全文获取类型
收费全文 | 7223篇 |
免费 | 470篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 70篇 |
儿科学 | 174篇 |
妇产科学 | 215篇 |
基础医学 | 833篇 |
口腔科学 | 266篇 |
临床医学 | 626篇 |
内科学 | 1570篇 |
皮肤病学 | 157篇 |
神经病学 | 373篇 |
特种医学 | 227篇 |
外国民族医学 | 4篇 |
外科学 | 1273篇 |
综合类 | 145篇 |
现状与发展 | 2篇 |
一般理论 | 2篇 |
预防医学 | 375篇 |
眼科学 | 171篇 |
药学 | 745篇 |
中国医学 | 62篇 |
肿瘤学 | 446篇 |
出版年
2023年 | 98篇 |
2022年 | 264篇 |
2021年 | 405篇 |
2020年 | 257篇 |
2019年 | 328篇 |
2018年 | 413篇 |
2017年 | 269篇 |
2016年 | 282篇 |
2015年 | 274篇 |
2014年 | 322篇 |
2013年 | 397篇 |
2012年 | 567篇 |
2011年 | 527篇 |
2010年 | 314篇 |
2009年 | 240篇 |
2008年 | 346篇 |
2007年 | 328篇 |
2006年 | 285篇 |
2005年 | 339篇 |
2004年 | 269篇 |
2003年 | 250篇 |
2002年 | 206篇 |
2001年 | 61篇 |
2000年 | 55篇 |
1999年 | 55篇 |
1998年 | 45篇 |
1997年 | 29篇 |
1996年 | 31篇 |
1995年 | 27篇 |
1994年 | 14篇 |
1993年 | 20篇 |
1992年 | 28篇 |
1991年 | 26篇 |
1990年 | 22篇 |
1989年 | 27篇 |
1988年 | 27篇 |
1987年 | 24篇 |
1986年 | 28篇 |
1985年 | 30篇 |
1984年 | 18篇 |
1983年 | 22篇 |
1982年 | 10篇 |
1981年 | 15篇 |
1980年 | 15篇 |
1979年 | 20篇 |
1978年 | 11篇 |
1977年 | 15篇 |
1976年 | 13篇 |
1975年 | 15篇 |
1972年 | 8篇 |
排序方式: 共有7736条查询结果,搜索用时 15 毫秒
31.
Mahmoud Hassanein El-Saied A. Aly Yousf A. Abbas Samia M. El-Sigeny 《Macromolecular chemistry and physics.》1993,194(6):1817-1825
To overcome mass transfer limitations which are usually encountered on immobilizing active catalysts, cationic latex particles were used as support for the cobalt(II) complex of disodium N,N′-bis(salicylidene)ethylenediamine-5,5′-disulfonate ( 1 ). The cationic latex 2 was prepared by emulsion copolymerization of chloromethylstyrene (m/p-isomer mixture 60/40) and divinylbenzene (m/p-isomer mixture) followed by treatment with trimethylamine. The latexbound catalyst from 1 and 2 was found to considerably increase the reaction rate of the autoxidation of 2,6-di-tert-butylphenol in water as compared with the conventional polymer-free system. Reaction products were identified as the oxidative coupling product 3,3′,5,5′-tetra-tert-butyldiphenoquinone (3,3′,5,5′-tetra-tert-butyl-4,4′-dioxo-1,1′-bicyclohexa-2,5-dienylidene) and 2,6-di-tert-butyl-1,4-benzoquinone. All reactions showed an induction period before the start of dioxygen consumption. The rate of autoxidation in the three-phase mixtures of water, latex particles, and phenol droplets was not affected significantly by the method of mixing. The reaction rate increased as the concentration of 1 increased. Increasing the partial pressure of dioxygen in the range between 0,25 and 1,0 atm (2,53. 104 – 1,01. 105 Pa) gave a small increase in rate. The colloidal latex catalyst from 1 and 2 showed some loss of activity after successive runs. 相似文献
32.
Ahmed Hassan Albelbeisi Ali Albelbeisi Abdel Hamid El Bilbeisi Mahmoud Taleb Amirhossein Takian Ali Akbari-Sari 《Ethiopian journal of health sciences》2021,31(1):73
BackgroundDespite the huge numbers of the universally produced and employed protocols, the adherence with them is still low to moderate in the healthcare settings. This study was employed to assess the attitudes of Palestinian healthcare professionals in Gaza Strip to health education and counseling on healthy behaviours protocol (WHO-PEN Protocol 2), for patients with non-communicable diseases in the Ministry of Health primary healthcare centers.MethodsThis cross-sectional study was conducted with a census sample of all governmental family physicians and nurses (n=175). The study questionnaire was developed based on Cabana theoretical framework. The Arabic version questionnaire was developed based on the cross-cultural adaptation framework. The psychometric properties of the Arabic version questionnaire was finally evaluated.ResultsThe psychometric properties of the Arabic version questionnaire showed good construct validity and internal consistency reliability. The overall adherence level to WHO-PEN Protocol 2 was 70.0, SD=6.9. The main perceived barriers were lack of incentive, patients'' factors, and lack of time. In general, most of healthcare professional respondents had a positive attitude toward the protocol, but this attitude was not predictor to protocol adherence.ConclusionThe good validity and reliability of the questionnaire can provide support for the accuracy of the study results. Varied implementation strategies targeting the major barriers derived from the study are extremely required for addressing the lack of incentives, patients'' factors and time constraints. 相似文献
33.
