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   3248241篇
  免费   282194篇
  国内免费   14605篇
耳鼻咽喉   45622篇
儿科学   99486篇
妇产科学   82746篇
基础医学   513108篇
口腔科学   87984篇
临床医学   297338篇
内科学   567883篇
皮肤病学   89610篇
神经病学   283582篇
特种医学   129228篇
外国民族医学   199篇
外科学   516776篇
综合类   102130篇
现状与发展   92篇
一般理论   2273篇
预防医学   272731篇
眼科学   74327篇
药学   220305篇
  22篇
中国医学   9184篇
肿瘤学   150414篇
  2021年   55952篇
  2020年   37388篇
  2019年   58738篇
  2018年   73725篇
  2017年   56903篇
  2016年   62791篇
  2015年   77041篇
  2014年   113894篇
  2013年   179053篇
  2012年   90459篇
  2011年   89128篇
  2010年   119305篇
  2009年   125695篇
  2008年   75823篇
  2007年   77845篇
  2006年   89481篇
  2005年   84005篇
  2004年   86071篇
  2003年   76586篇
  2002年   65984篇
  2001年   85513篇
  2000年   77234篇
  1999年   81209篇
  1998年   64696篇
  1997年   62866篇
  1996年   60232篇
  1995年   55701篇
  1994年   49724篇
  1993年   46395篇
  1992年   57792篇
  1991年   55133篇
  1990年   52217篇
  1989年   51831篇
  1988年   48522篇
  1987年   47418篇
  1986年   45213篇
  1985年   45762篇
  1984年   43715篇
  1983年   40348篇
  1982年   40388篇
  1981年   38172篇
  1980年   36108篇
  1979年   36953篇
  1978年   33583篇
  1977年   30917篇
  1976年   28080篇
  1975年   26598篇
  1974年   27731篇
  1973年   26662篇
  1972年   25099篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
941.
The author describes a concept of automobilisation of the cervical spine and suboccipital joints. The well known biomechanic peculiarities of cervical spine are transformed in a therapeutic setting to allow a form of automobilisation within a closed system of head and underlying base. The so resulting new patterns of movement – the so-called “advanced movement”– differ from those usually exercised. Slow motion moving and low strength efforts are resulting in mobilisation of important vertebral and soft tissue structures.  相似文献   
942.
Prat  F. 《Acta endoscopica》2002,32(2):507-510
Acta Endoscopica - L’hémorragie iatrogène en endoscopie digestive reste pour l’essentiel l’apanage des techniques de résection tumorale et de la...  相似文献   
943.
944.
In standing, there are small sways of the body. Our interest is to use an artificial task to illuminate the mechanisms underlying the sways and to account for changes in their size. Using the ankle musculature, subjects balanced a large inverted pendulum. The equilibrium of the pendulum is unstable and quasi-regular sway was observed like that in quiet standing. By giving full attention to minimising sway subjects could systematically reduce pendulum movement. The pendulum position, the torque generated at each ankle and the soleus and tibialis anterior EMGs were recorded. Explanations about how the human inverted pendulum is balanced usually ignore the fact that balance is maintained over a range of angles and not just at one angle. Any resting equilibrium position of the pendulum is unstable and in practice temporary; movement to a different resting equilibrium position can only be accomplished by a biphasic 'throw and catch' pattern of torque and not by an elastic mechanism. Results showed that balance was achieved by the constant repetition of a neurally generated ballistic-like biphasic pattern of torque which can control both position and sway size. A decomposition technique revealed that there was a substantial contribution to changes in torque from intrinsic mechanical ankle stiffness; however, by itself this was insufficient to maintain balance or to control position. Minimisation of sway size was caused by improvement in the accuracy of the anticipatory torque impulses. We hypothesise that examination of centre of mass and centre of pressure data for quiet standing will duplicate these results.  相似文献   
945.
