全文获取类型
收费全文 | 4715篇 |
免费 | 234篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 115篇 |
妇产科学 | 119篇 |
基础医学 | 441篇 |
口腔科学 | 115篇 |
临床医学 | 401篇 |
内科学 | 1195篇 |
皮肤病学 | 51篇 |
神经病学 | 178篇 |
特种医学 | 232篇 |
外国民族医学 | 1篇 |
外科学 | 828篇 |
综合类 | 141篇 |
一般理论 | 3篇 |
预防医学 | 276篇 |
眼科学 | 133篇 |
药学 | 366篇 |
中国医学 | 13篇 |
肿瘤学 | 353篇 |
出版年
2023年 | 48篇 |
2022年 | 141篇 |
2021年 | 232篇 |
2020年 | 97篇 |
2019年 | 134篇 |
2018年 | 177篇 |
2017年 | 94篇 |
2016年 | 93篇 |
2015年 | 133篇 |
2014年 | 177篇 |
2013年 | 206篇 |
2012年 | 307篇 |
2011年 | 295篇 |
2010年 | 217篇 |
2009年 | 166篇 |
2008年 | 248篇 |
2007年 | 268篇 |
2006年 | 234篇 |
2005年 | 237篇 |
2004年 | 160篇 |
2003年 | 161篇 |
2002年 | 156篇 |
2001年 | 66篇 |
2000年 | 79篇 |
1999年 | 54篇 |
1998年 | 56篇 |
1997年 | 36篇 |
1996年 | 37篇 |
1995年 | 25篇 |
1994年 | 23篇 |
1993年 | 34篇 |
1992年 | 47篇 |
1991年 | 53篇 |
1990年 | 39篇 |
1989年 | 37篇 |
1988年 | 38篇 |
1987年 | 25篇 |
1986年 | 34篇 |
1985年 | 20篇 |
1984年 | 19篇 |
1983年 | 16篇 |
1980年 | 12篇 |
1977年 | 14篇 |
1970年 | 11篇 |
1969年 | 12篇 |
1959年 | 15篇 |
1958年 | 16篇 |
1957年 | 14篇 |
1955年 | 15篇 |
1954年 | 19篇 |
排序方式: 共有4988条查询结果,搜索用时 15 毫秒
51.
Ach Taieb Saad Ghada Gorchne Asma Ben Abdelkrim Asma Kacem Maha Ach Koussay 《Clinical Case Reports》2022,10(5)
We report a case of a patient who presented for ACTH‐dependent Cushing after a confirmed hypercortisolism and an inadequate normal ACTH. A transsphenoidal surgery of a pituitary picoadenoma has been done. After surgery, the patient showed the persistence of hypercortisolism. CT scan revealed adrenal adenomas removed surgically and improved the patient. 相似文献
52.
Causal effect of disconnection lesions on interhemispheric functional connectivity in rhesus monkeys
Jill X. O’Reilly Paula L. Croxson Saad Jbabdi Jerome Sallet MaryAnn P. Noonan Rogier B. Mars Philip G.F. Browning Charles R. E. Wilson Anna S. Mitchell Karla L. Miller Matthew F. S. Rushworth Mark G. Baxter 《Proceedings of the National Academy of Sciences of the United States of America》2013,110(34):13982-13987
In the absence of external stimuli or task demands, correlations in spontaneous brain activity (functional connectivity) reflect patterns of anatomical connectivity. Hence, resting-state functional connectivity has been used as a proxy measure for structural connectivity and as a biomarker for brain changes in disease. To relate changes in functional connectivity to physiological changes in the brain, it is important to understand how correlations in functional connectivity depend on the physical integrity of brain tissue. The causal nature of this relationship has been called into question by patient data suggesting that decreased structural connectivity does not necessarily lead to decreased functional connectivity. Here we provide evidence for a causal but complex relationship between structural connectivity and functional connectivity: we tested interhemispheric functional connectivity before and after corpus callosum section in rhesus monkeys. We found that forebrain commissurotomy severely reduced interhemispheric functional connectivity, but surprisingly, this effect was greatly mitigated if the anterior commissure was left intact. Furthermore, intact structural connections increased their functional connectivity in line with the hypothesis that the inputs to each node are normalized. We conclude that functional connectivity is likely driven by corticocortical white matter connections but with complex network interactions such that a near-normal pattern of functional connectivity can be maintained by just a few indirect structural connections. These surprising results highlight the importance of network-level interactions in functional connectivity and may cast light on various paradoxical findings concerning changes in functional connectivity in disease states. 相似文献
53.
