全文获取类型
收费全文 | 27375篇 |
免费 | 1309篇 |
国内免费 | 105篇 |
专业分类
耳鼻咽喉 | 343篇 |
儿科学 | 702篇 |
妇产科学 | 496篇 |
基础医学 | 3756篇 |
口腔科学 | 2308篇 |
临床医学 | 1985篇 |
内科学 | 5472篇 |
皮肤病学 | 618篇 |
神经病学 | 2155篇 |
特种医学 | 568篇 |
外国民族医学 | 2篇 |
外科学 | 3085篇 |
综合类 | 167篇 |
一般理论 | 6篇 |
预防医学 | 3723篇 |
眼科学 | 359篇 |
药学 | 1881篇 |
中国医学 | 226篇 |
肿瘤学 | 937篇 |
出版年
2023年 | 242篇 |
2022年 | 535篇 |
2021年 | 908篇 |
2020年 | 633篇 |
2019年 | 749篇 |
2018年 | 1042篇 |
2017年 | 793篇 |
2016年 | 778篇 |
2015年 | 928篇 |
2014年 | 1130篇 |
2013年 | 1429篇 |
2012年 | 2206篇 |
2011年 | 2330篇 |
2010年 | 1073篇 |
2009年 | 774篇 |
2008年 | 1535篇 |
2007年 | 1540篇 |
2006年 | 1244篇 |
2005年 | 1550篇 |
2004年 | 1403篇 |
2003年 | 1142篇 |
2002年 | 800篇 |
2001年 | 499篇 |
2000年 | 465篇 |
1999年 | 382篇 |
1998年 | 124篇 |
1997年 | 73篇 |
1996年 | 53篇 |
1995年 | 64篇 |
1994年 | 80篇 |
1993年 | 53篇 |
1992年 | 187篇 |
1991年 | 175篇 |
1990年 | 165篇 |
1989年 | 159篇 |
1988年 | 145篇 |
1987年 | 96篇 |
1986年 | 112篇 |
1985年 | 90篇 |
1984年 | 64篇 |
1983年 | 55篇 |
1979年 | 73篇 |
1978年 | 47篇 |
1974年 | 50篇 |
1973年 | 53篇 |
1970年 | 69篇 |
1969年 | 91篇 |
1968年 | 63篇 |
1967年 | 69篇 |
1966年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
91.
This study investigated the effects of riluzole (Ril), creatine (Cr) and a combination of these treatments on the onset and progression of clinical signs and neuropathology in an animal model of familial amyotrophic lateral sclerosis, the G93A transgenic mouse (n=13-17 per group). The onset of clinical signs was delayed (P<0.05) by about 12 days in all treatment groups compared with control; however, no differences occurred between treatments. All animals were killed at 199 days of age. At the end of the experimental period the severity of clinical signs was less (P<0.05) with all treatments compared with control. Again no differences between treatments were observed. The treatments had no effect on the number of neurons in ventral horns of the lumbar region of the spinal cord. Transgenic mice ingesting Cr displayed elevated (P<0.05) total Cr levels in cerebral hemispheres (5%) and spinal cord (8%), but not skeletal muscles. These data demonstrate that treatment with Ril and Cr were both effective in delaying disease onset and clinical disability. To the age of killing, no additional benefit was conferred by co-administration of Ril and Cr. 相似文献
92.
Quantitative evaluation of the rRNA in Alzheimer's disease 总被引:2,自引:0,他引:2
da Silva AM Payão SL Borsatto B Bertolucci PH Smith MA 《Mechanisms of ageing and development》2000,120(1-3):57-64
93.
Rodolphe Thiébaut Jérémie Guedj Hélène Jacqmin-Gadda Geneviève Chêne Pascale Trimoulet Didier Neau Daniel Commenges 《BMC medical research methodology》2006,6(1):38-9
Background
Mathematical models are widely used for studying the dynamic of infectious agents such as hepatitis C virus (HCV). Most often, model parameters are estimated using standard least-square procedures for each individual. Hierarchical models have been proposed in such applications. However, another issue is the left-censoring (undetectable values) of plasma viral load due to the lack of sensitivity of assays used for quantification. A method is proposed to take into account left-censored values for estimating parameters of non linear mixed models and its impact is demonstrated through a simulation study and an actual clinical trial of anti-HCV drugs. 相似文献94.
The isthmo-optic nuclei (ION) and ectopic neurons, which constitute the centrifugal visual system (CVS), are thought to be cholinoceptive and nitrergic. However, it is not clear which neurons express these markers, namely the ones that project to the retina rather than in neurons that only participate in a local circuit. Therefore, to characterize the neurochemical patterns of the centrifugal visual system in the post-hatched chick, retinopetal cells of the isthmo-optic nuclei and the ectopic region were identified via immunolabeling for cholera toxin, a neuronal tracer, which has been injected in the ocular globe. Then, double labeled with acetylcholinesterase histochemistry to reveal cholinergic synapses, or NADPH-diaphorase histochemistry as a nitrergic marker. Briefly, acetylcholinesterase activity was present mainly in cholera toxin labeled cell bodies of the isthmo-optic nucleus and the ectopic region indicating that retinal projecting neurons of centrifugal visual system comprise a cholinoceptive pathway. On the other hand, NADPH-diaphorase histochemistry was present in the neuropile and sparse cell bodies inside of the isthmo-optic nucleus and in ectopic neurons which were not cholera toxin positive suggesting their role in an intrinsic circuit of the centrifugal visual system. These data support the idea that these two neurochemical systems are present in distinct neuronal populations in the centrifugal visual system. 相似文献
95.
