全文获取类型
收费全文 | 13250篇 |
免费 | 490篇 |
国内免费 | 62篇 |
专业分类
耳鼻咽喉 | 76篇 |
儿科学 | 265篇 |
妇产科学 | 327篇 |
基础医学 | 1751篇 |
口腔科学 | 483篇 |
临床医学 | 1103篇 |
内科学 | 3703篇 |
皮肤病学 | 334篇 |
神经病学 | 1282篇 |
特种医学 | 318篇 |
外科学 | 1679篇 |
综合类 | 59篇 |
一般理论 | 2篇 |
预防医学 | 678篇 |
眼科学 | 194篇 |
药学 | 679篇 |
中国医学 | 36篇 |
肿瘤学 | 833篇 |
出版年
2024年 | 55篇 |
2023年 | 103篇 |
2022年 | 215篇 |
2021年 | 449篇 |
2020年 | 242篇 |
2019年 | 305篇 |
2018年 | 428篇 |
2017年 | 261篇 |
2016年 | 336篇 |
2015年 | 344篇 |
2014年 | 505篇 |
2013年 | 637篇 |
2012年 | 1051篇 |
2011年 | 1063篇 |
2010年 | 591篇 |
2009年 | 586篇 |
2008年 | 941篇 |
2007年 | 939篇 |
2006年 | 873篇 |
2005年 | 769篇 |
2004年 | 695篇 |
2003年 | 612篇 |
2002年 | 627篇 |
2001年 | 72篇 |
2000年 | 68篇 |
1999年 | 91篇 |
1998年 | 102篇 |
1997年 | 103篇 |
1996年 | 88篇 |
1995年 | 70篇 |
1994年 | 70篇 |
1993年 | 61篇 |
1992年 | 39篇 |
1991年 | 41篇 |
1990年 | 36篇 |
1989年 | 33篇 |
1988年 | 27篇 |
1987年 | 19篇 |
1986年 | 22篇 |
1985年 | 13篇 |
1984年 | 32篇 |
1983年 | 27篇 |
1982年 | 21篇 |
1981年 | 21篇 |
1980年 | 17篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 18篇 |
1974年 | 11篇 |
1972年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Marina Sironi Cecilia Muoz Teresa Pollicino Andrea Siboni Francesca Luisa Sciacca Sergio Bernasconi Annunciata Yecchi Francesco Colotta Alberto Mantovani 《European journal of immunology》1993,23(10):2692-2695
Interleukin-10 (IL-10), a product of T helper type 2 (TH2) cells and monocytes, inhibits cytokine production in mononuclear phagocytes. Given the similarities and interrelationship between cells of the monocyte-macrophage lineage and endothelial cells, we examined the effects of IL-10 on vascular endothelium. Murine IL-10 induced low levels of IL-6 production and amplified induction of IL-6 by lipopolysaccharide (LPS) or IL-1 in the murine tEND.1 endothelioma line, used for these studies because it retains properties of normal endothelium. The effect was more evident after prolonged (48–72 h) exposure to IL-10. IL-10 had similar activity on other endothelioma lines, whereas it inhibited IL-6 production by peritoneal macrophages. Induction and amplification of cytokine production by IL-10 was associated with higher levels of mRNA, which were maintained longer (up to 48 h) than in controls. In addition to IL-6, murine IL-10 induced or amplified expression of the chemoattractant cytokines monocyte chemotactic protein-1 (MCP-1) and KG Human IL-10 inhibited IL-6 release by LPS-stimulated human peripheral blood mononuclear cells, whereas it did not interfere with cytokine production by LPS- or IL-1-stimulated human umbilical vein endothelial cells. The selective inhibitory action of IL-10 on mononuclear phagocytes versus endothelial cells may play a role in the pathophysiology of TH2-directed responses. 相似文献
992.
