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   4027829篇
  免费   285325篇
  国内免费   9088篇
耳鼻咽喉   55995篇
儿科学   131901篇
妇产科学   110708篇
基础医学   574624篇
口腔科学   112317篇
临床医学   370827篇
内科学   777042篇
皮肤病学   93106篇
神经病学   326484篇
特种医学   152494篇
外国民族医学   1151篇
外科学   601737篇
综合类   83693篇
现状与发展   15篇
一般理论   1604篇
预防医学   315348篇
眼科学   93827篇
药学   296761篇
  16篇
中国医学   7869篇
肿瘤学   214723篇
  2019年   32370篇
  2018年   44757篇
  2017年   33922篇
  2016年   39034篇
  2015年   43941篇
  2014年   61342篇
  2013年   92917篇
  2012年   125234篇
  2011年   132962篇
  2010年   79951篇
  2009年   76054篇
  2008年   124467篇
  2007年   132297篇
  2006年   134233篇
  2005年   129580篇
  2004年   124678篇
  2003年   120175篇
  2002年   116242篇
  2001年   183317篇
  2000年   188165篇
  1999年   159122篇
  1998年   47309篇
  1997年   41550篇
  1996年   41701篇
  1995年   40072篇
  1994年   36826篇
  1993年   34637篇
  1992年   124762篇
  1991年   120953篇
  1990年   117644篇
  1989年   114025篇
  1988年   104919篇
  1987年   102824篇
  1986年   96815篇
  1985年   92795篇
  1984年   69385篇
  1983年   59079篇
  1982年   35226篇
  1981年   31728篇
  1979年   62983篇
  1978年   44779篇
  1977年   37809篇
  1976年   35585篇
  1975年   38031篇
  1974年   45338篇
  1973年   43203篇
  1972年   40662篇
  1971年   38193篇
  1970年   35174篇
  1969年   33839篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Biopsies from the diseased bones of patients with familial expansile osteolysis (FEO) were examined by light and electron microscopy. Focal concentrations of multinuclear osteoclasts were present, and these contained viral-like microcylindrical inclusions which appeared exclusive to their nuclei. No consistent relationship was found between osteoclast size and the number of osteoclast nuclei containing microcylindrical inclusions. Quantitative histomorphometry showed evidence of increased bone remodelling with high bone cell densities and a decrease of the reversal period in bone remodelling. The lesions contained prominent woven bone and fibrovascular tissue, together with mononuclear cells and adipocytes. Little bone was found in the most radiolucent lesions, which were almost totally occupied by adipocytes and fibrovascular tissue. Serology did not reveal any significant differences between the viral antibody titres of patients and their age- and sex-matched controls. The present study suggests that intranuclear viral-like microcylindrical inclusions of osteoclasts are not a specific feature of Paget's disease, and are found in other disorders of osteoclast function, including pycnodysostosis, osteopetrosis, giant cell tumours, and familial expansile osteolysis.  相似文献   
992.
993.
994.
There is much mystique surrounding the acquisition by a young practitioner of his or her first dental practice, arising largely from his fear of the unknown. In fact, provided that he or she obtains sound legal and commercial advice, he or she can purchase a dental practice almost exclusively out of borrowed capital. Whilst repaying capital (and interest) over a 10-year period, it is possible to earn more from day one than as a relatively experienced associate on the usual commission arrangement.  相似文献   
995.
OBJECTIVE: To determine whether the use of dimenhydrinate was associated with delay in the diagnosis and management of treatable illnesses or with direct adverse effects in children with vomiting presenting to an emergency department. DESIGN: Questionnaire survey and review of drug reaction and telephone inquiry records. SETTING: The emergency department of a tertiary care children's hospital and a provincial poison information centre. PATIENTS: The parents of 148 children who presented with vomiting completed the questionnaire. The database at the poison information centre included 474 reports of adverse drug reactions over an 8-year period and 105 reports of telephone inquiries over a 4-year period. MAIN RESULTS: Twenty-one (14%) of 148 children had received dimenhydrinate before arrival at the emergency department. The patients who had received dimenhydrinate were more likely than the others to present more than 12 hours after the onset of vomiting (14 [67%] of 21 v. 43 [34%] of 127, p less than 0.01). The discharge diagnoses for those who had received dimenhydrinate included asthma, pelvic inflammatory disease and urinary tract infection. No clinically important direct adverse reactions to dimenhydrinate were documented. CONCLUSIONS: The use of dimenhydrinate in children with vomiting is associated with a risk of delay in the diagnosis of treatable medical conditions.  相似文献   
996.
In the clinical management of Graves' thyrotoxicosis, one of the most important subject is when to stop antithyroid drugs after achieving an euthyroid state. T3 suppression test and other methods have been used to forecast the outcome after drug cessation, but the results were not always satisfactory. We have attempted to predict remission of Graves' disease by single measurement of early technetium uptake without administration of triiodothyronine. Drugs were discontinued in the seventy-five patients with Graves' disease on maintenance doses of either methimazole or propylthiouracil who showed normalized uptake (4.0% or less). Of 64 patients evaluable after twelve months, 55 (86%) remained euthyroid, 8 relapsed, and 1 became hypothyroid. With its accuracy in prediction of short-term remission comparable or superior to T3 suppression test, this rapid and simple method seemed suitable for routine use in clinical practice.  相似文献   
997.
Long bone injuries in clinical cases are studied by comparison of roentgenograms with a rational mechanical analysis of the injuries. Fractures produced by torsional loads have a spiral shape with a smooth and even surface. Fractures induced by bending loads have uneven and rugged fracture surfaces perpendicular to the bone axis. Long bones are weak in torsion but strong in tensile stress produced by bending. This result corresponds to the clinical fact that a large direct external force is needed to produce a transverse fracture while a spiral fracture is produced by a relatively small torque.  相似文献   
998.
A case of papilliferous keratoameloblastoma is reported which is only the second ever documented. The patient was a 76-yr-old black woman with a large expansile multilocular radiolucency of the body, angle and ramus of the mandible. Histologically the lesion consisted of sheets of cystic follicles filled with necrotic debris and sometimes parakeratin. The vast majority of the follicles were lined by a papilliferous epithelium consisting of large rounded cells with centrally placed nuclei. True papillary projections with cores of connective tissue were also present. The remainder of the follicles were lined by a thin parakeratinising stratified squamous epithelium. Histological features characteristic of ameloblastoma were absent. Final classification of these lesions will have to await the reporting of further cases.  相似文献   
999.
1000.
The precision and accuracy of manual reticulocyte counts using the Miller disc reticle, other ruled reticle and no reticle are compared with the reticulocyte results from the automated Hematrak 590 instrument. Two slides of each of 50 patient blood specimens were sent to the hematology laboratories of each of six participating hospitals. In addition to between-method comparison (precision), the manual method results using the three different counting techniques were each compared with the Hematrak results to determine if there were significant differences in reported results (accuracy). Statistical analysis revealed that the Miller disc method was the most precise and accurate manual method as compared with the Hematrak. Methods without a Miller disc reported significantly higher reticulocyte counts. Imprecision was also higher among non-Miller manual methods. By using the Miller disc, the accuracy and precision of manual methods may be increased to that of the automated Hematrak method.  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