全文获取类型
收费全文 | 13280篇 |
免费 | 959篇 |
国内免费 | 168篇 |
专业分类
耳鼻咽喉 | 94篇 |
儿科学 | 444篇 |
妇产科学 | 406篇 |
基础医学 | 1790篇 |
口腔科学 | 273篇 |
临床医学 | 1175篇 |
内科学 | 2559篇 |
皮肤病学 | 215篇 |
神经病学 | 921篇 |
特种医学 | 461篇 |
外科学 | 2283篇 |
综合类 | 635篇 |
一般理论 | 4篇 |
预防医学 | 728篇 |
眼科学 | 349篇 |
药学 | 791篇 |
1篇 | |
中国医学 | 79篇 |
肿瘤学 | 1199篇 |
出版年
2023年 | 134篇 |
2022年 | 183篇 |
2021年 | 342篇 |
2020年 | 236篇 |
2019年 | 312篇 |
2018年 | 336篇 |
2017年 | 263篇 |
2016年 | 294篇 |
2015年 | 352篇 |
2014年 | 443篇 |
2013年 | 549篇 |
2012年 | 860篇 |
2011年 | 918篇 |
2010年 | 554篇 |
2009年 | 483篇 |
2008年 | 724篇 |
2007年 | 706篇 |
2006年 | 718篇 |
2005年 | 713篇 |
2004年 | 670篇 |
2003年 | 593篇 |
2002年 | 554篇 |
2001年 | 526篇 |
2000年 | 418篇 |
1999年 | 353篇 |
1998年 | 125篇 |
1997年 | 120篇 |
1996年 | 97篇 |
1995年 | 91篇 |
1994年 | 67篇 |
1993年 | 62篇 |
1992年 | 167篇 |
1991年 | 149篇 |
1990年 | 163篇 |
1989年 | 162篇 |
1988年 | 136篇 |
1987年 | 139篇 |
1986年 | 108篇 |
1985年 | 86篇 |
1984年 | 53篇 |
1983年 | 44篇 |
1981年 | 34篇 |
1980年 | 29篇 |
1979年 | 52篇 |
1978年 | 37篇 |
1977年 | 32篇 |
1976年 | 26篇 |
1975年 | 25篇 |
1974年 | 21篇 |
1973年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Jeremy Yuen-Chun Teoh Terry Cheuk-Fung Yip Grace Chung-Yan Lui Vincent Wai-Sun Wong Viola Chi-Ying Chow Tracy Hang-Yee Ho Timothy Chun-Man Li Yee-Kit Tse Peter Ka-Fung Chiu Chi-Fai Ng David Shu-Cheong Hui Henry Lik-Yuen Chan Cheuk-Chun Szeto Grace Lai-Hung Wong 《Journal of the American Society of Nephrology : JASN》2021,32(4):961
BackgroundSevere acute respiratory syndrome (SARS) and coronavirus disease 2019 (COVID-19) are closely related. The effect of AKI on the clinical outcomes of these two conditions is unclear.MethodsThis retrospective, territory-wide cohort study used an electronic public healthcare database in Hong Kong to identify patients with SARS or COVID-19 by diagnosis codes, virologic results, or both. The primary endpoint was a composite of intensive care unit admission, use of invasive mechanical ventilation, and/or death.ResultsWe identified 1670 patients with SARS and 1040 patients with COVID-19 (median ages, 41 versus 35 years, respectively). Among patients with SARS, 26% met the primary endpoint versus 5.3% of those with COVID-19. Diabetes mellitus, abnormal liver function, and AKI were factors significantly associated with the primary endpoint among patients with either SARS or COVID-19. Among patients with SARS, 7.9%, 2.1%, and 3.7% developed stage 1, stage 2, and stage 3 AKI, respectively; among those with COVID-19, 6.6%, 0.4%, and 1.1% developed stage 1, stage 2, and stage 3 AKI, respectively. In both groups, factors significantly associated with AKI included diabetes mellitus and hypertension. Among patients with AKI, those with COVID-19 had a lower rate of major adverse clinical outcomes versus patients with SARS. Renal function recovery usually occurred within 30 days after an initial AKI event.ConclusionsAKI rates were higher among patients with SARS than those with COVID-19. AKI was associated with major adverse clinical outcomes for both diseases. Patients with diabetes mellitus and abnormal liver function were also at risk of developing severe consequences after SARS and COVID-19 infection. 相似文献
63.
64.
Cloning and Characterization of the Rat Gene Encoding GAP-43 总被引:1,自引:0,他引:1
Grabczyk E Zuber MX Federoff HJ Ng SC Pack A Fishman MC 《The European journal of neuroscience》1990,2(10):822-827
65.
