全文获取类型
收费全文 | 13316篇 |
免费 | 736篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 107篇 |
儿科学 | 390篇 |
妇产科学 | 193篇 |
基础医学 | 1686篇 |
口腔科学 | 405篇 |
临床医学 | 1397篇 |
内科学 | 2669篇 |
皮肤病学 | 165篇 |
神经病学 | 1249篇 |
特种医学 | 375篇 |
外科学 | 2061篇 |
综合类 | 110篇 |
一般理论 | 9篇 |
预防医学 | 883篇 |
眼科学 | 308篇 |
药学 | 1068篇 |
中国医学 | 20篇 |
肿瘤学 | 983篇 |
出版年
2023年 | 105篇 |
2022年 | 132篇 |
2021年 | 244篇 |
2020年 | 223篇 |
2019年 | 319篇 |
2018年 | 298篇 |
2017年 | 288篇 |
2016年 | 316篇 |
2015年 | 305篇 |
2014年 | 440篇 |
2013年 | 683篇 |
2012年 | 904篇 |
2011年 | 914篇 |
2010年 | 483篇 |
2009年 | 487篇 |
2008年 | 818篇 |
2007年 | 855篇 |
2006年 | 800篇 |
2005年 | 729篇 |
2004年 | 720篇 |
2003年 | 677篇 |
2002年 | 617篇 |
2001年 | 149篇 |
2000年 | 115篇 |
1999年 | 160篇 |
1998年 | 176篇 |
1997年 | 164篇 |
1996年 | 124篇 |
1995年 | 109篇 |
1994年 | 118篇 |
1993年 | 85篇 |
1992年 | 87篇 |
1991年 | 98篇 |
1990年 | 96篇 |
1989年 | 90篇 |
1988年 | 77篇 |
1987年 | 77篇 |
1986年 | 80篇 |
1985年 | 91篇 |
1984年 | 75篇 |
1983年 | 68篇 |
1982年 | 92篇 |
1981年 | 53篇 |
1980年 | 56篇 |
1979年 | 61篇 |
1978年 | 42篇 |
1977年 | 36篇 |
1976年 | 38篇 |
1975年 | 29篇 |
1974年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Grasp stability during object manipulation is achieved by the grip forces applied normal to the grasped surfaces increasing and decreasing in phase with increases and decreases of destabilizing load forces applied tangential to the grasped surfaces. This force coordination requires that the CNS anticipates the grip forces that match the requirements imposed by the self-generated load forces. Here, we use functional MRI (fMRI) to study neural correlates of the grip-load force coordination in a grip-load force task in which six healthy humans attempted to lift an immovable test object held between the tips of the right index finger and thumb. The recorded brain activity was compared with the brain activity obtained in two control tasks in which the same pair of digits generated forces with similar time courses and magnitudes; i.e., a grip force task where the subjects only pinched the object and did not apply load forces, and a load force task, in which the subjects applied vertical forces to the object without generating grip forces. Thus neither the load force task nor the grip force task involved coordinated grip-load forces, but together they involved the same grip force and load force output. We found that the grip-load force task was specifically associated with activation of a section of the right intraparietal cortex, which is the first evidence for involvement of the posterior parietal cortex in the sensorimotor control of coordinated grip and load forces in manipulation. We suggest that this area might represents a node in the network of cortical and subcortical regions that implement anticipatory control of fingertip forces for grasp stability. 相似文献
52.
Sana Eltayeb Anna-Lena Berg Hans Lassmann Erik Wallström Maria Nilsson Tomas Olsson Anders Ericsson-Dahlstrand Dan Sunnemark 《Journal of neuroinflammation》2007,4(1):14-13
Background
The CC chemokine receptors CCR1, CCR2 and CCR5 are critical for the recruitment of mononuclear phagocytes to the central nervous system (CNS) in multiple sclerosis (MS) and other neuroinflammatory diseases. Mononuclear phagocytes are effector cells capable of phagocytosing myelin and damaging axons. In this study, we characterize the regional, temporal and cellular expression of CCR1, CCR2 and CCR5 mRNA in the spinal cord of rats with myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (MOG-EAE). While resembling human MS, this animal model allows unique access to CNS-tissue from various time-points of relapsing neuroinflammation and from various lesional stages: early active, late active, and inactive completely demyelinated lesions. 相似文献53.
54.
55.
Anders B. Fischer M.D. 《World journal of surgery》1984,8(3):293-302
One thousand twenty-five patients underwent a Billroth II resection for duodenal ulcer between 1948 and 1956. The operative mortality rate was 2.4%. At follow-up between 22 and 30 years later, 522 had died and 423 patients were traced. Recurrent ulcer appeared in 2.6% of the cases. Postgastrectomy symptoms occurred with the following frequency: dumping 10%, diarrhea 5%, vomiting 7%, and pain 4%. Anemia developed in 18%, hypoalbuminemia and hypocalcemia in 40 and 15%, respectively. Eleven percent had lost more than 10 kg in weight. Tuberculosis was found in 3% of the cases. While 90% of the patients were satisfied with the result, 10% were failures. The overall mortality rate was significantly increased because of suicide. Gastric carcinoma was the cause of death no more often than expected.
