全文获取类型
收费全文 | 5899篇 |
免费 | 377篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 104篇 |
妇产科学 | 55篇 |
基础医学 | 1027篇 |
口腔科学 | 65篇 |
临床医学 | 486篇 |
内科学 | 1057篇 |
皮肤病学 | 119篇 |
神经病学 | 716篇 |
特种医学 | 309篇 |
外科学 | 909篇 |
综合类 | 16篇 |
一般理论 | 3篇 |
预防医学 | 146篇 |
眼科学 | 236篇 |
药学 | 379篇 |
中国医学 | 14篇 |
肿瘤学 | 617篇 |
出版年
2023年 | 46篇 |
2022年 | 76篇 |
2021年 | 142篇 |
2020年 | 109篇 |
2019年 | 134篇 |
2018年 | 143篇 |
2017年 | 113篇 |
2016年 | 177篇 |
2015年 | 218篇 |
2014年 | 243篇 |
2013年 | 312篇 |
2012年 | 468篇 |
2011年 | 471篇 |
2010年 | 290篇 |
2009年 | 268篇 |
2008年 | 408篇 |
2007年 | 430篇 |
2006年 | 399篇 |
2005年 | 422篇 |
2004年 | 380篇 |
2003年 | 334篇 |
2002年 | 281篇 |
2001年 | 63篇 |
2000年 | 42篇 |
1999年 | 32篇 |
1998年 | 49篇 |
1997年 | 25篇 |
1996年 | 31篇 |
1995年 | 21篇 |
1994年 | 25篇 |
1993年 | 20篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 14篇 |
1982年 | 12篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1972年 | 6篇 |
1968年 | 2篇 |
1965年 | 4篇 |
排序方式: 共有6318条查询结果,搜索用时 421 毫秒
151.
A spectrum of biophysical interaction modes between T cells and different antigen-presenting cells during priming in 3-D collagen and in vivo 总被引:6,自引:2,他引:6
下载免费PDF全文
![点击此处可从《Blood》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Gunzer M Weishaupt C Hillmer A Basoglu Y Friedl P Dittmar KE Kolanus W Varga G Grabbe S 《Blood》2004,104(9):2801-2809
For activation T cells engage antigen-presenting cells (APCs) in lymphatic tissues. The contact duration and kinetics (static versus dynamic) vary considerably in different model systems; however, it is unclear whether T cells, APCs, or the environment are responsible for the observed discrepancies. Using 3-D collagen matrices as structural scaffold, we directly compared the kinetics of T-cell engagement and activation by functionally major APC types, ie, dendritic cells (DCs) and resting or activated B cells. Resting B cells engaged T cells in long-lived (several hours), adhesive, and leukocyte function-associated antigen-1 (LFA-1)-dependent conjugates in 3-D collagen as well as in intact lymph nodes in vivo. DCs and preactivated B cells, however, supported predominantly dynamic, short-lived (minutes), and sequential contacts to T cells that were dependent on high cytoskeletal activity of the APCs but could not be inhibited by anti-LFA-1 treatment. Naive T cells were most strongly activated by DCs and activated B cells, whereas resting B cells were 100-fold less efficient to induce T-cell proliferation. Thus, in the same 3-D environment, naive T cells respond with a spectrum of different interaction modes dependent on the type and activation state of the APCs. Thereby, more dynamic interaction kinetics is positively correlated with higher T-cell priming efficiency. 相似文献
152.
Dicko A Mantel C Kouriba B Sagara I Thera MA Doumbia S Diallo M Poudiougou B Diakite M Doumbo OK 《Tropical medicine & international health : TM & IH》2005,10(6):550-556
BACKGROUND: Modelling malaria parasitaemia as function of fever has been proposed as best alternative to estimate the attributable fraction of malaria fever and the sensitivity and specificity of different case definitions of malaria disease. OBJECTIVES: To determine the prevalence of fever and its relation to malaria parasitaemia and to establish a pyrogenic threshold for malaria disease in the area. METHODS: We conducted two cross-sectional surveys in children of 6 months to 9 years of age (2434 during the rainy season of 1993 and 2353 during the dry season of 1994) randomly selected from 21 areas of Bandiagara district, Mali. RESULTS: The relationship between fever and Plasmodium falciparum parasitaemia depends strongly on the season, thus affecting the malaria-attributable fraction of fever cases and the sensitivity and specificity of malaria case definitions. The overall proportion of fever attributable to malaria parasitaemia was 33.6% during the rainy season and 23.3% during the dry season, with the highest proportion occurring among the youngest children. The cut-off value, where the sensitivity curve crosses the specificity curve, was around 3200 pf/microl for all age categories during the rainy season and 200 pf/microl during the dry season. CONCLUSIONS: Malaria remains a main cause of fever in this area of Mali. The pyrogenic threshold of parasitaemia depends strongly on the season, and different cut-off levels of parasitaemia should be used during the two seasons to define malaria cases in this area. 相似文献
153.
