全文获取类型
收费全文 | 10158篇 |
免费 | 554篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 123篇 |
儿科学 | 302篇 |
妇产科学 | 193篇 |
基础医学 | 1263篇 |
口腔科学 | 285篇 |
临床医学 | 998篇 |
内科学 | 1956篇 |
皮肤病学 | 91篇 |
神经病学 | 1101篇 |
特种医学 | 287篇 |
外科学 | 1400篇 |
综合类 | 49篇 |
一般理论 | 6篇 |
预防医学 | 839篇 |
眼科学 | 193篇 |
药学 | 785篇 |
中国医学 | 21篇 |
肿瘤学 | 850篇 |
出版年
2023年 | 47篇 |
2022年 | 79篇 |
2021年 | 145篇 |
2020年 | 144篇 |
2019年 | 181篇 |
2018年 | 235篇 |
2017年 | 191篇 |
2016年 | 212篇 |
2015年 | 229篇 |
2014年 | 295篇 |
2013年 | 538篇 |
2012年 | 653篇 |
2011年 | 671篇 |
2010年 | 390篇 |
2009年 | 366篇 |
2008年 | 639篇 |
2007年 | 635篇 |
2006年 | 656篇 |
2005年 | 607篇 |
2004年 | 568篇 |
2003年 | 549篇 |
2002年 | 532篇 |
2001年 | 112篇 |
2000年 | 65篇 |
1999年 | 105篇 |
1998年 | 120篇 |
1997年 | 111篇 |
1996年 | 101篇 |
1995年 | 112篇 |
1994年 | 92篇 |
1993年 | 96篇 |
1992年 | 74篇 |
1991年 | 92篇 |
1990年 | 64篇 |
1989年 | 67篇 |
1988年 | 58篇 |
1987年 | 50篇 |
1986年 | 48篇 |
1985年 | 70篇 |
1984年 | 79篇 |
1983年 | 54篇 |
1982年 | 82篇 |
1981年 | 73篇 |
1980年 | 38篇 |
1979年 | 30篇 |
1978年 | 37篇 |
1977年 | 52篇 |
1976年 | 30篇 |
1975年 | 33篇 |
1974年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Low-dose exposure of neonatal mice to nicotine has earlier been shown to induce an altered behavioral response to nicotine in adulthood. Organophosphorus insecticides are known to affect the cholinergic system by inhibition of acetylcholinesterase. This study was undertaken to investigate whether neonatal exposure to nicotine makes mice more susceptible to a known cholinergic agent. Neonatal, 10-day-old, male mice were exposed to nicotine-base (33 microg/kg body weight) or saline s.c. twice daily on five consecutive days. At 5 months of age the animals were exposed to paraoxon (0.17 or 0.25 mg/kg body weight [29% and 37% inhibition of cholinesterase, respectively]) or saline sc every second day for 7 days. Before the first paraoxon injection, the animals were observed for spontaneous motor behavior. The spontaneous motor behavior test did not reveal any differences in behavior between the treatment groups. Immediately after the spontaneous behavior test, the animals received the first injection of paraoxon and were observed for acute effects of paraoxon on spontaneous motor behavior. The acute response to paraoxon in the spontaneous motor behavior test was a decreased level of activity in mice neonatally exposed to nicotine. Control animals showed no change in activity. Two months after the paraoxon treatment, the animals were again tested for spontaneous motor behavior. Animals neonatally exposed to nicotine and exposed to paraoxon as adults showed a deranged spontaneous motor behavior, including hyperactivity and lack of habituation. 相似文献
92.
Rita K. Schmutzler Bjrn Schmitz-Luhn Bettina Borisch Peter Devilee Diana Eccles Per Hall Judith Balmaa Stefania Boccia Peter Dabrock Günter Emons Wolfgang Gaissmaier Jacek Gronwald Stefanie Houwaart Stefan Huster Karin Kast Alexander Katalinic Sabine C. Linn Sowmiya Moorthie Paul Pharoah Kerstin Rhiem Tade Spranger Dominique Stoppa-Lyonnet Johannes Jozef Marten van Delden Marc van den Bulcke Christiane Woopen 《Breast care (Basel, Switzerland)》2022,17(2):208
BackgroundRisk-adjusted cancer screening and prevention is a promising and continuously emerging option for improving cancer prevention. It is driven by increasing knowledge of risk factors and the ability to determine them for individual risk prediction. However, there is a knowledge gap between evidence of increased risk and evidence of the effectiveness and efficiency of clinical preventive interventions based on increased risk. This gap is, in particular, aggravated by the extensive availability of genetic risk factor diagnostics, since the question of appropriate preventive measures immediately arises when an increased risk is identified. However, collecting proof of effective preventive measures, ideally by prospective randomized preventive studies, typically requires very long periods of time, while the knowledge about an increased risk immediately creates a high demand for action.SummaryTherefore, we propose a risk-adjusted prevention concept that is based on the best current evidence making needed and appropriate preventive measures available, and which is constantly evaluated through outcome evaluation, and continuously improved based on these results. We further discuss the structural and procedural requirements as well as legal and socioeconomical aspects relevant for the implementation of this concept. 相似文献
93.
