全文获取类型
收费全文 | 4063篇 |
免费 | 295篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 74篇 |
妇产科学 | 77篇 |
基础医学 | 560篇 |
口腔科学 | 67篇 |
临床医学 | 379篇 |
内科学 | 936篇 |
皮肤病学 | 81篇 |
神经病学 | 270篇 |
特种医学 | 130篇 |
外科学 | 565篇 |
综合类 | 79篇 |
一般理论 | 2篇 |
预防医学 | 329篇 |
眼科学 | 237篇 |
药学 | 296篇 |
中国医学 | 29篇 |
肿瘤学 | 242篇 |
出版年
2024年 | 9篇 |
2023年 | 52篇 |
2022年 | 129篇 |
2021年 | 208篇 |
2020年 | 155篇 |
2019年 | 189篇 |
2018年 | 230篇 |
2017年 | 155篇 |
2016年 | 175篇 |
2015年 | 162篇 |
2014年 | 190篇 |
2013年 | 257篇 |
2012年 | 376篇 |
2011年 | 364篇 |
2010年 | 231篇 |
2009年 | 179篇 |
2008年 | 257篇 |
2007年 | 246篇 |
2006年 | 195篇 |
2005年 | 132篇 |
2004年 | 122篇 |
2003年 | 105篇 |
2002年 | 65篇 |
2001年 | 16篇 |
2000年 | 20篇 |
1999年 | 17篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有4395条查询结果,搜索用时 15 毫秒
991.
Zamani S Vazirian M Nassirimanesh B Razzaghi EM Ono-Kihara M Mortazavi Ravari S Gouya MM Kihara M 《AIDS and behavior》2010,14(4):885-890
This study was conducted to compare needle and syringe sharing practices among injecting drug users (IDUs) in two neighborhoods,
one with and one without a needle and syringe program (NSP). In 2005, 419 street-based IDUs were interviewed at specific locations
in two neighborhoods where IDUs are known to congregate. We compared self-reported needle and syringe access and use between
IDUs from a neighborhood with an active NSP to IDUs from a neighborhood without such an intervention. A significantly smaller
proportion of IDUs from the former neighborhood reported having used a shared needle/syringe over a 1-month period (21.0%)
compared to IDUs from the latter neighborhood (39.9%; adjusted odds ratio, 0.24; 95% confidence interval, 0.13–0.45). These
findings indicate that access to an NSP may reduce needle and syringe sharing practices. Therefore, these programs should
be intensified in settings with concentrated HIV epidemics among IDUs in Iran. 相似文献
992.
Mohammad J. Kaviani Mohsen Pirastehfar Ali Azari Mehdi Saberifiroozi 《Saudi Journal Of Gastroenterology》2010,16(4):253-259
Background/Aim:
The prevalence of acute upper gastrointestinal bleeding (AUGIB) has undergone a change after implementation of eradication therapy for Helicobacter pylori in peptic ulcers effective prevention of esophageal variceal bleeding and eventually, progressive use of low dose aspirin and other nonsteroidal antiinflammatory drugs (NSAIDs). To evaluate this subject, we performed a prospective study in two main University Hospitals of Shiraz (the largest city of southern Iran).Materials and Methods:
All adults who were admitted in emergency room with impression of AUGIB and existing patients who developed AUGIB were included in the study. Gastroscopy was done with a follow-up for the next 15 days.Results:
572 patients (mean age: 54.9 years) entered in the study. The most common presenting symptom was hematemesis or coffee-ground vomits (68%). 75% of patients gave history of consumption of low dose aspirin or other NSAIDs regularly. Gastric and/or duodenal ulcers were the most common causes (252/572, 44%) of AUGIB (Gastric ulcer: 173/572, 30% and duodenal ulcer: 93/572, 16%, respectively). Esophageal varices were the third common cause (64/572, 11%). 36 (6%) of the patients died. Mean age of these patients was higher than the patients who were alive (64.8 vs. 54.2 years, P = 0.001). Other than age, orthostatic hypotension on arrival (267/536 vs. 24/36, P = 0.018) and consumption of steroids (43/536 vs. 10/36, P = 0.001) were significant factors for increasing mortality.Conclusions:
The most common cause of AUGIB, secondary only to NSAIDs consumption, is gastric ulcer. Mortality of older patients, patients who consumed NSAIDs and steroids concomitantly, and patients with hemodynamic instability on arrival were higher. 相似文献993.
