全文获取类型
收费全文 | 165279篇 |
免费 | 7108篇 |
国内免费 | 546篇 |
专业分类
耳鼻咽喉 | 2661篇 |
儿科学 | 4812篇 |
妇产科学 | 3813篇 |
基础医学 | 22289篇 |
口腔科学 | 5702篇 |
临床医学 | 10709篇 |
内科学 | 39987篇 |
皮肤病学 | 5200篇 |
神经病学 | 13430篇 |
特种医学 | 3696篇 |
外国民族医学 | 2篇 |
外科学 | 19765篇 |
综合类 | 1022篇 |
一般理论 | 50篇 |
预防医学 | 16311篇 |
眼科学 | 3654篇 |
药学 | 11597篇 |
中国医学 | 902篇 |
肿瘤学 | 7331篇 |
出版年
2023年 | 1080篇 |
2022年 | 1887篇 |
2021年 | 4506篇 |
2020年 | 2269篇 |
2019年 | 4238篇 |
2018年 | 5933篇 |
2017年 | 3553篇 |
2016年 | 3418篇 |
2015年 | 3884篇 |
2014年 | 5212篇 |
2013年 | 7494篇 |
2012年 | 11638篇 |
2011年 | 12540篇 |
2010年 | 6634篇 |
2009年 | 5161篇 |
2008年 | 9683篇 |
2007年 | 10247篇 |
2006年 | 9445篇 |
2005年 | 9434篇 |
2004年 | 8375篇 |
2003年 | 7797篇 |
2002年 | 7226篇 |
2001年 | 4448篇 |
2000年 | 5005篇 |
1999年 | 3939篇 |
1998年 | 925篇 |
1997年 | 717篇 |
1996年 | 586篇 |
1995年 | 526篇 |
1994年 | 426篇 |
1993年 | 345篇 |
1992年 | 1521篇 |
1991年 | 1269篇 |
1990年 | 1148篇 |
1989年 | 943篇 |
1988年 | 821篇 |
1987年 | 749篇 |
1986年 | 759篇 |
1985年 | 655篇 |
1984年 | 470篇 |
1983年 | 401篇 |
1979年 | 435篇 |
1975年 | 301篇 |
1974年 | 388篇 |
1973年 | 389篇 |
1972年 | 333篇 |
1971年 | 358篇 |
1970年 | 325篇 |
1969年 | 350篇 |
1968年 | 304篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
J I?igo A Arce E Rodríguez D García de Viedma E Palenque M J Ruiz Serrano L Cabello F Chaves 《The international journal of tuberculosis and lung disease》2006,10(5):550-553
SETTING: Tuberculosis (TB) cases reported from nine districts of Madrid, where the percentage of immigrant population varied from 1.9% in 1996 to 12.2% in 2003. OBJECTIVE: To describe the trends in TB incidence from 1994 to 2003. DESIGN: Observational study. RESULTS: Between 1994-1995 and 2002-2003, the TB rate decreased from 48.5 (95% CI 45.8-51.1) to 23.3 per 100000 population (95% CI 21.5-25.1) (P < 0.001). The percentage of TB cases co-infected with HIV decreased from 55.9% in 1994 to 14.3% in 2003 (P < 0.001), whereas TB cases in foreigners increased from 2.6% in 1994 to 33.7% in 2003 (P < 0.001). CONCLUSION: Although the TB rates showed a marked decrease in the study period, the increasing impact of immigration contributed to slowing down the trend. 相似文献
64.
Marcondes C Fran?a Maria E Calcagnotto Jaderson C da Costa Iscia Lopes-Cendes 《Movement disorders》2006,21(7):1051-1053
Spinocerebellar ataxia (SCA) types 2 and 3 are autosomal-dominant neurodegenerative disorders caused by mutations in two different genes. We identified mutations for SCA2 and SCA3 segregating simultaneously in a single Brazilian family. The index patient had SCA2, whereas her two second-degree cousins had SCA3. Disease was more rapidly progressive in the SCA2 patient, who presented severe brainstem and pancerebellar atrophy, as opposed to the two SCA3 patients, who had only mild cerebellar vermian atrophy. In such situations, molecular confirmation of all patients may avoid misdiagnosis of SCA subtypes and eventual errors in predictive testing of unaffected family members. 相似文献
65.
o. goetze a. b. nikodem j. wiezcorek † m. banasch h. przuntek † t. mueller † w. e. schmidt & d. woitalla † 《Neurogastroenterology and motility》2006,18(5):369-375
Predictors of gastric emptying (GE) in patients with idiopathic Parkinson's disease (PD) of a solid and liquid meal are not well defined. For measurement of GE 80 patients with PD were randomly assigned to receive either a solid meal (250 kcal) containing 13C-octanoate (n = 40) or a liquid meal (315 kcal) with 13C-acetate (n = 40). All patient groups were off medication affecting motility and were matched for age, gender, body mass index, disease duration and severity, using Unified Parkinson's Disease Rating Scale (UPDRS). Gastric emptying was compared with a healthy control group (n = 40). Multiple regression analysis was used to determine predictors of gastric emptying. Exactly 88% and 38% of PD patients had delayed GE of solids and liquids respectively. Solid and liquid emptying was similar in women and men. There were no differences in GE in PD patients < 65 years of age when compared with patients > or = 65 years. Multiple regression analysis showed that motor handicaps such as rigour and action tremor are independent predictors of solid GE (r = 0.68, P < 0.001). The severity of motor impairment, but not any other neurological symptom, as assessed by UPDRS is associated with gastroparesis in PD and solid emptying is more likely to be delayed. 相似文献
66.
