全文获取类型
收费全文 | 138143篇 |
免费 | 5732篇 |
国内免费 | 302篇 |
专业分类
耳鼻咽喉 | 2147篇 |
儿科学 | 4553篇 |
妇产科学 | 3051篇 |
基础医学 | 18678篇 |
口腔科学 | 4532篇 |
临床医学 | 8415篇 |
内科学 | 33831篇 |
皮肤病学 | 4251篇 |
神经病学 | 10813篇 |
特种医学 | 3320篇 |
外国民族医学 | 1篇 |
外科学 | 17249篇 |
综合类 | 710篇 |
一般理论 | 39篇 |
预防医学 | 13387篇 |
眼科学 | 3178篇 |
药学 | 9514篇 |
中国医学 | 633篇 |
肿瘤学 | 5875篇 |
出版年
2023年 | 873篇 |
2022年 | 666篇 |
2021年 | 2848篇 |
2020年 | 1427篇 |
2019年 | 3036篇 |
2018年 | 5211篇 |
2017年 | 3094篇 |
2016年 | 2899篇 |
2015年 | 3239篇 |
2014年 | 3697篇 |
2013年 | 5549篇 |
2012年 | 9641篇 |
2011年 | 10282篇 |
2010年 | 5154篇 |
2009年 | 3637篇 |
2008年 | 8125篇 |
2007年 | 8692篇 |
2006年 | 8072篇 |
2005年 | 8064篇 |
2004年 | 7180篇 |
2003年 | 6772篇 |
2002年 | 6374篇 |
2001年 | 4157篇 |
2000年 | 4731篇 |
1999年 | 3575篇 |
1998年 | 613篇 |
1997年 | 399篇 |
1996年 | 398篇 |
1995年 | 306篇 |
1992年 | 1461篇 |
1991年 | 1214篇 |
1990年 | 1086篇 |
1989年 | 916篇 |
1988年 | 778篇 |
1987年 | 764篇 |
1986年 | 778篇 |
1985年 | 665篇 |
1984年 | 508篇 |
1983年 | 392篇 |
1979年 | 468篇 |
1978年 | 294篇 |
1975年 | 362篇 |
1974年 | 441篇 |
1973年 | 455篇 |
1972年 | 395篇 |
1971年 | 404篇 |
1970年 | 404篇 |
1969年 | 397篇 |
1968年 | 386篇 |
1967年 | 344篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
Several extracts of Santolina chamaecyparissus ssp. squarrosa antagonized in a concentration-dependent way the contractions of rat duodenum, guinea-pig ileum, rat vas deferens and rat uterus as induced by acetylcholine, histamine, noradrenaline, oxytocin and serotonin. Polar extracts were less active than apolar extracts, and it was necessary to assay the former at higher concentrations. Only the lyophilized aqueous extract produced a slight hypotensive effect when given intravenously at 150 mg/kg to urethananesthetized rats. 相似文献
202.
Ana Cecília Montes Gil Raquel Lorenzetti Gun Bergsten Mendes André Moreno Morcillo Adyléia Aparecida Dalbo Contrera Toro Marcos Tadeu Nolasco da Silva Maria Marluce dos Santos Vilela 《Revista paulista de medicina》2007,125(4):205-209
CONTEXT AND OBJECTIVE: Adverse drug reactions are a significant problem in patients on antiretroviral therapy (ART). We determined liver enzyme elevation frequencies in HIV-infected children and adolescents receiving ART, and their association with risk factors. DESIGN AND SETTING: Cross-sectional study, at the Pediatrics Immunodeficiency Division, University Hospital, Universidade Estadual de Campinas. METHODS: Medical records of 152 children and adolescents (54.6% male; median age 7.48 years) were analyzed, with a mean of 2.6 liver enzyme determinations per patient. Clinically, patients were classified in categories N (6), A (29), B (78) and C (39). Serum levels of aspartate aminotransferase and alanine aminotransferase were evaluated. Hepatotoxicity was scored as grade 1 (1.1-4.9 times upper limit of normality, ULN), grade 2 (5.0-9.9 times ULN), grade 3 (10.0-15.0 times ULN) and grade 4 (> 15.0 times ULN). To assess hepatotoxicity risk factors, odds ratios (OR) and adjusted odds ratios (aOR) for age, gender, TCD4+ cell count, viral load and medication usage were calculated. RESULTS: We observed grade 1 hepatotoxicity in 19.7 % (30/152) patients. No cases of grade 2, 3 or 4 were detected. There was a significant association between hepatotoxicity and use of sulfonamides (OR, 3.61; 95% confidence interval (CI), 1.50-8.70; aOR, 3.58; 95% CI, 1.44-8.85) and antituberculous agents (OR, 9.23; 95% CI, 1.60-53.08; aOR, 9.05; 95% CI, 1.48-55.25). No toxicity was associated with ART. CONCLUSIONS: One fifth of patients experienced mild hepatotoxicity, attributed to antituberculous agents and sulfonamides. Our results suggest that ART was well tolerated. 相似文献
203.
