全文获取类型
收费全文 | 18252篇 |
免费 | 1894篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 160篇 |
儿科学 | 660篇 |
妇产科学 | 318篇 |
基础医学 | 2547篇 |
口腔科学 | 348篇 |
临床医学 | 1939篇 |
内科学 | 3466篇 |
皮肤病学 | 456篇 |
神经病学 | 1717篇 |
特种医学 | 575篇 |
外国民族医学 | 11篇 |
外科学 | 1997篇 |
综合类 | 304篇 |
一般理论 | 25篇 |
预防医学 | 2001篇 |
眼科学 | 733篇 |
药学 | 1484篇 |
中国医学 | 11篇 |
肿瘤学 | 1414篇 |
出版年
2021年 | 261篇 |
2020年 | 151篇 |
2019年 | 314篇 |
2018年 | 302篇 |
2017年 | 212篇 |
2016年 | 249篇 |
2015年 | 316篇 |
2014年 | 419篇 |
2013年 | 593篇 |
2012年 | 818篇 |
2011年 | 883篇 |
2010年 | 471篇 |
2009年 | 432篇 |
2008年 | 712篇 |
2007年 | 728篇 |
2006年 | 730篇 |
2005年 | 736篇 |
2004年 | 756篇 |
2003年 | 669篇 |
2002年 | 636篇 |
2001年 | 629篇 |
2000年 | 673篇 |
1999年 | 526篇 |
1998年 | 203篇 |
1997年 | 191篇 |
1996年 | 175篇 |
1995年 | 183篇 |
1994年 | 153篇 |
1993年 | 154篇 |
1992年 | 423篇 |
1991年 | 422篇 |
1990年 | 410篇 |
1989年 | 412篇 |
1988年 | 358篇 |
1987年 | 410篇 |
1986年 | 336篇 |
1985年 | 352篇 |
1984年 | 283篇 |
1983年 | 263篇 |
1982年 | 153篇 |
1981年 | 154篇 |
1980年 | 152篇 |
1979年 | 279篇 |
1978年 | 218篇 |
1977年 | 154篇 |
1976年 | 159篇 |
1975年 | 162篇 |
1974年 | 182篇 |
1973年 | 172篇 |
1972年 | 171篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
E I Traboulsi J C Silva M T Geraghty I H Maumenee D Valle W R Green 《American journal of ophthalmology》1992,113(3):269-280
The eyes of a 22-month-old girl with the cobalamin C complementation type of combined methylmalonic aciduria and homocystinuria were studied with light and electron microscopy. We observed vacuolization of the iris pigment epithelium, loss of photoreceptors in the central 3.3 mm of the macula, partial loss of the nerve fiber and ganglion cell layers between the fovea and optic disk, and partial optic atrophy. The sclera in the posterior pole was thickened with deposition of mucopolysaccharide. Electron microscopy showed inclusions containing fine granular material in conjunctival fibrocytes; corneal epithelium, keratocytes, and endothelial cells; iris pigment epithelium; ganglion cells; retinal pigment epithelium; and choroid and scleral fibrocytes. Enlarged mitochondria and clear vacuoles distended the corneal endothelial cells. We found evidence of possible lysosomal dysfunction and mucopolysaccharide storage, as well as a clinicopathologic correlation of the macular degeneration in this disease. 相似文献
72.
L. Valinsky S. Simhoni R. Bassal V. Agmon R. Yishai M. S. Green D. Cohen 《Clinical microbiology and infection》2006,12(10):968-973
A seroepidemiological study was performed to evaluate immunity to diphtheria and to determine the correlates of diphtheria toxoid antibody levels among children and adults in Israel. In total, 3,185 sera from an age-stratified sample of children and adults, obtained in 2000-2001, were tested for diphtheria toxoid antibodies by an in-house double-antigen ELISA. A level of or=0.1 IU/mL (full protection or seropositivity). Seronegativity increased significantly in subjects aged >50 years, reaching levels of 9.7%, 12.6% and 18.9% in the groups aged 50-54, 55-59 and >60 years, respectively (p 0.001), with rates of basic immunity following a similar pattern. Subjects born abroad had higher seronegativity rates than those born in Israel (7.7% vs. 4.9%; p 0.019). No difference in diphtheria toxoid antibody levels was found according to other demographical variables, such as gender, Jewish or Arab ethnicity, urban or rural settlements, and the subjects' place of residence. The level of immunity to diphtheria among children and adults in Israel was satisfactory, with the exception of individuals aged >50 years. The risk of diphtheria outbreaks is low, but sporadic cases may occur among individuals lacking basic immunity against the disease. 相似文献
73.