BACKGROUND: The risk for allergic reactions depends on the sensitivity of individuals and the quantities of offending food ingested. The sensitivity varies among allergic individuals, as does the threshold dose of a food allergen capable of inducing an allergic reaction. OBJECTIVE: This study aimed at determining the distribution of minimum provoking doses of hazelnut in a hazelnut-allergic population. METHODS: Thirty-one patients with a history of hazelnut-related allergic symptoms, a positive skin prick test to hazelnut and/or an elevated specific IgE level, were included. Double-blind, placebo-controlled food challenges (DBPCFC) were performed with seven increasing doses of dried hazelnut (1 mg to 1 g hazelnut protein) randomly interspersed with seven placebo doses. RESULTS: Twenty-nine patients had a positive challenge. Itching of the oral cavity and/or lips was the first symptom in all cases. Additional gastrointestinal symptoms were reported in five patients and difficulty in swallowing in one patient. Lip swelling was observed in two patients, followed by generalized urticaria in one of these. Threshold doses for eliciting subjective reactions varied from a dose of 1 mg up to 100 mg hazelnut protein (equivalent to 6.4-640 mg hazelnut meal). Extrapolation of the dose-response curve showed that 50% of our hazelnut-allergic population will suffer from an allergic reaction after ingestion of 6 mg (95% CI, 2-11 mg) of hazelnut protein. Objective symptoms were observed in two patients after 1 and 1,000 mg, respectively. CONCLUSION: DBPCFCs demonstrated threshold doses in half of the hazelnut-allergic patients similar to doses previously described to be hidden in consumer products. This stresses the need for careful labelling and strategies to prevent and detect contamination of food products with hazelnut residues.  相似文献   
946.
947.
Ten oxacillin-sensitive Staphylococcus aureus strains were grown on agar containing four times their ciprofloxacin MIC to determine if exposure to ciprofloxacin would increase their resistance to oxacillin. All strains grew on the ciprofloxacin-containing agar and subsequently grew on oxacillin-salt agar. The geometric mean MICs for oxacillin increased one- to sixteen-fold and remained elevated after ten passages on antibiotic-free agar. The mecA gene was not detected in any strain. There was no increase in oxacillin MICs when the bacteria were passaged on agar containing four times their MIC of piperacillin/tazobactam. Exposure of oxacillin-sensitive strains of Staphylococcus aureus to ciprofloxacin may increase their MICs to oxacillin. Electronic Publication  相似文献   
948.
E. Soncini  A. Petit   《ITBM》2002,23(3):172
Regulations evolve and risks management becomes one of the biomedical engineers' preoccupations. Thus, risks are various, and consequently it is difficult to identify, to manage and to bring them under control. Furthermore, regulations exist for sectors like healthcare technology monitoring, but it is not the same thing for instance for the risks linked to the maintenance. Thus regulation in the sector of maintenance evolves and the decree of the 1st July law of health safety is going to modify the biomedical environment. The goal of this work is to study the tools and the methods of risks management that have been used for several years in the industrial field and to use them for some biomedical equipment like monitors or IV pumps. These methods adapted to these equipment will allow us to determine some appropriate rules of maintenance.  相似文献   
949.
950.
Polyploidization and centrosome hyperamplification in inflammatory bronchi   总被引:1,自引:0,他引:1  
OBJECTIVE AND DESIGN: Inflammatory and tumorous bronchi were screened in order to obtain new tumor relevant cytogenetic parameters. MATERIAL OR SUBJECTS: Bronchial cells of 32 patients were cultivated by standard cell culture procedures. METHODS: Tetraploidy and aneuploidy was determined by enumeration of chromosome 7 and 8 versus the number of centrosomes. The resulting data were correlated with histopathological data. RESULTS: Tetra- and aneuploidy of epithelial cells were detectable in 76% of tumor cell cultures, 75% of high grade inflammatory tissues and 40% of non- and low grade-inflammatory tissues. Additionally, we observed centrosome hyper-amplification and multipolar mitoses not only in the tumor but also in the early stages of inflammation. CONCLUSION: Inflammatory bronchi already show tumor-specific features and may consequently represent the preliminary genetic stage of cancer development in bronchi.  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