全文获取类型
收费全文 | 12334篇 |
免费 | 657篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 112篇 |
儿科学 | 869篇 |
妇产科学 | 306篇 |
基础医学 | 1303篇 |
口腔科学 | 236篇 |
临床医学 | 751篇 |
内科学 | 2524篇 |
皮肤病学 | 327篇 |
神经病学 | 697篇 |
特种医学 | 357篇 |
外国民族医学 | 1篇 |
外科学 | 1936篇 |
综合类 | 314篇 |
一般理论 | 12篇 |
预防医学 | 507篇 |
眼科学 | 545篇 |
药学 | 1195篇 |
中国医学 | 56篇 |
肿瘤学 | 988篇 |
出版年
2023年 | 90篇 |
2022年 | 223篇 |
2021年 | 419篇 |
2020年 | 228篇 |
2019年 | 326篇 |
2018年 | 374篇 |
2017年 | 299篇 |
2016年 | 335篇 |
2015年 | 342篇 |
2014年 | 480篇 |
2013年 | 667篇 |
2012年 | 910篇 |
2011年 | 975篇 |
2010年 | 544篇 |
2009年 | 392篇 |
2008年 | 681篇 |
2007年 | 626篇 |
2006年 | 544篇 |
2005年 | 509篇 |
2004年 | 474篇 |
2003年 | 368篇 |
2002年 | 359篇 |
2001年 | 293篇 |
2000年 | 299篇 |
1999年 | 247篇 |
1998年 | 96篇 |
1997年 | 67篇 |
1996年 | 92篇 |
1995年 | 65篇 |
1994年 | 48篇 |
1993年 | 45篇 |
1992年 | 119篇 |
1991年 | 159篇 |
1990年 | 126篇 |
1989年 | 106篇 |
1988年 | 107篇 |
1987年 | 75篇 |
1986年 | 85篇 |
1985年 | 91篇 |
1984年 | 65篇 |
1983年 | 68篇 |
1979年 | 66篇 |
1978年 | 44篇 |
1977年 | 35篇 |
1975年 | 34篇 |
1973年 | 38篇 |
1972年 | 41篇 |
1971年 | 44篇 |
1969年 | 32篇 |
1968年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Transport of molecules across tumor vasculature 总被引:16,自引:0,他引:16
Rakesh K. Jain 《Cancer metastasis reviews》1987,6(4):559-593
The vascular-extravascular exchange of fluid and solute molecules in a tissue is determined by three transport parameters (vascular permeability, P, hydraulic conductivity, Lp, and reflection coefficient, ); the surface area for exchange, A; and the transluminal concentration and pressure gradients. The transport parameters and the exchange area for a given molecule are governed by the structure of the vessel wall. In general, tumor vessels have wide interendothelial junctions; large number of fenestrae and transendothelial channels formed by vesicles; and discontinuous or absent basement membrane. While these factors favor movement of molecules across tumor vessels, high interstitial pressure and low microvascular pressure may retard extravasation of molecules and cells, especially in large tumors. These characteristics of the transvascular transport have significant implications in tumor growth, metastasis, detection and treatment. 相似文献
72.
Macrocarposide, a new isoflavanone c-glucoside from Pterocarpus macrocarpus heart wood 总被引:1,自引:0,他引:1
Macrocarposide has been isolated for the first time as a natural product from the heartwood of PTEROCARPUS MACROCARPUS along with some known compounds. Based on its spectral and chemical evidence, it has been assigned the structure dalbergioidin-6- C-glucoside ( 1). 相似文献
73.
Satinder Kumar Jain Virwar Kumar Jha Ganesh Kumar Mani 《Indian Journal of Thoracic and Cardiovascular Surgery》2021,37(4):438
A 46-year-old male presented with breathlessness for a few months. He had been operated twice for liver hydatid cysts and once for right pulmonary hydatid cysts at other hospitals. Now he was found to have one hydatid cyst in the upper lobe of the left lung and multiple hydatid cysts adjoining left heart border. On computed tomography (CT) scan chest and echocardiography, it was difficult to ascertain whether these cysts were pulmonary or intrapericardial. Left ventricular ejection fraction (LVEF) was 25%. Enzyme-linked immunosorbent assay (ELISA) was positive for hydatid. Left posterolateral thoracotomy revealed dead hydatid cyst in upper lobe of the lung that was removed. Infected mother hydatid cyst was encountered inside pericardial sac. Scores of daughter hydatid cysts, varying in size from 1 to 30 mm, were scooped out intact from the pericardial cavity. There was significant improvement in cardiac activity, once the tamponade effect of hydatid cyst was removed. Pericardium was about 1 cm thick with lot of purulent and necrotic slough. To prevent future constrictive pericarditis, subtotal pericardiectomy was done. Intrapericardial hydatid cyst should be kept in mind whenever it obscures the heart border and patient has features of cardiac tamponade. Early surgical intervention may be required in these cases. 相似文献
74.
75.
