全文获取类型
收费全文 | 275篇 |
免费 | 17篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 21篇 |
妇产科学 | 1篇 |
基础医学 | 18篇 |
口腔科学 | 7篇 |
临床医学 | 28篇 |
内科学 | 66篇 |
皮肤病学 | 3篇 |
神经病学 | 4篇 |
特种医学 | 64篇 |
外科学 | 54篇 |
综合类 | 8篇 |
预防医学 | 4篇 |
药学 | 7篇 |
肿瘤学 | 19篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2011年 | 5篇 |
2010年 | 13篇 |
2009年 | 12篇 |
2008年 | 5篇 |
2007年 | 12篇 |
2006年 | 1篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 16篇 |
1997年 | 12篇 |
1996年 | 13篇 |
1995年 | 10篇 |
1994年 | 17篇 |
1993年 | 13篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 10篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 4篇 |
排序方式: 共有305条查询结果,搜索用时 31 毫秒
1.
Fahim Zaman Atta Nawabi Kenneth D Abreo Gazi B Zibari 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2005,9(3):262-265
Laparoscopic procedures continue to gain popularity over traditional open procedures for a number of abdominal and pelvic surgeries. With increasing experience, the application of this technique is rising because it provides an alternative, less invasive, approach to various surgical procedures. Herein, we report our experience with adult patients with polycystic kidney disease, requiring bilateral laparoscopic nephrectomy before renal transplantation. 相似文献
2.
目的 探索LDH实验检测细胞活力的可行性。方法 原代培养骨髓细胞和软骨细胞,用LDH实验测定上述两组细胞的活力,并与镜下活体观察到细胞的生长状况相比较。与目前比较成熟的测定细胞活力的MTS实验的测得的值相比较。结果 LDH实验对上述两组细胞的活力的测定结果与镜下活体观察到的结果相符合。与MTS实验的测得的结果经统计学处理无显著差异。结论 LDH实验可用于细胞活力的直接测定,而对活细胞的生存、繁殖无影响。 相似文献
3.
Mutations in the Ca(2+)-sensing receptor gene cause autosomal dominant and sporadic hypoparathyroidism 总被引:3,自引:0,他引:3
Baron J; Winer KK; Yanovski JA; Cunningham AW; Laue L; Zimmerman D; Cutler GB Jr 《Human molecular genetics》1996,5(5):601-606
Parathyroid hormone secretion is negatively regulated by a 7- transmembrane
domain, G-protein coupled Ca(2+)-sensing receptor. We hypothesized that
activating mutations in this receptor might cause autosomal dominant
hypoparathyroidism (ADHP). Consistent with this hypothesis, we identified,
in two families with ADHP, heterozygous missense mutations in the
Ca(2+)-sensing receptor gene that cosegregated with the disorder. None of
50 normal controls had either mutation. We also identified a de novo,
missense Ca(2+)-sensing receptor mutation in a child with severe sporadic
hypoparathyroidism. The amino acid substitution in one ADHP family affected
the N-terminal, extracellular domain of the receptor. The other mutations
involved the transmembrane region. Unlike patients with acquired
hypoparathyroidism, patients with these mutations had hypercalciuria even
at low serum calcium concentrations. Their greater hypercalciuria
presumably reflected activation of Ca(2+)-sensing receptors in kidney
cells, where the receptor negatively regulates calcium reabsorption. This
augmented hypercalciuria increases the risk of renal complications and thus
has implications for the choice of therapy.
相似文献
4.
5.
