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   3670篇
  免费   380篇
  国内免费   33篇
耳鼻咽喉   34篇
儿科学   215篇
妇产科学   32篇
基础医学   506篇
口腔科学   103篇
临床医学   423篇
内科学   735篇
皮肤病学   28篇
神经病学   214篇
特种医学   155篇
外科学   412篇
综合类   102篇
一般理论   2篇
预防医学   515篇
眼科学   50篇
药学   344篇
中国医学   2篇
肿瘤学   211篇
  2022年   25篇
  2021年   56篇
  2019年   54篇
  2018年   67篇
  2017年   54篇
  2016年   49篇
  2015年   63篇
  2014年   95篇
  2013年   130篇
  2012年   144篇
  2011年   150篇
  2010年   112篇
  2009年   91篇
  2008年   141篇
  2007年   181篇
  2006年   153篇
  2005年   119篇
  2004年   139篇
  2003年   125篇
  2002年   131篇
  2001年   114篇
  2000年   119篇
  1999年   131篇
  1998年   86篇
  1997年   53篇
  1996年   58篇
  1995年   48篇
  1994年   73篇
  1993年   43篇
  1992年   101篇
  1991年   109篇
  1990年   100篇
  1989年   74篇
  1988年   87篇
  1987年   67篇
  1986年   62篇
  1985年   58篇
  1984年   43篇
  1983年   45篇
  1982年   37篇
  1981年   25篇
  1979年   34篇
  1978年   29篇
  1977年   33篇
  1976年   32篇
  1975年   27篇
  1974年   37篇
  1973年   37篇
  1972年   30篇
  1970年   27篇
排序方式: 共有4083条查询结果,搜索用时 15 毫秒
1.
While once considered as incurable systemic disease, treatment options for liver metastases have increased over the last 30 years and safety has improved dramatically, such that for a selected group of patients the hope of cure can now be offered with radical treatment, and low morbidity interventions can be offered which prolong survival, even in patients with more widely disseminated disease. Advances have been made in selection and surgical technique for liver resection and several adjuncts to resection now exist in the form of portal vein embolization, thermal ablation and targeted drug or radiotherapy delivery options. A natural consequence of these developments has been the delivery of services within fewer specialist units, with the result that later complications of therapy may present to local hospitals, rather than directly to the specialist centres. This article will describe the current common liver-directed therapies and outline the presentation and management of their complications.  相似文献   
2.
A K Carruth  D Booth 《AAOHN journal》1991,39(9):427-431
Future trends include a decrease in the number of adult children, an increase in the number of individuals over age 65, single parent families, working women, and individuals with no health care insurance. As more women with multiple roles and responsibilities enter and continue as part of the work force, employers recognize the need for support of family issues. Currently many employers lack initiative to make these needed changes. The occupational health nurses' role in relation to future policy for working caregivers includes assessment of how employment and caregiving impact work performance, job satisfaction, and health; and participation in defining public policy issues.  相似文献   
3.
Purpose To demonstrate that laparoscopic adjustable gastric banding may promote oesophageal dilatation or interfere with oesophageal motility. Methodology We report a case of a 67 year old female with a complex medical history who developed secondary achalasia from a slipped laparoscopic adjustable gastric band for weight loss. This led to recurring episodes of aspiration pneumonia requiring multiple admissions at North Shore Hospital, Auckland, New Zealand. Results A decision was made to remove the gastric band, five years after its initial insertion. At one month follow up, she was swallowing normally and oesophageal manometry had returned to normal. Conclusion Oesophageal dysmotility is sometimes seen in patients who have bands that are adjusted too tightly or in whom the band has slipped. This can lead to serious complications if unrecognized and incorrectly treated. Oesophageal symptoms in patients with adjustable bands must be considered secondary to the band until proven otherwise ie removal of the band or complete deflation.  相似文献   
4.
