全文获取类型
收费全文 | 3644篇 |
免费 | 242篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 121篇 |
妇产科学 | 113篇 |
基础医学 | 323篇 |
口腔科学 | 139篇 |
临床医学 | 534篇 |
内科学 | 586篇 |
皮肤病学 | 55篇 |
神经病学 | 149篇 |
特种医学 | 380篇 |
外科学 | 450篇 |
综合类 | 243篇 |
一般理论 | 3篇 |
预防医学 | 329篇 |
眼科学 | 41篇 |
药学 | 202篇 |
2篇 | |
中国医学 | 34篇 |
肿瘤学 | 198篇 |
出版年
2022年 | 48篇 |
2021年 | 51篇 |
2020年 | 43篇 |
2019年 | 26篇 |
2018年 | 46篇 |
2017年 | 47篇 |
2016年 | 40篇 |
2015年 | 71篇 |
2014年 | 99篇 |
2013年 | 129篇 |
2012年 | 145篇 |
2011年 | 171篇 |
2010年 | 126篇 |
2009年 | 136篇 |
2008年 | 120篇 |
2007年 | 135篇 |
2006年 | 163篇 |
2005年 | 121篇 |
2004年 | 105篇 |
2003年 | 118篇 |
2002年 | 113篇 |
2001年 | 77篇 |
2000年 | 96篇 |
1999年 | 68篇 |
1998年 | 100篇 |
1997年 | 90篇 |
1996年 | 84篇 |
1995年 | 80篇 |
1994年 | 56篇 |
1993年 | 65篇 |
1992年 | 58篇 |
1991年 | 64篇 |
1990年 | 59篇 |
1989年 | 67篇 |
1988年 | 84篇 |
1987年 | 85篇 |
1986年 | 66篇 |
1985年 | 70篇 |
1984年 | 56篇 |
1983年 | 38篇 |
1982年 | 30篇 |
1981年 | 25篇 |
1980年 | 23篇 |
1977年 | 25篇 |
1976年 | 23篇 |
1959年 | 22篇 |
1958年 | 30篇 |
1956年 | 30篇 |
1955年 | 42篇 |
1954年 | 35篇 |
排序方式: 共有3934条查询结果,搜索用时 66 毫秒
61.
The transoral approaches have become commonplace in modern neurosurgical practice for treatment of ventral midline lesions of the clivus and upper cervical spine. Although the standard technique of transoral surgery is conceptually simple, anatomic relationships are not so readily appreciated. The present study was undertaken in an effort to define more clearly the midline anatomic relationships as they pertain to the standard transoral and transpalatine operations. The anatomic relationships involved in planning microsurgical transoral approaches were examined in 15 human cadavers. Landmarks approximating the midline of the skull base and the upper cervical spinal canal were defined to assist the surgeon's orientation. Measurements were made in axial, sagital, and parasagittal planes to various neurovascular structures in the posterior cranial fossa and upper cervical spinal canal. The study revealed that, for the standard transoral and transoral-transpalatine dissections, the carotid arteries, abducens nerves, interior petrosal sinuses, hypoglossal nerves, and vertebral arteries would be a greatest risk being 0.76, 1.06, 1.51, 1.34, and 1.52 cm from the midline at specified locations. The measurements and the computed tomography images provide a useful reference for the surgeon. 相似文献
62.
目的 探讨人胰弹力蛋白酶Ⅰ (Humanpancreaticelastase 1 ,HPE1 )放射免疫测定 (Radioimmunoassay ,RIA)和核糖核酸酶(Ribonuclease ,RNase)活性检测的临床价值。方法 参照Satake等建立的改良HPE1RIA和Thomas等的改良酸溶性产物法检测 82例正常成年人和 2 2 2例各类患者血清并分析结果。结果 82例健康成人HPE1值为 2 3.8( 3.4ng L) ,RNase活性为 5 7.0 3( 1 2 .1 6 μ ml) ;急性胰腺炎和胰腺癌HPE1 值明显高于其他疾病 (P <0 .0 1 )。联合检测HPE1 、RNase活性可提高胰腺癌的检出率 ( 92 .47% )。结论 HPE1 RIA对急性胰腺炎有诊断价值 ,联合检测HPE1 、RNase活性检测对胰腺癌诊断有一定的临床价值 相似文献
63.