Summary Ovulation was induced in immature mice by injections of pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG) spaced 48 hours apart. The mice were divided into six groups: one group received intraperitoneal injections of normal saline, another group received alcoholic saline which was used as the vehicle of pineal indoles, and the remaining groups received respectively hydroxyindoleacetic acid (HIAA), melatonin (MEL), methoxytryptamine (MTA) and methoxytryptophol (MTP). The pineal indoles were administered 24 hours before, on the same day as, 24 hours after and 48 hours after the PMSG injection. The mice were sacrificed 24 hours after the HCG injection. The numbers of growing primary follicles, multilaminar primary follicles, Graafian follicles, preovulatory follicles and corpora lutea in the ovary were not altered by treatment with pineal indoles. However, there was an increased incidence of follicular atresia in the groups treated with MEL, MTA and MTP. The pineal indoles did not affect the number of ovulated oocytes, but there was a large number of degenerated and fragmented ovulated oocytes in the MTA- and MTP-treated groups. Treatment with MEL, MTA and MTP also resulted in lower plasma levels of estradiol-17 and progesterone. 相似文献
66.
We determined if we could transfer X-radiation resistance from CHO AA8 cells to their radiosensitive, mutant V3 cells by several methods. These methods include co-incubating the two cell lines for three days before irradiation, adding heavily-irradiated AA8 to V3 cells following irradiation of the latter and then co-incubating these cells for at least eight days during the colony-forming assay and lastly, adding conditioned medium from unirradiated, subconfluent AA8 cells to V3 cultures and incubating for two days before irradiation. None of these procedures enhanced the clonogenic survival of the V3 cells to a single dose of 4 Gy X-radiation. Adding heavily-irradiated V3, instead of AA8, cells did not increase the clonogenic survival of the 4 Gy-irradiated V3 cells either, indicating that there was no autocrine mode of action. Moreover, adding conditioned medium from a related CHO cell line, K1, to its own radiosensitive, mutant 5-11 and incubating for two days before irradiation did not enhance clonogenic survival of the latter to a single dose of 3 Gy X-radiation. We therefore conclude that it is unlikely that CHO cells have the X-radiation resistance factor that has been reported in some mouse melanoma cell lines by other investigators. 相似文献
67.
68.
J Ponsford C Willmott A Rothwell P Cameron G Ayton R Nelms C Curran K T Ng 《The Journal of head trauma rehabilitation》1999,14(4):360-372
OBJECTIVES: To investigate outcome in children with mild traumatic head injury (THI) at 1 week and 3 months postinjury and to identify factors associated with persisting problems. DESIGN: Postconcussional symptomatology, behavior ratings, and neuropsychological test performance were examined at 1 week and 3 months postinjury. SETTING: Participants were recruited from successive presentations to emergency departments of two major hospitals. PARTICIPANTS: 130 Children with mild THI were compared with 96 children having other minor injuries as controls. RESULTS: Children with mild THI experienced headaches, dizziness, and fatigue but exhibited no cognitive impairments, relative to controls, at 1 week postinjury. By 3 months, symptoms had resolved. However, 17% of children showed significant ongoing problems. They were more likely to have a history of previous head injury, learning difficulties, neurological or psychiatric problems, or family stressors. CONCLUSIONS: Persisting problems following mild head injury in children are more common in those with previous head injury, preexisting learning difficulties, or neurological, psychiatric, or family problems. These "at-risk" children should be identified in the emergency department and monitored. 相似文献
69.
Dopamine (DA) release in the striatum is regulated by 5-hydroxytryptamine (5-HT, serotonin) through putative heteroreceptors. However, the effect of 5-HT is controversial. The present study investigated the effects of different 5-HT receptor ligands on DA release in the rat striatum by using in vivo microdialysis in conscious and freely moving rats. Perfusion with 5-carboxamidotryptamine, anpirtoline, pindobind-5-HT1A, and isamoltane demonstrated the involvement of 5-HT1A and 5-HT1B receptors in facilitating DA release. In contrast, 5-HT2 receptors mediated inhibition of DA efflux, as shown by experiments with DOI [R-(-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane] and ketanserin. A 5-HT3 agonist (1-(m-chlorophenyl)-biguanide hydrochloride) did not have any effect. None of the agonists used affected DA uptake into striatal synaptosomes. Unilateral 6-hydroxydopamine lesioning of the nigrostriatal DA pathway led to a selective decrease in 5-HT2 receptors. It is concluded that there are 5-HT2 heteroreceptors at the dopaminergic terminals that mediate inhibition of DA release. Further investigation is required to clarify the localization of the 5-HT1 receptors in the striatum. 相似文献
70.