34.
Vignesh T. Packiam Craig V. Labbate Stephen A. Boorjian Robert Tarrell John C. Cheville Svetlana Avulova Vidit Sharma Matvey Tsivian Brittany Adamic Mohammad Mahmoud Ryan P. Werntz Norm D. Smith R. Jeffrey Karnes Matthew K. Tollefson Gary D. Steinberg Igor Frank 《Urologic oncology》2021,39(7):436.e1-436.e8
IntroductionWhile numerous current clinical trials are testing novel salvage therapies (ST) for patients with recurrent nonmuscle invasive bladder cancer (NMIBC) after bacillus Calmette-Guérin (BCG), the natural history of this disease state has been poorly defined to date. Herein, we evaluated oncologic outcomes in patients previously treated with BCG and ST who subsequently underwent radical cystectomy (RC).MethodsWe identified 378 patients with high-grade NMIBC who received at least one complete induction course of BCG (n = 378) with (n = 62) or without (n = 316) additional ST and who then underwent RC between 2000 and 2018. Oncologic outcomes were compared using the Kaplan-Meier method and Cox proportional hazards models. Sensitivity analyses were conducted stratifying by presenting tumor stage, matched 1:3 for receipt vs. no receipt of ST.ResultsPatients receiving ST were more likely to initially present with CIS (26% vs. 17%) and less likely with T1 disease (34% vs. 50%, P = 0.06) compared to patients not treated with ST. Receipt of ST was not associated with increased risk of adverse pathology (≥pT2 or pN+) at RC (31% vs. 41%, P = 0.14). Likewise, 5-year cancer-specific survival did not significantly differ between groups on univariable Kaplan-Meier analysis (73% for ST and 74% for no ST, P = 0.7). Moreover, on multivariable analysis, receipt of ST was not significantly associated the risk of death from bladder cancer (HR 1.12; 95% CI 0.60–2.09, P = 0.7). Results were unchanged on sensitivity analysis.ConclusionsThese data suggest that, in carefully selected patients, ST following BCG for high grade NMIBC does not compromise oncologic outcomes for patients who ultimately undergo RC. 相似文献
35.
Dalia O. Mohamed Mona M. Sayed Islam F. Abdelkawi Mahmoud H. Elshoieby Salah M. Khallaf Lamia M. Khallaf Doaa M. Fouad 《Current Urology》2021,15(1):11
Background:Randomizing patients to bladder preservation or radical cystectomy (RC) for the treatment of bladder cancer has not been practical, due to patient and physician preferences. Therefore, continually comparing the 2 treatment modalities is needed, in order to make the proper choice for each patient.Patients and methods:The records of T1–4N0M0 bladder cancer patients, who presented to the South Egypt Cancer Institute between 2007 and 2017 and were treated by either bladder preservation or RC were reviewed.Results:Out of the 166 included patients, 81 (48.8%) patients were treated by bladder preservation and 85 (51.2%) patients had RC. For the patients treated by bladder preservation and the patients treated by RC, the 5-year overall survival (OS) was 56% and 60% (p = 0.67), the 5-year local recurrence-free survival was 69% and 73% (p = 0.69), and the 5-year disease-free survival was 45% and 53% (p = 0.16), respectively. After propensity matching analysis, the mean 5-year OS was 58% for the bladder preservation patients and 61% for the RC patients (p = 0.51). It is notable that among the bladder preservation group, 8 patients (10%) had squamous cell carcinoma (SCC) pathology and refused RC. Their OS was 56% compared to 53% for the SCC patients treated by RC (p = 0.6).Conclusion:Bladder preservation is a safe alternative to cystectomy in transitional cell carcinoma stages T1–4aN0M0, and its use in SCC bladder cancer should be further studied, as it could be feasible to spare them from initial cystectomy. 相似文献
36.
