全文获取类型
收费全文 | 2738篇 |
免费 | 391篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 22篇 |
儿科学 | 128篇 |
妇产科学 | 36篇 |
基础医学 | 256篇 |
口腔科学 | 45篇 |
临床医学 | 457篇 |
内科学 | 817篇 |
皮肤病学 | 79篇 |
神经病学 | 252篇 |
特种医学 | 301篇 |
外科学 | 309篇 |
综合类 | 44篇 |
一般理论 | 1篇 |
预防医学 | 192篇 |
眼科学 | 30篇 |
药学 | 88篇 |
中国医学 | 5篇 |
肿瘤学 | 110篇 |
出版年
2023年 | 54篇 |
2022年 | 20篇 |
2021年 | 48篇 |
2020年 | 102篇 |
2019年 | 30篇 |
2018年 | 112篇 |
2017年 | 80篇 |
2016年 | 82篇 |
2015年 | 70篇 |
2014年 | 109篇 |
2013年 | 145篇 |
2012年 | 83篇 |
2011年 | 85篇 |
2010年 | 90篇 |
2009年 | 123篇 |
2008年 | 78篇 |
2007年 | 78篇 |
2006年 | 74篇 |
2005年 | 52篇 |
2004年 | 48篇 |
2003年 | 57篇 |
2002年 | 53篇 |
2001年 | 53篇 |
2000年 | 48篇 |
1999年 | 52篇 |
1998年 | 95篇 |
1997年 | 113篇 |
1996年 | 88篇 |
1995年 | 80篇 |
1994年 | 57篇 |
1993年 | 67篇 |
1992年 | 55篇 |
1991年 | 41篇 |
1990年 | 47篇 |
1989年 | 69篇 |
1988年 | 57篇 |
1987年 | 35篇 |
1986年 | 36篇 |
1985年 | 36篇 |
1984年 | 25篇 |
1983年 | 23篇 |
1982年 | 22篇 |
1981年 | 28篇 |
1980年 | 23篇 |
1979年 | 21篇 |
1977年 | 20篇 |
1974年 | 18篇 |
1971年 | 23篇 |
1968年 | 22篇 |
1933年 | 18篇 |
排序方式: 共有3172条查询结果,搜索用时 656 毫秒
101.
DM Clarkson 《Journal of medical engineering & technology》2013,37(3):125-131
An overview is provided of the scope and application of IEC TR 60825-9 in determination of hazards of non coherent optical radiation sources. Specific areas reviewed in detail include those relating to hazards of ultraviolet radiation, retinal thermal hazard and blue light photochemical hazard. The effect of spectral temperature on relative risk relating to retinal thermal hazard and blue light photochemical hazard are outlined. Assessment of risk factors of these hazards was determined using a range of measurement devices including spectral radiometer, broad band power meter and a locally developed device for determination of pulse profile of pulsed light sources. 相似文献
102.
103.
Jinjiao Wang Todd B. Monroe Adam Simning Yeates Conwell Thomas V. Caprio Xueya Cai Helena Temkin-Greener Ulrike Muench Fang Yu Song Ge Yue Li 《Pain Management Nursing》2021,22(1):36-43
BackgroundPain is common yet under-studied among older Medicare home health (HH) patients with Alzheimer's disease and related dementias (ADRD).AimsExamine (1) the association between ADRD and severe pain in Medicare HH patients; and (2) the impact of severe pain and ADRD on unplanned facility admissions in this population.DesignAnalysis of the Outcome and Assessment Information Set (OASIS) and Medicare claims data.Settings/Participants6,153 patients ≥65 years receiving care from a nonprofit HH agency in 2017.MethodsStudy outcomes included presence of severe pain and time-to-event measures of unplanned facility admissions (hospital, nursing home, or rehabilitation facilities). ADRD was identified using ICD-10 diagnosis codes and cognitive impairment symptoms. Logistic regression and Cox proportional hazard models were used to examine, respectively, the association between ADRD and severe pain, and the independent and interaction effects of severe pain and ADRD on unplanned facility admission.ResultsPatients with ADRD (n = 1,525, 24.8%) were less likely to have recorded severe pain than others (16.4% vs. 23.6%, p < .001). Adjusting for demographics, comorbidities, mental and physical functional status, and use of HH services, having severe pain was related to a 35% increase (hazard ratio [HR] = 1.35, p = .002) in the risk of unplanned facility admission, but the increase in such risk was the same whether or not the patient had ADRD.ConclusionsHH patients with ADRD may have under-recognized pain. Severe pain is a significant independent predictor of unplanned facility admissions among HH patients. 相似文献
104.
