全文获取类型
收费全文 | 3600篇 |
免费 | 187篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 115篇 |
妇产科学 | 37篇 |
基础医学 | 407篇 |
口腔科学 | 313篇 |
临床医学 | 347篇 |
内科学 | 620篇 |
皮肤病学 | 28篇 |
神经病学 | 311篇 |
特种医学 | 197篇 |
外科学 | 554篇 |
综合类 | 65篇 |
预防医学 | 172篇 |
眼科学 | 27篇 |
药学 | 349篇 |
肿瘤学 | 236篇 |
出版年
2021年 | 25篇 |
2020年 | 34篇 |
2019年 | 35篇 |
2018年 | 67篇 |
2017年 | 47篇 |
2016年 | 36篇 |
2015年 | 37篇 |
2014年 | 69篇 |
2013年 | 147篇 |
2012年 | 120篇 |
2011年 | 132篇 |
2010年 | 86篇 |
2009年 | 85篇 |
2008年 | 132篇 |
2007年 | 134篇 |
2006年 | 177篇 |
2005年 | 143篇 |
2004年 | 157篇 |
2003年 | 141篇 |
2002年 | 129篇 |
2001年 | 123篇 |
2000年 | 127篇 |
1999年 | 111篇 |
1998年 | 60篇 |
1997年 | 56篇 |
1996年 | 44篇 |
1995年 | 65篇 |
1994年 | 47篇 |
1993年 | 37篇 |
1992年 | 77篇 |
1991年 | 67篇 |
1990年 | 64篇 |
1989年 | 81篇 |
1988年 | 86篇 |
1987年 | 91篇 |
1986年 | 74篇 |
1985年 | 84篇 |
1984年 | 51篇 |
1983年 | 63篇 |
1982年 | 32篇 |
1981年 | 24篇 |
1980年 | 22篇 |
1979年 | 39篇 |
1978年 | 45篇 |
1977年 | 37篇 |
1976年 | 28篇 |
1973年 | 26篇 |
1972年 | 28篇 |
1971年 | 21篇 |
1967年 | 25篇 |
排序方式: 共有3796条查询结果,搜索用时 203 毫秒
1.
Timothee Dub Bolette Sborg Peter Henrik Andersen Thorolfur Gudnason Hanne Nkleby Ann Lindstrand Rose-Marie Carlsson Hanna Nohynek 《Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin》2021,26(4)
Healthcare workers (HCWs) are at increased risk of both exposure and transmission of infectious disease. Two European Union (EU) directives state that health services are responsible for assessing their employees’ potential exposure to infectious diseases and offering immunisation free of charge. We assessed current policy for immunisation of HCWs and the availability of vaccine coverage data in the Nordic countries by surveying national vaccination experts in Denmark, Finland, Iceland, Norway and Sweden, as well as Swedish county medical officers (CMOs). All national experts and 17 of 21 Swedish CMOs responded. All EU countries had transposed the European directives into national law, while Norway and Iceland had similar national legislation. Recommendations or guidelines were issued in Denmark, Finland, Iceland, Norway and 15 of 17 responding Swedish counties. The range of diseases covered differed by countries and Swedish counties. HCW vaccine coverage data were not systematically collected; incomplete estimates were only available for Finland and two Swedish counties. In conclusion, recommendations or guidelines exist in the Nordic countries, but their impact cannot be assessed, as vaccine uptake among HCWs is not currently measured. Systematic collection of data is a necessary step towards improving HCW immunisation policy and practice in the Nordic countries. 相似文献
2.
S Bengtson A Carlsson M Relander K Knutson L Lidgren 《Acta orthopaedica Scandinavica》1987,58(6):662-665
Ten knees with early tissue breakdown after knee arthroplasty resulting in exposed prostheses were treated with different plastic surgical techniques. Six knees were successfully covered: four using a gastrocnemius musculocutaneous flap, one using a fasciocutaneous flap, and one using split-skin grafts. Four knees failed: two using local skin flaps and two using split-skin grafts. A gastrocnemius musculocutaneous flap seems to provide a reliable coverage of the exposed knee joint. 相似文献
3.
