首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   176852篇
  免费   15419篇
  国内免费   5534篇
耳鼻咽喉   1096篇
儿科学   2825篇
妇产科学   1971篇
基础医学   9209篇
口腔科学   3191篇
临床医学   19485篇
内科学   24201篇
皮肤病学   3285篇
神经病学   8256篇
特种医学   4537篇
外国民族医学   44篇
外科学   13633篇
综合类   24493篇
现状与发展   27篇
一般理论   5篇
预防医学   8469篇
眼科学   2456篇
药学   37571篇
  95篇
中国医学   13650篇
肿瘤学   19306篇
  2024年   300篇
  2023年   3004篇
  2022年   4290篇
  2021年   7438篇
  2020年   7125篇
  2019年   6627篇
  2018年   6448篇
  2017年   7161篇
  2016年   7288篇
  2015年   7043篇
  2014年   12542篇
  2013年   17524篇
  2012年   11017篇
  2011年   11549篇
  2010年   9429篇
  2009年   8574篇
  2008年   8252篇
  2007年   8599篇
  2006年   7679篇
  2005年   6746篇
  2004年   5548篇
  2003年   5048篇
  2002年   4064篇
  2001年   3667篇
  2000年   3005篇
  1999年   2434篇
  1998年   2055篇
  1997年   1811篇
  1996年   1503篇
  1995年   1377篇
  1994年   1121篇
  1993年   888篇
  1992年   873篇
  1991年   728篇
  1990年   631篇
  1989年   544篇
  1988年   534篇
  1987年   491篇
  1986年   386篇
  1985年   439篇
  1984年   374篇
  1983年   276篇
  1982年   266篇
  1981年   241篇
  1980年   184篇
  1979年   175篇
  1978年   129篇
  1977年   87篇
  1976年   94篇
  1975年   79篇
排序方式: 共有10000条查询结果,搜索用时 58 毫秒
21.
22.
Major depressive disorder is a serious and common neuropsychiatric disorder that affects more than 350 million people worldwide. Electroconvulsive therapy is the oldest and most effective treatment available for the treatment of severe major depressive disorder. Electroconvulsive therapy modifies structural network changes in patients with major depressive disorder and schizophrenia. And it can also affect neuroinflammatory responses and may have neuroprotective effects. Electroconvulsive therapy plays an irreplaceable role in the treatment of major depressive disorder.  相似文献   
23.
24.
Metformin, a drug for type 2 diabetes mellitus, has shown therapeutic effects for various cancers. However, it had no beneficial effects on the survival rate of human malignant mesothelioma (HMM) patients. The present study was performed to elucidate the underlying mechanism of metformin resistance in HMM cells. Glucose‐starved HMM cells had enhanced resistance to metformin, demonstrated by decreased apoptosis and autophagy and increased cell survival. These cells showed abnormalities in mitochondria, such as decreased ATP synthesis, morphological elongation, altered mitochondrial permeability transition pore and hyperpolarization of mitochondrial membrane potential (MMP). Intriguingly, Mdr1 was significantly upregulated in mitochondria but not in cell membrane. The upregulated mitochondrial Mdr1 was reversed by treatment with carbonyl cyanide m‐chlorophenyl hydrazone, an MMP depolarization inducer. Furthermore, apoptosis and autophagy were increased in multidrug resistance protein 1 knockout HMM cells cultured under glucose starvation with metformin treatment. The data suggest that mitochondrial Mdr1 plays a critical role in the chemoresistance to metformin in HMM cells, which could be a potential target for improving its therapeutic efficacy.  相似文献   
25.
Adjuvant irradiation is the standard treatment after breast conservative surgery. Normofractionated regimen with an overall treatment time of 5 to 6 weeks is often considered as a limiting factor for irradiation compliance. In order to answer this issue, moderate and more recently extreme hypofractionated protocols appeared. We report here oncological outcomes and toxicity of hypofractionated breast irradiation. After defining the frame of moderate and extreme hypofractionated breast irradiations based on overall treatment time, patient selection criteria were listed. According to their levels of proof, the results of moderate and extreme hypofractionated breast irradiation were analysed. Overall treatment time for moderate hypofractionated breast irradiation ranged from 3 to 4 weeks, while for extreme hypofractionated breast irradiation, it was less than 1 week. For moderate hypofractionated breast irradiation, whole breast irradiation was currently performed with or without lymph node irradiation. Moderate hypofractionated breast irradiation has proven to be as safe and as efficient as normofractionated breast irradiation with level IA evidence. For extreme hypofractionated breast irradiation, phase III randomized trials confirmed that accelerated partial breast irradiation was non-inferior in terms of local control compared to normofractionated whole breast irradiation (with external beam radiation therapy and multicatheter brachytherapy), with similar acute and late toxicity. While the use of intraoperative breast irradiation remains under debate, new very accelerated partial breast irradiation (overall treatment time not exceeding 2 days) protocols emerged with encouraging results. Accelerated partial breast irradiation is warranted for extreme hypofractionated breast irradiation and is indicated for low-risk breast cancers. Moderate and extreme hypofractionated breast irradiation regimens are validated and can be routinely proposed according to patient selection criteria.  相似文献   
26.
27.
Menopause is generally experienced as a biopsychosocial process involving physiological changes, and influenced by a wide range of psychological, social and cultural factors. The loss of ovarian oestrogen production may cause debilitating symptoms, including hot flushes, night sweats, sleep disturbance, vaginal dryness, dyspareunia, bladder dysfunction, loss of libido, and mood changes. Experience of the menopause transition varies widely between individuals, depending on the age of onset, personal health and wellbeing, social context, environment and culture.Hormone Replacement Therapy (HRT) remains the most effective treatment for the management of vasomotor symptoms and vaginal dryness, but has no proven role in the treatment of chronic diseases of ageing. Treatment should be individualized, and for most healthy women aged 50–59 years the risks of HRT are low. An understanding of the pathophysiology of menopausal symptoms and the risks and benefits of both hormonal and non-hormonal treatments assists in the individual management of patients.  相似文献   
28.
29.
30.
  1. The common marmoset (Callithrix jacchus) is a useful experimental animal to evaluate the pharmacokinetics of drug candidates. Cytochrome P450 (P450) 2B enzyme in marmoset livers has been identified; however, only limited information on the enzymatic properties and distribution has been available.

  2. Marmoset P450 2B6 amino acids showed high sequence identities (>86%) with those of primates including humans and cynomolgus monkeys. Phylogenetic analysis using amino acid sequences indicated that marmoset P450 2B6 was closer to human and cynomolgus monkey P450 2B6 than to P450 2B orthologs of other species, including pigs, dogs, rabbits and rodents.

  3. Quantitative polymerase chain reaction analysis using specific primers showed P450 2B6 mRNA predominantly expressed in livers among the five marmoset tissues, similar to those of humans and cynomolgus monkeys.

  4. Marmoset P450 2B6 heterologously expressed in Escherichia coli membranes oxidized 7-ethoxycoumarin, pentoxyresorufin, propofol and testosterone, at roughly similar rates to those of humans and/or cynomolgus monkeys. A high capacity of marmoset P450 2B6 with propofol 4-hydroxylation (at low ionic strength conditions) with a low Km value was relatively comparable to that for marmoset livers.

  5. These results collectively indicated a high propofol 4-hydroxylation activity of P450 2B6 expressed in marmoset livers.

  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号