The use of FDG-positron emission tomography for the evaluation of colorectal metastases of the liver 总被引:6,自引:0,他引:6
Boykin KN Zibari GB Lilien DL McMillan RW Aultman DF McDonald JC 《The American surgeon》1999,65(12):1183-1185
Each year at least 130,000 people in the United States are diagnosed with colorectal carcinoma. Approximately 14,000 of these patients will have liver metastases, and 20 per cent of these patients will die from these metastases. Surgical resection is the only possible chance for cure in patients with only intrahepatic metastases, and extrahepatic disease is a contraindication to glucose metabolism. Positron emission tomography (PET) allows the in vivo study of the uptake and use of glucose in human cells. Here, we review our experience with the use of PET imaging for the diagnosis and management of colorectal metastases of the liver. We conducted a retrospective chart review of 14 patients undergoing PET imaging for known or suspected hepatic metastases from colorectal carcinoma. Results of CT, magnetic resonance imaging, and PET images were compared with pathological specimens. CT scan identified 7 lesions, and PET identified 31 intrahepatic lesions. Of the 6 patients who underwent surgery, CT identified 4 (20%) and PET identified 17 (85%) of the 20 intrahepatic metastases histologically confirmed. The accuracy (number of lesions) of CT and PET was 20 per cent and 85 per cent, respectively. CT scans had a sensitivity (number of patients) of 50 per cent, and PET had a sensitivity of 100 per cent in patients undergoing surgical resection. PET imaging altered the management in 49 per cent of patients. Twenty-one per cent of patients had their surgery cancelled due to previously undiagnosed extrahepatic metastases. Twenty-one per cent of patients had negative CT scans and underwent surgery on the basis of their PET images, and all had histologically proven disease. One patient avoided a second-look laparotomy when PET revealed a lesion seen on CT to be false positive. PET is an ideal imaging modality to detect intra- and extrahepatic metastases from colorectal carcinomas and would aid in the surgical management of these patients. 相似文献
6.
Effects of dextran and pentoxifylline on hemorrhagic shock-induced P-selectin expression 总被引:4,自引:0,他引:4
Akgür FM Zibari GB McDonald JC Granger DN Brown MF 《The Journal of surgical research》1999,87(2):232-238
BACKGROUND: Dextran and pentoxifylline have been shown to prevent leukocyte-endothelium adherence encountered after hemorrhagic shock. P-Selectin is the first endothelial cell adhesion molecule to be upregulated after an ischemic insult. We investigated the effects of resuscitation with dextran 70 and administration of pentoxifylline during resuscitation on hemorrhagic shock-induced P-selectin expression. MATERIAL AND METHODS: Hemorrhagic shock was induced in C57BL/6 mice by withdrawing blood to reduce mean arterial blood pressure to 30 mm Hg for 45 min. Animals were resuscitated by infusing one of the following solutions (each n:5): (1) Ringer's lactate, (2) 6% dextran 70, (3) Ringer's lactate plus 50 mg/kg pentoxifylline, (4) 5% human albumin. Afterward shed blood was infused. In vivo P-selectin expression was determined using dual-radiolabeled monoclonal antibody technique in lung, heart, liver, kidney, mesentery, stomach, small bowel, and colon 5 h after resuscitation. RESULTS: P-Selectin was significantly upregulated in all of the organs studied in the Ringer's lactate resuscitation group (P < 0.001). Resuscitation with dextran 70 and administration of pentoxifylline during resuscitation prevented P-selectin upregulation. Resuscitation with human albumin caused significant attenuation but could not prevent P-selectin upregulation (p < 0.01). CONCLUSION: Our study implies that the prevention of hemorrhagic shock-induced leukocyte-endothelium adherence by dextran 70 and pentoxifylline observed in other studies may be mediated by prevention of P-selectin expression by these agents. 相似文献
7.
8.
