全文获取类型
收费全文 | 252679篇 |
免费 | 13252篇 |
国内免费 | 6788篇 |
专业分类
耳鼻咽喉 | 2853篇 |
儿科学 | 9346篇 |
妇产科学 | 3636篇 |
基础医学 | 18196篇 |
口腔科学 | 4569篇 |
临床医学 | 29499篇 |
内科学 | 47031篇 |
皮肤病学 | 3316篇 |
神经病学 | 12189篇 |
特种医学 | 12859篇 |
外国民族医学 | 24篇 |
外科学 | 37160篇 |
综合类 | 23128篇 |
现状与发展 | 35篇 |
一般理论 | 3篇 |
预防医学 | 21391篇 |
眼科学 | 4833篇 |
药学 | 25335篇 |
107篇 | |
中国医学 | 5020篇 |
肿瘤学 | 12189篇 |
出版年
2023年 | 2194篇 |
2022年 | 7311篇 |
2021年 | 11100篇 |
2020年 | 6058篇 |
2019年 | 12654篇 |
2018年 | 7822篇 |
2017年 | 6172篇 |
2016年 | 7430篇 |
2015年 | 10387篇 |
2014年 | 19194篇 |
2013年 | 16864篇 |
2012年 | 20042篇 |
2011年 | 16879篇 |
2010年 | 15417篇 |
2009年 | 14903篇 |
2008年 | 13335篇 |
2007年 | 13349篇 |
2006年 | 11201篇 |
2005年 | 7458篇 |
2004年 | 3812篇 |
2003年 | 3320篇 |
2002年 | 2654篇 |
2001年 | 2154篇 |
2000年 | 1919篇 |
1999年 | 1254篇 |
1998年 | 1668篇 |
1997年 | 1543篇 |
1996年 | 1258篇 |
1995年 | 1299篇 |
1994年 | 1244篇 |
1993年 | 921篇 |
1992年 | 1145篇 |
1991年 | 1015篇 |
1990年 | 1059篇 |
1989年 | 1039篇 |
1988年 | 954篇 |
1987年 | 842篇 |
1985年 | 2293篇 |
1984年 | 2776篇 |
1983年 | 2067篇 |
1982年 | 2199篇 |
1981年 | 2154篇 |
1980年 | 1881篇 |
1979年 | 1829篇 |
1978年 | 1549篇 |
1977年 | 1292篇 |
1976年 | 1367篇 |
1975年 | 1019篇 |
1974年 | 1000篇 |
1973年 | 1010篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
7β-(6-取代-2-喹诺酮-3-乙酰氨基)头孢菌素的合成 总被引:1,自引:0,他引:1
以6-取代-2-喹诺酮-3-乙酸为侧链,用CDI法和潘化酯法与7-ADCA,7-ACA,7-ACT,和7-ACD缩合,合成了16个新的7β-(6-取代-2-喹诺酮-3-乙酰氨基)头孢菌素类化合物,通过溶媒转提,葡聚糖凝胶(Sephadex LH-20)柱层析及离心薄层层析分离精制,得到纯品。初步体外抑菌试验表明:新化合物对革兰氏阳性及某些阴性菌具有高度敏感性。大多数化合物对所试试验菌的抗菌活性与头孢唑啉和青霉素G钠相当,有些比它们还强。 相似文献
982.
Intercostal catheterization 总被引:1,自引:0,他引:1
Twenty-one patients scheduled to undergo thoracotomy or median sternotomy had intercostal catheters inserted pre-operatively. During thoracotomy, under direct vision, the spread of 20 ml of a solution containing bupivacaine and methylene blue was followed. In most cases the spread involved one or two intercostal spaces. However, in all but one patient, dye spread medially to the paravertebral space where it then spread in both caudad and cephalad directions to reach between two and five vertebrae. In three cases, dye was seen crossing the anterior surface of the vertebrae to reach the contralateral aspect. It is concluded that a major component of dermatomal block during intercostal catheterisations may be secondary to paravertebral spread. 相似文献
983.
A clinical discussion is presented of sources of sexual stress for women and how they might interfere with healthy sexual functioning. Several therapeutic techniques to reduce sexual stress are described and clinical case examples are given to clarify their use in clinical practice. 相似文献
984.
目的了解那曲地区藏族学生龋病患病情况,为当地制定口腔预防保健措施提供基线资料。方法采用单纯随机抽样方法,按照WHO 1997年的《口腔健康调查基本方法》,对12~17岁的471名藏族学生进行恒牙龋病检查。结果藏族学生恒牙总患龋率为56.7%,男生患龋率为53.9%,女生患龋率为59.1%,差异无统计学意义(χ2=1.258,P=0.262);龋均为(4.09±2.11),男生龋均为(4.04±2.10),女生龋均为(4.13±2.11),差异无统计学意义(t=-0.646,P=0.518)。结论那曲地区藏族学生恒牙龋病患病率较高、程度较重,预防治疗措施急需加强。 相似文献
985.
