镜下子宫双侧动脉阻断术联合清宫术治疗,比较两组患者出血量、住院时间、月经复潮时间、术后人绒毛膜促性腺激素(hCG)降至正常时间,并发症情况及术前(T0)、术后第1d(T1)、第3d(T2)神经内分泌激素水平.结果 ①B组患者出血量低于A组,住院时间、月经复潮时间短于A组,比较差异有统计学意义(t出血量=31.85,k院时间=9.36,t月经复t潮时间=16.37,均P<0.05);②B组患者并发症发生率为8.00%,低于A组的15.63%,比较差异有统计学意义(x2=9.35,P<0.05);③B组T1、T2血清COR、β-EP、GLU水平低于A组(CORF交互=17.67,β-EPF交互=132.36,6LUF交互=155.38,均P<0.05).结论 腹腔镜下子宫双侧动脉阻断术联合清宫术治疗剖宫产瘢痕妊娠微创优势明显,安全性高,对内分泌影响较轻.  相似文献   
89.
90.
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