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   9245篇
  免费   728篇
  国内免费   16篇
耳鼻咽喉   74篇
儿科学   188篇
妇产科学   284篇
基础医学   1052篇
口腔科学   120篇
临床医学   928篇
内科学   2252篇
皮肤病学   202篇
神经病学   900篇
特种医学   330篇
外科学   1273篇
综合类   194篇
一般理论   2篇
预防医学   779篇
眼科学   370篇
药学   571篇
中国医学   2篇
肿瘤学   468篇
  2021年   146篇
  2020年   72篇
  2019年   157篇
  2018年   174篇
  2017年   92篇
  2016年   119篇
  2015年   130篇
  2014年   220篇
  2013年   308篇
  2012年   425篇
  2011年   464篇
  2010年   277篇
  2009年   216篇
  2008年   341篇
  2007年   449篇
  2006年   389篇
  2005年   392篇
  2004年   368篇
  2003年   343篇
  2002年   339篇
  2001年   307篇
  2000年   327篇
  1999年   266篇
  1998年   123篇
  1997年   89篇
  1996年   88篇
  1995年   78篇
  1994年   79篇
  1993年   66篇
  1992年   163篇
  1991年   156篇
  1990年   210篇
  1989年   172篇
  1988年   190篇
  1987年   174篇
  1986年   193篇
  1985年   159篇
  1984年   107篇
  1983年   109篇
  1982年   74篇
  1980年   78篇
  1979年   138篇
  1978年   91篇
  1977年   80篇
  1976年   78篇
  1975年   74篇
  1974年   64篇
  1973年   69篇
  1972年   75篇
  1971年   66篇
排序方式: 共有9989条查询结果,搜索用时 15 毫秒
11.
Uveal melanoma radiation. 125I brachytherapy versus helium ion irradiation   总被引:4,自引:0,他引:4  
The optimum radiation therapy for uveal melanoma is uncertain. Both helium ion irradiation and 125I brachytherapy have been used to treat this neoplasm. This investigation analyzed the control and complication rates of uveal melanomas treated with helium ions of 125I plaques. In both a retrospective and a prospective dynamically balanced study, the control rates appeared to be similar. There were more posterior segment complications after 125I plaques and more anterior segment complications, including neovascular glaucoma, after helium ion irradiation. The follow-up period is too short to draw definitive conclusions on the radiation complications. Overall, approximately 89% of eyes were retained and less than 4% of treated eyes were removed because of failure to control the tumor.  相似文献   
12.
Difficulties with self-injection, including inabillity to self-inject, are common for individuals taking home-administered injectable medications. In relapsing-remitting multiple sclerosis (MS), all of the currently available disease-modifying medications are injectables marketed for self-injection. Problems with self-injection pose a barrier to treatment adherence for many patients. Clinicians at the University of California, San Francisco (UCSF) Multiple Sclerosis Center have developed a number of strategies to help patients who experience anxiety associated with self-injection. These strategies have been empirically tested and found to be effective and easily implemented by mental health professionals and nurses. This article offers case examples and discussion of the principles of the techniques developed at UCSF to remediate patients' difficulties with self-injection. Nurses are most often the healthcare providers responsible for training MS patients in self-injection and monitoring their compliance. Nurses who are familiar with these tools have the opportunity to have a significant positive impact on patient comfort, confidence, and, ultimately, successful long-term adherence to disease-modifying medications.  相似文献   
13.
The purpose of this study is to show the spectrum of adjacent organ invasion and to make a brief review of hepatic alveolar hydatid disease (AHD), using CT and MR imaging. We retrospectively reviewed CT and MR images of three patients with various adjacent organ invasions surgically and histologically proven to be AHD. Local invasion to right kidney and adrenal, right hemidiaphragm and lung were detected in one patient, right adrenal in another patient and gall bladder, duodenum, gastric wall and pancreas invasion in the other. AHD may rarely extend to the gall bladder, stomach, duodenum, pancreas, right adrenal and kidney, diaphragm, pleura and lung. The extension of the disease outside the liver is usually encountered in patients with large, peripherally located masses in the advanced stage of the disease.  相似文献   
14.
Non-Hodgkin's lymphoma usually presents with lymphadenopathy at multiple sites but can also involve any part of the musculoskeletal system. Occasionally the presentation is with a soft tissue mass. The presentation of large, superficial lymphomatous masses is similar both clinically and radiologically to that of soft tissue sarcomas. The six cases of lymphoma presenting to the Exeter Sarcoma Service as suspected soft tissue sarcomas, over a two-year period (2002-2004), are presented. We describe the clinical and imaging characteristics of these tumours and their subsequent management. Our cases showed variability in presentation. Only one of the six cases presented with pain and one with tenderness. Four of the cases had no lymphadenopathy and the other two had lymphadenopathy restricted to one nodal basin. Overlying soft tissue swelling occurred in four cases and in distal limb swelling beyond the mass in one case. Radiologically, lymphomas are known to be likely to exhibit confluent lymphadenopathy that is rare in patients with soft tissue sarcoma. Confluent lymphadenopathy was demonstrated in only one case of this series of patients. It is thought that lymphomas infiltrate across anatomical fascial planes more readily than sarcomas and in four of our six cases this feature was present. Clinical history, examination and MRI are insufficient to differentiate between soft tissue sarcoma and lymphoma and the importance of obtaining a pathological diagnosis prior to surgery is clear. It is crucial to differentiate lymphoma from sarcoma in order to avoid unnecessary excisional procedures in lymphoma patients.  相似文献   
15.
