全文获取类型
收费全文 | 1058篇 |
免费 | 58篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 32篇 |
妇产科学 | 35篇 |
基础医学 | 144篇 |
口腔科学 | 23篇 |
临床医学 | 139篇 |
内科学 | 206篇 |
皮肤病学 | 15篇 |
神经病学 | 53篇 |
特种医学 | 30篇 |
外科学 | 129篇 |
综合类 | 28篇 |
预防医学 | 74篇 |
眼科学 | 55篇 |
药学 | 103篇 |
中国医学 | 8篇 |
肿瘤学 | 37篇 |
出版年
2024年 | 4篇 |
2023年 | 18篇 |
2022年 | 32篇 |
2021年 | 53篇 |
2020年 | 32篇 |
2019年 | 36篇 |
2018年 | 59篇 |
2017年 | 35篇 |
2016年 | 46篇 |
2015年 | 48篇 |
2014年 | 63篇 |
2013年 | 72篇 |
2012年 | 119篇 |
2011年 | 112篇 |
2010年 | 72篇 |
2009年 | 55篇 |
2008年 | 53篇 |
2007年 | 46篇 |
2006年 | 25篇 |
2005年 | 35篇 |
2004年 | 24篇 |
2003年 | 32篇 |
2002年 | 18篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有1120条查询结果,搜索用时 19 毫秒
51.
In this paper, a distributed model predictive control is proposed to control Lipschitz nonlinear systems. The cooperative distributed scheme is considered where a global infinite horizon objective function is optimized for each subsystem, exploiting the state and input information of other subsystems. Thus, each control law is obtained separately as a state feedback of all system's states by solving a set of linear matrix inequalities. Due to convexity of the design, convergence properties at each iteration are established. Additionally, the proposed algorithm is modified to optimize only one control input at a time, which leads to a further reduction in the computation load. Finally, two application cases are studied to show the effectiveness of the proposed method. 相似文献
52.
53.
Javad Yoosefi lebni Morteza Mansourian Mohammad Hossain Taghdisi Bahar Khosravi Arash Ziapour Gülcan Demir Özdenk 《Burns : journal of the International Society for Burn Injuries》2019,45(7):1715-1722
Self-immolation is one of the most painful methods of suicide which is widespread among women in Kurdish regions of Iran. The present study aimed to explore the causes and sociocultural groundwork of choosing self-immolation methods by women in Kurdish regions of Iran.This present study was conducted using a qualitative approach and conventional content analysis. The research population included women who self-immolated and were rescued in Kurdish regions of Iran. The data collection method was a deep interview as well as observation. The sampling method was based on objective and snowball sampling. The data collection continued to theoretical saturation, the number of participants reached 25 in the end, and Lincoln and Guba criteria were used to strengthen the research. From the analysis of the data obtained in this study, the 8 sub-themes related to cause of suicide attempt from the participants’ viewpoints including unbridled coherence, lack of supportive social and environmental structures, economic pressure, aggravation of violence, humiliated ego, dominance of modern values over the local and indigenous ones, incoherent family, and giving up on changing conditions as well as 6 sub themes based on the cause of choosing the method of self-immolation including protesting, frightening the family, catching more attention, championing and showing courage, inducing more guilty feelings in the family and society, fashion or imitation, and easy access were revealed. Self-immolation is one of the most important problems in the Kurdish regions of Iran, which is rooted in various economic, social, psychological and cultural causes. To reduce this social harm, there is a need for comprehensive programs that cover all dimensions. 相似文献
54.
Experimental Investigation of Left Ventricular Flow Patterns After Percutaneous Edge‐to‐Edge Mitral Valve Repair 下载免费PDF全文
Mitral valve percutaneous edge‐to‐edge repair (PEtER) is a viable solution in high‐risk patients with severe symptomatic mitral regurgitation. However, the generated double‐orifice configuration poses challenges for the evaluation of the hemodynamic performance of the mitral valve and may alter flow patterns in the left ventricle (LV) during diastole. This in vitro study aims to evaluate the hemodynamic modifications following a simulated PEtER. A custom‐made mitral valve was developed, and two configurations were tested: (i) a single‐orifice valve with mitral regurgitation and (ii) a double‐orifice mitral valve configuration following PEtER. The hemodynamic performance of the valve was evaluated using Doppler echocardiography and catheterization, while the flow patterns in the LV were investigated using particle image velocimetry (PIV). The tests were run at a stroke volume of 65 mL and a heart rate of 70 bpm. PEtER was found to significantly reduce the regurgitant volume (15 vs. 34 mL). There was a good agreement between Doppler and catheter transmitral pressure gradients (peak gradient: 9 vs. 7 mm Hg; mean gradient: 4 vs. 3 mm Hg) as well as an excellent agreement between maximal velocity measured by Doppler and PIV (1.60 vs. 1.58 m/s). Vortex development in the LV during diastole was significantly different after repair. PEtER significantly increased the amplitude of Reynolds and viscous shear stresses, as well as the number of high shear regions in the LV, potentially promoting thromboembolism events. 相似文献
55.
