全文获取类型
收费全文 | 732844篇 |
免费 | 28984篇 |
国内免费 | 540篇 |
专业分类
耳鼻咽喉 | 8180篇 |
儿科学 | 24191篇 |
妇产科学 | 16217篇 |
基础医学 | 113128篇 |
口腔科学 | 14093篇 |
临床医学 | 62543篇 |
内科学 | 132052篇 |
皮肤病学 | 12795篇 |
神经病学 | 52477篇 |
特种医学 | 29757篇 |
外国民族医学 | 53篇 |
外科学 | 113060篇 |
综合类 | 10427篇 |
现状与发展 | 2篇 |
一般理论 | 111篇 |
预防医学 | 58294篇 |
眼科学 | 14936篇 |
药学 | 51837篇 |
1篇 | |
中国医学 | 1766篇 |
肿瘤学 | 46448篇 |
出版年
2021年 | 4176篇 |
2019年 | 4065篇 |
2018年 | 29017篇 |
2017年 | 22867篇 |
2016年 | 26978篇 |
2015年 | 6540篇 |
2014年 | 8170篇 |
2013年 | 11625篇 |
2012年 | 23143篇 |
2011年 | 39845篇 |
2010年 | 29568篇 |
2009年 | 21481篇 |
2008年 | 37784篇 |
2007年 | 42996篇 |
2006年 | 17864篇 |
2005年 | 19297篇 |
2004年 | 20651篇 |
2003年 | 21876篇 |
2002年 | 19029篇 |
2001年 | 22987篇 |
2000年 | 23822篇 |
1999年 | 19284篇 |
1998年 | 5585篇 |
1997年 | 4767篇 |
1996年 | 4627篇 |
1995年 | 4355篇 |
1992年 | 14619篇 |
1991年 | 16040篇 |
1990年 | 16178篇 |
1989年 | 15815篇 |
1988年 | 14466篇 |
1987年 | 14369篇 |
1986年 | 13295篇 |
1985年 | 12818篇 |
1984年 | 9497篇 |
1983年 | 8081篇 |
1982年 | 4293篇 |
1979年 | 9058篇 |
1978年 | 6466篇 |
1977年 | 5175篇 |
1976年 | 5584篇 |
1975年 | 6627篇 |
1974年 | 7465篇 |
1973年 | 7174篇 |
1972年 | 6606篇 |
1971年 | 6325篇 |
1970年 | 5929篇 |
1969年 | 5526篇 |
1968年 | 5199篇 |
1967年 | 4635篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
The authors describe 21 cases with resection of the retinal rupture valve with Nd:YAG laser impulse, performed to reduce the vitreoretinal tractions. Resection of the 'dump' rupture valve has been carried out in 10 cases, in the rest 11 the operation has been performed in the presence of a detachment of the retina. Anatomic success (detachment of the valve from the retina) has been achieved in 16 cases. The technique of the surgery is described, as are indications and contraindications to the operation. 相似文献
992.
Sodium channel blocking activity was measured in a series of newly synthesized tertiary amine compounds and their quaternary derivatives applied externally on internally in the rat sensory neuron. The large difference in effectiveness of the quaternary compounds on external and or internal application became smaller and even disappeared with increasing lipophilicity of the compounds. No such difference was observed in the tertiary analogs. It was concluded that lipophilicity played an important role in determining the channel blocking activity of externally applied quaternary compounds. The results suggest that, in addition to the neutral form, highly lipophilic amine local anesthetics may penetrate into and/or pass across the neuronal membrane probably as electroneutral ion pair complexes consisting of the cationic form and an appropriate anion. The present results support our hypothesis which stresses, in addition to dissociability, the role of lipophilicity of amine local anesthetics in the pH dependence of their effect. 相似文献
993.
994.
995.
R J Calvert D M Klurfeld S Subramaniam G V Vahouny D Kritchevsky 《Journal of the National Cancer Institute》1987,79(4):875-880
It has been reported previously that populations with a decreased concentration of fecal bile acids have a lower incidence of colon cancer. We examined the importance of fecal bile acid dilution by wheat bran (WB) in inhibiting colonic tumorigenesis in an experimental animal model. Male F344 rats received oral doses of the colon carcinogen 1,2-dimethylhydrazine [CAS: 540-73-8] and were assigned randomly to groups fed one of four semipurified diets for 26 weeks. The diets were fiber-free (FF), 10% WB, FF + bile salts, or WB + bile salts. The amount of bile salts added was adjusted to produce a fecal bile acid concentration in the group fed WB + bile salts equal to that found in the FF groups. Fecal bile acid concentrations at 12 and 24 weeks in the WB + bile salts group were similar to those in the FF group. Gross and microscopic findings at necropsy revealed a reduced total number and multiplicity of colon tumors in both bran-fed groups. Although the fecal bile acid concentrations of the FF and WB + bile salts groups were equal, the latter showed a significant reduction in tumor yield. 相似文献
996.
Chlamydia trachomatis recently has emerged as the most frequently diagnosed sexually transmitted disease (STD) agent. An estimated three million cases are diagnosed annually in the United States. Because the infection is not reportable, only estimates can be made. The most common STD, it also is often transmitted to infants through infected mothers. Prevention and treatment of the disease in newborns require different procedures from those for gonorrhea, as do diagnostic and treatment methods for infected adults. Chlamydia also appears to pose a threat to pregnancy. 相似文献
997.
T Lotti V Mirone C Imbimbo A Russo 《The Journal of international medical research》1987,15(4):240-244
Twenty patients (15 males; five females) aged 11-70 years, with urinary tract infections were treated with one 250 mg tablet of ciprofloxacin every 12 h for 5-10 days. Clinical response to this treatment was the complete disappearance of symptoms in 85% of cases and the elimination of the micro-organism responsible for infection. In only three patients, who all had urinary calculus in addition to an infection, clinical failure of the therapy occurred and the causative micro-organism persisted. Tolerance to the therapy was excellent in this study, no adverse reactions connected with the treatment being reported. 相似文献
998.
999.
Structural basis of impairment of the external respiratory function in the post-resuscitation period
External enhancement of free-radical processes followed by considerable tissue accumulation of toxic lipid peroxidation products in an early postresuscitation period is the main pathochemical mechanism which causes lung air-blood barrier disturbance. The basis of animal respiratory insufficiency morphogenesis after clinical death is ventilation failure (dis- and atelectasis), circulation disorder (edema, hemorrhage) being secondary. However, morphological examination of lungs of animals after four-minutes clinical death from an acute blood loss and resuscitation showed that it is the severity of circulation disorders that determines the animals condition in the postresuscitation period. 相似文献
1000.
Ohne Zusammenfassung 相似文献