全文获取类型
收费全文 | 79989篇 |
免费 | 3950篇 |
国内免费 | 273篇 |
专业分类
耳鼻咽喉 | 1283篇 |
儿科学 | 2712篇 |
妇产科学 | 1622篇 |
基础医学 | 10364篇 |
口腔科学 | 3480篇 |
临床医学 | 5389篇 |
内科学 | 18791篇 |
皮肤病学 | 2533篇 |
神经病学 | 6721篇 |
特种医学 | 2306篇 |
外国民族医学 | 2篇 |
外科学 | 10417篇 |
综合类 | 606篇 |
现状与发展 | 1篇 |
一般理论 | 25篇 |
预防医学 | 6878篇 |
眼科学 | 1913篇 |
药学 | 5118篇 |
中国医学 | 493篇 |
肿瘤学 | 3558篇 |
出版年
2023年 | 592篇 |
2022年 | 1024篇 |
2021年 | 2467篇 |
2020年 | 1234篇 |
2019年 | 2267篇 |
2018年 | 3217篇 |
2017年 | 1928篇 |
2016年 | 1841篇 |
2015年 | 1970篇 |
2014年 | 2651篇 |
2013年 | 3654篇 |
2012年 | 5681篇 |
2011年 | 6294篇 |
2010年 | 3213篇 |
2009年 | 2410篇 |
2008年 | 4781篇 |
2007年 | 4808篇 |
2006年 | 4393篇 |
2005年 | 4327篇 |
2004年 | 4013篇 |
2003年 | 3726篇 |
2002年 | 3399篇 |
2001年 | 2281篇 |
2000年 | 2707篇 |
1999年 | 1763篇 |
1998年 | 537篇 |
1997年 | 376篇 |
1996年 | 387篇 |
1995年 | 322篇 |
1994年 | 272篇 |
1993年 | 233篇 |
1992年 | 539篇 |
1991年 | 476篇 |
1990年 | 454篇 |
1989年 | 402篇 |
1988年 | 393篇 |
1987年 | 352篇 |
1986年 | 311篇 |
1985年 | 283篇 |
1984年 | 232篇 |
1983年 | 189篇 |
1982年 | 116篇 |
1981年 | 96篇 |
1980年 | 99篇 |
1979年 | 148篇 |
1978年 | 111篇 |
1975年 | 115篇 |
1974年 | 105篇 |
1973年 | 88篇 |
1967年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
41.
Milena Soares Santos Guilherme de Sousa Ribeiro Tainara Queiroz Oliveira Renan Cardoso Nery Santos Edilane Gouveia Kátia Salgado Daniele Takahashi Cleuber Fontes Leila Carvalho Campos Mitermayer Galvão Reis Albert Icksang Ko Joice Neves Reis 《International journal of infectious diseases》2009,13(4):456-461
42.
43.
Aneurisma de aorta abdominal infrarrenal en asociación con riñón en herradura: aportación de un caso
Nerea Senarriaga Ruiz de la Illa Reyes Vega Manrique Isabel Lacasa Viscasillas Iñaki Iriarte Soldevilla Miguel Unda Urzaiz 《Actas urologicas espa?olas》2009,33(10):1141-1144
We review the association between surgically resolvable aortic disease and horseshoe kidney with a discussion of diagnostic problems and therapeutic options.Male patient 81 years of age with horseshoe kidney and an abdominal aortic aneurysm that was discovered by chance in an abdominal ultrasound during a check-up for his prostate condition.A retroperitoneal approach was used in order to resect the aneurysm and perform an aorto-aortic bypass with no complications occurring. Two years after the diagnosis, the patient is still asymptomatic from a vascular point of view.The co-presence of horseshoe kidney and aortic disease needing surgical correction is infrequent, but it significantly increases the technical complexity of aortic reconstruction. A literature review is included. 相似文献
44.
In the present paper, the results obtained are shown after a study by means of multivariant statistical analysis, of the quantity of Eimeria spp. oocyst elimination in sheep, bearing in mind the variations observed in the different areas, in the different age-groups, from month to month, and from year to year. Climatic factors, development of immunity, lambing seasons, and poor hygienic conditions seem to be the factors responsible for the statistically significant differences found when analysing the aforementioned main effects. 相似文献
45.
