全文获取类型
收费全文 | 7348篇 |
免费 | 387篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 81篇 |
儿科学 | 208篇 |
妇产科学 | 157篇 |
基础医学 | 856篇 |
口腔科学 | 314篇 |
临床医学 | 539篇 |
内科学 | 1610篇 |
皮肤病学 | 215篇 |
神经病学 | 660篇 |
特种医学 | 138篇 |
外科学 | 1182篇 |
综合类 | 37篇 |
一般理论 | 2篇 |
预防医学 | 665篇 |
眼科学 | 217篇 |
药学 | 387篇 |
中国医学 | 60篇 |
肿瘤学 | 432篇 |
出版年
2023年 | 59篇 |
2022年 | 108篇 |
2021年 | 244篇 |
2020年 | 144篇 |
2019年 | 193篇 |
2018年 | 242篇 |
2017年 | 145篇 |
2016年 | 168篇 |
2015年 | 189篇 |
2014年 | 281篇 |
2013年 | 334篇 |
2012年 | 599篇 |
2011年 | 544篇 |
2010年 | 326篇 |
2009年 | 298篇 |
2008年 | 507篇 |
2007年 | 533篇 |
2006年 | 441篇 |
2005年 | 456篇 |
2004年 | 405篇 |
2003年 | 362篇 |
2002年 | 361篇 |
2001年 | 74篇 |
2000年 | 55篇 |
1999年 | 54篇 |
1998年 | 52篇 |
1997年 | 33篇 |
1996年 | 38篇 |
1995年 | 32篇 |
1994年 | 23篇 |
1993年 | 24篇 |
1992年 | 28篇 |
1991年 | 23篇 |
1990年 | 25篇 |
1989年 | 27篇 |
1988年 | 27篇 |
1987年 | 22篇 |
1986年 | 19篇 |
1985年 | 19篇 |
1984年 | 22篇 |
1983年 | 21篇 |
1982年 | 22篇 |
1981年 | 18篇 |
1980年 | 18篇 |
1979年 | 32篇 |
1978年 | 18篇 |
1977年 | 10篇 |
1976年 | 10篇 |
1975年 | 14篇 |
1974年 | 11篇 |
排序方式: 共有7760条查询结果,搜索用时 46 毫秒
1.
2.
Effect of leptin on the regulation of placental hormone secretion in cultured human placental cells.
Raquel Coya Pedro Martul Jaime Algorta Ma Angeles Aniel-Quiroga Ma Angeles Busturia Rosa Se?arís 《Gynecological endocrinology》2006,22(11):620-626
Placenta is an important source of leptin during pregnancy that contributes to the high plasma leptin levels in pregnant women. Leptin and its functional receptors are synthesized in trophoblast cells that, in turn, secrete gestational hormones supporting a paracrine or autocrine role for leptin in the endocrine activity of the placenta. In the present study we examined the effect of leptin on in vitro release of gestational hormones (human chorionic gonadotropin (hCG), human placental lactogen (hPL), progesterone, estrogens and testosterone) by human term placental cells in culture. Placentas at term were obtained immediately after delivery from mothers with uncomplicated pregnancies. Progesterone, hCG, hPL, estradiol, estrone, estriol and testosterone levels were measured by different assays in culture media of cells maintained in monolayer culture after incubation for 12, 24, 48 or 72 h with leptin or placebo. Incubation with leptin did not modify hCG, hPL, progesterone, estriol and estrone secretion for any of the doses and times assayed. However, leptin led to a dose-dependent decrease in estradiol release. This effect was observed when treatment with recombinant human leptin spanned from 12 to 72 h. At this time an increase in testosterone levels was observed in leptin-treated cells versus placebo. These results indicate that leptin can be considered a gestational hormone implied in the endocrine function of the placenta, with an important role in control of the production of steroid reproductive hormones in placental cells in vitro. 相似文献
3.
Ronald Martin Jaime Williams Thomas Hadjistavropoulos Heather D Hadjistavropoulos Michael MacLean 《Revue canadienne de recherche en sciences infirmières》2005,37(2):142-164
The literature suggests that pain in the elderly, especially among seniors with dementia, is under-assessed and under-treated.This qualitative study solicited the perspectives of seniors, front-line nursing staff, nursing-home administrators, and informal caregivers of seniors with dementia on the current status of pain assessment and management. The views of these participants complement the research findings reported in the literature. While some of their explanations and potential solutions concerning under-treatment of pain in seniors echo views that have been presented in the literature, the participants also pointed to factors and avenues that have been given less formal consideration (e.g., systemic barriers to effective assessment and treatment of pain).They also highlighted the need for pain-control strategies beyond medication. The implications of these findings are discussed. 相似文献
4.
