全文获取类型
收费全文 | 56352篇 |
免费 | 8757篇 |
国内免费 | 541篇 |
专业分类
耳鼻咽喉 | 990篇 |
儿科学 | 1652篇 |
妇产科学 | 1321篇 |
基础医学 | 5495篇 |
口腔科学 | 3192篇 |
临床医学 | 7478篇 |
内科学 | 12679篇 |
皮肤病学 | 1234篇 |
神经病学 | 4477篇 |
特种医学 | 2323篇 |
外国民族医学 | 16篇 |
外科学 | 8120篇 |
综合类 | 1353篇 |
现状与发展 | 13篇 |
一般理论 | 4篇 |
预防医学 | 5464篇 |
眼科学 | 1050篇 |
药学 | 2909篇 |
5篇 | |
中国医学 | 627篇 |
肿瘤学 | 5248篇 |
出版年
2024年 | 167篇 |
2023年 | 1340篇 |
2022年 | 796篇 |
2021年 | 1780篇 |
2020年 | 1932篇 |
2019年 | 1372篇 |
2018年 | 2427篇 |
2017年 | 2071篇 |
2016年 | 2273篇 |
2015年 | 2489篇 |
2014年 | 3174篇 |
2013年 | 3934篇 |
2012年 | 3043篇 |
2011年 | 3011篇 |
2010年 | 2758篇 |
2009年 | 3103篇 |
2008年 | 2431篇 |
2007年 | 2226篇 |
2006年 | 2323篇 |
2005年 | 2029篇 |
2004年 | 1716篇 |
2003年 | 1616篇 |
2002年 | 1501篇 |
2001年 | 1528篇 |
2000年 | 1425篇 |
1999年 | 1383篇 |
1998年 | 855篇 |
1997年 | 796篇 |
1996年 | 803篇 |
1995年 | 607篇 |
1994年 | 508篇 |
1993年 | 441篇 |
1992年 | 709篇 |
1991年 | 667篇 |
1990年 | 622篇 |
1989年 | 583篇 |
1988年 | 587篇 |
1987年 | 514篇 |
1986年 | 478篇 |
1985年 | 472篇 |
1984年 | 338篇 |
1983年 | 282篇 |
1982年 | 205篇 |
1981年 | 174篇 |
1979年 | 250篇 |
1978年 | 150篇 |
1977年 | 170篇 |
1976年 | 147篇 |
1974年 | 159篇 |
1972年 | 144篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
31.
目的 研究模拟舰船两种剂量水平磁场复合噪声、高温对机体联合作用的特点。方法 采用有交互作用的三因素二水平的正交试验设计方法及方差分析法,按正交表L8(2^7)的要求安排8种复合暴露剂量组合,分别将兔和大鼠分为8个复合暴露组和8个对照组。结果 兔球结膜毛细血管管径、大鼠肝和脾脏HSP70的分析结果显示出磁场是对其影响的主因素(均为P〈0.01),其次是高温(均为P〈0.05),大鼠下丘脑AVP和大鼠脑组织HSP70的分析结果显示出磁场是对其影响的主因素(均为P〈0.05)。兔血浆内皮素的分析结果显示出磁场与噪声交互作用所对应的F值有非常显著性意义(P〈0.01),磁场与噪声、高温三者之间交互作用所对应的F值也有显著性意义(P〈0.05)。结论 磁场是对上述指标影响的主因素,而高温也是重要因素;磁场与噪声有交互作用,磁场与噪声、高温三者之间也有交互作用;应该重视舰船环境因素对舰船人员的复合作用。 相似文献
32.
Reem Haj-Ali BDS DDS MS ; Mary Walker DDS PhD ; Karen Williams PhD ; Yong Wang PhD ; Paulette Spencer DDS PhD 《Journal of prosthodontics》2006,15(2):82-88
PURPOSE: The purpose of this study was to compare the dentin/adhesive interfacial characteristics when bonding to noncarious as well as caries-affected dentin. MATERIALS AND METHODS: Seven extracted, unerupted, third molars were sectioned into halves. Artificial caries was created on one-half of each tooth, leaving the other half as a control. Dentin surfaces were treated with UNO adhesive according to the manufacturer's instructions for the wet-bonding technique and under environmental conditions present in the oral cavity. Dentin/adhesive interface sections of each half-tooth were stained with Goldner's trichrome, a classic bone stain, and examined using light microscopy. The width of exposed collagen was measured directly from photomicrographs, and adhesive penetration was analyzed qualitatively. RESULTS: The degree and extent to which the adhesive encapsulated the demineralized dentin matrix were reflected in the color difference in the stained sections with the noncarious dentin sections showing a degree of collagen encapsulation superior to that of the caries-affected dentin sections. The overall mean widths of exposed collagen were significantly (p < or = .05) greater at the caries-affected dentin/adhesive interface, 8.6 (1.7) microm, as compared with those at the noncarious dentin/adhesive interface, 6.0 (1.5) microm. CONCLUSIONS: The morphologic characteristics of the caries-affected dentin/interface suggest an increase in the exposed collagen zone and a decrease in the quality of the adhesive infiltration when compared with noncarious dentin. The evidence suggests that dentin substrate characteristics have a significant effect on the dentin/adhesive interface structure. 相似文献
33.