口服莫沙必利治疗功能性消化不良的随机对照试验 总被引:5,自引:0,他引:5
目的 观察新型促胃肠动力药莫沙必利 (胃 5 HT4受体促进剂 )对功能性消化不良 (FD)的随机对照试验。方法 FD患者 42例 ,随机分为试验组 (2 1例 ,服枸橼酸莫沙必利片 )和对照组 (2 1例 ,服吗叮啉片 )。采用GCP标准 ,双盲法观察 ,在实验开始前、服药第 1 4、2 8天记录症状变化及副作用发生情况。随机抽取部分患者于实验开始前和结束时做99MTc胃排空试验。结果 莫沙必利对FD症状的疗效与吗叮啉组相当 (P >0 .0 5 )。99MTc胃排空测定发现莫沙必利组治疗后的半排时间 (45 .0 5± 1 2 .2 1 )min缩短 ,1 2 0min残留率 (2 9.73%± 8.5 1 % )减少 (P <0 .0 5 ) ,两组病例未发现毒副反应。结论 莫沙必利对于FD疗效良好 ,对胃排空延迟有良好疗效 ,安全度高。 相似文献
64.
达建 《中华医学教育杂志》2001,(4):41-44
本文从医学人才培养的高度,论述高校与附属医院建立非隶属关系的附属医院的过程、体会和思考,指出目前存在的问题和解决途径.对进一步深化临床教育教学改革具有重要意义. 相似文献
65.
The purpose of this study was to determine the magnitude and specific foci of anxiety experienced by patients receiving their initial hyperbaric treatment. The Spielberger State-Trait Inventory questionnaire and a personal interview were administered to 24 patients to determine anxiety levels. Upon arrival at the hyperbaric clinic and prior to any type of health teaching, the State and Trait questionnaire was administered to the patients. One hour prior to the treatment, the State questionnaire was repeated to determine any significant changes in anxiety levels. No significance was found in anxiety levels between pre-health and pre-treatment. The Trait questionnaire revealed that this specific group of patients, regardless of the circumstances, felt they were not very anxious individuals. Post-treatment, the State questionnaire was administered again and these anxiety levels did differ significantly from the pre-health and pre-treatment levels. The findings indicate the need to continue to validate clients' perceived needs during hyperbaric treatment, which will help direct future nursing practice. 相似文献
66.
McEligot AJ Rock CL Flatt SW Newman V Faerber S Pierce JP 《The Journal of nutrition》1999,129(12):2258-2263
We investigated predictors of change in plasma carotenoids from baseline to 3 y and examined plasma carotenoid concentrations at 1 and 3 y in response to a high vegetable diet. Participants were 56 women diagnosed with breast cancer and enrolled in a randomized feasibility study for a trial examining the effect of a diet high in vegetables and fruits on the risk of breast cancer recurrence. Independent t test analysis revealed that the intervention group had significantly higher vegetable and fruit servings and fiber at 12 mo and significantly higher vegetable servings at 36 mo compared with the control group (P < 0.05). Energy intake from fat was significantly lower in the intervention group at 12 and 36 mo. The intervention group had significantly higher consumption of beta-carotene, alpha-carotene, lutein and beta-cryptoxanthin at 12 mo (P < 0.05). beta-Carotene, alpha-carotene and lutein intakes also were significantly higher at 36 mo (P < 0.05). At 36 mo, the intervention group had significantly higher plasma concentrations of alpha-carotene and beta-carotene compared with the control group. Repeated-measures ANOVA revealed that the intervention group had significantly increased (P < 0.05 with Bonferroni correction) plasma beta-carotene, alpha-carotene, lutein and lycopene concentrations at 12 and 36 mo compared with baseline. Baseline carotenoid concentrations were significantly inversely predictive (P < 0.05) of plasma carotenoid change. In addition, change in body mass index (BMI) and plasma cholesterol concentrations were predictive of plasma carotenoid change from baseline to 3 y. Results of this study demonstrate that change in plasma carotenoid concentrations is associated with change in BMI, change in plasma cholesterol and baseline carotenoid concentrations. Plasma carotenoid response can be an indicator of long-term high vegetable intake for women at risk of breast cancer recurrence. 相似文献
67.
