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   36013篇
  免费   7291篇
  国内免费   335篇
耳鼻咽喉   521篇
儿科学   752篇
妇产科学   988篇
基础医学   2720篇
口腔科学   2136篇
临床医学   7995篇
内科学   7946篇
皮肤病学   842篇
神经病学   4105篇
特种医学   1279篇
外国民族医学   1篇
外科学   4984篇
综合类   926篇
现状与发展   2篇
一般理论   4篇
预防医学   3620篇
眼科学   793篇
药学   1462篇
  4篇
中国医学   185篇
肿瘤学   2374篇
  2024年   239篇
  2023年   1441篇
  2022年   615篇
  2021年   1231篇
  2020年   1484篇
  2019年   913篇
  2018年   1992篇
  2017年   2036篇
  2016年   2059篇
  2015年   2233篇
  2014年   2532篇
  2013年   2690篇
  2012年   1760篇
  2011年   1863篇
  2010年   1928篇
  2009年   2166篇
  2008年   1469篇
  2007年   1313篇
  2006年   1341篇
  2005年   1069篇
  2004年   974篇
  2003年   908篇
  2002年   839篇
  2001年   785篇
  2000年   607篇
  1999年   663篇
  1998年   486篇
  1997年   472篇
  1996年   431篇
  1995年   376篇
  1994年   298篇
  1993年   269篇
  1992年   365篇
  1991年   342篇
  1990年   298篇
  1989年   303篇
  1988年   275篇
  1987年   228篇
  1986年   223篇
  1985年   226篇
  1984年   153篇
  1983年   141篇
  1982年   95篇
  1980年   75篇
  1979年   100篇
  1978年   92篇
  1977年   80篇
  1975年   104篇
  1974年   79篇
  1972年   75篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Zusammenfassung Grundlagen Die pulmonale Thrombendarterektomie stellt eine effektive Therapie zur Behandlung von Patienten mit chronisch thromboembolischer pulmonalar Hypertonie dar. Wir berichten über unsere Erfahrungen mit dieser Operationstechnik bei den ersten 9 Patienten. Methodik Zwischen 1992 und Oktober 1994 wurde bei 9 Patienten eine pulmonale Thrombendarterektomie durchgeführt. über eine mediane Sternotomie wurden die Pulmonalarterien beider Seiten bis in ihre subsegmentalen Aufzweigungen im Sinne einer echten Endarterektomie vom organisierten thromboembolischen Material befreit. Zumeist waren Perioden des totalen Kreislaufstillstandes in tiefer Hypothermie notwendig, wobei diese zunehmend verkürzt werden konnten und 3 Patienten vollst?ndig ohne Kreislaufstopp operiert wurden. Ergebnisse Die perioperative Mortalit?t betrug 11%, wobei der 1. Patient am 14. postoperativen Tag an den Folgen eines Reperfusions?dems verstarb. Alle anderen Patienten sind 4 bis 22 Monate (im Mittel 13 Monate) nach dem Eingriff am Leben und zeigen eine Hochsignifikante Verbesserung ihrer h?modynamischen Situation (mean PAP pr?operativ: 62 mm Hg, postoperativ: 30 mm Hg p<0,001; Cardiac Index pr?operativ: 2,1 1/min/m2, postoperativ: 3,6 l/min/m2 p=0,001). W?hrend pr?operativ alle Patienten in NYHA-Klasse III oder IV waren, sind die 8 überlebenden jetzt alle in Klasse I oder II. Schlu?folgerungen Die pulmonale Thrombendarterektomie bietet eine erfolgreiche Therapiem?glichkeit für Patienten mit chronisch thromboembolischer pulmonaler Hypertonie mit einer in Anbetracht fehlender konservativer Altermativen akzeptablen Mortalit?t und ausgezeichneten funktionellen Langzeitergebnissen.   相似文献   
73.
Food policy and public health.   总被引:1,自引:0,他引:1  
T Lang 《Public health》1992,106(2):91-125
  相似文献   
74.
The principles of promoting autonomy and independence underpin many approaches to improving the quality of nursing care for older people in whatever setting, and are in line with wider developments in health care such as the Patient's Charter. However, these concepts require careful definition if nursing practices which might promote autonomy and independence are to be identified. Although the generalizability of the research-based literature in this field is limited by a focus upon older people in continuing-care settings, a review of the literature found a number of indicators associated with attempts to promote patient autonomy and independence. These were grouped into the following categories: systems of care delivery which promote comprehensive individualized assessment and multidisciplinary care planning; attempts to encourage patients/clients to participate in decisions about their care; patterns of communication which avoid exerting power and control over patients/clients and attempts to modify the environment to promote independence and minimize risk. It is suggested that the review identifies a number of principles for nursing practice which can be applied in a range of care settings in order to promote the autonomy and independence of older people.  相似文献   
75.
