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   3698篇
  免费   278篇
  国内免费   26篇
耳鼻咽喉   14篇
儿科学   207篇
妇产科学   54篇
基础医学   331篇
口腔科学   40篇
临床医学   446篇
内科学   448篇
皮肤病学   31篇
神经病学   254篇
特种医学   262篇
外科学   398篇
综合类   38篇
预防医学   291篇
眼科学   821篇
药学   126篇
肿瘤学   241篇
  2021年   48篇
  2020年   26篇
  2019年   60篇
  2018年   53篇
  2017年   51篇
  2016年   43篇
  2015年   54篇
  2014年   68篇
  2013年   134篇
  2012年   156篇
  2011年   197篇
  2010年   104篇
  2009年   97篇
  2008年   129篇
  2007年   160篇
  2006年   168篇
  2005年   176篇
  2004年   164篇
  2003年   133篇
  2002年   124篇
  2001年   121篇
  2000年   126篇
  1999年   86篇
  1998年   70篇
  1997年   61篇
  1996年   64篇
  1995年   34篇
  1994年   46篇
  1993年   39篇
  1992年   89篇
  1991年   79篇
  1990年   65篇
  1989年   70篇
  1988年   80篇
  1987年   76篇
  1986年   62篇
  1985年   73篇
  1984年   63篇
  1983年   38篇
  1982年   44篇
  1981年   31篇
  1980年   33篇
  1979年   42篇
  1978年   37篇
  1977年   34篇
  1976年   25篇
  1975年   25篇
  1974年   24篇
  1968年   22篇
  1966年   20篇
排序方式: 共有4002条查询结果,搜索用时 15 毫秒
1.
In a prospective, randomized, single-masked, cross-over study, 18 patients with primary open-angle glaucoma were treated for one month with each of the following regimens: timolol 0.5% twice daily, timolol 0.5% plus dipivefrin 0.1% twice daily given ten minutes apart, and timolol 0.5% plus dipivefrin 0.1% given twice daily four hours apart. An eight-hour intraocular pressure curve was obtained before treatment and at the end of each monthly regimen. When added to timolol therapy, dipivefrin produced a small but statistically significant additional mean decrease in intraocular pressure. The difference in intraocular pressure reduction between the two regimens for combined timolol and dipivefrin therapy was not statistically significant.  相似文献   
2.
Brain morphology was examined using magnetic resonance imaging in 30 first-episode patients with a schizophreniclike psychosis, 15 chronic schizophrenics, and 20 neurological controls. Statistical analyses of computer-generated measurements of regions of interest were controlled for gender, age, social class, and total brain volume. Lateral ventricular size was increased in both first-episode and chronic schizophrenic patients, with greater significance on the left than on the right side. Only the chronic patients, however, had reduced temporal lobe size, which also was greater on the left side. No major correlations of regional brain morphological measurements with cognitive functioning were found, although some measurements of verbal memory were correlated with parahippocampal size. This is a report of a preliminary study that suggests that some morphological brain changes may be present at the time of first treatment for a psychotic illness, whereas others may occur later in the course of illness. Future prospective studies may determine the clinical significance of these changes and whether they progress with the development of illness chronicity.  相似文献   
3.
Neonatal Graves'' disease.   总被引:1,自引:1,他引:0       下载免费PDF全文
A newborn boy was noted by his mother to have a prominent left eye at birth, but an eye examination was delayed until age 7 months, at which time his ophthalmologist diagnosed exophthalmos. Computed tomography was interpreted as showing mild, diffuse, optic nerve thickening bilaterally suggestive of optic nerve gliomas. Subsequent examination in our clinic revealed pseudoproptosis secondary to retraction of the left upper eyelid. Magnetic resonance imaging demonstrated normal orbital structures. The mother was noted to be clinically hyperthyroid, and abnormal thyroid function tests confirmed the diagnosis. Although the infant was euthyroid, neonatal Graves' ophthalmopathy was diagnosed. He was managed by close observation while his mother was treated for her hyperthyroidism.  相似文献   
4.