Platelet concentrates were prepared at twice the normal concentration and stored at room temperature for 7 days in either standard bags (controls) or bags to which 1 or 2 g of Amberlite resin beads charged with dibasic phosphate had been added. The resin beads served as a buffer system by providing a "slow release" form of phosphate ions as well as by binding CO2 produced during platelet metabolism. Control platelets demonstrated rapid falls in pH, ATP content, morphology score, and thrombin-induced nucleotide release after 24 hr of storage with a fall in pH to less than 6.0 by day 3. Profound ultrastructural changes and a rise in pO2, suggesting loss of platelet viability, accompanied these changes. In contrast, the resin-stored platelets remained near normal after 24 hr of storage, with preservation of discoid morphology, 95% of ATP levels, excellent ultrastructural appearance, and evidence of continued oxygen consumption after 3 days of storage. Even after 7 days of storage, ATP levels remained greater than 50% of baseline and ultrastructurally intact platelets were seen. In the 1-g resin bags the pH remained at baseline levels (6.9-7.0), while there was a rise in pH in the 2-g resin bags. These results demonstrate the beneficial effects of maintaining a higher pH during platelet storage and provide a new approach to studying the metabolic changes that occur during longer term storage. 相似文献
105.
New abnormalities in the morphology, cell surface receptors, and electrolyte metabolism of In(Lu) erythrocytes 总被引:1,自引:0,他引:1
The In(Lu) phenotype is inherited as an autosomal dominant trait and is characterized by suppression of the Lutheran, P1, i, and Aua erythrocyte blood group antigens. We have developed a monoclonal antibody (L21) that strongly agglutinates all erythrocytes except In(Lu), and we have identified eight In(Lu) individuals among 42,000 blood donors tested. Studies of two families confirmed the dominant mode of inheritance and revealed several new features of this phenotype. The erythrocytes of all five affected individuals from the two families exhibited diminished hemagglutination by the lectin concanavalin A, although they reacted normally with several other lectins. The erythrocytes of two affected individuals in one family exhibited marked acanthocytosis. The erythrocytes of the proposita of the other family exhibited a mild degree of poikilocytosis, but the cells of the other two affected individuals in this family had normal morphology. The osmotic fragility of fresh In(Lu) erythrocytes was normal, but after incubation for 24 hours at 37 degrees C in plasma the In(Lu) cells exhibited a marked increase in resistance to osmotic lysis. During the incubation period the erythrocytes lost K+ and their total cation content was diminished. These data indicate that in addition to the suppression of blood group antigens noted previously, the In(Lu) phenotype includes a variety of morphological abnormalities and a defect in electrolyte metabolism. The use of L21 and similar monoclonal antibodies provides a more sensitive means of detecting In(Lu) erythrocytes than typing with human anti-Lub antisera. 相似文献
106.
Previously reported cases of botulism in infants have been diagnosed as infant botulism; that is, botulism caused by intestinal colonization by Clostridium botulinum with intraluminal production and absorption of toxin. Foodborne botulism is caused by ingestion of preformed toxin. We describe an unusual case of foodborne botulism in a 6-month-old infant caused by the ingestion of improperly prepared home-canned baby food. This represents the youngest age of onset for foodborne botulism in the United States of which we are aware and illustrates the need to rule out foodborne botulism, which represents a public health emergency, regardless of the patient's age. The diagnosis could have been readily missed or delayed in this case because the weakness was rapidly progressive rather than insidious, as is typical of infant botulism. 相似文献
107.