Morteza Mahdizadeh Masoumeh Masoumpour Hossein Ashraf 《Acta ophthalmologica. Supplement》2008,86(3):297-301
Purpose: To compare the anatomical results of scleral buckling with and without retinopexy and to assess the effect of retinopexy on the scleral buckling outcome. Methods: This randomized clinical trial was performed on 55 patients. Twenty‐two eyes were treated with scleral buckling (segmental or encircling) with or without drainage of subretinal fluid without any type of retinopexy (group 1); 33 patients received transscleral retinal cryopexy around retinal break(s) in addition to the former procedure. The two groups were matched regarding age, sex, myopia, aphakia, stage of proliferative vitroretinopathy (PVR) and number, type and location of the break(s). Results: In the non‐retinopexy group, 19 patients (86%) had complete retinal reattachment and one patient had partial reattachment after 34–48 months of follow‐up. One patient did not develop attachment because of missed break out of the buckle, and one had no attachment at all because of PVR. Overall success rate was 91% (20 of 22) in this group. In the retinal cryopexy group, 26 patients (79%) had complete retinal reattachment and two had partial reattachment during 35–56 months of follow‐up. In two patients, no attachment was achieved because of missed break out of the buckle; three patients developed redetachment after 1 and 3 months because of PVR. Overall success rate was 85% (28 of 33). The anatomical results in these two groups were the same statistically. Conclusion: With the permanent scleral buckling technique, retinal cryopexy adds no benefit to the success rate of anatomical retinal reattachment. 相似文献
56.
57.
Boshtam M Rafiei M Sadeghi K Sarraf-Zadegan N 《International journal for vitamin and nutrition research. Internationale Zeitschrift für Vitamin- und Ern?hrungsforschung. Journal international de vitaminologie et de nutrition》2002,72(5):309-314
This triple-blind placebo-controlled clinical trial was performed to determine the effects of the anti-oxidant vitamin E on blood pressure and heart rate in patients with mild hypertension. A total of 70 new mild hypertensive subjects (systolic blood pressure, SBP: 140-160 mmHg; diastolic blood pressure, DBP: 90-100 mmHg) without secondary hypertension were selected from among people referred to the Hypertension Unit of Isfahan Cardiovascular Research Center and divided randomly into two groups of drug (DG) and placebo (PG). All subjects were aged from 20 to 60 years old, without any other cardiovascular risk factors. The drug group received vitamin E tablets (200 IU/day) and the placebo group received placebo only for 27 weeks. At the beginning and the end of the study, the blood vitamin E level was measured fluorimetrically in all subjects according to the Hansen and Warwick method [14, 15]. Blood pressure and heart rate were measured at the beginning, during, and at the end of the study. Blood pressure was measured by a physician using one random zero mercury sphygmomanometer. Personal information and dietary habits of subjects were collected by separate questionnaire. At the end of the study, it was found that the vitamin E supplement had caused a remarkable decrease in SBP (-24% in DG versus -1.6% in PG) and a less remarkable decrease in DBP (-12.5% in DG versus -6.2% in PG) (p < 0.05). The change in heart rate was -4.3% in DG, and -14.0% in PG (p < 0.05). It is concluded that a vitamin E supplement of 200 IU/day can be effective in mild hypertensive patients in the long term, probably due to nitric oxide, and improve their blood pressure status. Therefore, vitamin E supplement could be recommended to such patients. 相似文献
58.
Javad Nasrollahzadeh Fereydoun Siassi Mahmood Doosti Mohammad Reza Eshraghian Fazel Shokri Mohammad Hossein Modarressi Javad Mohammadi-Asl Khosro Abdi Arash Nikmanesh Seyed Morteza Karimian 《Lipids in health and disease》2008,7(1):45
Background
Experimental studies indicate that gamma linolenic acid (GLA) and docosahexaenoic acid (DHA) may inhibit glioma cells growth but effects of oral consumption of these fatty acids on brain tumor fatty acid composition have not been determined in vivo. 相似文献59.
