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   736篇
  免费   32篇
  国内免费   32篇
儿科学   47篇
妇产科学   53篇
基础医学   46篇
口腔科学   15篇
临床医学   35篇
内科学   129篇
皮肤病学   14篇
神经病学   9篇
特种医学   116篇
外科学   137篇
综合类   89篇
预防医学   15篇
眼科学   3篇
药学   48篇
肿瘤学   44篇
  2022年   2篇
  2021年   3篇
  2020年   2篇
  2019年   6篇
  2018年   9篇
  2017年   6篇
  2016年   12篇
  2015年   14篇
  2014年   25篇
  2013年   29篇
  2012年   37篇
  2011年   39篇
  2010年   19篇
  2009年   20篇
  2008年   39篇
  2007年   38篇
  2006年   27篇
  2005年   28篇
  2004年   20篇
  2003年   21篇
  2002年   22篇
  2001年   18篇
  2000年   22篇
  1999年   19篇
  1998年   34篇
  1997年   27篇
  1996年   23篇
  1995年   22篇
  1994年   18篇
  1993年   17篇
  1992年   9篇
  1991年   14篇
  1990年   9篇
  1989年   19篇
  1988年   18篇
  1987年   15篇
  1986年   13篇
  1985年   5篇
  1984年   12篇
  1983年   10篇
  1982年   9篇
  1981年   12篇
  1980年   11篇
  1979年   2篇
  1978年   6篇
  1977年   3篇
  1976年   4篇
  1975年   7篇
  1974年   2篇
  1972年   1篇
排序方式: 共有800条查询结果,搜索用时 296 毫秒
791.
792.

Background

Although every step in the in vitro fertilisation (IVF) procedure is important, the impact of embryo transfer (ET) on pregnancy rate (PR) is significant. Of all the crucial aspects of ET the type of catheter used and the technique of transfer on the PR has drawn the maximum attention and controversy. We aimed to compare the outcome of two different ET catheters on the PR.

Method

A prospective analysis comparing the classical Frydman (Laboratoire CCD, France) and the soft Cook (Cook Medical, Indiana, USA) ET catheters was performed. Primary end-point was clinical pregnancy rate (CPR); secondary end-points were rates of difficult transfer. A total of 1,446 ETs were performed in women undergoing IVF treatment, of which 723 cycles were randomised to the Cook catheter and 723 to the Frydman catheter.

Results

It was observed that, although the Cook catheter was related to a slightly higher PR, the overall comparison failed to indicate a significant difference in CPR. It was also seen that the ease of transfer did not significantly affect the PRs.

