全文获取类型
收费全文 | 34702篇 |
免费 | 1999篇 |
国内免费 | 165篇 |
专业分类
耳鼻咽喉 | 345篇 |
儿科学 | 841篇 |
妇产科学 | 840篇 |
基础医学 | 5049篇 |
口腔科学 | 1959篇 |
临床医学 | 2881篇 |
内科学 | 7826篇 |
皮肤病学 | 1019篇 |
神经病学 | 3081篇 |
特种医学 | 567篇 |
外科学 | 3038篇 |
综合类 | 140篇 |
一般理论 | 25篇 |
预防医学 | 3827篇 |
眼科学 | 601篇 |
药学 | 2684篇 |
中国医学 | 206篇 |
肿瘤学 | 1937篇 |
出版年
2024年 | 45篇 |
2023年 | 414篇 |
2022年 | 920篇 |
2021年 | 1641篇 |
2020年 | 914篇 |
2019年 | 1343篇 |
2018年 | 1609篇 |
2017年 | 1066篇 |
2016年 | 1020篇 |
2015年 | 1287篇 |
2014年 | 1673篇 |
2013年 | 2041篇 |
2012年 | 3160篇 |
2011年 | 3298篇 |
2010年 | 1664篇 |
2009年 | 1412篇 |
2008年 | 2317篇 |
2007年 | 2269篇 |
2006年 | 1956篇 |
2005年 | 1714篇 |
2004年 | 1493篇 |
2003年 | 1249篇 |
2002年 | 1076篇 |
2001年 | 130篇 |
2000年 | 88篇 |
1999年 | 119篇 |
1998年 | 146篇 |
1997年 | 143篇 |
1996年 | 92篇 |
1995年 | 75篇 |
1994年 | 73篇 |
1993年 | 53篇 |
1992年 | 59篇 |
1991年 | 44篇 |
1990年 | 30篇 |
1989年 | 25篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 17篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 15篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 15篇 |
1978年 | 7篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1973年 | 5篇 |
1972年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Ana Ortega Ph.D. George Dranitsaris M.Sci.Phm. Jeremy Sturgeon M.D. Heather Sutherland M.Sci. Amit Oza M.D. 《Gynecologic oncology》1997,66(3):454-463
The standard treatment for patients with advanced ovarian cancer (AOC) has been cyclophosphamide and cisplatin (CP). Recently, the results of a large randomized comparative trial demonstrated that the combination of paclitaxel and cisplatin (TP) provided a progression-free survival benefit of 5 months. In this study, a cost–utility analysis was performed from a Canadian health care system perspective to estimate the incremental cost-effectiveness of the TP combination. Twelve AOC patients who received treatment with TP were matched for age and disease stage on a 1-to-2 basis with a CP control. Total hospital resource consumption was then collected for all patients. Treatment preferences were estimated from a cohort of 20 patients and 40 healthy female volunteers using the time trade-off technique. The outcomes were then generated through a decision-analytic model. First-line treatment costs with TP were approximately fourfold greater on a per-cycle basis than the CP alternative (Can$1911 vs Can$459). When progression-free survival benefit and patient treatment preferences were incorporated into the analysis, the results of the decision model revealed an incremental cost between Can$12,000 and Can$24,000 per quality-adjusted progression-free year with the TP protocol. Even though the TP combination has a considerably higher drug acquisition cost, the results of the current analysis suggest that this new chemotherapy regimen does provide patients with substantial quality-adjusted progression-free survival benefit at a reasonable cost to the Canadian health care system. 相似文献
62.
Jesús M. Cesar Ana Vecino Mikel Perez-Vaquero Jos L. Navarro 《European journal of haematology》1993,50(4):234-236
Abstract: Red cell phospholipids (PLs) were assessed in 11 patients with essential thrombocythemia and 5 patients with polycythemia vera. Platelet and plasma PLs were also determined in 10 of these patients, and the results were compared with studies performed in 16 healthy volunteers. The amount of platelet PLs in patients was similar to controls (556 ± 90 nmol/109cells, versus 481 ± 91 nmol/109cells), as was the percentage of the main specimens of these compounds, including phosphatidylserine (11.1 ± 0.8%), which is relevant for platelet procoagulant activity. We did not find differences between red cell PLs of patients (300 ± 60 nmol/109cells), versus controls (289 ± 71 nmol/109cells), and the sphingomyelin/phosphatidylcholine ratio in these cells was the same in both groups (0.75 ± 0.1). Finally, we did not detect any alteration in the amount of plasma PLs specimens. 相似文献
63.