In Sweden, a psychiatry reform, aimed at improving the living conditions of the psychiatrically disabled, came into force in 1995. The aim of the present study was to evaluate the impact of the reform by investigating quality of life and standard of living 2 years later in a randomly selected group of people with longstanding psychiatric disability. Self-ratings and interviews were conducted in a study group and a control group. The study group consisted of 19 women and 18 men (mean age 46.1 years) diagnosed with neurosis, schizophrenia or affective disorder. The control group consisted of 19 women and 17 men (mean age 48.7 years). Self-rated quality of life was significantly poorer in the study group (P < 0.0001, unpaired t-test), and so was housing (P < 0.001, test of similar proportions in independent samples). We found no significant positive correlation between subjective quality of life and standard of living in either group but a significant negative correlation in the control group (P < 0.05; r = 0.40, Pearson correlation coefficient). The results suggest that, in 1997, people with longstanding psychiatric disability still had poorer quality of life than the general population. This may be due to factors other than outward standard of living. 相似文献
4.
5.
The effects of MPP+ (2.5–20 mg/kg) on the adrenal glands and heart were investigated in rats. At various periods after s.c. drug administration the rats were decapitated and tissue catecholamine levels were determined by means of HPLC with electrochemical detection. Adrenal dopamine (DA) levels were reduced at 2–8 h after MPP+ administration, but this decrease was followed by an elevation after 16 h and return to the control values after one week. Three successive injections of MPP+ caused a statistically significant elevation in adrenal DA, one day, with a tendency to elevation four and seven days after the last injection, whereas a severe (up to 96%) decrease in heart noradrenaline (NA) was found one day after the last injection. Seven days after the last injection a 50% depletion of NA in the heart was still observed. Pretreatment with GBR 12909 (30 mg/kg, 4 h) blocked the MPP+ (10 mg/kg, 2 h) induced reduction of adrenal DA levels, but at the same time GBR 12909 failed to block the effects of MPP+ in the heart. One day after three successive daily injections of MPP+ (10 mg/kg each), the DA-uptake inhibitor GBR 12909 (30 mg/kg, 6 h) could still induce an increase in adrenal DA.MPP+ appears to lack persistent cytotoxic action in the adrenal medulla but rather to cause a transient inhibition of DA synthesis followed by a compensatory stimulation. The inhibition can be blocked by specific inhibitor of the DA-uptake mechanism, suggesting a direct effect of MPP+ taken up by adrenomedullary cells. The data obtained so far do not suggest any involvement of peripheral dopaminergic nerves in the action of MPP+ on the adrenal medulla. The long-lasting depletion of the heart NA, however, suggests a lesion of peripheral noradrenergic nerves.Part of this work was presented at 6th International Symposium on Chromaffin Cell Biology, Marburg, Germany, 18–23 August 1991
Correspondence to: M. Kujacic at the above address 相似文献
6.
7.
Pneumonia: a deadly disease despite intensive care treatment 总被引:3,自引:0,他引:3
In a retrospective study of 30 patients with pneumonia treated in the intensive care unit, it was found that cultures from sputum and bronchial secretions did poorly correspond with blood cultures or serological tests. In only 15 of the patients a reliable etiological diagnosis was ever established. Mechanical ventilation was used in 22 patients, usually with a high oxygen need. At the start of this ventilation a significant blood pressure fall and a further pulmonary deterioration was observed. In fatal cases this pulmonary dysfunction was progressive. The overall mortality was 47%. When an FI02 above 0.6 was needed in the ventilator the mortality was 13/14 (93%). 相似文献
8.