Conclusion

Individual variables during ET may not contribute significantly to the success of an IVF programme; however, a holistic approach encompassing all the factors is quintessential to improve the PR.  相似文献   
793.
794.
The incidence of cardiovascular disease is greatly increased in the HIV-infected population compared with people of the same age without HIV. Cardiovascular manifestations of HIV/AIDS include, but are not limited to, accelerated atherosclerosis, pulmonary arterial hypertension, vasculitis, myocarditis, cardiomyopathy, pericardial diseases, malignancy (myocardial Kaposi sarcoma and B-cell immunoblastic lymphoma), and endocarditis. Drug effects and interactions that challenge the cardiovascular system are even more prevalent in this population, and careful review and surveillance of medication effects is crucial as is careful selection of highly active antiretroviral therapy. A focused assessment and understanding of disease prevalence and presentation is needed as symptoms may be non-specific and cardiovascular physical examination findings indeterminate due to co-morbid conditions in the patient population now living with chronic HIV infection.  相似文献   
795.
Cardiotoxicity was an unanticipated side effect elicited by the clinical use of imatinib (Imb). This toxicity has been examined in only a limited number of experimental studies. The present study sought, by a variety of approaches, to identify important characteristics of Imb-induced cardiac alterations. Male spontaneously hypertensive rats (SHRs) received oral doses of 10, 30, or 50 mg/kg Imb or water daily for 10 d. Cardiac lesions, detected at all doses, were characterized by cytoplasmic vacuolization and myofibrillar loss. In a second experiment, cardiac lesions were found in Sprague Dawley (SD) and SHR rats given 50 or 100 mg/kg Imb for 14 d. Mean cardiac lesion scores and serum levels of cardiac troponin I were higher in SHRs than in SD rats. Imb induced myocyte death by necrosis, autophagy, and apoptosis. Dose-related increases in cardiac expression were observed for several genes associated with endoplasmic reticulum stress response, protein folding, and vascular development and remodeling. Imb caused alterations in isolated myocytes (myofibrillar loss, highly disrupted and disorganized sarcomeric α-actinin, apoptosis, and increased lactate dehydrogenase release) at low concentrations (5 mM). The authors conclude that Imb exerts cardiotoxic effects that are manifest through a complex pattern of cellular alterations, the severity of which can be influenced by arterial blood pressure.  相似文献   
796.
Cardiac troponins have proved to be reliable blood biomarkers for identifying a variety of myocardial alterations in humans and animals. Recently, an ultrasensitive cTnI assay (Erenna IA) has been used to demonstrate increases in baseline cTnI resulting from drug-induced myocardial injury in rats, dogs, and monkeys, as well as to document baseline cTnI ranges in Sprague-Dawley (SD) rats. The present study was initiated to use the Erenna cTnI assay to further document baseline cTnI concentrations in normal control animals from multiple strains, including SD, Spontaneous Hypertensive (SHR), Wistar, Wistar-Kyoto (WKY), and Fisher strains. Baseline cTnI concentrations were quantified in all rats tested, and males had higher mean cTnI concentrations than females of the same strain. SHR males had the highest mean cTnI concentrations and the largest cTnI variability. Interestingly, cTnI concentrations increased in castrated SHR compared with unaltered male SHR, whereas cTnI concentrations decreased in ovariectomized SHR compared with unaltered female SHR. These results show significant differences in cTnI concentrations between strains, sexes, and noncardiac surgical alterations in control animals, and identify these as potential contributing factors to cTnI baseline variability that should be taken into account when using ultrasensitive cTnI as a biomarker to assess preclinical cardiotoxicity.  相似文献   
797.

Background

This study retrospectively analyses the initial experience of liver transplantation (LT) in the Indian Armed Forces.

Methods

Fifty-three patients underwent LT at Army Hospital (R&R) Delhi Cantt. between March 2007 and March 2011. Of these 35 patients underwent deceased donor liver transplantation (DDLT) and living donor liver transplantation (LDLT) was carried out in 18 patients. The surgical techniques, complications and mortality were analysed.

Results

A high consent rate of 35.9% for organ donation was achieved by the Armed Forces Organ Retrieval and Transplantation Authority (AORTA). Biliary complications occurred in five patients (9.4%). However, most of them could be managed by endoscopic interventions. Hepatic artery thrombosis (HAT) occurred in five patients (9.4%). Of these, two DDLT grafts were revascularised following HAT, by creating extra-anatomic arterial conduits with excellent outcome. The overall mortality was 18.8% (n = 10). There was no significant difference in the overall complications or mortality in patients undergoing DDLT or LDLT.

Conclusion

The overall survival and morbidity in this study is comparable to those from other centres. Urgent revascularisation of grafts following HAT should be attempted as it can salvage grafts with satisfactory outcome. There is a reduction in the incidence of biliary complications with refinements in surgical techniques.  相似文献   
798.
799.
800.
以豚鼠离体回肠和结肠带为标本,观察蛇床子素(Ost)的作用与Ca~(2+)的关系。结果表明:Ost和钙拮抗剂Ver产生剂量依赖性抑制乙酰胆碱(ACh)、组胺及KCl所致回肠条或结肠带的收缩;非竞争性拮抗CaCl_2累积量—效曲线,pD_2分别为4.41±0.15,7.0±0.2。Ost 100μmol/L和Ver 1μmol/L均能对抗小剂量Ca~(2+)所致结肠带收缩,但被加入较大量Ca~(2+)所取消。Ost和Ver均能抑制ACh诱导的依内钙性收缩,不影响依外钙性收缩。结果提示Ost具有钙拮抗作用,其作用方式与Ver类似。  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