Saurabh Kumar Bhushan Shah Ashok Johari Rashid Anjum Devansh Garg Rashmi Salhotra Asha Tyagi Amir Maroof Khan Anil Kumar Jain 《Indian Journal of Orthopaedics》2021,55(2):506
Covid-19 is a respiratory disease caused by coronavirus 2 (SARS-CoV-2) first identified in Wuhan, China (December 2019). The disease rapidly crossed the barrier of countries, continents and spread globally. Non-pharmaceutical measures such as social distancing, face mask, frequent hand washing and use of sanitizer remained the best available option to prevent the spread of disease. OPD, IPD admissions, elective O. Ts were curtailed. Orthopedic care was only limited to emergency and semi-urgent procedures like necrotizing fasciitis, open fracture, and compartment syndrome. These measures were taken to preserve infrastructure and manpower to manage covid-19 pandemic. The children were thought to have a low susceptibility to covid-19 as compared to an adult. Deferring the patient during pandemic has led to high orthopedic disease burden, morbidity and disease-related sequelae, hence elective care must be resumed with modified hospital infrastructure. Resumption of elective/emergent orthopedic care should be slow, phasic and strategic, much similar to unlocking. Cases must be stratified depending on covid status and severity. Dedicated O.Ts with neutral/negative pressure and HEPA filter for covid positive and suspected patients are to be used. All symptomatic and suspected patients should be investigated for covid-19 by RT-PCR, blood counts and CT scan. Regional anaesthesia should be preferred to General anaesthesia. Power drill/saw/burr/pulse lavage should be minimized to avoid aerosol generation. Postoperatively continuous surveillance and monitoring to be done for covid related symptoms. Medical institutes rapidly shifted to the online mode of education. Blended learning (virtual & physical) and imparting skills have to be continued in post covid phase with equitable distribution of teaching hours to students of different years. 相似文献
76.
Sameer Haveri Kiran S. Patil Rajendra B. Uppin Santosh Patil B. B. Putti 《Indian Journal of Orthopaedics》2021,55(2):457
Background and AimSeveral patient-related factors have been identified which are responsible for the development of rotator cuff tears. The purpose of the study was to assess various parameters which can be risk factors for the development of supraspinatus tendon tear.MethodsA total of 100 patients with symptomatic rotator cuff tear, aged > 18 years, of either gender, presenting to the outpatient department were included in this cross-sectional study. Magnetic resonance imaging was done and based on its results; patients were identified for the type of tear. Demographic, clinical, and biochemical factors affecting the tears were assessed using logistic regression analysis.ResultsFactors such as age, gender, pain radiation, night pain, and analgesic intake had significant association with supraspinatus tendon tears.Conclusion“Pain radiation” and “Analgesic intake” were two new parameters found associated with the supraspinatus tendon tears. New parameters that have been assessed as risk factors will help in better understanding of supraspinatus tendon tears. 相似文献
77.
78.
BackgroundWith the improved health afforded by cystic fibrosis transmembrane conductance regulator (CFTR) modulators, pregnancy rates are increasing in women with CF. In animal reproductive models, the three components of elexacaftor-tezacaftor-ivacaftor (ETI) did not cause teratogenicity at normal human doses. Although the limited human data available in the literature for previously approved modulators did not suggest cause for concern, there is currently no data in the literature regarding use of ETI in pregnant women. Thus, the decision to continue therapy during pregnancy (with the associated unknown fetal impact) versus discontinuing therapy (with the known risk of maternal health decline) is challenging.MethodsCF Center staff completed an anonymous questionnaire regarding pregnancy and infant outcomes for women who used ETI during pregnancy and/or lactation.ResultsOf 45 ETI-exposed pregnancies reported to date, complications in 2 mothers and in 3 infants (2 born to mothers with poorly controlled diabetes) were rated by clinicians as unknown (possible) or suspected relatedness to ETI use. Two women terminated unplanned pregnancies. Miscarriage rates were consistent with that known in the general U.S. population. Five of the six women who discontinued ETI out of concern for unknown fetal risk restarted because of clinical deterioration. No infant cataracts were reported though only two infants were formally evaluated.ConclusionsIn the context of the known increased rate of complications in women with CF and their infants, data from this retrospective survey is reassuring for women who choose to continue ETI during pregnancy. However, a large, multi-center prospective study is needed to assess impact of use of ETI in pregnancy. 相似文献
79.
Douglas J Conrad Joanne Billings Charlotte Teneback Jonathan Koff Daniel Rosenbluth Barbara A Bailey Raksha Jain 《Journal of cystic fibrosis》2021,20(1):91-96
BackgroundCystic Fibrosis (CF) is a multi-systemic disorder resulting from genetic variation in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene which can result in bronchiectasis, chronic sinusitis, pancreatic malabsorption, cholestatic liver disease and distal intestinal obstructive syndrome. This study generates multi-dimensional clinical phenotypes that capture the complexity and spectrum of the disease manifestations seen in adult CF patients using statistically robust techniques.MethodsPre-transplant clinical data from adult (age ≥18 years) CF patients (n = 992) seen in six regionally distinct US CF centers between 1/1/2014 and 6/30/2015 were included. Demographic, spirometry, nutritional, microbiological and therapy data were used to generate clusters using the Random Forests statistical-learning and Partitioning around Medoids (PAM) clustering algorithms. Five commonly measured demographic, physiological and nutritional parameters were needed to create the final phenotypes that are highly similar to a regionally matched group of patients from the CF Foundation Patient RegistryResultsThis approach identified high-risk phenotypes with expected characteristics including high rates of pancreatic insufficiency, diabetes and Pseudomonas aeruginosa colonization. It also identified unexpected populations including a) a male-dominated, well-nourished group with good lung function with a high prevalence of severe genotypes (i.e. 60% subjects had two minimal function CFTR variations), b) and an older, “survivor” phenotype that had high rates of chronic P. aeruginosa infection.ConclusionsThis study identified recognizable phenotypes that capture the clinical complexity in a statistically robust manner and which may aide in the identification of specific genetic and environmental factors responsible for these disease manifestation patterns. 相似文献
80.