Casillas S Delaney CP Senagore AJ Brady K Fazio VW 《Diseases of the colon and rectum》2004,47(10):1680-1685
PURPOSE Conversion during laparoscopic colectomy varies in frequency according to the surgeons experience and case selection. However, there remains concern that conversion is associated with increased morbidity and higher hospital costs.METHODS From January 1999 to August 2002, 430 laparoscopic colectomies were performed by two surgeons, with 51 (12 percent) cases converted to open surgery. Converted cases were matched for operation and age to 51 open cases performed mostly by other colorectal surgeons from our department. Data collected included gender, American Society of Anesthesiology score, operative indication, resection type, operative stage at conversion, in-hospital complications, direct hospital costs, unexpected readmission within 30 days, and mortality.RESULTS There were no significant differences between the groups for age (converted, 55 ± 19; open, 62 ± 16), male:female ratio (converted, 17:34; open, 23:28), or American Society of Anesthesiology score distribution. Indications for surgery were neoplasia (converted, 16; open, 31); diverticular disease (converted, 21; open, 13); Crohns disease (converted, 12; open, 5); and other disease (converted, 2; open, 2). Operative times were similar (converted, 150 ± 56 minutes; open, 132 ± 48 minutes). Conversions occurred before defining the major vascular pedicle/ureter (50 percent), in relation to intracorporeal vascular ligation (15 percent), or during bowel transection or presacral dissection (35 percent). Specific indications for conversion were technical (41 percent), followed by adhesions (33 percent), phlegmon or abscess (23 percent), bleeding (6 percent), and failure to identify the ureter (6 percent). Median hospital stay was five days for both groups. In-hospital complications (converted 11.6 percent; open 8 percent), 30-day readmission rate (converted 13 percent vs. open 8 percent), and direct costs were similar between groups. There were no mortalities.CONCLUSION Conversion of a laparoscopic colectomy does not result in inappropriately prolonged operative times, increased morbidity or length of stay, increased direct costs, or unexpected readmissions compared with similarly complex laparotomies. A policy of commencing most cases suitable for a laparoscopic approach laparoscopically offers patients the benefits of a laparoscopic colectomy without adversely affecting perioperative risks.Read at the meeting of The American Society of Colon and Rectal Surgeons, New Orleans, Louisiana, June 21 to 26, 2003. 相似文献
993.
Barretta ML Catalano O Setola SV Granata V Marone U D'Errico Gallipoli A 《Abdominal imaging》2011,36(6):729-734
The objective of this study is to report the diagnostic features of hematogenous gallbladder metastasis using various imaging
modalities. We carried out a single-center retrospective analysis of 13 patients with gallbladder metastasis. The primary
malignancy was cutaneous melanoma (11 cases), hepatocellular carcinoma (1 case), and non-Hodgkin lymphoma (1 case). All patients
underwent sonography (US), with color-power-Doppler assessment in 11 cases. Contrast-enhanced US (CEUS) was performed in 8
patients, MDCT in 8, and MR imaging in 1. Four subjects studied by whole-body PET. The gallbladder lesions were first detected
with US in 9 cases and with MDCT in 3 cases. The remaining patient was investigated because of hepatic fluorodeoxyglucose
uptake at PET; CEUS failed to detect any liver metastasis in this subject but identified a gallbladder lesion. Typical findings
included multiplicity of gallbladder vegetations, broad base, limited mural thickening, presence of contrast enhancement,
absence of gallstones and gallbladder bed infiltration, presence of combined lesions within other organs. Only two patients
presented an isolated location in the gallbladder and were successfully treated with surgery. Gallbladder metastasis is a
rare but possible occurrence. Knowledge of the typical imaging features and careful evaluation of the gallbladder may avoid
an incorrect or false negative diagnosis. 相似文献
994.
