全文获取类型
收费全文 | 27624篇 |
免费 | 1905篇 |
国内免费 | 83篇 |
专业分类
耳鼻咽喉 | 235篇 |
儿科学 | 677篇 |
妇产科学 | 511篇 |
基础医学 | 4068篇 |
口腔科学 | 345篇 |
临床医学 | 2592篇 |
内科学 | 6676篇 |
皮肤病学 | 714篇 |
神经病学 | 2419篇 |
特种医学 | 822篇 |
外国民族医学 | 3篇 |
外科学 | 4040篇 |
综合类 | 283篇 |
一般理论 | 28篇 |
预防医学 | 2007篇 |
眼科学 | 504篇 |
药学 | 1720篇 |
1篇 | |
中国医学 | 56篇 |
肿瘤学 | 1911篇 |
出版年
2022年 | 147篇 |
2021年 | 364篇 |
2020年 | 243篇 |
2019年 | 383篇 |
2018年 | 466篇 |
2017年 | 323篇 |
2016年 | 375篇 |
2015年 | 444篇 |
2014年 | 668篇 |
2013年 | 1002篇 |
2012年 | 1460篇 |
2011年 | 1641篇 |
2010年 | 978篇 |
2009年 | 1001篇 |
2008年 | 1538篇 |
2007年 | 1716篇 |
2006年 | 1701篇 |
2005年 | 1805篇 |
2004年 | 1651篇 |
2003年 | 1579篇 |
2002年 | 1570篇 |
2001年 | 445篇 |
2000年 | 388篇 |
1999年 | 425篇 |
1998年 | 387篇 |
1997年 | 345篇 |
1996年 | 302篇 |
1995年 | 292篇 |
1994年 | 266篇 |
1993年 | 241篇 |
1992年 | 344篇 |
1991年 | 330篇 |
1990年 | 312篇 |
1989年 | 275篇 |
1988年 | 239篇 |
1987年 | 228篇 |
1986年 | 251篇 |
1985年 | 245篇 |
1984年 | 231篇 |
1983年 | 205篇 |
1982年 | 228篇 |
1981年 | 234篇 |
1980年 | 187篇 |
1979年 | 159篇 |
1978年 | 144篇 |
1977年 | 152篇 |
1976年 | 123篇 |
1975年 | 119篇 |
1974年 | 115篇 |
1973年 | 113篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
The aim of the present work was to assess the effects of long-term exposure to Cd on the sulfatation of glomerular membranes and their relation with proteinuria and urinary glycosaminoglycans (GAG). For this purpose the in vitro incorporation of [35S]sulfate was investigated in female Sprague-Dawley rats given 100 ppm of Cd in drinking water for 7 months. When compared with their controls, glomeruli from Cd-treated rats showed a 12.8% decrease in the incorporation of the label into glomerular membranes. This effect, which was not explained by differences in viability or in sulfate uptake by the glomeruli, suggests that sulfatation of glomerular membranes is impaired in Cd-treated rats. In support of this, in another independent experiment, a decrease, 17.4% on average, of the sulfate content of glomerular membranes was observed in long-term Cd-treated rats (100 ppm in drinking water for 4 months). This effect was significantly correlated with albuminuria and transferrinuria but not with beta 2-microglobinuria, suggesting that a loss of heparan sulfate of the glomerular capillary wall could be involved in the Cd-induced glomerular proteinuria. On the other hand an enhanced urinary excretion of GAG, negatively correlated with the sulfate content of glomerular membranes, was also observed in Cd-treated rats. Moreover GAG excretion was associated with tubular and glomerular proteinuria, which suggests that GAG might be a useful marker of Cd-induced nephrotoxicity. 相似文献
73.
Antoine Feydy MD PhD Alexandre Krainik MD Bernard Bussel MD Marc A. Maier PhD 《Journal of neuroimaging》2004,14(1):49-53
The authors report the case of a 33-year-old woman who exhibited, at the age of 17, a left-sided hemiplegia, which was followed by good motor recovery, though with a permanent deficit in fine finger movements. She had a widespread loss of neural tissue in the right hemisphere (crossed cerebrocerebellar atrophy), including (1) marked atrophy and thinning of the precentral and postcentral gyri; (2) widespread deep white matter destruction, including the corticospinal tract; and (3) crossed cerebellar atrophy. Except over the supplementary motor area (SMA), transcranial magnetic stimulation did not elicit motor evoked potentials in the affected hand. Nevertheless, during opening and closing of the affected hand, functional magnetic resonance imaging showed an activation of the lesioned primary sensorimotor cortex (SMC), as well as of the intact SMA and the parietal areas, but not of the ipsilateral motor areas. The authors speculate that recovery was achieved by a motor command generated in the SMC and the parietal cortex, passing through corticospinal axons originating in the SMA. 相似文献
74.