In this study, the effect of l-dopa and bromocriptine on morphine withdrawal syndrome was compared. Both l-dopa (125, 250 mg/kg, i.p.) and low doses of bromocriptine (0.04, 0.08 mg/kg, i.p.) potentiated naloxone-induced morphine withdrawal symptoms such as jumping, climbing and rearing in mice. Higher doses of bromocriptine (0.16, 0.32 mg/kg, i.p.) attenuated these naloxone-induced symptoms. SKF 83566, D(1) dopamine antagonist (0.4, 0.8 mg/kg, i.p.) and sulpiride, D(2) dopamine antagonist (5, 10 mg/kg, i.p.) when used alone, also produced inhibitory effects on naloxone-induced morphine withdrawal symptoms. Pretreatment with sulpiride (5, 10 mg/kg, i.p.) and SKF 83566 (0.4, 0.8 mg/kg, i.p.) attenuated the potentiating effects of l-dopa on withdrawal symptoms significantly. Pretreatment with sulpiride also decreased the potentiating effect of bromocriptine and reinforced the inhibitory action of it, but SKF 83566 pretreatment just reinforced the effect of higher doses of bromocriptine. Concurrent pretreatment of animals with sulpiride (10 mg/kg, i.p.) and SKF 83566 (0.8 mg/kg, i.p.) markedly decreased the potentiating effects of l-dopa and bromocriptine and reinforced the inhibitory action of bromocriptine on the naloxone-induced morphine withdrawal syndrome. Prazosin, alpha(1) antagonist (1, 2 mg/kg, i.p.) decreased the naloxone-induced morphine withdrawal syndrome significantly. Pretreatment with yohimbine, alpha(2)-antagonist (5 mg/kg, i.p.) reversed the inhibitory effects of bromocriptine (0.16, 0.32 mg/kg, i.p.) on naloxone-induced morphine withdrawal syndrome significantly. In conclusion, our results show that bromocriptine at lower doses (0.04, 0.08 mg/kg, i.p.) acts similar to l-dopa, but at higher doses (0.16, 0.32 mg/kg, i.p.) shows different effects on naloxone-induced morphine withdrawal syndrome which may be due to the interaction of bromocriptine with alpha-adrenoceptors. Copyright 2000 John Wiley & Sons, Ltd. 相似文献
60.
Behjati F Atri M Najmabadi H Nouri K Zamani M Mehdipour P 《Pathology oncology research : POR》2005,11(3):157-163
Breast cancer is amongst the leading causes of death in women worldwide and the most common cancer amongst Iranian women.
Unfortunately, the current clinical and histological criteria can only help 60 percent of women with breast cancer in diagnosis
and long-term treatment. Therefore, genetic markers both at single gene and chromosomal level can play an important role in
improving the diagnosis and prognosis of breast cancer patients. The aim of this retrospective study was to investigate the
role of chromosome 1 and 8 copy number assessed by interphase fluorescence in situ hybridization (FISH), as prognostic parameters
in 50 Iranian women, aged 35 to 64 years, with sporadic invasive ductal breast carcinoma. Chromosome 1 and 8 copy numbers
were evaluated in relation to established clinicopathological parameters, the immunohistochemical markers ER, PR, P53 and
cathepsin D, DNA index by flow cytometry, age and survival status of the patients. FISH using centromeric probes for chromosomes
1 and 8 was applied to interphase cell suspensions prepared from archived, Carnoyfixed tumor cells and selected paraffin-embedded
tumor sections. Aneusomy for chromosomes 1 and 8 was present in all 50 patients to different levels. The total abnormality
rate for chromosome 1 was 33.92 percent (4.24 percent monosomy and 29.68 percent polysomy), whereas for chromosome 8 this
rate was 28.30 percent (6.48 percent monosomy and 21.82 percent polysomy). Statistically significant association (p<0.05)
was demonstrated between monosomy 1 and patients’ age below 50 years, and between monosomy 1 and poor survival, respectively.
Disomy 8 was significantly associated with P53 expression. A borderline significant correlation was demonstrated between polysomy
8 and diploid DNA content, as well as between disomy 1 and disease-free status of the patients. Chromosome 1 and 8 copy numbers
may be considered as useful prognostic markers in invasive ductal carcinoma of the breast. 相似文献