Comparative in vivo evaluation of technetium and iodine labels on an anti-HER2 affibody for single-photon imaging of HER2 expression in tumors. 总被引:1,自引:0,他引:1
Anna Orlova Fredrik Y Nilsson Maria Wikman Charles Widstr?m Stefan St?hl J?rgen Carlsson Vladimir Tolmachev 《Journal of nuclear medicine》2006,47(3):512-519
In vivo diagnosis with cancer-specific targeting agents that have optimal characteristics for imaging is an important development in treatment planning for cancer patients. Overexpression of the HER2 antigen is high in several types of carcinomas and has predictive and prognostic value, especially for breast cancer. A new type of targeting agent, the Affibody molecule, was described recently. An Affibody dimer, His6-(ZHER2:4)2 (15.4 kDa), binds to HER2 with an affinity of 3 nmol/L and might be used for the imaging of HER2 expression. The use of 99mTc might improve the availability of the labeled conjugate, and Tc(I)-carbonyl chemistry enables the site-specific labeling of the histidine tag on the Affibody molecule. The goals of the present study were to prepare 99mTc-labeled His6-(ZHER2:4)2 and to evaluate its targeting properties compared with the targeting properties of 125I-4-iodobenzoate-His6-(ZHER2:4)2 [125I-His6-(ZHER2:4)2]. METHODS: The labeling of His6-(ZHER2:4)2 with 99mTc was performed with an IsoLink kit. The specificity of 99mTc-His6-(ZHER2:4)2 binding to HER2 was evaluated in vitro with SK-OV-3 ovarian carcinoma cells. The comparative biodistributions of 99mTc-His6-(ZHER2:4)2 and 125I-His6-(ZHER2:4)2 in tumor-bearing BALB/c nu/nu mice were determined. RESULTS: The labeling yield for 99mTc-His6-(ZHER2:4)2 was approximately 60% (50 degrees C), and the radiochemical purity was greater than 97%. The conjugate was stable during storage and under histidine and cysteine challenges and demonstrated receptor-specific binding. The biodistribution study demonstrated tumor-specific uptake levels (percentage injected activity per gram of tissue [%IA/g]) of 2.6 %IA/g for 99mTc-His6-(ZHER2:4)2 and 2.3 %IA/g for 125I-His6-(ZHER2:4)2 at 4 h after injection. Both conjugates provided clear imaging of SK-OV-3 xenografts at 6 h after injection. The tumor-to-nontumor ratios were much more favorable for the radioiodinated Affibody. CONCLUSION: The use of Tc(I)-carbonyl chemistry enabled us to prepare a stable, site-specifically labeled 99mTc-His6-(ZHER2:4)2 conjugate that was able to bind to HER2-expressing cells in vitro and in vivo. The indirectly radioiodinated conjugate provided better tumor-to-liver ratios. The labeling of Affibody molecules with 99mTc should be investigated further. 相似文献
9.
The first 150 words of the full text of this article appear below. Key points Coronary artery disease accounts for >30% ofdeaths in Western society. The diagnosis of myocardial infarctionshould be qualified by size, causation and time from occurrence. Mortalityis reduced by immediate or primary percutaneouscoronary intervention or thrombolysis within the first 24 hof onset of ST-segment elevation myocardial infarction. Strategiesto reduce platelet activation (glycoprotein IIb/IIIa receptorantagonists, or clopidogrel) are now recommended in the treatmentof high-risk non-ST-segment myocardial infarction/unstable angina. Elevatedserum troponins may be the result of non-ischaemic myocardialdamage, especially in critical illness.
Pathophysiology
Changes in the definition of terms relating to the diagnosisof myocardial infarction (MI) have evolved by better understandingof the pathophysiology culminating in the new term of acutecoronary syndrome (ACS). Figure 1 illustrates the processesthat occur in the development of an acute coronary event. 相似文献
10.
P S Eriksson B Carlsson O G Isaksson E Hansson L R?nnb?ck 《Brain research. Molecular brain research》1992,16(3-4):345-352
Primary astroglial cultures were incubated with delta (10(-6) M DPDPE) or kappa (10(-5) M U-50,488H) receptor agonists for 5 days. Thereafter, the acute inhibitory actions of delta or kappa receptor agonists on forskolin stimulated cAMP accumulation were assayed. The G alpha s, G alpha i-1 and G alpha i-2 mRNA levels were quantified after 5 days of either delta or kappa receptor agonist treatment using a solution hybridization, RNase protection assay. Pronounced effects were observed after 5 days of kappa receptor agonist [10(-5) M U-50,488H] incubation. This treatment resulted in an attenuation in the acute inhibitory action of delta and kappa receptor agonists. Furthermore, a decreased stimulatory action of forskolin was seen. Similar effects were also seen after delta receptor stimulation. We also investigated the effects after 24 h and 3 days of incubation with the kappa receptor agonist (10(-5) M) U-50,488H. The 24 h incubation resulted in a decreased sensitivity to the acute inhibitory action of delta and kappa receptor agonists in the astroglial cultures. This effect was further accentuated after the 3 days of incubation with 10(-5) M U-50,488H. No significant change was seen in the basal accumulation of cAMP after incubation with the kappa agonist U-50,488H. However, after 5 days of incubation with the delta agonist DPDPE, a significantly increased basal accumulation of cAMP was seen in the astroglial cultures. After 5 days of delta or kappa agonist incubation, an increase in G alpha s mRNA level and a decrease in G alpha i-2 mRNA level was seen compared with controls. No statistically significant alterations in the amount of G alpha i-1 mRNA were seen. The data obtained in the present study indicate that the effects of long-term opioid treatment alters the sensitivity of glial cell opioid receptors. Furthermore, long term opioid treatment induces alterations in glial G-protein mRNA levels. 相似文献