Marcos F. Minicucci Elaine Farah Daniéliso R. Fusco Ana Lúcia Cogni Paula S. Azevedo Katashi Okoshi Silméia G. Zanati Beatriz B. Matsubara Sergio A. R. Paiva Leonardo A. M. Zornoff 《Arquivos brasileiros de cardiologia》2014,102(6):549-556
Background
The effects of modern therapy on functional recovery after acute myocardial infarction (AMI) are unknown.Objectives
To evaluate the predictors of systolic functional recovery after anterior wall AMI in patients undergoing modern therapy (reperfusion, aggressive platelet antiaggregant therapy, angiotensin-converting enzyme inhibitors and beta-blockers).Methods
A total of 94 consecutive patients with AMI with ST-segment elevation were enrolled. Echocardiograms were performed during the in-hospital phase and after 6 months. Systolic dysfunction was defined as ejection fraction value < 50%.Results
In the initial echocardiogram, 64% of patients had systolic dysfunction. Patients with ventricular dysfunction had greater infarct size, assessed by the measurement of total and isoenzyme MB creatine kinase enzymes, than patients without dysfunction. Additionally, 24.5% of patients that initially had systolic dysfunction showed recovery within 6 months after AMI. Patients who recovered ventricular function had smaller infarct sizes, but larger values of ejection fraction and E-wave deceleration time than patients without recovery. At the multivariate analysis, it can be observed that infarct size was the only independent predictor of functional recovery after 6 months of AMI when adjusted for age, gender, ejection fraction and E-wave deceleration time.Conclusion
In spite of aggressive treatment, systolic ventricular dysfunction remains a frequent event after the anterior wall myocardial infarction. Additionally, 25% of patients show functional recovery. Finally, infarct size was the only significant predictor of functional recovery after six months of acute myocardial infarction. 相似文献995.
Jesús Sotomayor-Bonilla Andrea Chaves Oscar Rico-Chávez Melinda K. Rostal Rafael Ojeda-Flores Mónica Salas-Rojas álvaro Aguilar-Setien Sergio Ibá?ez-Bernal Arturo Barbachano-Guerrero Gustavo Gutiérrez-Espeleta J. Leopoldo Aguilar-Faisal A. Alonso Aguirre Peter Daszak Gerardo Suzán 《The American journal of tropical medicine and hygiene》2014,91(1):129-131
996.
Small interfering RNA urokinase silencing inhibits invasion and migration of human hepatocellular carcinoma cells 总被引:21,自引:0,他引:21
The serine protease urokinase-type plasminogen activator (u-PA) is involved in a variety of physiologic and pathological processes; in particular, u-PA mRNA is up-regulated in human hepatocellular carcinoma (HCC) biopsies and its level of expression is inversely correlated with patients' survival. To determine the role of u-PA in the invasiveness properties of HCC, we successfully down-regulated u-PA by RNA interference (RNAi) technology, in an HCC-derived cell line at high level of u-PA expression. RNAi is a multistep process involving generation of small interfering RNAs (siRNA) that cause specific inhibition of the target gene. SKHep1C3 cells were transfected with a U6 promoter plasmid coding for an RNA composed of two identical 19-nucleotide sequence motifs in an inverted orientation, separated by a 9-bp spacer to form a hairpin dsRNA capable of mediating target u-PA inhibition. Stable transfectant cells showed a consistently decreased level of u-PA protein. In biological assays, siRNA u-PA-transfected cells showed a reduction of migration, invasion, and proliferation. In conclusion, u-PA down-regulation by RNAi technology decreases the invasive capability of HCC cells, demonstrating that stable expression of siRNA u-PA could potentially be an experimental approach for HCC gene therapy. 相似文献
997.
Israel Lerman Liliana Lozano Antonio
R. Villa Sergio Hernndez-Jimnez Katie Weinger A. Enrique
Caballero Carlos Aguilar Salinas Maria Luisa Velasco Francisco Javier Gmez-Prez Juan
A. Rull 《Biomedicine & Pharmacotherapy》2004,58(10):566-570
To examine the relationship between demographic, clinical and psychosocial variables and diabetes self-care management in Mexican type 2 diabetic patients. Cross-sectional study of 176 consecutive patients with type 2 diabetes aged 30-75 years, attending a tertiary health-care center in Mexico City. A brief medical history and previously validated questionnaires were completed. The study group consisted of 64 males/112 females, aged 55 +/- 11 years, mean diabetes duration of 12 +/- 8 years and HbA1c of 9.0 +/- 2.0%, 78.4% reported following the correct dose of diabetes pills or insulin, 58% ate the recommended food portions, and 44.3% did exercise three or more times per week. A good adherence to these three recommendations was observed in only 26.1% of the patients. These patients considered as a group were characterized by a greater knowledge about the disease (P < 0.00001), regular home blood glucose monitoring (P < 0.01), an inner perception of better diabetes control (P = 0.007), good health (P = 0.004) and better communication with their physician (P < 0.02). A poor adherence to two or the three main diabetes care recommendations was associated with a depressive state (OR 2.38, 95% CI 1.1-4.9, P < 0.01) and a history of excessive alcohol intake (OR 4.03, 95% CI 1.1-21.0, P = 0.03). Poor adherence to standard diabetes care recommendations is frequently observed in patients with type 2 diabetes attending a specialized health care center in Mexico City. Depression must be identified and treated effectively. 相似文献
998.