16.
Instillation of human neutrophil elastase (HNE) into hamster lungs produces milder emphysema but more pulmonary hemorrhage than an equivalent amount of porcine pancreatic elastase (PPE), whether equivalence is determined by elastolytic units or moles. We undertook a study of the mechanisms of these differences. 125I-HNE or 3H-PPE were instilled intratracheally into hamsters. The partitioning of radioactivity between bronchoalveolar lavage fluid (BAL) and lung tissue was similar for HNE and PPE as were the half-lives, 45 and 51 min, respectively, for uncomplexed, enzymatically active HNE and PPE. In BAL there was preferential binding and inactivation of HNE by the hamsters' alpha-1-protease inhibitor (a-1-PI) whereas PPE was preferentially bound by alpha-2-macroglobulin (a-2-M). This was also observed in vitro when HNE and PPE were incubated with plasma from untreated hamsters. Nevertheless, when the sum of the elastase binding capacity of a-1-PI and a-2-M was considered, hamster plasma had similar binding capacities for HNE and PPE. It is known that the enzymatic activity of elastases is inhibited by formation of a stable complex with a-1-PI. On the other hand, elastases bound to a-2-M are protected against a-1-PI inhibition but can free themselves by proteolysis and exhibit elastolytic activity. Preferential inactivation of HNE by a-1-PI may be one mechanism that accounts for the lesser emphysema-inducing potency of HNE than of PPE.  相似文献   
17.
When administered systemically, glucose attenuates deficits in memory produced by several classes of drugs, including cholinergic antagonists and opiate agonists. Glucose also enhances memory in aged rats, mice, and humans. In addition, glucose ameliorates age-related reductions in paradoxical sleep. Because deficits in paradoxical sleep are most marked in those individual aged rats that also have deficits in memory, treatments which improve one of these functions may similarly improve the other. The present experiments show that glucose attenuates deficits in paradoxical sleep and memory after atropine administration, with similar dose-response curves for both actions. In the first experiment, rats received saline, atropine (1 mg/kg), glucose (100 mg/kg) or combinations of atropine + glucose (10, 100, 250, and 500 mg/kg) 30 min before assessment on a spontaneous alternation task. In the second experiment, 3-h EEGs were assessed for spontaneous daytime sleep in rats administered saline, atropine (1 mg/kg), glucose (100 mg/kg) or combinations of atropine + glucose (10, 100 and 250 mg/kg). In both experiments, glucose significantly attenuated deficits at an optimal dose of 100 mg/kg. A third experiment assessed blood glucose levels after injections of atropine + glucose (100 mg/kg) and determined that blood glucose levels were similar to those produced by other treatments which enhance memory. These results are consistent with the view that paradoxical sleep and at least one test of memory are similarly influenced by atropine and glucose.  相似文献   
18.
The Child and Adolescent Trial for Cardiovascular Health (CATCH) is a multisite intervention research study that builds on significant progress made in school health education research in the 1980s. The study has three phases: Phase I deals with study design, intervention, and measurement development, Phase II involves the main trial in 96 schools in four states, and Phase III focuses on analysis. The intervention program targets third-fifth grade students and focuses on multiple cardiovascular health behaviors, including eating habits, physical activity, and cigarette smoking. Classroom curricula, school environmental change, and family involvement programs are developed for each grade level and behavioral focus. This paper describes Phase II of CATCH with a rationale for cardiovascular health promotion with youth. The process of change that appears to be necessary for school-based health promotion and that will be tested in CATCH are presented as a framework to guide these efforts.  相似文献   
19.
Tracheal intubation is a skill that should be considered supplementary to other aspects of airway management which are of vital importance in resuscitation. Doctors involved in resuscitation should develop and retain such skills, and be aware of potential dangers.  相似文献   
20.
Autosomal dominant neovascular inflammatory vitreoretinopathy   总被引:1,自引:0,他引:1  
S R Bennett  J C Folk  A E Kimura  S R Russell  E M Stone  E M Raphtis 《Ophthalmology》1990,97(9):1125-35; discussion 1135-6
Twenty-eight of 61 members of a six-generation family are affected by an autosomal dominant eye disease which has not been described previously. Affected patients are asymptomatic in early adulthood, but have vitreous cells and the selective loss of the b-wave on the electroretinogram. Later, peripheral retinal scarring and pigmentation, peripheral arteriolar closure, and neovascularization of the peripheral retina at the ora serrata or occasionally neovascularization of the optic disc develop. Cystoid macular edema, vitreous hemorrhage, tractional retinal detachment, and neovascular glaucoma can cause profound visual loss. Vitrectomy reduces traction on the retina and allows for retinal reattachment. The role of argon laser photocoagulation or cryopexy in reducing the neovascular complications remains uncertain.  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