67.
68.
Adalberto Parra Jorge Ramírez-Peredo Rocío Hidalgo Amelia Morales-Toquero Gabriela Velásquez-Ramírez Alejandro Ruiz-Argüelles Guillermo J Ruiz-Argüelles 《Biology of blood and marrow transplantation》2006,12(5):566-572
We compared the functional status of the hypothalamic dopaminergic tone in patients given an allogeneic hematopoietic stem cell transplantation (allo-HSCT) with chronic graft-versus-host disease (GVHD) with that observed in patients with allo-HSCT without chronic GVHD and in healthy controls. The effect of acute dopaminergic blockade with intravenous metoclopramide on serum prolactin (PRL) concentrations was evaluated. Twenty volunteers, 20 to 52 years of age, seronegative for both hepatitis C virus and the human immunodeficiency virus, were studied: (1) 10 clinically healthy men (group 1), and (2) 9 patients with leukemia, and 1 patient with refractory aplastic anemia who underwent allo-HSCT, 5 of whom (3 men and 2 women) developed chronic GVHD (group 2), and 5 (3 men and 2 women) who did not develop chronic GVHD (group 3). Serum PRL concentrations were measured both fasting and after intravenous administration of metoclopramide (10-mg bolus). The area under the PRL curve was calculated. Patients in group 2 were older than those in groups 1 and 3 (P<.018), but their body mass index was similar. Fasting serum PRL concentrations were similar among the 3 groups; however, group 2 had higher PRL concentrations throughout the test (P<.001) and a greater area under the PRL curve than groups 1 and 3 (P<.001), without differences between the last 2 groups. The differences remained significant after adjustment for age (P<.01). Our results in a small group of patients with chronic GVHD after allo-HSCT suggest the existence of an increased functional level of their hypothalamic dopamine tone, which would favor a tendency toward a diminished endogenous production, release of pituitary PRL, or both. This could represent an adaptive mechanism aiming to maintain circulating PRL concentrations within a physiological range. 相似文献
69.
Effect of leptin on the regulation of placental hormone secretion in cultured human placental cells.
Raquel Coya Pedro Martul Jaime Algorta Ma Angeles Aniel-Quiroga Ma Angeles Busturia Rosa Se?arís 《Gynecological endocrinology》2006,22(11):620-626
Placenta is an important source of leptin during pregnancy that contributes to the high plasma leptin levels in pregnant women. Leptin and its functional receptors are synthesized in trophoblast cells that, in turn, secrete gestational hormones supporting a paracrine or autocrine role for leptin in the endocrine activity of the placenta. In the present study we examined the effect of leptin on in vitro release of gestational hormones (human chorionic gonadotropin (hCG), human placental lactogen (hPL), progesterone, estrogens and testosterone) by human term placental cells in culture. Placentas at term were obtained immediately after delivery from mothers with uncomplicated pregnancies. Progesterone, hCG, hPL, estradiol, estrone, estriol and testosterone levels were measured by different assays in culture media of cells maintained in monolayer culture after incubation for 12, 24, 48 or 72 h with leptin or placebo. Incubation with leptin did not modify hCG, hPL, progesterone, estriol and estrone secretion for any of the doses and times assayed. However, leptin led to a dose-dependent decrease in estradiol release. This effect was observed when treatment with recombinant human leptin spanned from 12 to 72 h. At this time an increase in testosterone levels was observed in leptin-treated cells versus placebo. These results indicate that leptin can be considered a gestational hormone implied in the endocrine function of the placenta, with an important role in control of the production of steroid reproductive hormones in placental cells in vitro. 相似文献
70.
Hugo Maia Julio Casoy Tania Correia Luís Freitas Kleber Pimentel Célia Athayde Elsimar Coutinho 《Gynecological endocrinology》2006,22(10):547-551
OBJECTIVES: To determine whether aromatase expression in the eutopic endometrium and adenomyotic foci is affected by previous use of oral contraceptives containing gestodene, and to determine whether changes in cyclooxygenase-2 (COX-2) expression occur in adenomyosis during the menstrual cycle. PATIENT AND METHODS: This was a retrospective cohort study carried out in paraffin-embedded endometrial tissue obtained from patients with a histological diagnosis of adenomyosis obtained during the proliferative (n = 25) and luteal (n = 10) phases of the menstrual cycle and following the use of continuous oral contraception with gestodene/ethinyl estradiol (n = 7). COX-2 and aromatase expression were measured in both eutopic endometrium and adenomyotic foci using immunohistochemical methods. RESULTS: Aromatase expression was detected in 80% of the endometrial slices by immunohistochemistry. In positive cases, aromatase was mainly detected in the stromal cells of the eutopic endometrium, whereas in the adenomyotic foci this expression was negative in the majority of the cases. Oral contraceptives containing gestodene, on the other hand, were effective in suppressing aromatase expression in both eutopic and ectopic endometrium. COX-2 expression was detected by immunohistochemistry in the glandular epithelium of both eutopic endometrium and adenomyotic foci and there were no significant changes in its intensity throughout the menstrual cycle. CONCLUSION: Aromatase expression in the eutopic endometrium and adenomyotic foci is suppressed by oral contraceptives containing gestodene. Increased aromatase activity may be responsible for the persistent COX-2 expression during the luteal phase. 相似文献