全文获取类型
收费全文 | 18201篇 |
免费 | 862篇 |
国内免费 | 157篇 |
专业分类
耳鼻咽喉 | 125篇 |
儿科学 | 363篇 |
妇产科学 | 550篇 |
基础医学 | 2161篇 |
口腔科学 | 412篇 |
临床医学 | 1485篇 |
内科学 | 5274篇 |
皮肤病学 | 254篇 |
神经病学 | 1710篇 |
特种医学 | 716篇 |
外科学 | 2581篇 |
综合类 | 50篇 |
一般理论 | 1篇 |
预防医学 | 658篇 |
眼科学 | 238篇 |
药学 | 1023篇 |
中国医学 | 31篇 |
肿瘤学 | 1588篇 |
出版年
2023年 | 119篇 |
2022年 | 253篇 |
2021年 | 497篇 |
2020年 | 270篇 |
2019年 | 383篇 |
2018年 | 489篇 |
2017年 | 354篇 |
2016年 | 399篇 |
2015年 | 466篇 |
2014年 | 710篇 |
2013年 | 891篇 |
2012年 | 1297篇 |
2011年 | 1309篇 |
2010年 | 810篇 |
2009年 | 783篇 |
2008年 | 1318篇 |
2007年 | 1313篇 |
2006年 | 1243篇 |
2005年 | 1221篇 |
2004年 | 1100篇 |
2003年 | 950篇 |
2002年 | 872篇 |
2001年 | 115篇 |
2000年 | 103篇 |
1999年 | 129篇 |
1998年 | 192篇 |
1997年 | 143篇 |
1996年 | 164篇 |
1995年 | 109篇 |
1994年 | 112篇 |
1993年 | 112篇 |
1992年 | 108篇 |
1991年 | 78篇 |
1990年 | 82篇 |
1989年 | 58篇 |
1988年 | 43篇 |
1987年 | 49篇 |
1986年 | 41篇 |
1985年 | 49篇 |
1984年 | 49篇 |
1983年 | 41篇 |
1982年 | 45篇 |
1981年 | 49篇 |
1980年 | 40篇 |
1979年 | 32篇 |
1978年 | 17篇 |
1977年 | 14篇 |
1976年 | 17篇 |
1975年 | 16篇 |
1974年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Michael M Gezalian Luigi Mangiacotti Padmesh Rajput Nicklaus Sparrow Konrad Schlick Shouri Lahiri 《Journal of cerebral blood flow and metabolism》2021,41(4):693
Adrenoceptor and calcium channel modulating medications are widely used in clinical practice for acute neurological and systemic conditions. It is generally assumed that the cerebrovascular effects of these drugs mirror that of their systemic effects – and this is reflected in how these medications are currently used in clinical practice. However, recent research suggests that there are distinct cerebrovascular-specific effects of these medications that are related to the unique characteristics of the cerebrovascular anatomy including the regional heterogeneity in density and distribution of adrenoceptor subtypes and calcium channels along the cerebrovasculature. In this review, we critically evaluate existing basic science and clinical research to discuss known and putative interactions between adrenoceptor and calcium channel modulating pharmacotherapies, the neurovascular unit, and cerebrovascular anatomy. In doing so, we provide a rationale for selecting vasoactive medications based on lesion location and lay a foundation for future investigations that will define neuroprotective paradigms of adrenoceptor and calcium channel modulating therapies to improve neurological outcomes in acute neurological and systemic disorders. 相似文献
2.
3.
Elisa Giani Andrea Enzo Scaramuzza Gian Vincenzo Zuccotti 《World journal of diabetes》2015,6(8):999-1004
Technologies for diabetes management, such as continuous subcutaneous insulin infusion (CSII) and continuous glucose monitoring (CGM) systems, have improved remarkably over the last decades. These developments are impacting the capacity to achieve recommended hemoglobin A1c levels and assisting in preventing the development and progression of micro- and macro vascular complications. While improvements in metabolic control and decreases in risk of severe and moderate hypoglycemia have been described with use of these technologies, large epidemiological international studies show that many patients are still unable to meet their glycemic goals, even when these technologies are used. This editorial will review the impact of technology on glycemic control, hypoglycemia and quality of life in children and youth with type 1 diabetes. Technologies reviewed include CSII, CGM systems and sensor-augmented insulin pumps. In addition, the usefulness of advanced functions such as bolus profiles, bolus calculators and threshold-suspend features will be also discussed. Moreover, the current editorial will explore the challenges of using these technologies. Indeed, despite the evidence currently available of the potential benefits of using advanced technologies in diabetes management, many patients still report barriers to using them. Finally this article will highlight the importance of future studies tailored toward overcome these barriers to optimizing glycemic control and avoiding severe hypoglycemia. 相似文献
4.
5.
Anna Maria Lavezzi Giulia Ottaviani Lorella Terni Luigi Matturri 《International journal of developmental neuroscience》2006,24(6):365-371
The aim of this study was to investigate the histological and biological features of the human cerebellar cortex development and differentiation. We analyzed 52 brains of fetal and infant death victims, aged from 17 gestational weeks to 12th postnatal month. In particular, in the cerebellar cortex at different ages we evaluated, besides the structural aspects, the expression of several biomarkers implicated in proliferative processes (c-fos, PCNA and apoptosis). We observed morphological patterns progressively evolving every month, from the indefinite structure of the second gestational trimester to the four-layered structure (external granular layer, molecular layer, Purkinje cell layer, internal granular layer) of the late fetal cortex and subsequently to the three-layered postnatal definitive morphology, due to involution of the external granular layer. The evaluation of the biological features of the cerebellar cortex showed high proliferative activity mainly confined to the transient external granular layer in prenatal life, and high apoptotic index after birth. Thus, the histological examination, better with the support of biomarker investigations, allows with accuracy to describe the dynamic sequence of steps that occur in human cerebellar cortex development and to establish in each case the age, namely the pre- or postnatal month of life. Consequently, we can diagnose delayed or altered processes of differentiation during the development of the human cerebellar cortex. 相似文献
6.
