全文获取类型
收费全文 | 19807篇 |
免费 | 1771篇 |
国内免费 | 93篇 |
专业分类
耳鼻咽喉 | 225篇 |
儿科学 | 568篇 |
妇产科学 | 576篇 |
基础医学 | 2387篇 |
口腔科学 | 285篇 |
临床医学 | 2816篇 |
内科学 | 4717篇 |
皮肤病学 | 283篇 |
神经病学 | 1320篇 |
特种医学 | 885篇 |
外科学 | 2848篇 |
综合类 | 320篇 |
一般理论 | 9篇 |
预防医学 | 1355篇 |
眼科学 | 632篇 |
药学 | 1139篇 |
中国医学 | 50篇 |
肿瘤学 | 1256篇 |
出版年
2023年 | 125篇 |
2022年 | 99篇 |
2021年 | 286篇 |
2020年 | 217篇 |
2019年 | 371篇 |
2018年 | 416篇 |
2017年 | 387篇 |
2016年 | 377篇 |
2015年 | 427篇 |
2014年 | 601篇 |
2013年 | 850篇 |
2012年 | 1101篇 |
2011年 | 1091篇 |
2010年 | 739篇 |
2009年 | 725篇 |
2008年 | 1106篇 |
2007年 | 1175篇 |
2006年 | 1192篇 |
2005年 | 1113篇 |
2004年 | 1080篇 |
2003年 | 1044篇 |
2002年 | 966篇 |
2001年 | 334篇 |
2000年 | 300篇 |
1999年 | 295篇 |
1998年 | 296篇 |
1997年 | 295篇 |
1996年 | 251篇 |
1995年 | 285篇 |
1994年 | 214篇 |
1993年 | 169篇 |
1992年 | 228篇 |
1991年 | 190篇 |
1990年 | 180篇 |
1989年 | 192篇 |
1988年 | 202篇 |
1987年 | 181篇 |
1986年 | 170篇 |
1985年 | 153篇 |
1984年 | 143篇 |
1983年 | 151篇 |
1982年 | 153篇 |
1981年 | 133篇 |
1980年 | 131篇 |
1979年 | 102篇 |
1978年 | 114篇 |
1977年 | 123篇 |
1976年 | 96篇 |
1975年 | 74篇 |
1974年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Fred Poordad Robert Gish Adil Wakil Richard Garcia-Kennedy Paul Martin Francis Y. Yao 《American journal of transplantation》2003,3(11):1413-1417
Non-alcoholic fatty liver disease (NAFLD) is an increasingly recognized clinico-pathologic entity typically associated with obesity, type II diabetes and hyperlipidemia. It has been noted to recur after orthotopic liver transplantation (OLT). We report four patients who developed de novo NAFLD within 3 months of OLT without the typical predisposing factors of diabetes mellitus or obesity. Three of the four patients underwent OLT for hepatitis C-related cirrhosis, and the other for alcoholic cirrhosis. Examination of the liver explants revealed no evidence of steatosis. No surreptitious alcohol use or a drug-induced process could be identified in these patients. Treatment of recurrent hepatitis C infection in one patient with interferon and ribavirin led to sustained suppression of the viral RNA to undetectable levels, but no improvement in histology or liver enzymes. All four patients had histologic evidence of preservation injury on the initial post-OLT biopsies, but the significance of this finding in relationship to the development of NAFLD is unknown. NAFLD can develop without any of the known predisposing conditions after transplantation, and this raises further questions about the pathogenesis of this condition . 相似文献
92.
93.
Sally J Wellard RN BA Renal Cert MN Colleen Rolls RN RM Child Hlth Cert BAppSc Grad Dip Child Development MEdSt de Sales Ferguson RN BA BEd MN 《Journal of advanced nursing》1995,21(4):737-742
An Australian school of nursing's attempt to introduce an evaluation process required by management for clinical educators involved in undergraduate preregistration education is discussed Reliance on student feedback and clinical agencies' perceptions of the quality of teaching were seen as inadequate mechanisms for evaluation The evaluation process adopted incorporated observation of the educators together with self-reflection on their performance We conclude that post-briefings were poorly used and generally not reflective Educators relied heavily on their clinical skills and used a limited range of teaching strategies Whilst evaluation of clinical educators was time consuming and therefore costly, it is argued that it is essential to the integrity of the course The evaluation process has provided direction for support and development of clinical educators within the context of the curriculum 相似文献
94.
George G. Hartnell Francis M. Bradley 《Catheterization and cardiovascular interventions》1993,30(2):101-103
The recommended angiographic projections for optimally demonstrating various cardiac structures vary, and do not always achieve their aim. To determine the most appropriate radiographic projections to optimally demonstrate cardiac structures, we reviewed the orientations of major cardiac structures and the associated great vessels, as demonstrated by axial MRI. Measurements were made from 187 MRI examinations of the heart. These measurements confirmed that the optimum angiographic projections for various cardiac structures are at variance with a number of the recommended views. Recommendations for the angiographic projections most likely to provide optimum display of various cardiac structures and associated great vessels in different patient populations are presented. © 1993 Wiiey-Liss, Inc. 相似文献
95.