Francisco Sampaio Pedro Mateus Nuno Bettencourt Carla Costa Dias Luís Ad?o Lino Santos Madalena Teixeira Lino Sim?es Vasco Gama 《Revista portuguesa de cardiologia》2006,25(3):321-327
INTRODUCTION: Ischemic heart disease is a major cause of heart failure in western societies. However, the factors that may influence left ventricular function (LVF) recovery after an acute coronary syndrome (ACS) are still unclear. OBJECTIVE: To identify variables that may influence LVF evolution one year after ACS. METHODS: 104 patients hospitalized with ACS between 7/1/2001 and 12/31/2002 and with systolic dysfunction--defined as an echocardiographic ejection fraction (EF) < or = 45%--were randomly allocated to a planned coronary follow-up program (FUP) or a general cardiology clinic (GC); patients from both groups were also randomly referred to a structured cardiac rehabilitation program (CRP). EF was re-assessed at one year. We compared differences between patients who recovered left ventricular function (EF > 45%; group 1) and those who did not (group 2). RESULTS: One year after discharge, 44.2% of the patients had recovered function. There were no significant differences between the groups in gender (77.7 vs. 76.5% male), age (56 vs. 59 years), hypertension, diabetes, dyslipidemia, smoking habits or family history. A previous history of cardiovascular events was more frequent in group 2 (11.1% vs. 35.3%, p = 0.03). Cardiac catheterization was performed before discharge in 88.8% and 88.2% in groups 1 and 2 respectively (p = NS); no differences were found in coronary anatomy between the two groups. Angioplasty was performed in 54.2% in group 1 and 50% in group 2 (p = NS). There were no differences in the use of angiotensin-converting enzyme inhibitors (83.3% vs. 87.5%), beta-blockers (87.5% vs. 87.5%), nitrates (37.5% vs. 33.3%), aspirin (95.8% vs. 95.8%), statins (79.1% vs. 75%) or diuretics (20.8% vs. 45.8%). There was no significant difference in LVF recovery between patients randomized to FUP or GC (38.5% vs. 54.5%). 87.5% of patients who completed the CRP had normal EF at one year compared to 32.7% of patients not referred to the program (p = 0.009). Although EF improved in both groups, this improvement was greater in patients who completed a CRP (EF 8% vs. 5%, p = 0.003). CONCLUSION: A previous cardiovascular event and completion of a CRP were the only variables that influenced LVF recovery. Thus, enrollment in a CRP, in addition to standard therapy, could be an important therapeutic measure in patients with systolic dysfunction after ACS; our data suggest that these programs should be more widely used. 相似文献
46.
47.
Pascale Jolliet Stéphane Nion Gwena?lle Allain-Veyrac L Tilloy-Fenart Dorothée Vanuxeem Vincent Berezowski Roméo Cecchelli 《Pharmacological research》2007,56(1):11-17
PURPOSE: The objective of the current study was to determine the ability of some antiemetic compounds to cross the blood-brain barrier (BBB) and thereby to determine possible side effects of compounds for the central nervous system (CNS). METHODS: We compared the brain penetration of some antiemetic compounds using an in vitro BBB model consisting in brain capillary endothelial cells co-cultured with primary rat glial cells. RESULTS: This study clearly demonstrated that the metopimazine metabolite, metopimazine acid, has a very low brain penetration, lower than metopimazine and even less than the other antiemetic compounds tested in this study. CONCLUSIONS: The poor brain penetration of metopimazine acid, metopimazine biodisponible form, seems very likely related to the clinically observed difference in therapeutic and safety profile. 相似文献
48.
E. Wieczerzak E. Jankowska S. Rodziewicz‐Motowido A. Giedo J. giewka Z. Grzonka M. Abrahamson A. Grubb D. Brmme 《Chemical biology & drug design》2005,66(Z1):1-11
Abstract: We have designed and synthesized a new series of azapeptides which act as potential inhibitors of cathepsin B and/or cathepsin K. Their structures are based upon the inhibitory sites of natural cysteine protease inhibitors, cystatins. For the synthesized azapeptides, the equilibrium constants for dissociation of inhibitor–enzyme complex, Ki, were determined. Comparison of these values indicated that all of the azainhibitors act much stronger toward cathepsin B. Z‐Arg‐Leu‐His‐Agly‐Ile‐Val‐OMe ( 7 ) proved to be approximately 500 times more potent for cathepsin B than for cathepsin K. To be able to explain the obtained experimental values we used the molecular dynamics procedures to analyze the interactions between cathepsin B and compound 7 . We also determined the structure of the most potent and selective cathepsin B azainhibitor by means of NMR studies and theoretical calculations. In this report, we describe SAR studies of azapeptide inhibitors indicating the influence of the conformational flexibility of the examined compounds on inhibition of cathepsins B and K. 相似文献
49.
Francisco Jose Martinez-Guijarro Eduardo Soriano Jose Antonio del Rio Carlos Lopez-Garcia 《Brain research》1991,547(2)
An antibody against the calcium binding protein parvalbumin selectively labels a set of neurons in the cerebral cortex of lizards. Golgi-like immunostained bipolar, multipolar and pyramid-like neurons appear mainly located in the inner plexiform layers. Parvalbumin-immunoreactive (PARV-IR) puncta are concentrated in the cell layer of the dorsal and dorsomedial cortices showing a basket-like distribution. The morphology and distribution of PARV-IR neurons and puncta overlap GABA-immunostaining in the cerebral cortex of lizards. Thus, it is likely that PARV-IR neurons are a subset of the cortical GABAergic neurons of lizards. 相似文献
50.