The intention of this article is to introduce the reader to the Transograph from a historical perspective. The technical data presented are intended to help the reader understand the design of this unique instrument and how it was programmed, but will not provide the reader a thorough understanding of this philosophy. The article seeks neither to defend nor criticize the principles of Transographics. 相似文献
34.
Deng H. Le W. - D. Hunter C. B. 《世界核心医学期刊文摘》2006,2(6):17-18
背景:Parkin基因(PRKN)突变可导致常染色体隐性遗传性早发帕金森病(EOPD)。目的:探讨EOPD白人家族PRKN突变的表现和基因型-表型关系。设计:对EOPD家族的3代20例成员进行基因分析,该家族有4例患者。应用直接基因组DNA测序、半定量聚合酶链反应、实时定量聚合酶链反应以及逆转录酶聚合酶链反应分析以确定PRKN突变。结果:4例早发患者(年龄30—38岁)被确定有PRKN复合杂合突变(T240M和EX5_6缺失),虽然PRKN的杂合T240M和纯合EX5_6缺失突变已有描述,但是据悉,本文为上述复合杂合突变的首次报道。患者的表型为典型常染色体隐性遗传性EOPD的表现,其特征是对左旋多巴治疗有效、相对缓慢的进展和运动障碍。所有杂合突变的基因携带者(T240M或EX5_6缺失)和1例56岁的复合杂合突变女性携带者(T240M和EX5_6缺失)无任何神经系统症状。结论:研究发现,PRKN基因复合杂合突变(T240M和EX5_6缺失)导致一个大的白人家族中4例成员发生常染色体隐性遗传性EOPD。另外1例成员具有相同的突变,比4例患者的平均发病年龄大10岁,并且无本病的临床表现。不完全的外显率对遗传咨询具有暗示作用,并且提示复杂的基因一环境交互作用在PRKN相关EOPD的发病机制中发挥作用。 相似文献
35.
Alexander Stoff MD ; Angel A. Rivera PhD ; N. S. Banerjee PhD ; J. Michael Mathis PhD ; Antonio Espinosa-de-los-Monteros MD ; Long P. Le PhD ; Jorge I. De la Torre MD ; Luis O. Vasconez MD ; Thomas R. Broker PhD ; Dirk F. Richter MD ; Mariam A. Stoff-Khalili MD ; David T. Curiel MD PhD 《Wound repair and regeneration》2006,14(5):608-617
Genetically modified keratinocytes and fibroblasts are suitable for delivery of therapeutic genes capable of modifying the wound healing process. However, efficient gene delivery is a prerequisite for successful gene therapy of wounds. Whereas adenoviral vectors (Ads) exhibit superior levels of in vivo gene transfer, their transductional efficiency to cells resident within wounds may nonetheless be suboptimal, due to deficiency of the primary adenovirus receptor, coxsackie-adenovirus receptor (CAR). We explored CAR-independent transduction to fibroblasts and keratinocytes using a panel of CAR-independent fiber-modified Ads to determine enhancement of infectivity. These fiber-modified adenoviral vectors included Ad 3 knob (Ad5/3), canine Ad serotype 2 knob (Ad5CAV-2), RGD (Ad5.RGD), polylysine (Ad5.pK7), or both RGD and polylysine (Ad5.RGD.pK7). To evaluate whether transduction efficiencies of the fiber-modified adenoviral vectors correlated with the expression of their putative receptors on keratinocytes and fibroblasts, we analyzed the mRNA levels of CAR, alpha upsilon integrin, syndecan-1, and glypican-1 using quantitative polymerase chain reaction. Analysis of luciferase and green fluorescent protein transgene expression showed superior transduction efficiency of Ad5.pK7 in keratinocytes and Ad5.RGD.pK7 in fibroblasts. mRNA expression of alpha upsilon integrin, syndecan-1 and glypican-1 was significantly higher in primary fibroblasts than CAR. In keratinocytes, syndecan-1 expression was significantly higher than all the other receptors tested. Significant infectivity enhancement was achieved in keratinocytes and fibroblasts using fiber-modified adenoviral vectors. These strategies to enhance infectivity may help to achieve higher clinical efficacy of wound gene therapy. 相似文献
36.
37.
38.