Mehdi Ouaissi Catherine Hubert Robert Verhelst Parla Astarci Christine Sempoux Anne Jouret-Mourin Anderson Loundou Jean-François Gigot 《World journal of surgery》2010,34(11):2648-2661
Objective
Combined vascular and pancreatic resection improves long-term survival of patients suffering from ductal adenocarcinoma of the pancreatic head. This study was designed to compare the results of surgical resection in patients with pancreatic cancer with or without vascular resection. Late 10-year disease-free survival was considered as an indicator of patients’ disease cure. 相似文献994.
995.
Mehdi Ghasemi Hamed Shafaroodi Ali Reza Karimollah Taha Gholipour Behtash Ghazi Nezami Farzad Ebrahimi Ahmad Reza Dehpour 《Seizure》2010,19(1):53-58
Although there is evidence that diabetes affects seizure susceptibility, the underlying mechanism has not been completely understood. Several studies also suggest a pivotal role for KATP channels in the seizure modulation. The aim of the present study was to evaluate the seizure threshold induced by pentylenetetrazole in diabetic mice at different times (3 days, 1–8 weeks) after induction of diabetes with streptozocin and to examine the possible role of ATP-sensitive potassium (KATP) channels in this manner.Our data showed a time-dependent alteration in the threshold in diabetic mice, reaching a peak on week 2 after streptozocin injection and declining significantly afterwards. The seizure threshold in 8-week diabetic mice was even lower than control levels, though the difference was not significant. The KATP channel opener cromakalim (0.1–30 μg/kg, i.p.) significantly increased the seizure threshold in control mice. Although the KATP channel blocker glibenclamide (0.5, 1 mg/kg) had no effect, it prevented the effects of the potent dose of cromakalim (30 μg/kg) on seizure threshold in control mice. Glibenclamide (1 mg/kg, i.p.) also decreased the seizure threshold in 2-week diabetic mice to the control levels which was blocked by pre-treatment with cromakalim (10 μg/kg, i.p.). Cromakalim (10 μg/kg, i.p.) significantly increased the seizure threshold in 8-week diabetic mice which was inhibited by pre-treatment with glibenclamide (1 mg/kg, i.p.).We demonstrated a time-dependent alteration in the pentylenetetrazole-induced seizure threshold in diabetic mice. This phenomenon might be due to the probable alteration in the KATP channel functioning during the diabetic condition. 相似文献
996.
Mehrnoosh Kosaryan Hosein Karami Morteza Alizadeh Forootan Mehdi Ahangari 《Hemoglobin》2013,37(4):453-462
β-Thalassemia major (TM) is the most prevalent genetic disease in Mazandaran Province. Currently, about 2,700 TM patients have been registered and are under treatment in the province. This study was undertaken to evaluate the survival of patients attending a dedicated clinic at the Boo Ali Sina Teaching Hospital, Sari, Iran, which was established in 1986. This survival analysis was conducted from July 2004 to September 2006. New deaths were updated in September 2006. A total of 1,010 medical records were reviewed. Place of residence, date of birth, first transfusion, initiation date of chelation, diagnosis of cardiac complications, diabetes and death were recorded. Compliance to treatment assessed by calculating the percentage of actual usage to prescribed iron chelator medicine and also by asking the attending nurse who was constantly present throughout the last 15 years. Validity of the opinion of the nurse was ascertained in a previous study. Kaplan-Meier statistics were used for analysis. The odds ratio (OR) and its 95% confidence interval (CI) for some risk factors of death were calculated. The survival rate of patients born before and after 1986 was also compared. Survival of both genders for birth cohort before and after 1986 was not statistically significant although the cohort of patients born after 1986 was better at 30 years old (68 vs. 80%). The survival of TM patients is improving but the prevalence of complications is high. 相似文献
997.
