全文获取类型
收费全文 | 534409篇 |
免费 | 33951篇 |
国内免费 | 4019篇 |
专业分类
耳鼻咽喉 | 7378篇 |
儿科学 | 11159篇 |
妇产科学 | 13521篇 |
基础医学 | 75873篇 |
口腔科学 | 15101篇 |
临床医学 | 45403篇 |
内科学 | 107592篇 |
皮肤病学 | 12421篇 |
神经病学 | 39069篇 |
特种医学 | 21421篇 |
外国民族医学 | 82篇 |
外科学 | 81038篇 |
综合类 | 11932篇 |
现状与发展 | 6篇 |
一般理论 | 144篇 |
预防医学 | 27730篇 |
眼科学 | 13655篇 |
药学 | 44246篇 |
1篇 | |
中国医学 | 3663篇 |
肿瘤学 | 40944篇 |
出版年
2022年 | 3913篇 |
2021年 | 7326篇 |
2020年 | 4056篇 |
2019年 | 6247篇 |
2018年 | 8703篇 |
2017年 | 6511篇 |
2016年 | 7594篇 |
2015年 | 9492篇 |
2014年 | 12386篇 |
2013年 | 15601篇 |
2012年 | 22464篇 |
2011年 | 22417篇 |
2010年 | 13318篇 |
2009年 | 11885篇 |
2008年 | 18651篇 |
2007年 | 19415篇 |
2006年 | 18646篇 |
2005年 | 17392篇 |
2004年 | 15952篇 |
2003年 | 14777篇 |
2002年 | 13739篇 |
2001年 | 31091篇 |
2000年 | 31430篇 |
1999年 | 25975篇 |
1998年 | 6392篇 |
1997年 | 5240篇 |
1996年 | 4724篇 |
1995年 | 4323篇 |
1994年 | 3832篇 |
1993年 | 3472篇 |
1992年 | 17346篇 |
1991年 | 16121篇 |
1990年 | 15296篇 |
1989年 | 15019篇 |
1988年 | 13571篇 |
1987年 | 12962篇 |
1986年 | 11994篇 |
1985年 | 11129篇 |
1984年 | 7524篇 |
1983年 | 6166篇 |
1982年 | 3161篇 |
1979年 | 5967篇 |
1978年 | 3734篇 |
1977年 | 3359篇 |
1975年 | 2923篇 |
1974年 | 3420篇 |
1973年 | 3177篇 |
1972年 | 3138篇 |
1971年 | 2998篇 |
1969年 | 2735篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
971.
Background: Xenon is an odorless gas with low blood-gas solubility coefficient and without occupational and environmental hazards. This investigation was performed to evaluate the speed of induction, and respiratory and cardiovascular reactions to inhalation induction with xenon compared to an equianesthetic concentration of sevoflurane.
Results: Compared to equianesthetic sevoflurane, xenon produced a faster induction of anesthesia (14759 versus 71221 s, respectively) with smaller decreases in respiratory rate, tidal volume and minute ventilation. Both agents showed comparable cardiovascular stability and oxygen saturation during induction. One patient in the sevoflurane group had breath-holding and movements of extremities and another had only breath-holding. No patients in the xenon group experienced any complications.
Conclusion: Xenon produced a faster induction of anesthesia without any complications than sevoflurane. Xenon had smaller decreases in tidal volume and respiratory rate during induction than sevoflurane. Xenon might offer an alternative to sevoflurane for an inhalation induction.
Method Twenty-four adult ASA 1–2 patients premedicated with 0.05 mg/kg of midazolam were instructed to take vital capacity breaths of 1 minimum alveolar concentration (MAC) of either xenon or sevoflurane until they lost consciousness. Induction time, total ventilatory volume, tidal volume, respiratory rate, minute ventilation, end-tidal MAC fraction, cardiovascular parameters and oxygen saturation were recorded. The patients were interviewed on the following day to evaluate their acceptability rating of the inhalation inductions. 相似文献
Results: Compared to equianesthetic sevoflurane, xenon produced a faster induction of anesthesia (14759 versus 71221 s, respectively) with smaller decreases in respiratory rate, tidal volume and minute ventilation. Both agents showed comparable cardiovascular stability and oxygen saturation during induction. One patient in the sevoflurane group had breath-holding and movements of extremities and another had only breath-holding. No patients in the xenon group experienced any complications.
Conclusion: Xenon produced a faster induction of anesthesia without any complications than sevoflurane. Xenon had smaller decreases in tidal volume and respiratory rate during induction than sevoflurane. Xenon might offer an alternative to sevoflurane for an inhalation induction.