76.
The results from a cohort study on the incidence of cancer and the mortality in a cohort of 2391 male workers producing magnesium metal are presented. The study population was restricted to employees with more than one year of work experience in the study plant between 1951 and 1974 and the cohort was observed from 1953 to 1984. Altogether 152 new cases of cancer were observed versus 132.6 expected. Six cases of cancer of the lip were found against 2.3 expected, 21 of stomach cancer against 12.8 expected, and 32 of lung cancer against 18.2 expected. A possible causal relation between exposure to factors in the work environment and the development of cancer is discussed.  相似文献   
77.
Summary In a 66-year-old woman signs and symptoms of bilateral opercular syndrome (Foix-Chavany-Marie-syndrome) developed progressively over a period of more than 10 years. Facio-linguo-velo-pharyngeo-masticatory diplegia with automatic-vol-untary dissociation was accompanied by motor aphasia and oral apraxia leading to a state of almost complete anarthria. Although it initially resembled the anterior biopercular syndrome there are also features indicating involvement of the posterior opercula. Although the aetiology remains obscure without pathological data, a bilateral focal brain atrophy is assumed. This is probably the first case documented by MRI and SPECT.Supported by the Hirnliga, Heidelberg, Federal Republic of Germany  相似文献   
78.
Andrew G. Herzog  MD  MSc 《Headache》2007,47(S2):S68-S78
Migraine is 3 times more common in postpubertal women than in men. Migraine is frequently exacerbated perimenstrually and commonly occurs exclusively at that time. It is often benefited by pregnancy and menopause. Estrogen withdrawal has been implicated as a mechanism for triggering migraines. The mechanism, however, is not well understood. Reproductive steroids have neuroactive properties that can modulate neuronal morphology and physiology. Increasing evidence suggests that circulating reproductive steroid levels regulate the balance of neuroexcitatory and neuroinhibitory activities in some brain regions by influencing synaptic plasticity. Estrogen has neuroexcitatory, whereas progesterone has neuroinhibitory, effects in most preclinical and clinical models. Several neurotransmitter systems that are implicated in migraine vary with reproductive steroid levels during the reproductive cycle. Estrogen stabilization may provide effective treatment in susceptible women, especially for catamenially exacerbated migraine.  相似文献   
79.
Local tissue renin-angiotensin systems have recently been discovered in various organs, and evidence is accumulating that inhibition of these local renin-angiotensin systems may contribute to the actions of converting enzyme (CE) inhibitors. Measurements of CE activity and angiotensin II concentrations revealed that after oral administration of CE inhibitors, CE was inhibited not only in lung vascular endothelium and blood, but also in the heart, kidney, vascular wall, brain and other organs. The functional significance of tissue CE inhibition is suggested first by the antihypertensive effect of brain CE inhibition in spontaneously hypertensive rats, second by the concomitant persistence of blood pressure decrease and CE inhibition in vascular wall and kidney after long-term oral CE inhibitor treatment and third by ex vivo experiments demonstrating marked effects of oral CE inhibitor pretreatment on cardiac function in isolated rat hearts. Local inhibition of tissue renin-angiotensin systems may be an important factor involved in the beneficial effects of CE inhibitors in such cardiovascular diseases as arterial hypertension, congestive heart failure and cardiac arrhythmias.  相似文献   
80.
AIM: The aim of this study was to investigate the nature and organization of maternal needs and priorities in a neonatal unit. BACKGROUND: The relationship between maternal needs and priorities appears to be an under studied area in neonatal nursing. METHODS: A quantitative survey was carried out based on 209 mothers with premature infants. Two self-assessment schedules were used: critical care maternal needs inventory (J. Leske, Heart and Lung 15, 27-42) and a ranking scale. The data were analysed with multivariate analysis. FINDINGS: Data analysis revealed clear priorities in maternal needs. In particular the need for accurate infant related information was a priority for 93% of the mothers. Good communication practices with professionals were also valued. The mothers displayed altruistic behaviour, and self-related needs took second place. It is proposed that maternal needs demonstrate a hierarchical organization. CONCLUSION: It is important for nurses to consider the individual needs of the mothers, simply because the satisfaction of these needs is essential for maternal well-being.  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