全文获取类型
收费全文 | 986340篇 |
免费 | 68446篇 |
国内免费 | 2588篇 |
专业分类
耳鼻咽喉 | 13564篇 |
儿科学 | 30999篇 |
妇产科学 | 28028篇 |
基础医学 | 139505篇 |
口腔科学 | 26762篇 |
临床医学 | 83176篇 |
内科学 | 201216篇 |
皮肤病学 | 20361篇 |
神经病学 | 79530篇 |
特种医学 | 39749篇 |
外国民族医学 | 378篇 |
外科学 | 153664篇 |
综合类 | 19927篇 |
一般理论 | 338篇 |
预防医学 | 71614篇 |
眼科学 | 21863篇 |
药学 | 70085篇 |
1篇 | |
中国医学 | 1971篇 |
肿瘤学 | 54643篇 |
出版年
2019年 | 7783篇 |
2018年 | 10751篇 |
2017年 | 8382篇 |
2016年 | 9050篇 |
2015年 | 10296篇 |
2014年 | 14525篇 |
2013年 | 22695篇 |
2012年 | 30370篇 |
2011年 | 32144篇 |
2010年 | 19696篇 |
2009年 | 18515篇 |
2008年 | 30649篇 |
2007年 | 32587篇 |
2006年 | 32758篇 |
2005年 | 32121篇 |
2004年 | 30936篇 |
2003年 | 29792篇 |
2002年 | 29359篇 |
2001年 | 43224篇 |
2000年 | 44397篇 |
1999年 | 38103篇 |
1998年 | 11149篇 |
1997年 | 10097篇 |
1996年 | 9970篇 |
1995年 | 9307篇 |
1994年 | 8821篇 |
1993年 | 8316篇 |
1992年 | 29486篇 |
1991年 | 28210篇 |
1990年 | 27594篇 |
1989年 | 26541篇 |
1988年 | 24548篇 |
1987年 | 24220篇 |
1986年 | 23195篇 |
1985年 | 22059篇 |
1984年 | 16616篇 |
1983年 | 14240篇 |
1982年 | 8792篇 |
1979年 | 15224篇 |
1978年 | 10680篇 |
1977年 | 9076篇 |
1976年 | 8528篇 |
1975年 | 9382篇 |
1974年 | 11138篇 |
1973年 | 10561篇 |
1972年 | 10011篇 |
1971年 | 9203篇 |
1970年 | 8827篇 |
1969年 | 8266篇 |
1968年 | 7863篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Outbreaks of vesicular stomatitis, serotype New Jersey, during epidemics in the United States and northern Mexico, 1982-5, were examined by backward trajectories of winds to investigate spread and possible sources. The outbreaks selected for analysis did not involve introduction of disease by infected animals. The findings indicate that wind could have been responsible for carrying infection from northern Mexico to Arizona and New Mexico and thence to Colorado and Utah and on to Wyoming, Idaho and Montana. The results of these analyses are consistent with the findings from T1 RNAse fingerprinting of virus isolates from outbreaks during the epidemics. The arrival of the trajectories was associated with the passage of a front and rain or passage of a front alone or rain alone. At the time of the trajectories temperatures of 10 degrees C and higher were recorded at heights up to 2500-3500 m. Introduction by airborne particles would appear unlikely as it would have required a source of at least 10(5) infectious units per minute per animal. Vesicular stomatitis virus had been isolated from Simulium and Culicoides during the epidemic with amounts of virus from Simulium sufficient to suggest biological transmission. The possibility of Simulium infected with vesicular stomatitis virus being carried downwind to introduce disease is discussed in relation to the behaviour of Simulium and the pathogenesis of vesicular stomatitis in large animals. 相似文献
992.
The metabolic disposition of N-(1-methyl-3,3-diphenylpropyl) formamide was studied in rats. The water-soluble metabolites, N-acetyl-S-[N-(1-methyl-3,3-diphenylpropylcarbamoyl)]cysteine and S-[N-(1-methyl-3,3-diphenylpropylcarbamoyl)]glutathione, were identified in urine and bile, respectively, of rats doses with the secondary formamide. The structures of these metabolites were confirmed by comparison with synthetic standards and by using liquid chromatography mass spectrometry and fast atom bombardment mass spectrometry. Synthetic standards of these metabolites were obtained by reacting the N-(1-methyl-3,3-diphenylpropyl)isocyanate with glutathione or N-acetylcysteine in methanolic solutions. The isocyanate was obtained in high yield by reacting 1-methyl-3,3-diphenylpropylamine with trichloromethyl chloroformate. The S-linked conjugates released the isocyanate in mild alkali, but were stable under acidic conditions. The released isocyanate was characterized by comparison with the synthetic standard using GC/MS and HPLC. A mechanism is proposed for the base-catalyzed elimination of the isocyanate from the thiol conjugates. 相似文献
993.
