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   20691篇
  免费   1316篇
  国内免费   142篇
耳鼻咽喉   159篇
儿科学   671篇
妇产科学   554篇
基础医学   2973篇
口腔科学   324篇
临床医学   1607篇
内科学   4900篇
皮肤病学   464篇
神经病学   2729篇
特种医学   700篇
外科学   2176篇
综合类   37篇
一般理论   1篇
预防医学   1177篇
眼科学   199篇
药学   1475篇
中国医学   38篇
肿瘤学   1965篇
  2024年   35篇
  2023年   235篇
  2022年   469篇
  2021年   824篇
  2020年   468篇
  2019年   579篇
  2018年   853篇
  2017年   623篇
  2016年   701篇
  2015年   779篇
  2014年   930篇
  2013年   1252篇
  2012年   1671篇
  2011年   1601篇
  2010年   950篇
  2009年   851篇
  2008年   1374篇
  2007年   1246篇
  2006年   1121篇
  2005年   1029篇
  2004年   953篇
  2003年   823篇
  2002年   648篇
  2001年   164篇
  2000年   117篇
  1999年   171篇
  1998年   141篇
  1997年   80篇
  1996年   58篇
  1995年   57篇
  1994年   61篇
  1993年   34篇
  1992年   141篇
  1991年   136篇
  1990年   110篇
  1989年   97篇
  1988年   90篇
  1987年   85篇
  1986年   84篇
  1985年   72篇
  1984年   49篇
  1983年   38篇
  1982年   20篇
  1980年   25篇
  1979年   50篇
  1978年   26篇
  1976年   19篇
  1973年   28篇
  1969年   20篇
  1967年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Iron protein succinylate is a non-toxic therapeutic iron compound. We set out to characterise the structure of this compound and investigate the importance of digestion and intestinal reduction in determining absorption of the compound. The structure of the compound was investigated by variable temperature M?ssbauer spectroscopy, molecular size determinations and kinetics of iron release by chelators. Intestinal uptake was determined with radioactive compound force fed to mice. Reduction of the compound was determined by in vitro incubation with intestinal fragments. The compound was found to contain only ferric iron, present as small particles including sizes below 10 nm. The iron was released rapidly to chelators. Digestion with trypsin reduced the molecular size of the compound. Intestinal absorption of the compound was inhibited by a ferrous chelator (ferrozine), indicating that reduction to ferrous iron may be important for absorption. The native compound was a poor substrate for duodenal reduction activity, but digestion with pepsin, followed by pancreatin, released soluble iron complexes with an increased reduction rate. We conclude that iron protein succinylate is absorbed by a mechanism involving digestion to release soluble, available ferric species which may be reduced at the mucosal surface to provide ferrous iron for membrane transport into enterocytes.  相似文献   
993.
Diagnosis communication is a mainstay of the patient-physician relationship and in ALS represents the beginning of the treatment. In Europe, the diagnosis is now communicated to most patients, but with some differences from north to south. Communication is the basis of the patient's autonomy. When adequately informed, patients are able to consider their preferences about life-extending interventions. However, this discussion is sometimes entertained too late. Both the style and the context of this discussion have profound impact on patient satisfaction. The content of the communication should include all relevant information about the disease and should be performed honestly while preserving hope. Collusion with relatives can create difficulties in the relationship with a patient and isolate them from their family. Diagnostic communication is an ongoing process and should form part of every follow-up visit. Communication with the dying patient is often reinforced by non-verbal messages, acknowledgements of patients' emotions, and by listening. Written material may increase satisfaction of patients and their relatives, but should never substitute for face-to-face discussion.  相似文献   
994.
995.
Based on 32 cases of neoplastic and degenerative lesions, the indications and limits of auto- and alloplastic grafts are discussed. Grafting was successful in all of the cases, obtaining excellent clinical and radiographic results. An auto graft may be used to more rapidly fill cavities which remain after curettage has been performed, but the limited availability of grafts, the need for a second operation, and the weakening of the donor site encourage us to develop more practical methods of removal and preservation of the allograft.  相似文献   
996.
The Authors report some observations on gallbladder calcification with the presentation of two clinical cases. The pathologic anatomy and the clinical aspects of this infrequent affection are described. The Authors underline the importance of surgical treatment, considering the frequency of carcinoma in porcelain gallbladder.  相似文献   
997.
Late outcome in 12 children treated by radical surgery for craniopharyngioma is presented. None of the patients presented underwent fractionated traditional or stereotactic radiotherapy. The results show no neurological (except visual dysfunction in 6 subjects), cognitive or short-term memory deficits. Three children were found to have a minor attention deficit. In 5 cases “frontal lobe” malfunctioning was disclosed, and in 5 there were bursts of unpredictable anger. Three children showed worsening of functioning at school: a combination of various causes is suggested to explain the worsening of academic performances. The size of the sample calls for a careful evaluation of results, with due consideration for the influence of various factors on outcome. Multicentre studies are required to increase the sample size and achieve more general conclusions. Received: 25 November 1997  相似文献   
998.
Mutism is an infrequent and transitory complication observed following posterior fossa surgery. Patients become mute in the immediate postoperative period, with restoration of speech within a few weeks in the absence of additional neurological alterations. The anatomical structures thought to be involved are the connections between the cerebellar dentate nucleus, the ventrolateral nucleus of the contralateral thalamus and the supplementary motor area. In an attempt to understand the pathophysiology of this syndrome, and to depict the perfusion of different brain areas semiquantitatively, in two children who had become mute after posterior fossa surgery we performed a Tc99M-HM-PAO SPECT study during the period of mutism and again when normal speech had returned. In one patient, who had a left cerebellar astrocytoma, the SPECT study showed a marked reduction of cerebral perfusion in the right fronto-parietal region, and in the other, who had a medulloblastoma, a left fronto-temporo-parietal perfusion alteration was observed. When the patients regained normal speech, the follow-up SPECT studies revealed normalization of the cerebral perfusion. This study demonstrates the occurrence of a focal dysfunction of cerebral perfusion in children with cerebellar mutism after posterior fossa surgery. These observations are useful in extending our understanding of the pathophysiology of this postoperative clinical syndrome. Received: 12 September 1997 Revised: 17 November 1997  相似文献   
999.
1000.
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