96.
Thomas A. Blakely Jr. Francis M. Crinella Todd D. Fisher Lorraine Champaigne Frances W. Beck 《Journal of developmental and physical disabilities》1994,6(1):1-22
Since Samuel Orton's (1937) assertion that dyslexia reflects abnormal brain organization, the relationship of learning disabilities
to brain dysfunction has been the topic of considerable debate. Recently, learning-disabled individuals have been studied
in conjunction with those known to have neurological dysfunction, in a search for common subtypes. In the present study, a
population of 177 children, ages 9-0 to 14-0, were assessed on an augmented version of the Children's Halstead-Reitan Battery.
One hundred twenty-nine Ss were learning-disabled, 37 of whom also had verified brain damage. The remaining 48 children had
neither learning disabilities nor evidence of brain damage. Patterns of neuropsychological performance were determined using
Tryon's clustering methods. The procedure yielded six subject clusters: (A) and (B)—children with low general intellectual
ability; (C) children who are clumsy and lethargic; (D) children with language dysfunction; (E) children with faulty spatial
orientation; and (F) children with no detectable neuropsychological deficits. These clusters were similar to those identified
by investigators who have used other subject-clustering methods. Brain-damaged individuals were more prevalent in some clusters
(e.g., A and B) than in others (e.g., E and F), and substantial numbers of learning disabled subjects were also found in clusters
where brain-damaged individuals tended to cluster, indicating similar neuropsychological profiles. The cluster structure was
validated by comparison with subtypes identified by other investigators, as well as by tests of association between clusters
with exogenous factors (e.g., history of prematurity; seizures). 相似文献
97.
Anne-Marie Francois-Bellan Micheline Hery Maxime Faudon Francis Hery 《Journal of neuroendocrinology》1989,1(6):415-422
The purpose of this study was to test the capacity of oestradiol to modulate the stimulating effect of a-aminobutyric acid (GABA) on serotonin (5-HT) metabolism, previously described in the Suprachiasmatic area of the male rat. After an in vivo stimulation of GABA transmission by systemic administration of a GABA-transaminase inhibitor (amino-oxyacetic acid) or a GABAB agonist (RS-baclofen), the 5-HT metabolism was studied in the Suprachiasmatic area of ovariectomized, and ovariectomized oestradiol-treated rats. Amino-oxyacetic acid or RS-baclofen treatment increased the endogenous content of 5-HT in the Suprachiasmatic area of males and ovariectomized rats. These two treatments were without effect in ovariectomized oestradiol-treated rats. GABA transmission stimulation induced by amino-oxyacetic acid treatment failed to affect the release and synthesis of 5-HT in ovariectomized oestradiol-treated rats while it increased these two parameters of 5-HT metabolism in the Suprachiasmatic area of male and ovariectomized rats. To investigate the main target of oestradiol effect, comparative studies of the serotoninergic and GABAergic metabolism in the Suprachiasmatic area were performed in the three experimental groups. Under our experimental conditions the endogenous 5-HT metabolism was similar between ovariectomized and ovariectomized oestradiol-treated rats. Nevertheless, 5-HT metabolism was higher in the two female groups than in the male group. Neither GABA metabolism nor GABAergic response to GABA-related drug treatment differed between ovariectomized, and ovariectomized oestradiol-treated rats. However, the turnover of GABA was higher when compared to the two female groups. It is concluded that the lack of 5-HT responsiveness to GABA transmission stimulation in ovariectomized oestradiol-treated rats was not related to an effect of oestradiol on 5-HT metabolism or to an effect of the steroid on GABA turnover. Furthermore, our results suggest a sex difference in the activity of serotoninergic and GABAergic systems in the Suprachiasmatic area. 相似文献
98.
Nico J. D. Nagelkerke Stephen Moses Francis A. Plummer Robert C. Brunham David Fish 《Statistics in medicine》1995,14(8):769-775
In case-control studies, cases are sampled separately from controls. In such studies the primary analysis concerns the estimation of the effect of covariables on being a case or a control. To explore causal pathways, further secondary analysis could concern the relationships among the covariables. In this paper the validity of such secondary analysis is addressed. In particular, the use of multiple logistic regression in case-control studies where the dependent variable is not the case/control indicator is explored. It is shown that only under very restrictive conditions will sample regression coefficients correctly estimate their true value. In many situations, it may be valid to regress one covariable on others in the control group, but not in the case group or the combined sample. This principle is illustrated by a study of sexually transmitted disease in Kenya. 相似文献
99.
100.
Francis J. Podbielski Guillermo D. Marquez Darren G. Nelson Nancy A. Diettrich Mark M. Connolly 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》1997,1(1):75-77
A lung carcinoma with tumor involving more than one lobe or in close proximity to the mainstem bronchus often requires pneumonectomy for surgical cure. Inflammation, bulky tumors, and dense adhesions limit the operative field of vision and may result in the abandonment of procedures with potential for complete extirpation. This case illustrates the utility of thoracoscopy in visualization of the hilum and other neurovascular structures in a patient with a proximal tumor and dense intrathoracic adhesions. Successful resection was made possible by use of combined open and thoracoscopic modalities. 相似文献