Lohse N Hansen AB Jensen-Fangel S Kronborg G Kvinesdal B Pedersen C Larsen CS Møller A Willumsen L Obel N 《Scandinavian journal of infectious diseases》2005,37(5):338-343
We used a population-based cohort study design to describe the demographic characteristics of the HIV-infected population in Denmark and their variation over time. HIV treatment in Denmark is restricted to 9 centres, and all 3941 HIV-1 infected patients more than 15 y old seen at these centres in 1995-2003 were included. We found an estimated HIV prevalence of 70 per 100,000, and a mean annual incidence rate of 5.1 per 100,000 persons. The number of newly infected individuals was stable with a median of 231 per y (period 1995-2002), whereas the number of deaths decreased from 166 in 1995 to 50 in 2000 (p=0.000) and remained stable thereafter. Of the enrolled patients, 75% were males, 80% were Caucasian, 13% were black African, and the primary risk behaviour was male-to-male sexual contact (44%), heterosexual contact (36%), and injection drug use (11%). During the y 1995-2003 we found an increase in age at diagnosis (p=0.000), and no major changes in gender, race, mode of infection, or baseline CD4+ cell count and viral load, neither overall not within subgroups of patients. In this period 14.5% had AIDS at the time of HIV diagnosis. Our data do not confirm concerns about unmonitored evolution in the HIV epidemic in Denmark. 相似文献
154.
Jorge A. Wong David Conen Isabelle C. Van Gelder William F. McIntyre Harry J. Crijns Jia Wang Michael R. Gold Stefan H. Hohnloser C.P. Lau Alessandro Capucci Gianluca Botto Gerian Grönefeld Carsten W. Israel Stuart J. Connolly Jeff S. Healey 《Journal of the American College of Cardiology》2018,71(23):2603-2611
Background
Long-term continuous monitoring detects short-lasting, subclinical atrial fibrillation (SCAF) in approximately one-third of older individuals with cardiovascular conditions. The relationship between SCAF, its progression, and the development of heart failure (HF) is unclear.Objectives
This study examined the relationship between progression from shorter to longer SCAF episodes and HF hospitalization.Methods
Subjects in ASSERT (Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial) were ≥65 years old, had history of hypertension, no prior clinical AF, and an implanted pacemaker or defibrillator. We examined patients whose longest SCAF episode during the first year after enrollment was >6 min but ≤24 h (n = 415). Using time-dependent Cox models, we evaluated the relationship between subsequent development of SCAF >24 h or clinical AF and HF hospitalization.Results
Over a mean follow-up of 2 years, 65 patients (15.7%) progressed to having SCAF episodes >24 h or clinical AF (incidence 8.8% per year). Older age, greater body mass index, and longer SCAF duration within the first year were independent predictors of SCAF progression. The rate of HF hospitalization among patients with SCAF progression was 8.9% per year compared with 2.5% per year for those without progression. After multivariable adjustment, SCAF progression was independently associated with HF hospitalization (hazard ratio [HR]: 4.58; 95% confidence interval [CI]: 1.64 to 12.80; p = 0.004). Similar results were observed when we excluded patients with prior history of HF (HR: 7.06; 95% CI: 1.82 to 27.30; p = 0.005) or when SCAF progression was defined as development of SCAF >24 h alone (HR: 3.68; 95% CI: 1.27 to 10.70; p = 0.016).Conclusions
In patients with a pacemaker or defibrillator, SCAF progression was strongly associated with HF hospitalization. 相似文献155.