T Vera Castillo T Sánchez Santana M Castro Chávez E Pozo Madera V P Díaz Narváez B Fernández 《Revista cubana de enfermería》1986,2(3):217-231
A survey was conducted in early 1985 among 366 new mothers at 3 hospitals in Pinar del Rio, Cuba, to assess their level of health information regarding the care of newborns. The 11 study variables included breastfeeding, weaning, bathing the newborn, care of clothing and equipment for the baby, well baby visits, vaccination, accidents and safety, parent-child relations, sex education, and the puerperium. The level of information on these topics was generally low and was adequate only for breastfeeding. The information deficit was not related to urban or rural residence, parity, or educational level. The lack of knowledge of new mothers was attributed to the lack of motivation of health personnel at all levels to provide health education, inadequate use of existing information channels, and a lack of emphasis on health education within the general educational system. 相似文献
204.
205.
The activity from 55 septohippocampal neuron pairs was examined in rats anesthetized with urethane. In addition to the statistical characterization of the firing patterns of the recorded units, the functional interactions between pairs of neurons and between neurons and hippocampal theta (theta) waves were investigated with cross-correlation techniques. Pairs were classified according to the rhythmic or non-rhythmic discharge pattern of their neurons. (a) theta-Pairs were those in which both the medial septal (MS) and hippocampal (HPC) units were rhythmic (type 1 units). (b) Pairs with a rhythmic and a theta-related non-rhythmic unit (type 2 unit) were called mixed pairs. (c) Pairs composed of type 2 units were called type 2 pairs. theta-Pairs showed periodic cross-correlations and frequently fired with a phase difference which could change in different pairs. Mixed pairs also showed periodic cross-correlations although one of the units was non-rhythmic. Type 2 pairs showed non-periodic positive cross-correlations. Our data provide new information regarding the temporal relationship between MS and HPC rhythmic activities supporting the role of the MS in providing the afferent timing for the generation of theta-rhythm in the HPC. 相似文献
206.
The metabolic consequences of the uncoupling effect of phenylhydrazonopropanedinitrile and others uncouplers of oxidative phosphorylation on Ehrlich ascites carcinoma (EAC) cells were investigated. Upon application of uncouplers in concentrations stimulating the respiration of EAC cells the accelerate glucose uptake and lactate production was observed. The maximal glycolysis stimulation was fourfold in relation to control at the given experimental conditions. Simultaneously the degree of conversion of glucose on lactate was increased. The acceleration of glycolysis was accompanied by stimulation of 14C-labeled adenine and valine incorporation indicating the increased rate of biosynthetic processes. The prolongation of uncoupler action time and application of their higher concentrations cause the inhibition of glycolysis and biosynthetic processes which is evoked with nonspecific effects of the compounds. 相似文献
207.
208.
209.
210.
J C Marvizón J Vázquez M García Calvo F Mayor A Ruíz Gómez F Valdivieso J Benavides 《Molecular pharmacology》1986,30(6):590-597
The displacement by glycine of 3H-strychnine binding to rat spinal cord membranes cannot be explained by a simple competitive interaction. Indeed, protein-modifying reagents can completely abolish the inhibition of 3H-strychnine binding by glycine and other agonists, whereas the interaction of strychnine itself and other related compounds with the binding site is unimpaired. Moreover, glycine cannot inhibit completely saturable 3H-strychnine binding, the extent of its maximum inhibitory effect depending on the ionic composition of the medium. Hill coefficients less than 1 (whose magnitude also depends on the assay medium) were obtained from glycine displacement curves. These properties are consistent with a mathematical model of two different, but mutually interacting, binding sites for strychnine and glycine on the glycine receptor. The effect of ions and protein-modifying reagents might be explained in this model as modifications of the mechanisms that mediate the allosteric interaction, and/or the affinity of glycine for the receptor. The agonists beta-alanine and taurine and the new antagonists, THAZ, iso-THAZ, and 4,5-TAZA, also seem to interact with a site different from the strychnine-binding site, probably the glycine-binding site. 相似文献