Victor Aboyans Louis Labrousse Philippe Lacroix Jér?me Guilloux Seifeddine Sekkal Alexandre Le Guyader Elisabeth Cornu Marc Laskar 《European journal of cardio-thoracic surgery》2006,30(2):300-304
BACKGROUND: Despite major improvement in surgical techniques and intensive care management, stroke remains one of the most devastating complications of coronary artery bypass grafting (CABG). We aimed to determine factors predicting the occurrence of stroke during CABG. A special interest was focused on preoperative therapies. METHODS: We prospectively enrolled 810 consecutive candidates for CABG alone in a specific database, including all pre- and perioperative data (history, clinical, therapeutic, cardiac catheterization, surgical and intensive care data). Univariate tests and then multiple logistic regression analysis were used to determine independent predictive factors. RESULTS: During the first postoperative month, stroke occurred in 11 cases and transient ischemic attack (TIA) in 4 additive cases (cumulative rate: 1.85%). After the multivariate analysis, the following factors remained significant (p<0.05) in the predictive model, with corresponding odds ratios between brackets: redo cardiac surgery (7.45), unstable cardiac status (4.74), past history of cerebrovascular disease (4.14), past history of peripheral arterial disease (3.55), whereas the presence of preoperative statins was protective (0.24, 95% IC: 0.07-0.78). The addition of perioperative data (aortic calcification, postoperative arrhythmia, on/off-pump surgery) did not change the final predictive model. CONCLUSION: To our knowledge, this is the first real-world observational report highlighting the interest of statins for the prevention of stroke in the very special situation of CABG. Even though according to randomized trials coronary patients have a benefit from these drugs, a special level of interest should be directed towards those presenting the above-mentioned risk factors. 相似文献
39.
Y. Patrice Le Treut M.D. Jean Hardwigsen M.D. Pascal Ananian M.D. Jean Saïsse M.D. Emilie Grégoire M.D. Hubert Richa M.D. Pierre Campan M.D. 《Journal of gastrointestinal surgery》2006,10(6):855-862
Tumor thrombus in major vasculature is a frequent finding with a poor long-term prognosis in patients with hepatocellular
carcinoma (HCC). The utility of surgical resection is still controversial. This study compared morbidity and survival after
resection for HCC with and without tumor thrombus. Data of 108 patients who underwent major hepatic resection for HCC were
prospectively recorded. Patients were divided into two groups. The venous thrombectomy (VT) group included 26 patients who
had HCC with tumor thrombus in the portal or hepatic veins. The matched control group included 82 patients who had HCC without
tumor thrombus. Surgical technique, early outcome, and late survival were analyzed in each group. Multivariate analysis was
performed to assess the prognostic value of this feature. Surgical technique was comparable in the VT and control group with
regard to extent of hepatectomy, procedure duration, and transfusion requirements. Early postoperative outcome was also comparable.
Actuarial survival at 1, 3, and 5 years was 38%, 20%, and 13%, respectively, in the VT group (median: 9 months) versus 74%,
56%, and 33%, respectively, in the control group (median: 41 months). In the subgroup of patients with tumor thrombus limited
to the portal vein, actuarial survival at 1, 3, and 5 years was 50%, 26%, and 17%, respectively, (median: 12 months) and two
patients lived longer than 5 years. Multivariate analysis showed that incomplete resection, alphafetoprotein level greater
than 100 N, more than two tumor nodules, and tumor thrombus in major vasculature were independent factors of poor prognosis.
Survival after resection for HCC with tumor thrombus in the major vasculature is poorer than after resection for HCC without
tumor thrombus. However, an aggressive surgical strategy can provide significant survival with comparable morbidity in selected
cases, that is, tumor thrombus located in the portal vein only and expected complete resection of the lesions. 相似文献
40.
Lisa A. Lang DDS MS David C. Holmes DDS MS Craig Passon DDS MS Robert M. Trombly DDS JD Jeffrey D. Astroth DDS MSPH Arnold F. Tavel DMD 《Journal of prosthodontics》2003,12(3):206-210
Using complete denture treatment as an introduction to clinical patient care for dental students, the purposes of the Complete Denture Prosthodontics Transition Clinic at the University of Colorado School of Dentistry are to reduce the time lapse between the preclinical complete denture prosthodontics course and the first denture patient experience, and to encourage development of student self-confidence and skills. In the 2002 spring semester, faculty at the University of Colorado School of Dentistry initiated the Complete Denture Prosthodontics Transition Clinic for DS-II (second-year) dental students, as an introduction to clinical patient care. Each patient was assigned to a team of two dental students. Three Division of Prosthodontics faculty members staffed each clinic session, providing a student-to-faculty ratio of approximately 6.6:1 and a patient-to-faculty ratio of approximately 3.3:1. All DS-II students in the Class of 2004 delivered their first complete dentures no later than 8 months (average, 184 days) after the last day of the preclinical complete denture prosthodontics course. The time from the diagnostic appointment through the denture placement appointment averaged 39 days for patients treated in this program, compared with an average of 98 days or more for previous classes. The program was successful in achieving the goal of reducing the time lapse between the preclinical complete denture prosthodontics course and the first denture patient experience. 相似文献