F Prêteux A M Laval-Jeantet B Roger M H Laval-Jeantet 《European journal of radiology》1985,5(4):313-317
New prospects are foreseen in CT image processing via mathematical morphology (M.M.). M.M. is a set theory based upon the concept of "structuring elements" and allows texture analysis and pattern recognition by performing sequences of neighborhood transformations. This results in a wide range of quantifications. Mathematical morphology applied to CT densitometry allows obtaining the mean density of an organ after its automatic extraction from the background. This operation eliminates the approximations due to the manual selection of the Region of Interest (ROI). Precision, reliability and reproducibility are therefore improved. In this study, we performed the automatic isolation of a sole vertebral body in thoracic or abdominal CT slices to quantify numerous parameters, among them, density of the vertebral trabecular and cortical bones. On scans of the second and third metacarpals, morphomathematical analysis allowed quantification of the parameters of bone evolution: mean cortical density, directional cortico-diaphyseal index, and medullar area. In a different connection, M.M. has allowed automatic segmentation of lung parenchyma, the measurement of its mean density and the determination of the relative importance of the vascular network. 相似文献
96.
Michel Boucher Claude Dubray Pierre Duchêne-Marullaz 《Naunyn-Schmiedeberg's archives of pharmacology》1984,326(2):148-154
Summary The chronotropic effects of dopamine were studied in the conscious dog with chronic A-V block. Dopamine at 12.5–200 g/kg and 12.5–50 g/kg/min lowered atrial rate independently of dose. After blockade of muscarine receptors or alpha-adrenoceptors, it raised atrial rate. After blockade of dopamine receptors, dopamine still lowered atrial rate, and did so dose-relatedly after blockade of beta-adrenoceptors. It raised ventricular rate, and at high doses also induced ventricular rhythm disorders. Blockade of muscarine receptors enhanced the ventricular cardioaccelerator effect of dopamine (P<0.025) at 100 g/kg, while blockade of alpha-adrenoceptors reduced it (P<0.05). Blockade of dopamine receptors did not modify this effect, but blockade of beta-adrenoceptors reversed it. Dopamine at 25–200 g/kg raised mean blood pressure. This effect was enhanced by blockade of muscarine receptors, reversed by blockade of alpha-adrenoceptors, and was unaffected by blockade of beta-adrenoceptors or dopamine receptors. These results show that the atrial cardiomoderator effect of dopamine is a vagal reflex response to its hypertensive action, and that it is limited by its direct beta-adrenergic stimulating action. They also show that the ventricular cardioaccelerator effect of dopamine is attenuated by a reflex vagal depressor effect consequent to the induced hypertension. No evidence was found for the existence of positive chronotropic dopamine receptors in either atria or ventricles.A preliminary report of these findings was presented at the Symposium on Peripheral Dopaminergic Receptors, July 1978, in Strasbourg, France (Boucher et al. 1979b) 相似文献
97.
Camargo Carlos Henrique de Souza da Cunha Maria de Lourdes Ribeiro Caramori Jacqueline Costa Teixeira Mondelli Alessandro Lia Montelli Augusto Cezar Barretti Pasqual 《International urology and nephrology》2021,53(2):381-381
International Urology and Nephrology - In the original publication, article title was incorrectly published. 相似文献
98.
Neves Lia Mara Grosso Tim Carla Roberta Floriano Elaine Medeiros da Silva de Avó Lucimar Retto Fernandes João Batista Parizotto Nivaldo Antonio Cominetti Marcia Regina 《Lasers in medical science》2021,36(4):863-870
Lasers in Medical Science - Ultraviolet radiation (UVR) is the major etiologic agent of cutaneous photoaging, and different strategies are used to prevent and treat this condition. The... 相似文献
99.
do Amaral Leandro Custódio Reis Baltazar Leão Ribeiro-Oliveira Antônio da Silva Santos Thamires Marx Giannetti Alexandre Varella 《Neurosurgical review》2021,44(3):1687-1702
Neurosurgical Review - A preferred treatment for residual/recurrent pituitary adenomas has not been established. The existence of higher complication rates for revision surgeries remains under... 相似文献
100.
Daniela de Queiroz Moura Ramon Rawache Marília Ferreira Gomes Garcia Nathalia Farias Vasconcelos Priscila Santos Gustavo Rego Coelho Thiago Luis da Paz Santos Duílio Reis da Rocha Filho Sonia Leite da Silva Eliana Regia Barbosa de Almeida Paula F.C.B.C. Fernandes João Batista Cerqueira José Huygens Parente Garcia Claudia Maria Costa de Oliveira 《Transplantation proceedings》2021,53(4):1345-1349
Transplantation of any organ has some inherent risk of disease transmission, such as infection and malignancy. The present study aims to describe 2 cases of choriocarcinoma transmission after kidney and liver transplantation originating from the same patient. The donor was a 17-year-old woman who died of cerebral hemorrhage. Both organ recipients died of metastatic choriocarcinoma few months after the transplantation, within days after starting chemotherapy. Retrospective hCG (human chorionic gonadotropin hormone) analysis in donor's blood stored at the time of donation had a result of 9324 mIU/mL. Despite its rarity, clinicians should be aware of the risk of transplant-related choriocarcinoma from female donors in childbearing age. In some cases, hCG dosage should be performed before donation. 相似文献