Zusammenfassung Für die Todeszeitbestimmung kann der Speisebreiverteilung im Magendarmtrakt zentrale Bedeutung zukommen. Dabei würde die Zeitschätzung durch eine postmortale Magenentleerung zusätzlich erschwert. Auch anhand radiologischer Kontrolle unmittelbar postmortal in den Magen applizierten Röntgenkontrastbreies fand sich kein Anhalt für eine postmortale peristaltische Entleerung des Mageninhaltes im Tierexperiment.Herrn Prof. Dr. S. Berg in Verehrung zum 65. Geburtstag gewidmet 相似文献
986.
Yancu Hertzanu M.D. Menachem Hirsch Louis Goleman 《Cardiovascular and interventional radiology》1987,10(4):230-233
Two unusual cases of delayed synthetic graft complications resulting from manufacturing defects of knitted Dacron are presented.
Computed tomography appears to be a suitable noninvasive alternative examination to angiography in this condition. 相似文献
987.
Wheezing at 8 and 13 years: changing importance of bronchiolitis and passive smoking 总被引:2,自引:0,他引:2
A group of 153 children (51 with a history of bronchiolitis and 102 matched controls) were evaluated in a historical cohort study at a mean age of 8 years and again at 13 years to test the primary hypothesis that mild bronchiolitis, far more common than severe (hospitalized) bronchiolitis, predicts wheezing. A secondary hypothesis was that passive smoking also predicts wheezing. Many potentially confounding variables such as family history of asthma were controlled in analyses. Analysis at 13 years produced results that were not anticipated from previous analysis of interviews at age 8. Although mild bronchiolitis was a powerful predictor of wheezing at age 8 years, it was no longer a strong predictor of wheezing at age 13 in either bivariate or multivariate analysis. Although epidemiologic studies, by their nature, cannot prove causality, findings are consistent with the hypothesis that sequelae often follow mild bronchiolitis but diminish during childhood. Maternal smoking was a powerful predictor of wheezing at age 13 in bivariate analysis (Kendall's Tau B = 0.19, P less than 0.01) and in multivariate analysis (odds ratio = 2.67, P less than 0.01). In children at highest risk for wheezing, males with a family history of asthma, multivariate analysis suggested that maternal smoking is associated with an increase in wheezing from 36% to 60%. We conclude that passive smoking, previously identified as a risk factor in this population for both bronchiolitis in infancy and wheezing at age 8, is a risk factor for wheezing-associated morbidity throughout the childhood years. 相似文献
988.
腹腔镜与开腹幽门环肌切开术的前瞻性比较研究 总被引:2,自引:0,他引:2
目的研究比较腹腔镜幽门环肌切开术(LP)和开腹幽门环肌切开术(OP)治疗先天性幽门肥厚性狭窄的疗效及免疫功能的变化。方法自2003年4月-2006年7月将72例先天性幽门肥厚性狭窄患儿随机分成二组(LP组及OP组各36例),比较二组麻醉时间、手术时间、术后进食时间及术后并发症,监测二组术前、术后第一天、术后第三天的外周血T淋巴细胞亚群、C反应蛋白(CRP)及白细胞介素-6(IL-6)和肿瘤坏死因子(TNF)的变化并行对比研究。结果二组麻醉时间、手术时间、术后进食时间差异无统计学意义,OP组术后并发症要略多于LP组,比较二组术前、术后第一天、术后第三天的外周血T淋巴细胞亚群、CRP及IL-6和TNF的变化差异无统计学意义。结论腹腔镜幽门环肌切开术(LP)和开腹幽门环肌切开术(OP)治疗先天性幽门肥厚性狭窄的临床效果相近,二组患儿免疫功能的变化无显著性差异。腹腔镜幽门环肌切开术是一种稳定、可靠的手术,对于治疗先天性肥厚性幽门狭窄的效果满意。 相似文献
989.
Skills of communication are not easily taught to medical students. Three main clinical departments (general practice, medicine and mental health) of the Medical Faculty of the Queen's University, Belfast, introduced an integrated course in January 1988 to teach the basic principles. The course is held at the beginning of clinical training and is an integral part of the introductory clinical course. It was introduced in response to the Report of a Working Party of the Education Committee of the General Medical Council (1987) which advocated the need for improved training in history-taking and communication. It is a 12-week course and every Monday and Friday afternoon from 1400 to 1700 hours 12 students are seconded from ward work, four to the Department of Medicine, four to the Department of General Practice and four to the Department of Mental Health. Hand-outs about information to be obtained and interview style are standardized and the principles to be followed are clearly defined in an aide-mémoire. Staff from the Departments of General Practice and Mental Health experienced in teaching communication by videotape feedback and analysis of consultations prepared 12 tutors for their role and responsibilities. Procedures to be followed were carefully explained to all students beforehand. General practice and psychiatry traditionally have established teaching programmes in communication but the inclusion of the Department of Medicine has made a significant impact. Students have come to realize that the taking of a good history demands as much skill as the physical examination of the patient and is an important aspect of any clinical assessment. 相似文献
990.
J. F. McKenna 《Stress and health》1987,3(1):71-74
This article investigates the relationship between perceptions of equity, occupational stress and employee commitment in a health care setting. Significant relationships were found among these variables and implications for the health care field are discussed. 相似文献