Elymir S Galvis-Garc a Sergio Sobrino-Coss o Arturo Reding-Bernal Yesica Contreras-Mar n Karina Sol rzano-Acevedo Patricia Gonz lez-Zavala Rosa M Quispe-Siccha 《World journal of gastroenterology : WJG》2020,26(34):5169-5180
BACKGROUND Endoscopic ultrasound(EUS) and endoscopic ultrasound elastography(EUS-E) simulation lessens the learning curve; however, models lack realism, diminishing competitiveness.AIM To standardize the mechanical properties of polyvinyl alcohol(PVA) hydrogel for simulating organs and digestive lesions.METHODS PVA hydrogel(Sigma Aldrich, degree of hydrolysis 99%) for simulating EUS/EUS-E lesions was investigated in Unidad de Investigación y Desarrollo Tecnológico at Hospital General de México \"Dr. Eduardo Liceaga\", Mexico City. We evaluated physical, contrast, elasticity and deformation coefficient characteristics in lesions, applying Kappa's concordance and satisfaction questionnaire(Likert 4-points).RESULTS PVA hydrogel showed stable mechanical properties. Density depended on molecular weight(MW) and concentration(C). PVA bblocks with the greatest density showed lowest tensile strength(r =-0.8, P = 0.01). Lesions were EUSgraphically visible. Homogeneous and heterogeneous examples were created from PVA blocks or PVA phantoms, exceeding(MW_2 = 146000-186000, C_9 = 15% and C_(10) = 20%) with a density under(MW_1 = 85000-124000, C_1 = 7% and C_2 = 9%). We calculated elasticity and deformation parameters of solid(blue) areas, contrasting with the norm(Kappa = 0.8; high degree of satisfaction).CONCLUSION PVA hydrogels were appropriate for simulating organs and digestive lesions using EUS/EUS-E, facilitating practice and reducing risk. Repetition amplified skills, while reducing the learning curve. 相似文献
999.
The human insula is hidden in the depth of the cerebral hemisphere by the overlying frontal and temporal opercula, and consists of three cytoarchitectonically distinct regions: the anterior agranular area, posterior granular area, and the transitional dysgranular zone; each has distinct histochemical staining patterns and specific connectivity. Even though there are several studies reporting the functional connectivity of the insula with the cingulated cortex, its relationships with other brain areas remain elusive in humans. Therefore, we decided to use resting state functional connectivity to elucidate in details its connectivity, in terms of cortical and subcortical areas, and also of lateralization. We investigated correlations in BOLD fluctuations between specific regions of interest of the insula and other brain areas of right-handed healthy volunteers, on both sides of the brain. Our findings document two major complementary networks involving the ventral-anterior and dorsal-posterior insula: one network links the anterior insula to the middle and inferior temporal cortex and anterior cingulate cortex, and is primarily related to limbic regions which play a role in emotional aspects; the second links the middle-posterior insula to premotor, sensorimotor, supplementary motor and middle-posterior cingulate cortices, indicating a role for the insula in sensorimotor integration. The clear bipartition of the insula was confirmed by negative correlation analysis. Correlation maps are partially lateralized: the salience network, related to the ventral anterior insula, displays stronger connections with the anterior cingulate cortex on the right side, and with the frontal cortex on the left side; the posterior network has stronger connections with the superior temporal cortex and the occipital cortex on the right side. These results are in agreement with connectivity studies in primates, and support the use of resting state functional analysis to investigate connectivity in the living human brain. 相似文献