Background
Upper gastrointestinal bleeding (UGIB) causes over $1 billion in medical expenses annually.Aims
The purpose of this study was to examine changes of UGIB mortality risks and trends over the last three decades.Methods
We analyzed the National Hospital Discharge Sample from 1979 to 2009. Patients with primary ICD-9 code representing a diagnosis of UGIB were included. The UGIB mortality risks and trends in each decade by anatomical sites, bleeding causes, comorbidities, and other important variables were analyzed.Results
UGIB mortality risk decreased by 35.4 % from 4.8 % in the first decade to 3.1 % in the third decade (P < 0.001). Age and number of hospitalization days were significant risk factors in all decades. Most significant decreases were observed in patients over 65 years and during the first day of admission. Gastric (P < 0.001) and esophageal (P = 0.018) bleedings showed significant decreasing mortality risk trends. Duodenal bleeding mortality risk was stable in three decades. Mortality risk declined significantly among patients with renal failure (from 50.0 to 4.0 %) and heart failure (from 17.9 to 5.2 %; both P < 0.001) while changes in cases with ischemic heart disease, cancer, and liver failure were less significant.Conclusion
UGIB morality risks, especially of the first hospital day and geriatric patients, significantly decreased over the last three decades, presumably from recent advances in emergency medical care. Mortality risk of gastric, but not duodenal, bleeding had the most significant reduction. Critical care improvements in patients with various comorbidities may explain significant UGIB mortality risk reductions. This study provides invaluable insight into the causes and trends of UGIB mortality risks for future studies. 相似文献998.
The analysis of hundreds of SFRC mixtures compiled from papers published over the last 20 years is reported. This paper is focused on the relationships between the size and dosage of steel fibers and the relative amounts of the constituents of SFRC mixtures. Multiple linear regression is applied to the statistical modeling of such relationships, leading to four equations that show considerable accuracy and robustness in estimating SFRC mixture proportions as a function of fiber content and dimensions, maximum aggregate size, and water-to-cement ratio. The main trends described by these equations are discussed in detail. The importance of the interactions between aggregates, supplementary cementitious materials, and fibers in proportioning SFRC mixtures, as well as implications for workability and stability, are emphasized. The simplicity of these data-driven equations makes them a valuable tool to guide the proportioning of SFRC mixtures. Their predictive performance when used together as a data-driven mix design methodology is confirmed using a validation dataset. 相似文献
999.
1000.
Sara Soleimani Asl Kazem Mousavizedeh Bagher Pourheydar Mansoureh Soleimani Elnaz Rahbar Mehdi Mehdizadeh 《Metabolic brain disease》2013,28(4):677-686
Exposure to 3, 4-methylenedioxymethamphetamine (MDMA) leads to spatial memory impairment and hippocampal cell death. In the present study we have examined the protective effects of N-acetyl-L-cysteine (NAC) on MDMA-induced neurotoxicity. A total of 56 male Sprague Dawley rats (200–250 g) received twice daily intraperitoneal (IP) injections of 5, 10 or 20 mg/kg MDMA plus NAC (100 mg/kg). Rectal temperatures were recorded before and after daily treatment. We used a Morris water maze (MWM) to assess spatial learning and memory. At the end of the study rats’ brains were removed, cells were counted and the level of Bcl-2, Bax and caspase-3 expression in the hippocampi were measured. NAC pretreatment significantly reduced MDMA-induced hyperthermia. In the MWM, NAC significantly attenuated the MDMA-induced increase in distance traveled; however the observed increase in escape latency was not significant. The decrease in time spent in the target quadrant in MDMA animals was significantly attenuated (p?<?0.001, all groups). NAC protected against MDMA-induced cell death and the up -regulation of Bax and Caspase-3, in addition to the down-regulation of Bcl-2. This data suggested a possible benefit of NAC in the treatment of neurotoxicity among those who use MDMA. 相似文献