Daphna Mezad Mordechai Hallak Mahmoud Huleihel Limor Gortzak-Uzan Ana Smolin Moshe Mazor 《Magnesium research》2002,15(3-4):247-252
Our objective was to evaluate the effect of intravenous magnesium sulphate administration to patients with preterm labour on maternal serum and amniotic fluid IL-1beta, IL-6, IL-10 and TNFalpha concentrations. Thirty-six patients at 24-34 weeks of singleton gestation, who presented with contractions (> or = 8 in 60 min) had amniocentesis to rule out intrauterine infection. The patients received intravenous MgSO4 for tocolysis. Twenty-six patients had amniocentesis performed before initiation of MgSO4 (controls) while 10 others had the procedure during tocolytic therapy (study patients). Magnesium, IL-1beta, IL-6, TNFalpha and IL-10 concentrations were measured. Study and control groups were statistically compared using Student t test. Mean magnesium levels were significantly higher in the study group (P < 0.01). There were no significant differences between the cytokines levels in maternal serum and in amniotic fluid between the groups. Our results suggest that the mechanism of magnesium as a tocolytic agent may not be mediated via the examined cytokines. 相似文献
64.
Raquel Carreira Ana Duarte Pedro Monteiro Maria Sancha Santos Ana Cristina Rego Catarina R Oliveira Lino M Gon?alves Luís A Providência 《Revista portuguesa de cardiologia》2004,23(11):1447-1455
Ischemia negatively affects mitochondrial function by inducing the mitochondrial permeability transition (MPT). The MPT is triggered by oxidative stress, which occurs in mitochondria during ischemia as a result of diminished antioxidant defenses and increased reactive oxygen species production. It causes mitochondrial dysfunction and can ultimately lead to cell death. Therefore, drugs able to minimize mitochondrial damage induced by ischemia may prove to be clinically effective. We analyzed the effect of carvedilol, a beta-blocker with antioxidant properties, on mitochondrial dysfunction. Carvedilol decreased levels of TBARS (thiobarbituric acid reactive substances), an indicator of oxidative stress, which is consistent with its antioxidant properties. Regarding cell death by apoptosis, although ischemia did increase caspase-8-like activity, there were no changes in caspase-3-like activity, which is activated downstream of caspase-8; this may indicate that the apoptotic cascade is not activated by 60 minutes of ischemia. We conclude that carvedilol protects ischemic mitochondria by preventing oxidative mitochondrial damage, and, by so doing, it may also inhibit the formation of the MPT pore. 相似文献
65.
66.
Antonio C Pastorino Rejane D C Rimazza Cláudio Leone Ana Paula M Castro Dirceu Solé Cristina M A Jacob 《The Journal of asthma》2006,43(9):695-700
BACKGROUND: Identify risk factors for asthma in adolescents from S?o Paulo, Brazil. METHODS: total of 528 adolescents (141 asthmatics, 387 control subjects) from the ISAAC study (phase III) were submitted to a complementary questionnaire to evaluate risk factors, through response to questions regarding personal history, environment, and diet and an agreement to undergo the skin prick test (SPT) for aeroallergens. RESULTS: Positive SPT to at least one allergen occurred in 49.4% adolescents. The risk factors for asthma were: prematurity (OR: 3.84, 95% CI: 1.54-9.64), rhinitis (OR: 3.18, 95% CI: 1.71-5.91), positivity in the SPT (OR: 2.81, 95% CI: 1.48-5.32), eczema in characteristic skin-folds (OR: 2.86, 95% CI: 1.13-7.26), and an allergic mother (OR: 2.01, 95% CI: 1.02-3.93). The consumption of cooked vegetables was a protective factor for asthma (OR: 0.37, 95% CI: 0.18-0.79) CONCLUSIONS: Asthma is a multifatorial disease. An allergic mother, aeroallergen sensitization, rhinitis, eczema and prematurity were considered risk factors and the consumption of cooked vegetables was considered a protective factor for asthma in this population. 相似文献
67.