The irreversible muscarinic agonist, BM123 (63 mu moles kg-1, IV), was shown to produce central and peripheral physiological signs characteristic of cholinergic agonists. It also induced hypothermia, elevated nociceptive thresholds, reduced locomotor activity and disrupted spontaneous alternation performance in rats. The centrally acting muscarinic antagonist, atropine (50 mu mole kg-1) prevented or reduced all the above effects of BM123 when given SC 40 min prior to the BM123 injection. In contrast, the peripherally acting muscarinic antagonist, N-methyl atropine, prevented only the peripheral effects and the elevated nociceptive thresholds. Habituation of activity during a 20 min session was observed in all groups despite different levels of general activity. These findings are consistent with a model in which atropine and N-methyl atropine compete with BM123 for reversible association with the muscarinic receptor. In the case of BM123 administered alone, the association results, first, in agonist effects and proceeds to form an irreversible complex. Our present results show that by competing with BM123 for mAChR sites during the initial, reversible state of the interaction, atropine blocks the cholinomimetic effects of the agonist during both this state and its otherwise subsequent irreversible state.  相似文献   
5.
Paul L. Booth  W. Eric Thomas   《Brain research》1991,548(1-2):163-171
Ramified microglial cells were investigated in primary cultures of dissociated cerebral cortical tissue from rats. The identification of these cells was confirmed through immunohistochemical staining with 7 monoclonal antibodies selective for microglia. While there was significant variation in staining intensity with different antibodies, all stained the identified ramified cells; the antibodies OX-42 and ED1 yielded the most intense immunoreactivity. Based on distinctive morphological features, the microglia could be identified in living cultures where they were monitored using time-lapse video recording. This technique revealed extremely dynamic features of cellular plasticity and motility. Ramified microglia exhibited constant and rapid alterations in the size and shape of their cell body with an associated extension and retraction of processes; concomitantly, the cells moved about in a circumscribed area. These features of plasticity and motility were unique to this cell type, and correlated with OX-42 immunostaining. The microglia also possessed a differentially high level of pinocytotic activity; this too was correlated with OX-42 staining. From the nature of their morphological plasticity and motility, high pinocytosis, and cellular distribution, it is hypothesized that the ramified microglia specifically function as a system of fluid cleansing in normal brain tissue.  相似文献   
6.
A novel chiral redox-active ferrocene compound (FcVI) with amphiphilic properties has been synthesized. Cryogenic Transmission Electron Microscopy (cryo-TEM) has been used to estimate the shape and size of the FcVI aggregates in solution. Uni- and multi-lamellar vesicles (between 40 and 300 nm in diameter) were observed in water. Large particles (of more than 1 μm in diameter) with a hexagonal fine structure were found in 50 mM aqueous Na2SO4 solution. Sonication transformed the latter into ‘rosette’-like structures. Cyclic voltammetry has been employed to investigate the electrochemical properties of FcVI. The amphiphile adsorbed on graphite electrodes and a reversible electrochemical behaviour, characteristic of ferrocene, was observed with redox potentials between 330 and 350 mV.  相似文献   
7.
用混合粘合剂碳糊电极测定丁螺环酮   总被引:6,自引:1,他引:5  
用混合粘合剂碳糊电极测定丁螺环酮张正奇,曾鸽鸣,刘传桂,黎艳飞(湖南大学化学化工系,长沙410082)碳糊电极无毒,制作方便,表面更新容易,应用电位范围广,在药物分析中已有应用[1~5]。我们在液体石腊中加入添加剂,组成混合粘合剂,可显著改善电极的检...  相似文献   
8.
9.
In a series of experiments in which Mongolian gerbils were trained to jump over a variable gap, it was demonstrated that computation of the distance to be jumped was dependent on both image size and retinal motion, the latter cue being generated by the production of vertical translation movements of the head (head bobs). When image size was not a reliable cue, the animals produced more head bobs, thereby increasing the availability of retinal motion cues. The performance of the gerbils on various probe trials strongly suggested that they computed absolute distance by combining information about the velocity (or amplitude) of their head bobs with information about the velocity (or displacement) of the moving image of the landing platform.  相似文献   
10.
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