Walter J Paulus Carsten Tsch?pe John E Sanderson Cesare Rusconi Frank A Flachskampf Frank E Rademakers Paolo Marino Otto A Smiseth Gilles De Keulenaer Adelino F Leite-Moreira Attila Borbély István Edes Martin Louis Handoko Stephane Heymans Natalia Pezzali Burkert Pieske Kenneth Dickstein Alan G Fraser Dirk L Brutsaert 《European heart journal》2007,28(20):2539-2550
Diastolic heart failure (DHF) currently accounts for more than 50% of all heart failure patients. DHF is also referred to as heart failure with normal left ventricular (LV) ejection fraction (HFNEF) to indicate that HFNEF could be a precursor of heart failure with reduced LVEF. Because of improved cardiac imaging and because of widespread clinical use of plasma levels of natriuretic peptides, diagnostic criteria for HFNEF needed to be updated. The diagnosis of HFNEF requires the following conditions to be satisfied: (i) signs or symptoms of heart failure; (ii) normal or mildly abnormal systolic LV function; (iii) evidence of diastolic LV dysfunction. Normal or mildly abnormal systolic LV function implies both an LVEF > 50% and an LV end-diastolic volume index (LVEDVI) <97 mL/m(2). Diagnostic evidence of diastolic LV dysfunction can be obtained invasively (LV end-diastolic pressure >16 mmHg or mean pulmonary capillary wedge pressure >12 mmHg) or non-invasively by tissue Doppler (TD) (E/E' > 15). If TD yields an E/E' ratio suggestive of diastolic LV dysfunction (15 > E/E' > 8), additional non-invasive investigations are required for diagnostic evidence of diastolic LV dysfunction. These can consist of blood flow Doppler of mitral valve or pulmonary veins, echo measures of LV mass index or left atrial volume index, electrocardiographic evidence of atrial fibrillation, or plasma levels of natriuretic peptides. If plasma levels of natriuretic peptides are elevated, diagnostic evidence of diastolic LV dysfunction also requires additional non-invasive investigations such as TD, blood flow Doppler of mitral valve or pulmonary veins, echo measures of LV mass index or left atrial volume index, or electrocardiographic evidence of atrial fibrillation. A similar strategy with focus on a high negative predictive value of successive investigations is proposed for the exclusion of HFNEF in patients with breathlessness and no signs of congestion. The updated strategies for the diagnosis and exclusion of HFNEF are useful not only for individual patient management but also for patient recruitment in future clinical trials exploring therapies for HFNEF. 相似文献
156.
Lukas F. Mager Carsten Riether Christian M. Schürch Yara Banz Marie-Hélène Wasmer Regula Stuber Alexandre P. Theocharides Xiaohong Li Yu Xia Hirohisa Saito Susumu Nakae Gabriela M. Baerlocher Markus G. Manz Kathy D. McCoy Andrew J. Macpherson Adrian F. Ochsenbein Bruce Beutler Philippe Krebs 《The Journal of clinical investigation》2015,125(7):2579-2591
Myeloproliferative neoplasms (MPNs) are characterized by the clonal expansion of one or more myeloid cell lineage. In most cases, proliferation of the malignant clone is ascribed to defined genetic alterations. MPNs are also associated with aberrant expression and activity of multiple cytokines; however, the mechanisms by which these cytokines contribute to disease pathogenesis are poorly understood. Here, we reveal a non-redundant role for steady-state IL-33 in supporting dysregulated myelopoiesis in a murine model of MPN. Genetic ablation of the IL-33 signaling pathway was sufficient and necessary to restore normal hematopoiesis and abrogate MPN-like disease in animals lacking the inositol phosphatase SHIP. Stromal cell–derived IL-33 stimulated the secretion of cytokines and growth factors by myeloid and non-hematopoietic cells of the BM, resulting in myeloproliferation in SHIP-deficient animals. Additionally, in the transgenic JAK2V617F model, the onset of MPN was delayed in animals lacking IL-33 in radio-resistant cells. In human BM, we detected increased numbers of IL-33–expressing cells, specifically in biopsies from MPN patients. Exogenous IL-33 promoted cytokine production and colony formation by primary CD34+ MPN stem/progenitor cells from patients. Moreover, IL-33 improved the survival of JAK2V617F-positive cell lines. Together, these data indicate a central role for IL-33 signaling in the pathogenesis of MPNs. 相似文献
157.
Austin Stephen F. Mors Ole Nordentoft Merete Hjorthøj Carsten R. Secher Rikke G. Hesse Morten Hagen Roger Spada Marcantonio Wells Adrian 《Cognitive therapy and research》2015,39(1):61-69
Cognitive Therapy and Research - The Self Regulatory Executive Function (S-REF) model implicates maladaptive metacognitive beliefs and processes in the predisposition and/or maintenance of positive... 相似文献
158.
159.
Effect of surgical approach on erectile function recovery following bilateral nerve‐sparing radical prostatectomy: an evaluation utilising data from a randomised,double‐blind,double‐dummy multicentre trial of tadalafil vs placebo
下载免费PDF全文
![点击此处可从《BJU international》网站下载免费的PDF全文](/ch/ext_images/free.gif)
160.