Method Twenty-four adult ASA 1–2 patients premedicated with 0.05 mg/kg of midazolam were instructed to take vital capacity breaths of 1 minimum alveolar concentration (MAC) of either xenon or sevoflurane until they lost consciousness. Induction time, total ventilatory volume, tidal volume, respiratory rate, minute ventilation, end-tidal MAC fraction, cardiovascular parameters and oxygen saturation were recorded. The patients were interviewed on the following day to evaluate their acceptability rating of the inhalation inductions. 相似文献
972.
S Kawano H Tanimura N Sato S Tsuji Y Takei T Ogihara K Nagano H Fusamoto T Kamada 《European journal of pharmacology》1992,211(1):55-60
Proton pump inhibitors have been reported to have a cytoprotective action in addition to the anti-secretory action of acid. The precise mechanism, however, remains obscure. In this study, the effects of proton pump inhibitors (omeprazole and NC-1300) on gastric mucosa hemodynamics and tissue oxygenation were investigated using organ reflectance spectrophotometry in a hemorrhagic shock-reperfusion model involving anesthetized rats. Neither drug affected gastric mucosa hemodynamics nor tissue oxygenation in the basal state before hemorrhage. During the hemorrhagic shock state, however, these drugs maintained tissue oxygenation and reduced ulcer formation, although they did not show a significant effect on gastric mucosa blood volume. The results suggest that both proton pump inhibitors have an anti-ulcer action by maintaining mucosal oxygenation in addition to the anti-secretory activity of acid. 相似文献
973.
We reported movement-related cortical potentials (MRCPs) in 11 patients with lesion of the dentate nucleus (Machado-Joseph disease (MJD) 7 cases, dentato-rubro-pallido-luysian atrophy (DRPLA)1, myoclonus epilepsy associated with ragged-red fibers (MERRF)1, dyssynergia cerebellaris myoclonica (DCM) 2), and compared with those of 7 cases of multiple system atrophy (MSA) who were postulated to have mild dentate lesions (striato-nigral degeneration 2 cases, Shy-Drager syndrome 2, sporadic olivo-ponto-cerebellar atrophy 3), and 7 control subjects without any neurological findings. Further we classified the diseases into the following two groups based on the lesion of the dentate nucleus. One was MJD group that had normal or slightly abnormal electroencephalogram (EEG), and the other was DN group (DRPLA, MERRF, DCM) that had markedly abnormal EEG. One of the main findings from this study was smaller slope of the Ns' in the MJD and DN group and normal slope of BP. There was no significant difference in the slope of Ns' between MJD patients and DN patients. This result shows EEG abnormalities have no influence on MRCP recordings. These results suggest that Ns' component may reflect the function in the cerebellar dentate nucleus, and that MRCP is a useful diagnostic method in patients with cerebellar ataxia. 相似文献
974.
We describe characteristic findings in a patient with Marchiafava-Bignami disease who was serially imaged with CT and MR. Involvement of the entire corpus callosum was visualized with both types of imaging. Following administration of gadolinium-DTPA, the lesion was clearly enhanced in the subacute stage.
Correspondence to: S. Otake 相似文献
975.
A Ishiguro T Nakahata Y Amano K Koike A Komiyama T Shimbo 《[Rinshō ketsueki] The Japanese journal of clinical hematology》1992,33(1):87-92
The cause of aplastic anemia associated with hepatitis (AAH) is as yet still unknown. There is a supposed relation to the immune mechanisms, however few reports have shown the effects of monocytes on the pathogenesis in the patients with AAH. We have reported a case of a 12-year-old boy with AAH related to cytomegaloviruses, and studied the hemopoietic progenitors. He showed pancytopenia and hypoplasia of the bone marrow on admission to our hospital. The culture studies showed that mononuclear cells (MNC) of the bone marrow produced few hemopoietic colonies in all cell lineages. However, the depletion of adherent cells from the MNC increased numbers of erythroid, neutrophil-macrophage and megakaryocyte colonies. Furthermore, the addition of adherent cells of the peripheral blood suppressed the colony formation in the aforementioned cell lineages by marrow MNC from which adherent cells, phagocytic cells and T-cells were abrogated. The results way suggest that monocytes play some soles in the pathogenesis of aplasia through inhibitor of hemopoiesis. 相似文献
976.
E Y Handelman 《AAOHN journal》1992,40(6):263-270
1. Health care workers need to know that hepatitis B vaccine provides a safe, effective protection for them against a significant occupational hazard. 2. Several theoretical models can be used to design hepatitis B education programs, including motivational theories, the Health Belief Model, and andragogy. Specific recommendations can be made about the plan, format, content, and evaluation of adult education programs about hepatitis B. Federal agencies, including the Department of Health and Human Services and the Department of Labor, have established criteria for hepatitis B education programs. 相似文献
977.