Supported by grants from the Danish Medical Research Council (No. 512-8760) and Købmand i Odense Johann & Hanne Weimann, født Seedorffs legat. 相似文献
Resumen En años anteriores la gastrectomía Billroth II fue un procedimiento operatorio de uso común en el tratamiento de la úlcera duodenal. Los promisorios resultados de la vagotomía con drenaje, vagotomía y antrectomía y, especialmente, la vagotomía de células parietales han reducido el rol de la resección de tipo Bilroth II. El propósito del presente estudio es describir los resultados a largo plazo en un grupo de pacientes sometidos a gastrectomía Billroth II por úlcera duodenal aproximadamente 25 años antes.Entre 1948 y 1956, 1 025 pacientes consecutivos, 810 hombres y 190 mujeres, fueron sometidos a resección Billroth II por úlcera duodenal. La mortalidad operatoria fué de 2,4%. Durante el período de seguimiento entre 22 y 30 años, 522 pacientes habían muerto y 423 pacientes pudieron ser ubicados para seguimiento. Síntomas de post-gastrectomía fueron observados con la incidencia siguiente: dumping 10%, diarrea 5%, vómito 7% y dolor 4%. La anemia se presentó en el 18%, hipoalbuminemia e hipocalcemia en el 40% y en el 15% respectivamente. Se presentó tuberculosis en el 3% de los casos. El 90% de los pacientes se mostraron satisfechos con el resultado de la operación, pero el 10% restante indicó la falla del tratamiento. La mortalidad global resultó significativamente incrementada debido a una alta incidencia de suicidio. El carcinoma gástrico fue causa de muerte con una frecuencia no aumentada, o sea que no se encontró un mayor riesgo de muerte por carcinoma de esófago o del remanente gástrico.
Résumé De 1948 à 1956, 1 025 malades atteints d'ulcère duodénal ont subi une opération de Billroth II. La mortalité a été de 2,4%. Au cours de l'évolution de 22 à 30 ans après l'intervention, 522 opérés sont décédés et 423 ont été suivis. La fréquence de la récidive a été de 2,6%. Les symptômes après gastrectomie ont atteint les taux suivants: dumping 10%, diarrhée 5%, vomissements 7%, douleur 4%. L'anémie a été constatée dans 18% des cas, l'hypoalbuminémie dans 40% des cas et l'hypocalcémie dans 15% des cas, onze pour cent des opérés ont accusé une chute pondérale supérieure à 10 kg; 3% ont présenté une tuberculose. Au total 90% des malades se sont déclarés satisfaits de l'intervention, encore que certains opérés se soient suicidés, ce nombre intervenant dans la mortalité globale. La mortalité par cancer n'a pas dépassé le taux accusé par la population en général.
Supported by grants from the Danish Medical Research Council (No. 512-8760) and Købmand i Odense Johann & Hanne Weimann, født Seedorffs legat. 相似文献
56.
A low intake of selenium is associated with increased cardiovascular mortality. This could be reduced by supplementation with selenium and coenzyme Q10. D-dimer, a fragment of fibrin mirroring fibrinolysis, is a biomarker of thromboembolism, increased inflammation, endothelial dysfunction and is associated with cardiovascular mortality in ischemic heart disease. The objective was to examine the impact of selenium and coenzyme Q10 on the level of D-dimer, and its relationship to cardiovascular mortality. D-dimer was measured in 213 individuals at the start and after 48 months of a randomised double-blind placebo-controlled trial with selenium yeast (200 µg/day) and coenzyme Q10 (200 mg/day) (n = 106) or placebo (n = 107). The follow-up time was 4.9 years. All included individuals were low in selenium (mean 67 μg/L, SD 16.8). The differences in D-dimer concentration were evaluated by the use of T-tests, repeated measures of variance and ANCOVA analyses. At the end, a significantly lower D-dimer concentration was observed in the active treatment group in comparison with those on placebo (p = 0.006). Although D-dimer values at baseline were weakly associated with high-sensitive CRP, while being more strongly associated with soluble tumour necrosis factor receptor 1 and sP-selectin, controlling for these in the analysis there was an independent effect on D-dimer. In participants with a D-dimer level above median at baseline, the supplementation resulted in significantly lower cardiovascular mortality compared to those on placebo (p = 0.014). All results were validated with a persisting significant difference between the two groups. Therefore, supplementation with selenium and coenzyme Q10 in a group of elderly low in selenium and coenzyme Q10 prevented an increase in D-dimer and reduced the risk of cardiovascular mortality in comparison with the placebo group. The obtained results also illustrate important associations between inflammation, endothelial function and cardiovascular risk. 相似文献
57.
58.
59.
