全文获取类型
收费全文 | 39764篇 |
免费 | 2761篇 |
国内免费 | 145篇 |
专业分类
耳鼻咽喉 | 257篇 |
儿科学 | 1373篇 |
妇产科学 | 915篇 |
基础医学 | 4608篇 |
口腔科学 | 735篇 |
临床医学 | 4146篇 |
内科学 | 8375篇 |
皮肤病学 | 767篇 |
神经病学 | 3948篇 |
特种医学 | 1286篇 |
外科学 | 6089篇 |
综合类 | 636篇 |
一般理论 | 60篇 |
预防医学 | 3215篇 |
眼科学 | 999篇 |
药学 | 2800篇 |
中国医学 | 41篇 |
肿瘤学 | 2420篇 |
出版年
2023年 | 124篇 |
2022年 | 206篇 |
2021年 | 600篇 |
2020年 | 385篇 |
2019年 | 636篇 |
2018年 | 763篇 |
2017年 | 608篇 |
2016年 | 617篇 |
2015年 | 793篇 |
2014年 | 1129篇 |
2013年 | 1706篇 |
2012年 | 2609篇 |
2011年 | 2812篇 |
2010年 | 1603篇 |
2009年 | 1458篇 |
2008年 | 2595篇 |
2007年 | 2811篇 |
2006年 | 2758篇 |
2005年 | 2850篇 |
2004年 | 2692篇 |
2003年 | 2481篇 |
2002年 | 2488篇 |
2001年 | 376篇 |
2000年 | 228篇 |
1999年 | 386篇 |
1998年 | 610篇 |
1997年 | 453篇 |
1996年 | 406篇 |
1995年 | 352篇 |
1994年 | 300篇 |
1993年 | 307篇 |
1992年 | 246篇 |
1991年 | 210篇 |
1990年 | 200篇 |
1989年 | 195篇 |
1988年 | 179篇 |
1987年 | 152篇 |
1986年 | 180篇 |
1985年 | 183篇 |
1984年 | 279篇 |
1983年 | 236篇 |
1982年 | 308篇 |
1981年 | 273篇 |
1980年 | 272篇 |
1979年 | 144篇 |
1978年 | 144篇 |
1977年 | 147篇 |
1976年 | 125篇 |
1974年 | 119篇 |
1973年 | 103篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
Yari Gvion Netta Horresh Yossi Levi-Belz Tsvi Fischel Ilan Treves Mark Weiser Haim Shem David Orit Stein-Reizer Alan Apter 《Comprehensive psychiatry》2014
Background
Unbearable mental pain, depression, and hopelessness have been associated with suicidal behavior in general, while difficulties with social communication and loneliness have been associated with highly lethal suicide attempts in particular. The literature also links aggression and impulsivity with suicidal behavior but raises questions about their influence on the lethality and outcome of the suicide attempt.Objectives
To evaluate the relative effects of aggression and impulsivity on the lethality of suicide attempts we hypothesized that impulsivity and aggression differentiate between suicide attempters and non-attempters and between medically serious and medically non-serious suicide attempters.Method
The study group included 196 participants divided into four groups: 43 medically serious suicide attempters; 49 medically non-serious suicide attempters, 47 psychiatric patients who had never attempted suicide; and 57 healthy control subjects. Data on sociodemographic parameters, clinical history, and details of the suicide attempts were collected. Participants completed a battery of instruments for assessment of aggression–impulsivity, mental pain, and communication difficulties.Results
The medically serious and medically non-serious suicide attempters scored significantly higher than both control groups on mental pain, depression, and hopelessness (p < .001 for all) and on anger-in, anger-out, violence, and impulsivity (p < .05 for all), with no significant difference between the two suicide attempter groups. Medically serious suicide attempters had significantly lower self-disclosure (p < .05) and more schizoid tendencies (p < .001) than the other three groups and significantly more feelings of loneliness than the medically non-serious suicide attempters and nonsuicidal psychiatric patients (p < .05). Analysis of aggression–impulsivity, mental pain, and communication variables with suicide lethality yielded significant correlations for self-disclosure, schizoid tendency, and loneliness. The interaction between mental pain and schizoid traits explained some of the variance in suicide lethality, over and above the contribution of each component alone.Conclusions
Aggression–impulsivity and mental pain are risk factors for suicide attempts. However, only difficulties in communication differentiate medically serious from medically non-serious suicide attempters. The combination of unbearable mental pain and difficulties in communication has a magnifying effect on the risk of lethal suicidal behavior. 相似文献993.