The paper described the treatment of a series of 47 mediastinal goitres. The importance of a thorough preoperative assessment of the lesion and of careful planning of the operative technique are underlined. Cervical collar incision provided adequate exposure in most patients. The Authors conclude that surgical treatment should be recommended in all cases. 相似文献
994.
N F Druik S P Galich V M Seliuk A V Reznikov A I Zimenko 《Ortopediia travmatologiia i protezirovanie》1990,(12):27-32
The authors have thoroughly studied the versions of anatomic structure, peculiarities of blood circulation and innervation of lateral arm graft at 20 recent cadavers. The graft can be utilized in different modifications; cutaneofascial, subcutaneofascial, musculocutaneous, osteocutaneous. In the clinic were made 8 free microsurgic transplantations of lateral arm graft for plasty of tissues of different genesis in functionally important zones of hand and foot. In long-term post-operative period all patients demonstrated good functional and cosmetic results. 相似文献
995.
We have used a vaginal speculum to insert a testicular prosthesis through the inguinal approach over the past four years. We have found this technique to be easily performed and reproducible in allowing the testicular prosthesis to be placed in the normal dependent position in the scrotum. 相似文献
996.
Granulomatous Pneumocystis carinii pneumonia in a patient with the acquired immunodeficiency syndrome. 总被引:2,自引:2,他引:0 下载免费PDF全文
A patient with an unusual granulomatous response to infection with Pneumocystis carinii is described. The diagnosis was made by open lung biopsy after two negative bronchoalveolar lavages. 相似文献
997.
Hyperacute rejection of vascularized, discordant xenografts is generally though to be initiated when natural antibodies of the recipient bind to endothelial cells of the donor organ. While rejection of such xenografts always occurs, the molecular targets of natural antibodies have not been elucidated. The aim of the experiments reported herein was to identify the molecules on porcine endothelial cells that would be recognized by human natural antibodies if a porcine organ were to be transplanted into a human (or rhesus). Toward the end, it was shown that the major components recognized by human serum on porcine endothelial cells are glycoproteins of 115kDa, 125kDa, and 135kDa (gp115/135). Reactivity with these glycoproteins was abrogated by enzymatic cleavage of N-linked oligosaccharides or of subterminal beta-D-gal residues suggesting that the determinants are located on oligosaccharides rather than on the polypeptide cores. The biological relevance of gp115/135 was suggested by experiments in which a similar series of components was shown to be recognized by rhesus natural antibodies and by the absorption of such antibodies by perfusion of porcine kidneys. The gp115/135 antigens were present on porcine platelets but not porcine RBC or lymphocytes. Nevertheless, purified RBC and lymphocytes absorbed human anti-gp115/135, suggesting that human natural antibodies recognize the same or crossreactive carbohydrate determinants expressed on the surface of a variety of cells. 相似文献
998.
999.
L H Hollier F I Smith J C Rice C H Kliger M D Kerstein 《American journal of surgery》1990,160(2):179-181
This investigation was designed to study the effects of home health care (HHC) on patients who have been hospitalized with peripheral vascular disease. For a patient to have HHC, the patient had to have a defined wound, educational needs, or both. Sixty patients, 30 with HHC and 30 without, were contacted approximately 30 days after their last hospital discharge. The 30 patients with HHC were deemed to be at increased risk because of multisystem disease with multiple medications, infirmity, early senility, and often complex wounds. In a prospective fashion, each patient was interviewed by either a registered nurse or medical student using a standardized data collection form. The following issues were assessed: incidence of postoperative complications, knowledge of the patient of his or her disease, compliance with medication (knowledge of, regular use), incidence of readmission, and unscheduled clinic or emergency department visits. Upon statistical analysis using the two-sample t-test and Pearson chi-square test, no significant differences were found between the two groups in terms of complications, compliance, or patient education. HHC, therefore, was found to be helpful to patients with peripheral vascular disease. In our study, the use of HHC made the risk of complications in a group of patients with defined teaching needs and wound care needs equal to that in a group with no such defined needs on discharge from the hospital. 相似文献
1000.