A case of gastric tube bleeding after an Ivor-Lewis esophagectomy with gastroesophageal anastomosis is reported. During the early postoperative course, the patient had a gastric tube stasis that improved progressively. The subsequent onset of a serious and intermittent hematemesis, which was endoscopically deemed to be the result of a hemorrhagic gastritis, required multiple blood transfusions. The evolution to a severe hemodynamic instability obliged us to reoperate on the patient. During surgery, a band-related obstruction of the first jejunal loop with local signs of vascular hypertension was noted. As soon as the obstruction was solved, the gastric bleeding stopped. The authors discuss the clinical aspects and physiopathology of the gastric tube bleeding and, in particular, they evaluate the influence of the intestinal obstruction with vascular involvement on the development of this exceptional and severe complication. 相似文献
7.
Giuseppe Lippi Gian Luca Salvagno Martina Montagnana Franco Manzato Gian Cesare Guidi 《Blood coagulation & fibrinolysis》2007,18(5):525-528
Preparation of blood specimens is a major bottleneck in the laboratory throughput. Reliable strategies for reducing the time required for specimen processing without affecting quality should be acknowledged, especially for laboratories performing stat analyses. The present investigation was planned to establish a minimal suitable centrifuge time for primary samples collected for routine coagulation testing. Five sequential primary vacuum tubes containing 0.109 mol/l buffered trisodium citrate were collected from 10 volunteers and were immediately centrifuged on a conventional centrifuge at 1500 x g, at room temperature for 1, 2, 5, 10 and 15 min, respectively. Hematological and routine coagulation testing, including prothrombin time, activated partial thromboplastin time and fibrinogen, were performed. The centrifugation time was inversely associated with residual blood cell elements in plasma, especially platelets. Statistically significant variations from the reference 15-min centrifuge specimens were observed for fibrinogen in samples centrifuged for 5 min at most and for the activated partial thromboplastin time in samples centrifuged for 2 min at most. Meaningful biases related to the desirable bias were observed for fibrinogen in samples centrifuged for 2 min at most, and for the activated partial thromboplastin time in samples centrifuged for 1 min at most. According to our experimental conditions, a 5-10 min centrifuge time at 1500 x g may be suitable for primary tubes collected for routine coagulation testing. 相似文献
8.
9.
10.
Ferrari Angela MD Lozzi Gian Piero MD Fargnoli Maria Concetta MD Peris Ketty MD 《Dermatologic surgery》2005,31(11):1448-1450
Background. A combined nevus most commonly consists of a blue nevus in combination with a Clark or Spitz nevus. Dermoscopically, combined nevus can mimic melanoma owing to the presence of dermoscopic features common to both types of lesions. Benign clinical and dermoscopic changes can occur in nevi over time, especially in children and young adults.
Objective. To describe the dermoscopic evolution of a congenital combined nevus showing unusual dermoscopic features.
Methods. Digital dermoscopic analysis was performed at the initial visit and after 8 months. The lesion was surgically excised and histopathologically examined.
Results. An asymptomatic plaque with a central blue area and peripheral brown pigmentation located on the back of a 13-year-old boy was diagnosed dermoscopically as combined nevus. Dermoscopic analysis 8 months later showed color changes from steel blue to gray-blue and black in the central area of the lesion, an increased number of blue-black dots or globules, and peripheral irregular streaks. Histopathology revealed typical features of a congenital combined nevus (blue nevus + compound nevus).
Conclusion. Over time, congenital combined nevus may show clinical and dermoscopic changes in size, color, and structure. Surgical excision is recommended when clinical and dermoscopic features are equivocal and the diagnosis of melanoma cannot be ruled out.
ANGELA FERRARI, MD, GIAN PIERO LOZZI, MD, MARIA CONCETTA FARGNOLI, MD, AND KETTY PERIS, MD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS. 相似文献
Objective. To describe the dermoscopic evolution of a congenital combined nevus showing unusual dermoscopic features.
Methods. Digital dermoscopic analysis was performed at the initial visit and after 8 months. The lesion was surgically excised and histopathologically examined.
Results. An asymptomatic plaque with a central blue area and peripheral brown pigmentation located on the back of a 13-year-old boy was diagnosed dermoscopically as combined nevus. Dermoscopic analysis 8 months later showed color changes from steel blue to gray-blue and black in the central area of the lesion, an increased number of blue-black dots or globules, and peripheral irregular streaks. Histopathology revealed typical features of a congenital combined nevus (blue nevus + compound nevus).
Conclusion. Over time, congenital combined nevus may show clinical and dermoscopic changes in size, color, and structure. Surgical excision is recommended when clinical and dermoscopic features are equivocal and the diagnosis of melanoma cannot be ruled out.
ANGELA FERRARI, MD, GIAN PIERO LOZZI, MD, MARIA CONCETTA FARGNOLI, MD, AND KETTY PERIS, MD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS. 相似文献