Smadar Nahaliel Eliane Sommerfeld Israel Orbach Aron Weller Alan Apter Gil Zalsman 《Comprehensive psychiatry》2014
Background
This study used path-analysis to examine the assumption that the presence of mental pain in adults mediates the relationship between self-destruction, number of losses experienced in one’s life, and suicidal tendency.Methods
Fifty suicidal inpatients, 50 non-suicidal inpatients and 50 healthy volunteers were assessed for self-destruction, losses experienced, depression, suicidal tendency, and mental pain.Results
Self-destruction was found to have both a direct effect on suicidal tendency as well as one mediated by the presence of mental pain. Number of losses effected suicidal tendency only indirectly, mediated by the presence of mental pain. Overall, self-destruction was a more significant determinant of suicidal tendency than were the number of losses experienced during one’s life. A competing model, with depression replacing mental pain as the mediator, was also found to fit the data.Discussion
These findings provide evidence that the presence of mental pain is a mediator in the relationships between both self-destruction and number of losses experienced, and between suicidal tendencies. More studies are needed in order to further differentiate between mental pain and depression as mediators in suicidal tendency. 相似文献994.
Alan E. Jones 《Chest》2012,141(5):1362-1363
995.
996.
One of the hallmarks of polycystic ovary syndrome (PCOS) is increased ovarian androgen secretion that contributes to the ovarian, hormonal, and metabolic features of this condition. Thecal cells from women with PCOS have an enhanced capacity for androgen synthesis. To investigate whether this propensity is a potential cause, rather than a consequence, of PCOS, we used an ovine prenatal androgenization model of PCOS and assessed ewes at 11 months of age. Pregnant Scottish Greyface ewes were administered 100 mg testosterone propionate (TP) or vehicle control twice weekly from d 62 to 102 of gestation, and female offspring (TP = 9, control = 5) were studied. Prenatal TP exposure did not alter ovarian morphology or cyclicity, or plasma androgen, estrogen, and gonadotropin concentrations, at this stage. However, follicle function was reprogrammed in vivo with increased proportions of estrogenic follicles (P < 0.05) in the TP-exposed cohort. Furthermore, in vitro the thecal cells of follicles (>4 mm) secreted more LH-stimulated androstenedione after prenatal androgenization (P < 0.05), associated with increased basal expression of thecal StAR (P < 0.01), CYP11A (P < 0.05), HSD3B1 (P < 0.01), CYP17 (P < 0.05), and LHR (P < 0.05). This provides the first evidence of increased thecal androgenic capacity in the absence of a PCOS phenotype, suggesting a thecal defect induced during fetal life. 相似文献
997.
Tartarin P Guibert E Touré A Ouiste C Leclerc J Sanz N Brière S Dacheux JL Delaleu B McNeilly JR McNeilly AS Brillard JP Dupont J Foretz M Viollet B Froment P 《Endocrinology》2012,153(7):3468-3481
AMP-activated protein kinase (AMPK), a key regulator of cellular energy homeostasis, is present in metabolic tissues (muscle and liver) and has been identified as a modulator of the female reproductive functions. However, its function in the testis has not yet been clearly defined. We have investigated the potential role of AMPK in male reproduction by using transgenic mice lacking the activity of AMPK catalytic subunit α1 gene [α1AMPK knockout (KO)]. In the testis, the α1AMPK subunit is expressed in germ cells and also in somatic cells (Sertoli and Leydig cells). α1AMPK KO male mice show a decrease in fertility, despite no clear alteration in the testis morphology or sperm production. However, in α1AMPK(-/-) mice, we demonstrate that spermatozoa have structural abnormalities and are less motile than in control mice. These spermatozoa alterations are associated with a 50% decrease in mitochondrial activity, a 60% decrease in basal oxygen consumption, and morphological defects. The α1AMPK KO male mice had high androgen levels associated with a 5- and 3-fold increase in intratesticular cholesterol and testosterone concentrations, respectively. High concentrations of proteins involved in steroid production (3β-hydroxysteroid dehydrogenase, cytochrome steroid 17 alpha-hydroxylase/17,20 lysate, and steroidogenic acute regulatory protein) were also detected in α1AMPK(-/-) testes. In the pituitary, the LH and FSH concentrations tended to be lower in α1AMPK(-/-) male mice, probably due to the negative feedback of the high testosterone levels. These results suggest that total α1AMPK deficiency in male mice affects androgen production and quality of spermatozoa, leading to a decrease in fertility. 相似文献
998.
999.
1000.