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   14009篇
  免费   1141篇
  国内免费   13篇
耳鼻咽喉   43篇
儿科学   351篇
妇产科学   547篇
基础医学   1998篇
口腔科学   736篇
临床医学   1618篇
内科学   2055篇
皮肤病学   309篇
神经病学   1277篇
特种医学   540篇
外科学   2230篇
综合类   59篇
一般理论   17篇
预防医学   1659篇
眼科学   149篇
药学   747篇
中国医学   5篇
肿瘤学   823篇
  2023年   276篇
  2022年   319篇
  2021年   513篇
  2020年   447篇
  2019年   371篇
  2018年   464篇
  2017年   450篇
  2016年   412篇
  2015年   439篇
  2014年   828篇
  2013年   805篇
  2012年   617篇
  2011年   583篇
  2010年   568篇
  2009年   581篇
  2008年   516篇
  2007年   530篇
  2006年   519篇
  2005年   438篇
  2004年   412篇
  2003年   396篇
  2002年   382篇
  2001年   421篇
  2000年   405篇
  1999年   347篇
  1998年   217篇
  1997年   167篇
  1996年   164篇
  1995年   165篇
  1994年   174篇
  1993年   143篇
  1992年   223篇
  1991年   210篇
  1990年   172篇
  1989年   156篇
  1988年   176篇
  1987年   83篇
  1986年   53篇
  1985年   76篇
  1984年   82篇
  1983年   63篇
  1982年   74篇
  1981年   61篇
  1980年   45篇
  1978年   50篇
  1976年   44篇
  1974年   34篇
  1973年   47篇
  1972年   37篇
  1971年   36篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Emotional distress in junior house officers   总被引:23,自引:0,他引:23  
In a study of 170 junior house officers who were followed up from their fourth year in medical school mean levels of stress were higher than in other reported occupational groups, and the estimated prevalence of emotional disturbance was 50%, with 28% of the subjects showing evidence of depression. Nearly a fifth of the subjects reported occasional or frequent bouts of heavy drinking, a quarter took drugs for physical illness, and a few took drugs for recreation. Those who were emotionally distressed at the initial study and the follow up were more empathetic and more self critical than those who had low levels of stress on both occasions. Overwork was the most stressful aspect of their jobs, though the number of hours worked was not related to stress levels, unlike diet and sleep. The more stressed they were the more unfavourably they viewed aspects of their jobs. The incidence of distress is unacceptably high in junior house officers, and both they and the hospitals need to deal with the causes of the distress.  相似文献   
62.
Is the grading of breast carcinomas affected by a delay in fixation?   总被引:6,自引:0,他引:6  
Summary The effect of delay in fixation on the modified Bloom and Richardson grade of eight breast carcinomas was investigated. Topologically shuffled samples of each tumour were immersed in fixative at times of 0.5, 2, 4, 6, 18 and 24 h after surgical removal. The grade of each tumour was assessed at delays of 0.5 and 6 h. The tubule formation and nuclear pleomorphism components of the grade showed no change with a delay in fixation of 6 h. The number of mitotic figures declined by a mean of 53% over the same period and this resulted in a decrease in the histological grade of one of the tumours. The implications of these findings for the handling of breast specimens in a diagnostic histopathological laboratory are discussed.Some of these data were presented at the 162nd meeting of the Pathological Society of Great Britain and Ireland at Cambridge, 3 January 1991. Published as an abstract in J Pathol (1991) 163:154A  相似文献   
63.
64.
The organization of daily procedures within the operating theatre is considered in terms of rival perspectives on their patient held by surgeon and anaesthetist. The privileging of the surgeon's authority is challenged in anaesthetists' efforts to fabricate a distinctive position on the patient. While surgeons focus on patient as the carrier of disease, for the anaesthetist, the focus is upon the patient's complement of fitness. A postmodern analysis of the organization of surgery reflects the continual struggle between the two specialisms to privilege its particular definition of the surgical patient. In some circumstances, the struggle can have damaging consequences for patient care.  相似文献   
65.
