全文获取类型
收费全文 | 2083篇 |
免费 | 266篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 75篇 |
妇产科学 | 96篇 |
基础医学 | 353篇 |
口腔科学 | 14篇 |
临床医学 | 246篇 |
内科学 | 361篇 |
皮肤病学 | 24篇 |
神经病学 | 193篇 |
特种医学 | 44篇 |
外科学 | 315篇 |
综合类 | 35篇 |
一般理论 | 1篇 |
预防医学 | 220篇 |
眼科学 | 26篇 |
药学 | 221篇 |
中国医学 | 1篇 |
肿瘤学 | 112篇 |
出版年
2021年 | 21篇 |
2018年 | 19篇 |
2016年 | 21篇 |
2015年 | 23篇 |
2014年 | 51篇 |
2013年 | 62篇 |
2012年 | 82篇 |
2011年 | 72篇 |
2010年 | 44篇 |
2009年 | 41篇 |
2008年 | 87篇 |
2007年 | 93篇 |
2006年 | 75篇 |
2005年 | 87篇 |
2004年 | 78篇 |
2003年 | 86篇 |
2002年 | 89篇 |
2001年 | 70篇 |
2000年 | 61篇 |
1999年 | 63篇 |
1998年 | 31篇 |
1997年 | 28篇 |
1996年 | 33篇 |
1995年 | 20篇 |
1994年 | 32篇 |
1993年 | 23篇 |
1992年 | 51篇 |
1991年 | 47篇 |
1990年 | 45篇 |
1989年 | 41篇 |
1988年 | 39篇 |
1987年 | 35篇 |
1986年 | 39篇 |
1985年 | 36篇 |
1984年 | 38篇 |
1983年 | 32篇 |
1982年 | 28篇 |
1981年 | 30篇 |
1980年 | 28篇 |
1979年 | 40篇 |
1978年 | 25篇 |
1977年 | 26篇 |
1976年 | 34篇 |
1975年 | 22篇 |
1974年 | 29篇 |
1973年 | 26篇 |
1972年 | 35篇 |
1971年 | 20篇 |
1969年 | 18篇 |
1968年 | 23篇 |
排序方式: 共有2351条查询结果,搜索用时 15 毫秒
91.
Charlotte F Kweldam Daan Nieboer Ferran Algaba Mahul B Amin Dan M Berney Athanase Billis David G Bostwick Lukas Bubendorf Liang Cheng Eva Compérat Brett Delahunt Lars Egevad Andrew J Evans Donna E Hansel Peter A Humphrey Glen Kristiansen Theodorus H van der Kwast Cristina Magi‐Galluzzi Rodolfo Montironi George J Netto Hemamali Samaratunga John R Srigley Puay H Tan Murali Varma Ming Zhou Geert J L H van Leenders 《Histopathology》2016,69(3):441-449
92.
Criscione JC Lorenzen-Schmidt I Humphrey JD Hunter WC 《Annals of biomedical engineering》1999,27(2):123-130
Finite extension and torsion tests on cardiac papillary muscles are presently the best way to directly measure the response to shear along myocardial fibers. Quantifying this response is necessary for determining the complete three-dimensional constitutive behavior of myocardium as a transversely isotropic material. Analysis of such tests is complicated, however, since papillary muscles are materially inhomogeneous, consisting of a myocardial core surrounded by an endocardial sheath that is rich in collagen. In this article, we show that the papillary muscle response to extension and torsion additively decouples into the response of the bare myocardial core plus the response of an endocardial sheath filled with fluid (assuming the muscle is a radially inhomogeneous and incompressible continuum with cylindrical symmetry). This result allows the endocardial response to be subtracted from the intact papillary muscle response to obtain the response of the bare myocardial core. An initial estimate suggests that the endocardial sheath affects the axial moment significantly (50% of torque for all twists at low stretch) but affects the axial force only slightly (<10% at moderate twists). © 1999 Biomedical Engineering Society.
PAC99: 8719Hh, 8719Rr, 8719Ff 相似文献
93.
Cerebral vasospasm is a poorly understood clinical condition that appears to result from complex biochemical and biomechanical
processes that manifest as yet another example of vascular growth and remodeling. We submit that mathematical modeling holds
great promise to help synthesize diverse types of data and thereby to increase our understanding of vasospasm. Toward this
ultimate goal, we present constitutive relations and parametric studies that illustrate the potential utility of a new theoretical
framework that combines information on wall mechanics, hemodynamics, and chemical kinetics. In particular, we show that chemical
and mechanical mediators of cellular and extracellular matrix turnover can differentially dominate the progression and resolution
of vasospasm. Moreover, based on our simulations, endothelial damage can significantly alter the time-course and extent of
vasospasm as can impairment of autoregulation. Although the present results are consistent with salient features of clinically
reported vasospasm, and thus provide some new insight, we suggest that most importantly they reveal areas of pressing need
with regard to the collection of additional experimental data. Without appropriate data, our understanding of cerebral vasospasm
will remain incomplete.