Marta Méndez-López Magdalena Méndez Fernando Sánchez-Patán Isabel Casado Maria-Angeles Aller Laudino López Maria-Teresa Corcuera Maria-Jose Alonso Maria-Paz Nava Jaime Arias Jorge-Luis Arias 《Journal of gastrointestinal surgery》2007,11(2):187-194
To obtain a new model of chronic portal hypertension in the rat, two classical methods to produce portal hypertension, partial portal vein ligation and the oral administration of thioacetamide (TAA), have been combined. Male Wistar rats were divided into four groups: 1 (control; n?=?10), 2 [triple partial portal vein ligation (TPVL); n?=?9], 3 (TAA; n?=?11), and 4 (TPVL plus TAA; n?=?9). After 3 months, portal pressure, types of portosystemic collateral circulation, laboratory hepatic function tests (aspartate aminotransferase, alanine aminotransferase, bilirubin, alkaline phosphatase, and gamma-glutamyl transpeptidase) and liver histology were studied. The animals belonging to group 2 (TPVL) developed extrahepatic portosystemic collateral circulation, associated with mesenteric venous vasculopathy without hepatic destructurization or portal hypertension. Animals from group 3 (TAA) developed cirrhosis and portal hypertension but not extrahepatic portosystemic collateral circulation, or mesenteric venous vasculopathy. Finally, the animals from group 4 (TPVL?+?TAA) developed cirrhosis, portal hypertension, portosystemic collateral circulation, and mesenteric venous vasculopathy. The association of TPVL and TAA can be used to obtain a model of chronic portal hypertension in the rat that includes all the alterations that patients with hepatic cirrhosis usually have. This could, therefore, prove to be a useful tool to study the pathophysiological mechanisms involved in these alterations. 相似文献
5.
Birgit T Priest Kenneth M Blumenthal Jaime J Smith Vivien A Warren McHardy M Smith 《Toxicon》2007,49(2):194-201
The tarantula venom peptides ProTx-I and ProTx-II inhibit voltage-gated sodium channels by shifting their voltage dependence of activation to a more positive potential, thus acting by a mechanism similar to that of potassium channel gating modifiers such as hanatoxin and VSTX1. ProTx-I and ProTx-II inhibit all sodium channel (Nav1) subtypes tested with similar potency and represent the first potent peptidyl inhibitors of TTX-resistant sodium channels. Like gating modifiers of potassium channels, ProTx-I and ProTx-II conform to the inhibitory cystine knot motif, and ProTx-II was demonstrated to bind to sodium channels in the closed state. Both toxins have been synthesized chemically, and ProTx-II, produced by recombinant means, has been used to map the interaction surface of the peptide with the Nav1.5 channel. In comparison, beta-scorpion toxins activate sodium channels by shifting the voltage dependence of activation to more negative potentials, and together these peptides represent valuable tools for exploring the gating mechanism of sodium channels. 相似文献
6.
7.
This study examines how acute hand injuries affect patients in their roles as spouse, caregiver, and/or worker. Qualitative data from patient interviews were used to analyze how these life roles were affected by the individuals' hand injuries. Data were extracted from interviews of three hand patients who had one or more roles of spouse, caregiver, and/or worker affected by their injury. Data were then examined and categorized for each life role by participant. Participants' views of how hand therapy affected their recovery and resumption of occupational role performance were also examined. Results showed that the participants expressed profound degrees of change in their ability to perform satisfactorily in their various life roles. 相似文献
8.
Metastatic tumors to the oral cavity are uncommon. Most of these cases involve the mandible or the maxilla. Rarely, metastasis occurs to the oral soft tissues from a distant primary tumor. The lung and breast are the most common primary sites. It is extremely rare to have an oral soft-tissue metastasis from a carcinoma of the colon. A case of primary adenocarcinoma of the colon with metastasis to the soft tissues of the mouth is described. Three similar case reports are reviewed. A metastatic lesion to the oral cavity could be the first indication of the presence of a primary tumor. 相似文献
9.
10.