Sofie Stampe Magnus Leth-Mller Eva Greibe Elke Hoffmann-Lücke Michael Pedersen Per Ovesen 《Nutrients》2022,14(13)
Artificial sweeteners (ASs) are calorie-free chemical substances used instead of sugar to sweeten foods and drinks. Pregnant women with obesity or diabetes are often recommended to substitute sugary products with ASs to prevent an increase in body weight. However, some recent controversy surrounding ASs relates to concerns about the risk of obesity caused by a variety of metabolic changes, both in the mother and the offspring. This study addressed these concerns and investigated the biodistribution of ASs in plasma and breast milk of lactating women to clarify whether ASs can transfer from mother to offspring through breast milk. We recruited 49 lactating women who were provided with a beverage containing four different ASs (acesulfame-potassium, saccharin, cyclamate, and sucralose). Blood and breast milk samples were collected before and up to six hours after consumption. The women were categorized: BMI < 25 (n = 20), BMI > 27 (n = 21) and type 1 diabetes (n = 8). We found that all four ASs were present in maternal plasma and breast milk. The time-to-peak was 30–120 min in plasma and 240–300 min in breast milk. Area under the curve (AUC) ratios in breast milk were 88.9% for acesulfame-potassium, 38.9% for saccharin, and 1.9% for cyclamate. We observed no differences in ASs distributions between the groups. 相似文献
94.
95.
96.
Qing Du Oyvind Nass Per Bergsjo Bernadette Nirmal Kumar 《Health care for women international》2013,34(11):957-970
Our purpose of this study was to investigate determinants and patterns of associations with high maternal mortality in poor and multiethnic populations from the Xinjiang Uigur autonomous region of Western China. The researcher found that the maternal mortality ratio of Xinjiang was very high; almost half of the participants delivered at home without clean delivery, and nearly one-fifth of the participants had not received any medical treatment. Eighty-seven percent of maternal deaths were among ethnic minority groups. In multiethnic areas in Xinjiang, social–culture factors, lack of health resources, and low health services utilization were related to high maternal mortality. 相似文献
97.
It has been suggested that environmental exposures and living conditions can explain some of the worldwide variation in atopic disorders. Norway has large environmental contrasts within the country. We compared skin prick sensitization rates among school children living in the southern subarctic and in the northern artic part of Norway. Approximately one quarter of the children were sensitized, mostly against pollen and animal dander, while mite and mould sensitization seemed to be a minor problem. Sensitization rates and profiles were similar in the north and south despite differences in living conditions and environmental exposures. 相似文献
98.
Hanna Zirath Anna Frenzel Ganna Oliynyk Lova Segerstr?m Ulrica K. Westermark Karin Larsson Matilda Munksgaard Persson Kjell Hultenby Janne Lehti? Christer Einvik Sven P?hlman Per Kogner Per-Johan Jakobsson Marie Arsenian Henriksson 《Proceedings of the National Academy of Sciences of the United States of America》2013,110(25):10258-10263
The MYC genes are the most frequently activated oncogenes in human tumors and are hence attractive therapeutic targets. MYCN amplification leads to poor clinical outcome in childhood neuroblastoma, yet strategies to modulate the function of MYCN do not exist. Here we show that 10058-F4, a characterized c-MYC/Max inhibitor, also targets the MYCN/Max interaction, leading to cell cycle arrest, apoptosis, and neuronal differentiation in MYCN-amplified neuroblastoma cells and to increased survival of MYCN transgenic mice. We also report the discovery that inhibition of MYC is accompanied by accumulation of intracellular lipid droplets in tumor cells as a direct consequence of mitochondrial dysfunction. This study expands on the current knowledge of how MYC proteins control the metabolic reprogramming of cancer cells, especially highlighting lipid metabolism and the respiratory chain as important pathways involved in neuroblastoma pathogenesis. Together our data support direct MYC inhibition as a promising strategy for the treatment of MYC-driven tumors. 相似文献
99.
100.
Per Camner MD Klas Philipson MSc Lars Friberg MD 《Archives of environmental & occupational health》2013,68(2):82-87
Tracheobronchial clearance was studied with a lest aerosol of 6μ-7μ monodisperse fluorinated ethylene propylene (Teflon 120) particles tagged with technetium 99m (half-life, 6.0 hours) and external measurements of the radioactivity in the lungs. Nine pairs of monozygotic and nine pairs of dizygotic twins were studied. The clearance patterns in the monozygotic pairs were highly similar. In the dizygotic pairs there was a tendency to similarity. Among the pairs there was a remarkable difference in the clearance patterns, Consequently the result indicates that tracheobronchial clearance to a great extent is constitutionally determined. The medical implications of this are discussed. 相似文献