R P Green D W Carlson J P Dieckert T J Tredici 《Aviation, space, and environmental medicine》1988,59(12):1170-1175
Idiopathic central serous chorioretinopathy (ICSC) is an uncommon disease with the potential to cause loss of visual acuity, decreased color vision, and decreased depth perception. These visual changes may become permanent and require removal of aviators from flight status. This study reviews 55 eyes of 47 USAF aviators with ICSC examined at the United States Air Force School of Aerospace Medicine (USAFSAM), Brooks AFB, TX. Clinical and aeromedical findings, both on initial and on follow-up ophthalmic examination were studied. Ninety-seven percent of aviators otherwise medically qualified were ultimately returned to flight status. Overall, 51% had recurrent episodes, 17% had bilateral disease, and 13% underwent laser photocoagulation. Visual acuity correlated with active disease, and there was a trend toward poor stereopsis and diminished color vision with worsening visual acuity. Eighty-six percent attained a final visual acuity of 20/20 or better. On final examination, 90% had normal stereopsis, 87% had normal color vision, and 49% had a normal central visual field. Eyes with recurrent disease tended to have degraded final visual acuity, stereopsis, color vision, and central visual field. The visual and aeromedical prognosis from a single attack of ICSC is generally favorable, but repeated attacks can lead to a significant decrease in visual functions that may jeopardize flying status. 相似文献
74.
Because burns are dynamic wounds that can change in apparent depth during the first 72 hours, we asked whether measuring changes in cutaneous blood flow might help predict the ultimate fate of burns that were not obviously shallow or deep. A laser Doppler flowmeter was used to study cutaneous perfusion for at least 72 hours in partial-thickness wounds on patients with burns of less than 15% TBSA and in experimental wounds of similar size on rats. Clinical wounds that healed without grafting consistently showed elevated perfusion levels which increased further within 72 hours, whereas wounds eventually requiring grafting experienced lower perfusion levels with no obvious pattern of increase. Differences between average flow levels for healing and nonhealing burns were statistically significant throughout the study period. Perfusion levels in experimental wounds were stratified according to burn severity, with shallower wounds showing a pattern of increase similar to the clinical wounds. 相似文献
75.
This study of a series of 40 mildly head injured (concussed) patients suggests that different physiologic pathways underlying the tests done in a six-part resting EEG, and for the 11 evoked electrical potential shifts occurring in the cerebral terrain, are testable. Further work seems likely in order to ascertain which clinical signs and symptoms may be related to specific individual types of recorded electronic brain imaging (EBI) abnormality. Which of the 11 parameters studied, EEG, VER, AER, and SER, would be more or less likely to be abnormal in their individual patterns (as being deviant from normal controls) also remains to be defined. The relationship of these neurophysiologic abnormalities to certain postconcussive symptoms, i.e., headache, dizziness, blurred vision, etc., at this point in time remains to be evaluated more precisely. The authors suggest that further research is necessary in evaluating the clinical use of somatosensory evoked responses as an additional parameter in electronic brain imaging (EBI) technology. 相似文献
76.
Fifteen patients with advanced head and neck cancer not curable with radiation or surgery were entered into a phase II study of 10-EdAM. None of the patients had received prior chemotherapy. 10-EdAM was administered intravenously at a dose of 80 mg/m2 each week. Four patients were not eligible for evaluation. Two died before completing four cycles of chemotherapy, one refused further treatment and one developed hepatic toxicity resulting in withdrawal. Of the remaining patients, three had a partial response. The major toxicities were leukopenia and mucositis. 相似文献
77.
78.
Using Queueing Theory to Increase the Effectiveness of Emergency Department Provider Staffing 总被引:4,自引:4,他引:0
Linda V. Green PhD João Soares PhD James F. Giglio MD Robert A. Green MD 《Academic emergency medicine》2006,13(1):61-68
Objectives: Significant variation in emergency department (ED) patient arrival rates necessitates the adjustment of staffing patterns to optimize the timely care of patients. This study evaluated the effectiveness of a queueing model in identifying provider staffing patterns to reduce the fraction of patients who leave without being seen. Methods: The authors collected detailed ED arrival data from an urban hospital and used a Lag SIPP queueing analysis to gain insights on how to change provider staffing to decrease the proportion of patients who leave without being seen. The authors then compared this proportion for the same 39‐week period before and after the resulting changes. Results: Despite an increase in arrival volume of 1,078 patients (6.3%), an average increase in provider hours of 12 hours per week (3.1%) resulted in 258 fewer patients who left without being seen. This represents a decrease in the proportion of patients who left without being seen by 22.9%. Restricting attention to a four‐day subset of the week during which there was no increase in total provider hours, a reallocation of providers based on the queueing model resulted in 161 fewer patients who left without being seen (21.7%), despite an additional 548 patients (5.5%) arriving in the second half of the study. Conclusions: Timely access to a provider is a critical dimension of ED quality performance. In an environment in which EDs are often understaffed, analyses of arrival patterns and the use of queueing models can be extremely useful in identifying the most effective allocation of staff. 相似文献
79.
80.
The graduate nurse year requires individuals to make a huge transition from university student to registered nurse as part of the health care workforce. New graduates experience steep learning curves throughout the first year of professional practice. This study sought to explore experiences and learning occurring throughout the graduate nurse program for a group of seven new nurse graduates. Focus group interviews were conducted at six months and 12 months into the program using the same set of guiding questions. The first interview highlighted that graduates early in the graduate year were internalised, concentrating on their own survival in managing workloads, facing practice realities and coming to terms with themselves as nurses. Learning was primarily about survival strategies and performing tasks. By the second interview, graduates were much less focussed on themselves. They understood their place in the health care team, had gained confidence in their relationships, and were showing concern for the next graduates arriving. Learning at this stage involved more higher order skills, including critical thinking. 相似文献