Lowe G Droz AS Vilaivan T Weaver GW Tweedale L Pratt JM Rock P Yardley V Croft SL 《Journal of medicinal chemistry》1999,42(6):999-1006
A range of (2,2':6',2'-terpyridine)platinum(II) complexes are shown to possess antiprotozoal activity in vitro against Leishmania donovani, Trypanosoma cruzi, and Trypanosoma brucei,the causative organisms of tropical diseases leishmaniasis and trypanosomiasis. The best compounds caused 100% and 78% inhibition of growth of the intracellular amastigote forms of L. donovani and T. cruzi, respectively, at a concentration of 1 microM and 100% inhibition of growth of the bloodstream trypomastigote forms of T. brucei at a concentration of 0.03 microM. The results obtained with complexes in which the fourth ligand to platinum(II) is capable of being substituted with a substitution inert hydroxyethanethiolate complex are compared. The ammine complexes show high antiprotozoal activity suggesting that the trans influence of the 2,2':6',2'-terpyridine ligand has a profound effect on the ease of displacement of the fourth ligand in (2,2':6',2' -terpyridine)platinum(II) complexes, although nonbonded interaction between the ammine ligand and the 6 and 6' ' hydrogens probably also weakens the ligation to Pt(II). 相似文献
68.
Z L Zhou S X Cai E R Whittemore C S Konkoy S A Espitia M Tran D M Rock L L Coughenour J E Hawkinson P A Boxer C F Bigge L D Wise E Weber R M Woodward J F Keana 《Journal of medicinal chemistry》1999,42(15):2993-3000
A structure-based search and screen of our compound library identified N-(2-phenoxyethyl)-4-benzylpiperidine (8) as a novel N-methyl-D-aspartate (NMDA) receptor antagonist that has high selectivity for the NR1/2B subunit combination (IC(50) = 0.63 microM). We report on the optimization of this lead compound in terms of potency, side effect liability, and in vivo activity. Potency was assayed by electrical recordings in Xenopus oocytes expressing cloned rat NMDA receptors. Side effect liability was assessed by measuring affinity for alpha(1)-adrenergic receptors and inhibition of neuronal K(+) channels. Central bioavailability was gauged indirectly by determining anticonvulsant activity in a mouse maximal electroshock (MES) assay. Making progressive modifications to 8, a hydroxyl substituent on the phenyl ring para to the oxyethyl tether (10a) resulted in a approximately 25-fold increase in NR1A/2B potency (IC(50) = 0.025 microM). p-Methyl substitution on the benzyl ring (10b) produced a approximately 3-fold increase in MES activity (ED(50) = 0.7 mg/kg iv). Introduction of a second hydroxyl group into the C-4 position on the piperidine ring (10e) resulted in a substantial decrease in affinity for alpha(1) receptors and reduction in inhibition of K(+) channels with only a modest decrease in NR1A/2B and MES potencies. Among the compounds described, 10e (4-hydroxy-N-[2-(4-hydroxyphenoxy)ethyl]-4-(4-methylbenzyl)piperid ine, Co 101244/PD 174494) had the optimum pharmacological profile and was selected for further biological evaluation. 相似文献
69.
Dichloromethane extracts of the root bark and stem bark of Kigelia pinnata collected from Zimbabwe exhibited antitrypanosomal activity against Trypanosoma brucei brucei in vitro. Activity-guided fractionation led to the isolation of four naphthoquinones from both the root and stem bark of the plant. The compounds were identified as 2-(1-hydroxyethyl)-naphtho[2,3-b]furan-4,9-quinone (1), isopinnatal (2), kigelinol (3), and isokigelinol (4). Subsequently, the compounds were assessed for antitrypanosomal activity against T. brucei brucei and T. brucei rhodesiense bloodstream form trypomastigotes in vitro. Compound 1 with a furanonaphthoquinone structure was found to possess pronounced activity against both parasites with IC50 values of 0.12 and 0.045 microM, respectively, although it was less active than the standard drug pentamidine. Compounds 2, 3, and 4 also exhibited activity against the parasites, although to a lesser extent. The activities of the compounds were further assessed by comparison with the cytotoxic activities obtained against KB cell lines. 相似文献
70.
Cerebrospinal fluid (CSF) leaks can be responsible for significant patient morbidity and mortality. While the majority of leaks induced after head trauma will seal without intervention, spontaneous or surgically-induced leaks often require operative repair. Many modifications on standard surgical technique are available for repair of CSF fistulae, but none assures adequate closure. We have studied the efficacy of a novel fibrin-based composite tissue adhesive (CTA) for closure of experimentally-induced CSF leaks in rats. Fistulae were created in two groups of animals. Two weeks after creation of the leaks, the animals were sacrificed and analyzed for persistence of leak. A 58% leakage rate was noted in the control group (n = 12), and no leaks were noted in the experimental group closed after application of CTA to the surgical defect followed by skin closure (n = 11). Comparing the control group to the experimental group, results were statistically significant (p = 0.015). These data suggest that CTA may be effective as an adjunct for the closure of CSF fistulae. 相似文献