Recurrent Spontaneous Paresthesia in the Upper Limb Could Be Due to Migraine: A Case Series 下载免费PDF全文
Sanjay Prakash DM Chaturbhuj Rathore DM Prayag Makwana MD Mitali Rathod MD 《Headache》2015,55(8):1143-1147
Transient neurologic dysfunction is a characteristic feature of migraine. About 20% of migraineurs may experience various symptoms in the absence of any headache at one time or another. Visual auras are the most common auras of migraine, and migraine is considered as the most common cause of transient vision loss in young patients. Sensory auras are the second most common migrainous auras. However, the literature is silent for isolated sensory aura as a migraine equivalent. Herein we report 14 patients with recurrent episodic paresthesia in the limbs and other body parts. All patients fulfilled the diagnostic criteria of “typical aura without headache” of ICHD‐3β. All patients were subjected to various investigations to rule out secondary causes. Ten patients received antimigraine drugs and all showed a positive response to therapy. Recurrent spontaneous paresthesia is quite common in the general population and many patients remain undiagnosed. We speculate that a subset of patients might be related to migrainous sensory auras. 相似文献
108.
109.
Leisha Diane Nolen Lynda Osadebe Jacques Katomba Jacques Likofata Daniel Mukadi Benjamin Monroe Jeffrey Doty Lem's Kalemba Jean Malekani Joelle Kabamba Pierre Lokwa Bomponda Jules Inonga Lokota Marcel Pie Balilo Toutou Likafi Robert Shongo Lushima Jean-Jacques Muyembe Tamfum Emile Wemakoy Okitolonda Andrea M. McCollum Mary G. Reynolds 《The American journal of tropical medicine and hygiene》2015,93(2):410-415
An increased incidence of monkeypox (MPX) infections in the Democratic Republic of the Congo was noted by the regional surveillance system in October 2013. Little information exists regarding how MPX is introduced into the community and the factors associated with transmission within the household. Sixty-eight wild animals were collected and tested for Orthopoxvirus. Two of three rope squirrels (Funisciurus sp.) were positive for antibodies to Orthopoxviruses; however, no increased risk was associated with the consumption or preparation of rope squirrels. A retrospective cohort investigation and a case–control investigation were performed to identify risk factors affecting the introduction of monkeypox virus (MPXV) into the community and transmission within the home. School-age males were the individuals most frequently identified as the first person infected in the household and were the group most frequently affected overall. Risk factors of acquiring MPXV in a household included sleeping in the same room or bed, or using the same plate or cup as the primary case. There was no significant risk associated with eating or processing of wild animals. Activities associated with an increased risk of MPXV transmission all have potential for virus exposure to the mucosa. 相似文献
110.
Tong S Lingappa JR Chen Q Shu B LaMonte AC Cook BT Birge C Chern SW Liu X Galloway R Mai le Q Ng WF Yang JY Butany J Comer JA Monroe SS Beard SR Ksiazek TG Erdman D Rota PA Pallansch MA Anderson LJ 《The Journal of infectious diseases》2004,190(6):1127-1131
Severe acute respiratory syndrome-associated coronavirus (SARS-CoV) emerged, in November 2002, as a novel agent causing severe respiratory illness. To study sequence variation in the SARS-CoV genome, we determined the nucleic acid sequence of the S and N genes directly from clinical specimens from 10 patients--1 specimen with no matched SARS-CoV isolate, from 2 patients; multiple specimens from 3 patients; and matched clinical-specimen/cell-culture-isolate pairs from 6 patients. We identified 3 nucleotide substitutions that were most likely due to natural variation and 2 substitutions that arose after cell-culture passage of the virus. These data demonstrate the overall stability of the S and N genes of SARS-CoV over 3 months during which a minimum of 4 generations for transmission events occurred. These findings are a part of the expanding investigation of the evolution of how this virus adapts to a new host. 相似文献