1-beta-allyloxycarbonyloxymethyl-5-fluorouracil (4) and 1,3-bis(beta-allyloxycarbonyloxymethyl)-5-fluorouracil (5) were synthesised by reacting 5-fluorouracil with formaldehyde followed by treating the product with isopropenyl chloroformate. The monomers 4 and 5 were copolymerized separately with N-vinylpyrrolidinone to form linear copolymers and cross-linked polymer networks, respectively. The monomer reactivity ratios in the copolymerization of 4 with NVP were evaluated by both linear and non-linear methods and the effect of monomer feed composition on copolymer molecular weight was examined. The degradation of the polymer networks in phosphate buffer (pH 7.4) was investigated. The hydrolytic scission of the carbonate groups resulted in release of 5-fluorouracil and a decrease in cross-linking density. The time-dependent fractional release of the 5-FU could be fitted by a power relationship with exponents between 0.10 and 0.25.  相似文献   
66.
67.
In an attempt to tap underlying competencies, the ability of children with autism to comprehend pretend acts carried out by an experimenter was compared with that shown by controls. These acts consisted of the pouring of a pretend substance from an appropriate container onto a target figure. There was no significant difference in the groups' ability to identify the pretend substance involved, to predict the pretend outcome of the actions, or to reflect on the pretend nature of the episodes. However, the performance of controls on these latter two tasks was surprisingly poor, limiting the implications that might be drawn from the observed absence of group differences in comprehension abilities.We are very grateful to the teachers and headteachers of the following schools for their cooperation and assistance throughout the period of this research: John Worrall School, Sheffield; Doucecroft School, Kelvedon; East Hill First and Middle School, Sheffield; East Hill Second School, Sheffield; Mossbrook School, Sheffield; Priory School, Doncaster; The Rowan School, Dore; St. Mary's School, Sheffield. We also thank James Russell for his helpful comments of earlier drafts of this paper.  相似文献   
68.
Chronically hypoxic (CH) and normoxic control rats were used to assess the action of S9581, a water-soluble analogue of almitrine bismesylate. S9581 increased ventilation (Ve) by 34% in control and 20% in CH rats. During acute hypoxia Ve was raised and S9581 caused a further increase of 20% in both groups. Low doses of S9581 and almitrine enhanced the hypoxic ventilatory response in CH rats while high doses depressed it in both groups. Effects of S9581 on the pulmonary circulation were assessed in the isolated perfused lung of rats. As with almitrine a complex relationship of dose-dependent vasoconstriction and dilatation was revealed. In low doses, S9581 enhanced the hypoxic pulmonary vasoconstrictor response to 2% O2 whilst this was attenuated by high doses in both control and CH rats. S9581 seemed to act like almitrine bismesylate on both the ventilation (peripheral chemoreceptor) and the pulmonary circulation. For studying almitrine-like activity the water solubility of S9581 provides considerable advantages for the researcher.  相似文献   
69.
To investigate whether or not there is any relation between endometrial morphology and subsequent pregnancy rate, 47 couples with unexplained infertility were followed up for 3 years after they had had an endometrial biopsy. Each woman had an LH-timed endometrial biopsy performed in the luteal phase of the cycle. The biopsy was dated chronologically according to the luteinizing hormone (LH) surge and histologically using morphometric criteria. None of the women received any form of treatment in the endometrial biopsy cycle. Of 47 women with unexplained infertility, 36 (76.6%) (Group I) had 'in phase' endometrial development and 11 (23.4%) (Group II) had retarded endometrium. Women with normal endometrial development had a higher pregnancy rate than women with retarded endometrial development (50% vs. 9%; P less than 0.02). The fecundability during treatment cycles was higher in Group I than in Group II (0.051 vs. 0.008; P less than 0.05). In women with 'in phase' endometrium, treatment increased the monthly probability of conception (0.051 vs. 0.006; P less than 0.001). A precisely timed endometrial biopsy should be considered as part of the investigations for women with unexplained reproductive failure, to help determine prognosis.  相似文献   
70.
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