Mostafa M. Baraka Hany M. Hefny Mahmoud A. Mahran Tamer A. Fayyad Haytham Abdelazim Amr Nabil 《Journal of children's orthopaedics》2021,15(1):12
PurposeSurgical treatment in advanced-stage infantile Blount’s disease with medial plateau (MP) depression is challenging. Several osteotomies and fixation methods have been described with no established benchmark. We conducted this study to evaluate the efficacy and safety of a new single-stage technique for acute medial condyle elevation and metaphyseal osteotomies with internal fixation.MethodsA prospective case series of 19 consecutive patients (21 knees) with severe infantile Blount’s disease underwent a single-stage MP elevation and metaphyseal osteotomies, with internal fixation. The mean age was 10.3 years (8.2 to 13.6) and the mean follow-up was 5.1 years (3.2 to 8.3). The outcome measures included clinical and radiological parameters and patient-reported pediatric outcomes data collection instrument (PODCI) score.ResultsThe mean PODCI score improved significantly from 50% to 88%. The mean internal tibial torsion improved from -27° to 11°. All cases maintained full knee extension, no limitation in flexion range of movement and no signs of instability or lateral thrust gait. All the radiographic parameters improved significantly; the mean tibiofemoral angle improved from -29° to 7°, the metaphyseal-diaphyseal angle improved from 33.4° to 4.7° and the angle of depressed MP improved from 38.3° to 2.4° (p < 0.001). At the latest follow-up, no cases of deformity recurrence were identified, the final limb-length discrepancy was < 1 cm in all patients.ConclusionSingle-stage MP elevation and metaphyseal osteotomies with internal fixation significantly improved the clinical and radiographic parameters and PODCI score in advanced infantile Blount’s disease and precluded the use of external immobilization, with no evidence of deformity recurrence.Level of evidenceIV 相似文献
37.
Interleukin (IL)-1β is a key innate cytokine that is essential for immune activation and promoting the inflammatory process. However, abnormal elevation in IL-1β levels has been associated with unwanted clinical outcomes. IL-1β is the most extensively studied cytokine among the IL-1 family of cytokines and its role in pathology is well established. During the course of human immunodeficiency virus type 1 (HIV-1) infection, the level of this proinflammatory cytokine is increased in different anatomical compartments, particularly in lymphatic tissues, and this elevation is associated with disease progression. The aim of this review is to address the pathological roles play by IL-1β in the light of enhancing HIV-1 replication, driving immune cell depletion, and chronic immune activation. The role of IL-1β in HIV-1 transmission (sexually or vertically ‘from mother-to-child’) will also be discussed. Additionally, the impact of the available antiretroviral therapy regimens on the levels of IL-1β in HIV-1 treated patients is also discussed. Finally, we will provide a glance on how IL-1β could be targeted as a therapeutic strategy. 相似文献
38.
Omar MT 《Archives of pharmacal research》1997,20(6):602-609
Some new 9H-thioxanthen-9-one incorporated into heterocyclic systems such as pyridone8, pyrazoline9, pyranone11, iminopyrane12, furopyrimidine17, imidazothiazole19, thiazole21, triazine24 and other related compounds through a para imminophenyl grouping at position-1 of the thioxanthenone ring were synthesized
and tested as antitumor agents, against L 1210 leukemia in mice. Some of the new compounds showed considerable antitumor activity. 相似文献
39.
Synthesis of 1-(heterocyclic substituted anilino)-9H-thioxanthon-9-ones and their antitumor activity
Omar MT 《Archives of pharmacal research》1997,20(6):610-619
Some new 9H-thioxanthen-9-one incorporated into heterocyclic systems such as pyridone8, pyrazoline9, pyranone11, iminopyrane12, furopyrimidine17, imidazothiazole19, thiazole21, triazine24 and other related compounds through a para imminophenyl grouping at position-1 of the thioxanthenone ring were synthesized and tested as antitumor agents, against L 1210 leukemia in mice. Some of the new compounds showed considerable antitumor activity. 相似文献
40.
In colorectal cancer and other tumors, proliferating cell nuclear antigen (PCNA) has been found to be a useful marker in immunohistochemical studies of cell proliferation, The presence of a correlation among PCNA labeling index (PCNA LI) and values of cell proliferation expressed by [H-3]thymidine labeling index (TLI) and flow cytometry (FC), the most common techniques used in the evaluation of proliferative activity in colorectal cancer were studied. In 50 operable colorectal cancer patients, TLI, PCNA LI and determination of S-phase fraction by FC were carried out in order to evaluate the correlation among these three indices. A good correlation was obtained between PCNA LI and both TLI (r=0.667; P=0.0001) and percent of cells in S-phase as determined by FC (r=0.819; P=0.0001). It is concluded that PCNA immunohistochemistry can be a reliable marker of the proliferative activity in colorectal rumours. Furthermore, because of its technical simplicity and lower cost it can be more advantageous than TLI or FC. 相似文献