68.
F lix F. Cruz-Sanchez Marco L. Rossi Adriana Cardozo Ana Picardo E. Tolosa 《Journal of the neurological sciences》1992,110(1-2):228-231
The grumose degeneration observed in the dentate nuclei of 7 cases of progressive supranuclear palsy (PSP) was studied with a panel of antibodies which included 2 neurofilaments, Tau and ubiquitin. Dentate nucleus neurons were negative with all antibodies except ubiquitin which showed a slightly positive homogeneous pattern of staining. The amorphous material surrounding swollen or normal neurons was strongly positive for neurofilament and subunits and numerous torpedoes were observed in the granular layer of the cerebellar cortex. Our results confirm that grumose degeneration consists in degeneration of terminal axons of Purkinje cells in the dentate nucleus. The positivity of dentate nucleus neurons for ubiquitin may support the concept of synaptic dysfunction between Purkinje cells and dentate nucleus neurons. 相似文献
69.
Sara Lucena Belsy Guerrero Ana M Salazar Amparo Gil Carmen L Arocha-Pi?ango 《Blood coagulation & fibrinolysis》2006,17(6):427-435
Lonomia achelous is a caterpillar distributed in southern Venezuela and in northern Brazil that causes an acute hemorrhagic syndrome in people who have contact with its bristles. The effect of the crude hemolymph and its chromatographic fractions (FDII, Lonomin V and Lonomin V-2) on extracellular matrix proteins was studied. The chromatographic fractions show activities similar to plasmin and urokinase. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, both lonomins appear as a protein band of 25 kDa under reduced conditions. By exclusion chromatography, the molecular weights of Lonomin V and Lonomin V-2 were 26.5 and 24.5 kDa, respectively. Fibronectin, laminin and vitronectin were degraded by all venom components. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, under reduced conditions, shows that lonomins degrade fibronectin in four main fragments of 116, 60, 50 and 30 kDa. Molecular exclusion chromatography in native conditions shows that the molecular masses of these fragments are > or = 300, 62 and 27 kDa. The proteolytic effect of lonomins was abolished by benzamidine/HCl, iodoacetic acid and aprotinin. The extracellular matrix protein degradation together with the fibrino(geno)lytic activity of hemolymph and its fractions could explain, in part, the hemorrhagic syndrome, and the wound dehiscence in persons who have had contact with the L. achelous caterpillar. 相似文献
70.
Juan A. Rey M. Josefa Bello Ana M. Jimenez-lara Jesus Vaquero M. Elena Kusak Jos M. de Campos Jos L. Sarasa Angel Pestana 《International journal of cancer. Journal international du cancer》1992,51(5):703-706
Loss of constitutional heterozygosity as determined through the analysis of restriction-fragment-length polymorphism (RFLP) on tumoral and constitutional DNA has proven to be helpful to delimit the location of tumor-suppressor genes in the human genome. In malignant gliomas this approach indicates that chromosomes 9p, 10, 17p, and 22 may contain genes of this category involved in its origin and/or progression. Regarding chromosome 22, the data so far provided by molecular studies confirmed those previously reported by cytogenetic studies, suggesting the existence of a sub-group of malignant gliomas characterized by monosomy of this chromosome. However, the precise location of the putative glioma suppressor gene on chromosome 22 remains ambiguous. We have performed a combined cytogenetic and RFLP study on a series of 31 gliomas, looking for structural abnormalities of this chromosome. In 3 instances, terminal deletions of the long arm of chromosome 22 were observed by both methodologies, suggesting that the band q13 region distal to the D22S80 marker might be the critical domain non-randomly involved in tumor suppression of gliomas. 相似文献