Jiri Vlach Jamil S. Saad 《Proceedings of the National Academy of Sciences of the United States of America》2013,110(9):3525-3530
Localization of the HIV type-1 (HIV-1) Gag protein on the plasma membrane (PM) for virus assembly is mediated by specific interactions between the N-terminal myristoylated matrix (MA) domain and phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2]. The PM bilayer is highly asymmetric, and this asymmetry is considered crucial in cell function. In a typical mammalian cell, the inner leaflet of the PM is enriched in phosphatidylserine (PS) and phosphatidylethanolamine (PE) and contains minor populations of phosphatidylcholine (PC) and PI(4,5)P2. There is strong evidence that efficient binding of HIV-1 Gag to membranes is sensitive not only to lipid composition and net negative charge, but also to the hydrophobic character of the acyl chains. Here, we show that PS, PE, and PC interact directly with MA via a region that is distinct from the PI(4,5)P2 binding site. Our NMR data also show that the myristoyl group is readily exposed when MA is bound to micelles or bicelles. Strikingly, our structural data reveal a unique binding mode by which the 2′-acyl chain of PS, PE, and PC lipids is buried in a hydrophobic pocket whereas the 1′-acyl chain is exposed. Sphingomyelin, a major lipid localized exclusively on the outer layer of the PM, does not bind to MA. Our findings led us to propose a trio engagement model by which HIV-1 Gag is anchored to the PM via the 1′-acyl chains of PI(4,5)P2 and PS/PE/PC and the myristoyl group, which collectively bracket a basic patch projecting toward the polar leaflet of the membrane. 相似文献
54.
55.
Saad Elzanaty 《International urology and nephrology》2013,45(3):669-674
Ten to fifteen percent of infertile men are azoospermic, and sixty percent of these men have been classified as having non-obstructive azoospermia (NOA). NOA results from testicular failure, and one of the causes of this is the presence of varicocele. Varicocele is observed in 5–10 % of men with NOA. This review discusses the impact of varicocele repair on semen quality and pregnancy rate among men with NOA. Based on the best available evidence, varicocele repair of men with NOA is associated with an improvement in semen quality and pregnancy rate. Thus, it appears to be an effective therapeutic option for this group of men, particularly for those with a female partner who is younger than 35 years of age, before an assisted reproductive technique (ART) is initiated. Semen cryopreservation is recommended once the patient has spermatozoa in the ejaculate. In addition, varicocele repair seems to improve the rate of spermatozoa recovery in testicular sperm extraction for those who requested ART. 相似文献
56.
I. ElMasry H. Elshiekh A. Abdlenabi A. Saad A. Arafa F. O. Fasina J. Lubroth Y. M. Jobre 《Transboundary and Emerging Diseases》2017,64(3):805-814
H5N1, a highly pathogenic avian influenza (H5N1 HPAI), is an endemic disease that is significant for public health in Egypt. Live bird markets (LBMs) are widespread in Egypt and play an important role in HPAI disease dynamics. The aim of the study was to evaluate the H5N1 HPAI prevalence in representative LBMs from 2009 to 2014, assess the effects of other variables and evaluate past outbreaks and human cases. It was found that ducks and geese are high‐risk species and that the prevalence of H5N1 HPAI was higher immediately after the political crises of 2011. The end of a calendar year (June to December) was a high‐risk period for positive samples, and the risk in urban LBMs was twice the risk in rural LBMs. Winter and political unrest was associated with higher H5N1 HPAI prevalence. Both human and poultry populations will continue to rise in Egypt, so continued poultry outbreaks are likely to be linked to more human cases. LBMs will continue to play a role in the dynamics of poultry disease in Egypt, and there is a need to reorganize markets in terms of biosecurity and traceability. It may also be beneficial to reduce inter‐governorate inter‐regional movements associated with poultry trade through promotion of regional trade or in the alternative provide sanitary features along the poultry market chain to reduce the speed of H5N1 HPAI infections. Policy formulation, design and enforcement must be pro‐poor, and consideration of the sociocultural and economic realities in Egypt is important. The LBMs provide ideal platforms to carry out sound surveillance plans and mitigate zoonotic risks of H5N1 HPAI to humans. 相似文献
57.
Minhaj S. Khaja Alan H. Matsumoto Wael E. Saad 《Cardiovascular and interventional radiology》2014,37(5):1137-1148
Vascular complications after solid-organ transplantation are not uncommon and may lead to graft dysfunction and ultimately graft loss. A thorough understanding of the surgical anatomy, etiologies, and types of vascular complications, their presentation, and the options for management are important for managing these complex patients. This article reviews the basic surgical anatomy, vascular complications, and endovascular management options of vascular complications in patients with renal transplants. 相似文献
58.
59.
60.