Y Mochizuki H Masuda S Kanazashi Y Hosoki K Itoh K Ohishi T Nishina Y Handa K Shiozawa Y Miwa 《Kansenshōgaku zasshi. The Journal of the Japanese Association for Infectious Diseases》1992,66(1):30-36
A systematic examination was performed for environmental food contamination by Salmonella in poultry farms, broiler chickens, broiler processing plants and meat on the market. Salmonella was isolated from 219 of 1197 samples and the serotypes showed a wide distribution. (Table 1-1). S. hadar accounted for 37.1% (96) of all isolations (259). The contamination rate of broiler chickens on arrival at broiler processing plants is relatively low. However, in the broiler processing plants, containers, processing machinery, cooling water and slaughters were highly contaminated by Salmonella, S. hadar being the most prominent serotype in the plants. 64% of chicken meat on the market was contaminated by Salmonella, S. hadar being the second most prominent serotype. 11% of the pork and none of the beef or horseflesh was contaminated by Salmonella. These results indicate that poultry is the main source of S. hadar infection in humans. However, no S. hadar was isolated from cultures of 119 samples of feed for chickens from each delivery (Table 1-1). Thus, as the main source of infection by S. hadar of broiler chickens, an association with the feed seems to be ruled out. S. hadar was isolated at three of 18 poultry farms within Shizuoka Prefecture. Follow-up studies were performed at the three poultry farms which revealed that in two of them, Salmonella was completely eradicated on completion of disinfection. In the other one farm, which is still being disinfected, various strains of Salmonella including S. hadar still survived. We conclude that the main cause of the problem is the magnification of contamination of Salmonella-free material during the process at the broiler processing plants.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
978.
T Ohashi F Yamamoto H Yamamoto H Ichikawa T Shibata Y Shimada T Ishikawa K Kagisaki Y Kumada Y Kawashima 《[Zasshi] [Journal]. Nihon Kyōbu Geka Gakkai》1992,40(11):1998-2004
The effects of potassium in reperfusion solution (RS) and the influence of sodium on this effect were studied. Experimental time course was as followed: 20 min working perfusion, 3 min cardioplegic infusion with St. Thomas Cardioplegic Solution followed by global ischemia for 33 or 35 min at 37.5 degrees C, 15 min early Langendorff reperfusion with several different potassium concentration modified with Krebs Henseleit Bicarbonate Buffer (KHBB) containing 145 mM and 110 mM sodium and 5 min late reperfusion with KHBB, followed by 20 min working perfusion. Potassium in RS possessed bell shaped dose response nature with optimal concentration of 10 mM in the condition of 145 mM sodium but 6 m in the condition of 110 mM in terms of percent recovery of aortic flow. Although higher potassium reperfusion produced less Creatine Kinase leakage. 相似文献
979.
K Ishino T Murakami H Nakayama M Yamada T Morimoto K Hisamochi T Tanaka Y Senoo S Teramoto 《Acta medica Okayama》1991,45(4):223-231
A biventricular bypass type total artificial heart (BVB-TAH) utilizing two pusher-plate pumps was developed and implanted in a sheep for 48 days with excellent results. A Hall effect sensor was utilized to operate each pump independently with a full stroke at variable rates (VR). With this system, the animal's hemodynamics was kept physiologically, and all metabolic parameters except hemoglobin and hematocrit returned to normal three weeks after implantation. However, signs of infection appeared on the forty-second day, and consequently the animal fell into a state of shock. Even at that time the BVB-TAH maintained circulation by increasing pumping rate automatically. On the forty-eighth day, the animal could not stand and suffered from anuria; the experiment was then terminated after 1,140 h pumping. At autopsy, there was an enlarged heart with an atrophic change, 1,900 ml of pleural effusion, and 3,100ml of ascites fluid. Blood culture taken on the forty-seventh day yielded Acinetobacter calcoaceticus. The BVB-TAH operated in an independent VR mode maintained entire circulation, and has a capability of substituting the native heart function in any situation. 相似文献
980.
Oxidative breakdown of octanoic acid is maintained in patients with cirrhosis despite advanced disease 总被引:1,自引:0,他引:1
M. Van de Casteele A. Luypaerts † B. Geypens † J. Fevery Y. Ghoos† & F. Nevens 《Neurogastroenterology and motility》2003,15(2):113-120
As an octanoic acid 13CO2 breath test is frequently used to test gastric emptying of solid food, the purpose of the present study was to study whether oxidative breakdown of octanoic acid is affected by severe liver disease. The design of our study was twofold. First, cirrhotic patients (n = 82) of varying severity were compared with healthy controls (n = 17). Values of half-time, time point of maximal expiration and cumulative recovery of octanoic acid breath tests (OBT) were not significantly different between them. Secondly, cirrhotic patients (n = 10) were studied before placement of transjugular intrahepatic portosystemic shunt, 4-7 days later and 1-2 months later. Values of half-time, time point of maximal expiration and cumulative recovery of consecutive OBTs did not change significantly. The OBT may therefore be a suitable test in the future to detect delayed gastric emptying of solids in cirrhotic patients with reduced liver function and portal hypertension. 相似文献