Jan Petter Arnestad M.D. Anders Bengtsson M.D. Ph.D. Jan-Peter Bengtson M.D. Ph.D. Larsolof Hafstrom M.D. Ph.D. Heinz Redl Ph.D. Günther Schlag M.D. 《World journal of surgery》1995,19(6):861-866
Fourteen patients with liver tumor malignancy and sixteen patients with malignant melanoma localized to one limb were studied regarding leukocyte activation with the release of polymorphonuclear neutrophilic (PMN) elastase and of neopterin and formation of cytokines (TNF- and Il-6) during the surgical treatment. Patients undergoing liver resection (n=10), abdominal hysterectomy (n=10), or hip replacement surgery (n=10) served as control groups. Isolated hyperthermic liver perfusion was performed with cytostatic-containing perfusate (melphalan and cisplatinum). Patients with recurrent malignant melanoma confined to one limb underwent isolated hyperthermic limb perfusion with cytostatic-containing perfusate (melphalan). Blood samples for determination of PMN elastase, neopterin, TNF-, and IL-6 were drawn from the patients preoperatively, 1 minute before the start of the perfusion, 60 and 120 minutes after the start of the perfusion, and 24 hours postoperatively. Samples from the perfusate were drawn 60 minutes after the start of the perfusion. High concentrations of plasma PMN clastase were found both in patients undergoing liver and limb perfusion and in patients undergoing liver resection surgery. Elevated concentrations of Il-6 were found in the patients undergoing liver perfusion and in patients undergoing liver resection. In none of the patients were there increased concentrations of neopterin or TNF-. The perfusate contained high concentrations of PMN elastase, neopterin, and IL-6. This study also demonstrated that major surgery leads to elevated concentrations of PMN elastase and IL-6. An increase of PMN elastase and IL-6 was seen in response to perfusion and to surgical trauma.
Resumen Catorce pacientes con tumores malignos del hígado y 16 pacientes con melanoma maligno localizado en una extremidad fueron estudiados en relación con la activación de leucocitos con liberación de elastasa de PMN y de neopterina y la formación de citocinas (FNT- e IL-6) en el curso del tratamiento quirúrgico. Pacientes sometidos a resección del hígado (n=10), histerectomía abdominal (n=10) y reemplazo de cadera (n=10) sirvieron como grupos control. Se realizó perfusión hipertérmica aislada del hígado con perfusato citostácico (melfalán y cisplatino). Los pacientes con melanoma maligno recurrente confinado a una extremidad fueron sometidos a perfusión hipertérmica aislada de la extremidad con perfusato citostácico (melfalán). Se tomaron muestras de sangre para determinación preoperatoria de elastasa de PMN, neopterina, FNT- e IL-6, un minuto antes de comenzar la perfusión, 60 y 120 minutos después del comienzo de la perfusión y 24 horas después de la operación. Se tomaron muestras del perfusato a los 60 minutos luego del comienzo de la perfusión. Se encontraron altas concentraciones de elastasa de PMN tanto en los pacientes sometidos a perfusión hepática o de la extremidad, como en los pacientes sometidos a resección hepática. Se encontraron concentraciones elevadas de IL-6 en los pacientes sometidos a perfusión hepática y en los pacientes sometidos a resección del hígado. En ningún paciente se encontraron concentraciones aumentadas de neopterina o de FNT-. El perfusato contenía altas concentraciones de elastasa de PMN, neopterina e IL-6. Se encontró un aumento en la elastasa de PMN y en la IL-6 en respuesta a la perfusión y al trauma quirúrgico.
Résumé Quatorze patients ayant une tumeur maligne du foie et 16 patients ayant un mélanome malin localisé à une extrémité ont été étudiés en ce qui concerne l'activation des leucocytes associée à un relargage d'élastase PMN et de néoptérine ainsi que la formation de cytokinines (TNF- et IL-6) pendant le traitement chirurgical. Trente patients avant eu soit une résection hépatique (n=10), soit une hystérectomie abdominale (n=10) ou une prothèse de hanche (n=10) ont servi de témoins. On a perfusé le foie avec un perfusât de cytostatiques (mélphalane et cis-platine). Les patients ayant un mélanome malin d'une extrémité ont eu une perfusion isolée hyperthermique avec une perfusion de cytostatique (mélphanane). Des échantillons du sang ont été retirés pour déterminer les taux d'élastase PMN, de la néoptérine, du TNF-, et de l'IL-6 en préopératoire, une minute avant le début de la perfusion, 60 et 120 minutes après le début de la perfusion, et 24 heures postopératoirement. Des échantillons ont été retirés 60 minutes après le début de la perfusion. Des concentration élevées d'élastase PMN ont été retrouvées à la fois chez les patients ayant une perfusion hépatique et de l'extrémité et chez les patients ayant eu une résection du foie. Des concentration élevées en IL-6 ont été retrouvées chez le patient ayant une perfusion du foie et chez le patient ayant une résection hépatique. Les concentrations en néoptérine et en TNF- n'étaient pas élevées. Le liquide de perfusion contenait des concentrations élevées en élastase PMN, néoptérine et en IL-6. Cette étude démontre aussi que la chirurgie majeure est associée avec des concentrations élevées en PMN elastase et IL-6. Une augmentation en PMN-élastase et en IL-6 a été retrouvée en réponse à la perfusion et au traumatisme chirurgical.相似文献
60.