Address correspondence to J. D. Humphrey, Department of Biomedical Engineering, Texas A&M University, 337 Zachry Engineering
Center, 3120 TAMU, College Station, TX 77843-3120, USA. Electronic mail: jhumphrey@tamu.edu
相似文献
相似文献
94.
McCaustland KA Krawczynski K Ebert JW Balayan MS Andjaparidze AG Spelbring JE Cook EH Humphrey C Yarbough PO Favorov MO Carson D Bradley DW Robertson BH 《Archives of virology》2000,145(9):1909-1918
Summary. Different patterns of disease were observed among 11 chimpanzees who were inoculated intravenously with hepatitis E virus
(HEV) positive fecal specimens from four different outbreaks (Nepal 1981, Uzbekistan 1981, Pakistan 1985, and Mexico 1986).
Five chimpanzees had marginal or no liver enzyme elevations within 70 days of inoculation. Two of the chimpanzees had limited
viremia, but did not produce detectable antibody. The four remaining chimpanzees had liver enzyme elevations, viral shedding,
viremia, seroconversion to anti-HEV, and detectable HEV antigen in liver biopsy specimens. These results may reflect the range
of infection patterns that develop in humans after natural exposure to the HEV.
Received December 29, 1999/Accepted February 21, 2000 相似文献
95.
96.
Obesity, especially morbid obesity, is reported to be a relative contraindication to laparoscopy. A technique for trocar introduction and laparoscopy of the obese patient to eliminate this contraindication is described. The technique presented herein differs from the traditional method by: 1, primary trocar entry at a 90 degree angle to the horizontal plane, and 2, confirmation for intraperitoneal position of the instruments before creating the pneumoperitoneum. A retrospective study was done to compare demographic, medical and surgical data of obese and non-obese patients. No important differences were found and it was also found that obesity was not a relative contraindication to laparoscopy. Obesity was defined by a ponderal index of less than 11.7. No operative complications were found for the 344 obese patients studied and all laparoscopy procedures were completed as intended. These differences in technique can avoid the pitfalls commonly reported concerning laparoscopy of the obese patient. 相似文献
97.
98.
Exaggerated signet-ring cell change in stromal nodule of prostate: a pseudoneoplastic proliferation 总被引:1,自引:0,他引:1
A stromal nodule of the prostate was incidentally identified in a simple prostatectomy specimen from a 66-year-old man with benign prostatic hyperplasia. Microscopically, the nodule consisted of short spindly cells with bland nuclear features. Many of the cells in the nodule, however, contained a large, clear cytoplasmic vacuole that displaced and indented the nucleus, generating signet-ring cell morphology. Immunohistochemically, these cells were strongly positive for vimentin and weakly positive for desmin, suggesting a myofibroblastic nature. Further immunostains demonstrated the cells to be negative for cytokeratins and prostate-specific antigen, excluding the possibility of signet-ring cell carcinoma. The cytoplasmic vacuoles also stained negative for mucin production. Electron microscopy revealed no intracytoplasmic lumina. Notably, thermal effect or other signs of cellular injury, frequently associated with signet-ring cell change seen in prostate specimens obtained by transurethral resection and needle biopsy, were not appreciated in this stromal nodule. This case demonstrates that signet-ring cell change may occur in benign, hyperplastic, prostatic stromal cells in the absence of cellular damage. 相似文献
99.
BACKGROUND: Few reliable and reproducible animal models of acute hepatic failure exist or conform to the criteria proposed by Terblanche and Hickman (Dig. Dis. Sci. 36: 770, 1991). In this prospective randomized study we describe the selective induction of CYP450 enzymes, depletion of glutathione, and hepatotoxic insult using acetaminophen in the development and characterization of a novel rabbit model of acute hepatic failure. MATERIALS AND METHODS: Male New Zealand white rabbits weighing 3-5 kg were used. After preliminary dose ranging experiments, two groups of New Zealand white (n = 8 in each group) rabbits had CYP450 induction with phenobarbitone (40 mg/kg ip for 5 days) or with 20-methylcholanthrene (80 mg/kg ip). The glutathione synthetase inhibitor buthionine sulfoxime (2 mmol/kg iv) was then administered prior to acetaminophen administration (500 mg/kg sc). Clinical observations were recorded and arterial blood was sampled over 72 h. RESULTS: Grade I-III encephalopathy occurred at 5-12, 12-25, and 28-56 h, respectively, in animals pretreated with 20-methylcholanthrene, but not in the phenobarbitone pretreated group. Mortality was 75% in the 20-methylcholanthrene group compared to 0% in the phenobarbitone group. Blood lactate (P < 0.05), prothrombin time (P < 0.005), aspartate transaminase (P < 0.005), and creatinine (P < 0.05) were higher in the 20-methylcholanthrene group compared to the phenobarbitone group. Histological changes were marked in the 20-methylcholanthrene group with massive coagulative hepatic necrosis compared to minimal histological damage in the phenobarbitone group. CONCLUSION: The induction with 20-methylcholanthrene, glutathione depletion with buthionine sulfoxime, and subcutaneous administration of acetaminophen have led to the development of an animal model that parallels clinical, biochemical, and histological features of human hepatic failure. 相似文献
100.