M C Richardson D W Davies R H Watson M L Dunsford C B Inman G M Masson 《Human reproduction (Oxford, England)》1992,7(1):12-18
In primates, corpus luteum development involves both gonadotrophin stimulation and exposure to low density lipoprotein (LDL) delivered through vascularization of the granulosa cell-derived layer. These regulatory influences were modelled in vitro using granulosa cells obtained during in-vitro fertilization (IVF) cycles controlled with gonadotrophin releasing hormone (GnRH) analogue, human menopausal gonadotrophin (HMG) and human chorionic gonadotrophin (HCG). Granulosa cells were cultured in defined medium on extracellular matrix. Without gonadotrophin or LDL in the medium, progesterone production declined progressively. With LDL alone, there was a short-lived elevation of progesterone output which subsequently declined. Culture with HCG alone resulted in a relatively unchanged rate of steroid production over 5 days despite morphological development. This contrasted with a marked and sustained increase in progesterone output over the same time when granulosa cells were cultured with combined HCG/LDL. Cultures were challenged with combined HCG/LDL on day 5. Where initial incubation included HCG, the challenge resulted in a recovery of progesterone output to values comparable to those of granulosa cells exposed to continuous HCG/LDL. Initial incubation without gonadotrophin led to a reduced response. Results suggest that LDL delivery to granulosa cells of the early corpus luteum causes a short-lived period of progesterone production. Sustained luteinization of granulosa cells and maintenance of gonadotrophin responsiveness requires continued exposure to gonadotrophin in the luteal phase. 相似文献
75.
76.
Melissa Kang Diana Bernard Michael Booth Susan Quine Garth Alperstein Tim Usherwood David Bennett 《The British journal of general practice》2003,53(497):947-952
BACKGROUND: To adequately address the complex health needs of young people, their access to services, and the quality of services received, must be improved. AIMS: To explore the barriers to service provision for young people and to identify the training needs of primary healthcare service providers in New South Wales (NSW), Australia. DESIGN OF STUDY: A cross-sectional, qualitative study of the perspectives of a range of health service providers. SETTING: A range of primary healthcare organisations across NSW. METHODS: Samples of general practitioners (GPs), youth health workers, youth health coordinators, and community health centre staff were drawn from urban and rural clusters across NSW. Focus groups and interviews were used to identify barriers to service provision and the training needs of service providers. Data were tape recorded, transcribed, and analysed. RESULTS: Barriers to service provision among GPs and community health centre staff included inadequate time, flexibility, skills, and confidence in working with young people, and poor linkages with other relevant services. Training needs included better knowledge of and skills in adolescent health requirements, working with adolescents, and working with other services. Barriers to service provision for youth health workers and coordinators included lack of financial resources and infrastructure. There were few linkages between groups of service providers. CONCLUSION: Models of service provision that allow stronger linkages between service providers, sufficient time for consultation with young people, adequate training and support of health professionals, and flexibility of service provision, including outreach, should be explored and evaluated. 相似文献
77.
78.
A Menget A Burguet C Fromentin Y Bernard N Cardot 《Archives fran?aises de pédiatrie》1989,46(9):701-702
Through the case report of severe digitalis intoxication in a premature born after 27 weeks of gestation with a birthweight of 800 g, the authors show that anti-digoxin antibodies constitute a very efficacious therapeutic tool which, up to the present, has not been used in prematures. 相似文献
79.
The issue of the preparation of effective teachers becomes more critical for teachers of early childhood programs. It has been hypothesized that better program quality depends on better-educated teachers. The purpose of this investigation was to explore the importance of a high level of education for all early childhood education teachers. This issue has intrigued early childhood researchers and has prompted a large amount of research studies over the past decades. In order to assess the status of this line of inquiry and to provide guidance for future research, a critical analysis of 40 studies on the preparation of early childhood education teachers and the quality of their educational programs that were published within a 15-year (1989-2004) period is presented here. The analysis consisted of literal and allegorical critical analysis and interpretative critical analyses, which generated results in three main areas that focused on the professional development of the teachers, including teachers' professional development, the importance of a Bachelor's Degree and educational standards for early childhood education teachers. 相似文献
80.