Cardiovascular disease (CVD), which includes myocardial infarction(MI), stroke, and peripheral vascular disease, remains the leading cause of death in the United States and in most developed countries. In the United States today, 25% of patients have metabolic syndrome-including those who have had a prior occlusive vascular disease event, those who are having an acute MI or ischemic stroke, and finally, the largest segment of the population,namely those who have not yet experienced a clinical CVD, but whose risks are substantial (10-year risk 10%). This article reviews the totality of evidence for aspirin in the treatment and prevention of CVD and emphasizes its importance as adjunctive therapy for patients with metabolic syndrome.  相似文献   
5.
A lesion with both the clinical and fluorescein angiographic appearance of the classical retinal pigment epithelial (RPE) tear was discovered over the dome of an actively growing metastatic choroidal tumor in a patient with a previous history of breast carcinoma. However, our patient exhibited no evidence of pigment epithelial detachment or age-related macular degeneration, the underlying cause of the RPE tear. Although we cannot be sure that a true RPE tear did not exist over our patient's tumor, more likely, we are observing a tumor induced zone of RPE dehiscence accompanied by RPE proliferation at its border, giving a very similar fundus appearance. Possible pathogenic mechanisms for the finding in our patient, and a comparison to those mechanisms responsible for the classical RPE tear, are discussed.  相似文献   
6.
Objective. To determine the stability of an admixture combining ziconotide with bupivacaine hydrochloride during simulated intrathecal infusion under laboratory conditions at 37°. Materials and Methods. An admixture containing ziconotide (25 µg/mL) and bupivacaine hydrochloride (5 mg/mL) was stored in SynchroMed® II pumps at 37° and in control vials at either 37° or 5°. Using high‐performance liquid chromatography, drug concentrations were determined from samples obtained at varying intervals during the 30‐day study. Results. After 30 days, pump ziconotide and bupivacaine hydrochloride concentrations measured an average of 86.9% and 99.4% of their initial concentrations, respectively. Control vials displayed similar degradation rates for both drugs. Statistical evaluation of the ziconotide 95% confidence interval indicated that the ziconotide concentration would meet or exceed 90% and 80% of initial concentration for 22 days and 45 days, respectively. Conclusions. An admixture containing 25 µg/mL ziconotide and 5 mg/mL bupivacaine hydrochloride was 90% stable for 22 days and 80% stable for 45 days (extrapolated) in SynchroMed® II infusion pumps.  相似文献   
7.
8.
Navajo birth outcomes in the Shiprock uranium mining area.   总被引:2,自引:0,他引:2  
The role of environmental radiation in the etiology of birth defects, stillbirths, and other adverse outcomes of pregnancy was evaluated for 13,329 Navajos born at the Public Health Service/Indian Health Service Hospital in the Shiprock, NM, uranium mining area (1964-1981). More than 320 kinds of defective congenital conditions were abstracted from hospital records. Using a nested case-control design, families of 266 pairs of index and control births were interviewed. The only statistically significant association between uranium operations and unfavorable birth outcome was identified with the mother living near tailings or mine dumps. Among the fathers who worked in the mines, those of the index cases had histories of more years of work exposure but not necessarily greater gonadal dosage of radiation. Also, birth defects increased significantly when either parent worked in the Shiprock electronics assembly plant. Overall, the associations between adverse pregnancy outcome and exposure to radiation were weak and must be interpreted with caution with respect to implying a biogenetic basis.  相似文献   
9.
10.
In a comparative trial, 21 patients (mean age 43 (range 19-66) years) with dilated upper urinary tracts underwent diuresis renography with both 123I-hippuran and the experimental agent. 99Tcm-thiodiglycolic acid (TDG). Deconvolution analysis of the derived renograms was also performed and the transit times were calculated. Excellent agreement was found between results with the two radiopharmaceuticals. There was complete agreement in interpretation of the response to diuresis with both agents and 84% agreement in the transit time estimations. Good images were produced with both agents and 99Tcm-TDG is considered to be a useful alternative to 123I-hippuran.  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