Dibenzo[a,l]pyrene-induced DNA adduction, tumorigenicity, and Ki-ras oncogene mutations in strain A/J mouse lung 总被引:1,自引:0,他引:1
Prahalad AK; Ross JA; Nelson GB; Roop BC; King LC; Nesnow S; Mass MJ 《Carcinogenesis》1997,18(10):1955-1963
Dibenzo[a,l]pyrene (DB[a,l]P), an environmental polycyclic aromatic
hydrocarbon, is the most potent carcinogen ever tested in mouse skin and
rat mammary gland. In this study, DB[a,l]P was examined for DNA adduction,
tumorigenicity, and induction of Ki-ras oncogene mutations in tumor DNA in
strain A/J mouse lung. Groups of mice received a single i.p. injection of
0.3, 1.5, 3.0, or 6.0 mg/kg DB[a,l]P in tricaprylin. Following treatment,
DNA adducts were measured at times between 1 and 28 days, while tumors were
counted at 250 days and analyzed for the occurrence of point mutations in
codons 12 and 61 of the Ki-ras oncogene. DB[a,l]P in strain A/J mouse lung
induced six major and four minor DNA adducts. Maximal levels of adduction
occurred between 5 and 10 days after injection followed by a gradual
decrease. DB[a,l]P-DNA adducts in lung tissue were derived from both anti-
and syn-11,12- dihydroxy-13,14-epoxy-
11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DB[a,l]PDE) and both
deoxyadenosine (dAdo) and deoxyguanosine (dGuo) residues in DNA as revealed
by cochromatography. The major adduct was identified as a product of the
reaction of an anti-DB[a,l]PDE with dAdo in DNA. DB[a,l]P induced
significant numbers of lung adenomas in a dose- dependent manner, with the
highest dose (6.0 mg/kg) yielding 16.1 adenomas/mouse. In
tricaprylin-treated control animals, there were 0.67 adenomas/mouse. Based
on the administered dose, DB[a,l]P was more active than other environmental
carcinogens including benzo[a]pyrene. As a function of time-integrated DNA
adduct levels, DB[a,l]P induced lung adenomas with about the same potency
as other PAHs, suggesting that the adducts formed by DB[a,l]P are similar
in carcinogenic potency to other PAHs in the strain A/J mouse lung model.
Analysis of the Ki- ras mutation spectrum in DB[a,l]P-induced lung tumors
revealed the predominant mutations to be G-->T transversions in the
first base of codon 12, A-->G transitions in the second base of codon
12, and A-->T transversions in the second or third base of codon 61,
concordant with the DNA adduct profile.
相似文献
9.
MS Anglesio Y Wang W Yang J Senz A Wan A Heravi‐Moussavi C Salamanca S Maines‐Bandiera DG Huntsman GB Morin 《The Journal of pathology》2013,229(3):400-409
Our group recently described recurrent somatic mutations of the miRNA processing gene DICER1 in non‐epithelial ovarian cancer. Mutations appeared to be clustered around each of four critical metal‐binding residues in the RNase IIIB domain of DICER1. This domain is responsible for cleavage of the 3′ end of the 5p miRNA strand of a pre‐mRNA hairpin. To investigate the effects of these cancer‐associated 'hotspot' mutations, we engineered mouse DICER1‐deficient ES cells to express wild‐type and an allelic series of the mutant DICER1 variants. Global miRNA and mRNA profiles from cells carrying the metal‐binding site mutations were compared to each other and to wild‐type DICER1. The miRNA and mRNA profiles generated through the expression of the hotspot mutations were virtually identical, and the DICER1 hotspot mutation‐carrying cells were distinct from both wild‐type and DICER1‐deficient cells. Further, miRNA profiles showed that mutant DICER1 results in a dramatic loss in processing of mature 5p miRNA strands but were still able to create 3p strand miRNAs. Messenger RNA (mRNA) profile changes were consistent with the loss of 5p strand miRNAs and showed enriched expression for predicted targets of the lost 5p‐derived miRNAs. We therefore conclude that cancer‐associated somatic hotspot mutations of DICER1, affecting any one of four metal‐binding residues in the RNase IIIB domain, are functionally equivalent with respect to miRNA processing and are hypomorphic alleles, yielding a global loss in processing of mature 5p strand miRNA. We further propose that this resulting 3p strand bias in mature miRNA expression likely underpins the oncogenic potential of these hotspot mutations. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. 相似文献
10.
Influence of oxygen tension on the viscoelastic behavior of red blood cells in sickle cell disease 总被引:2,自引:0,他引:2
Although the rheological behavior of sickle cell suspensions and of hemoglobin S solutions is known to be strongly dependent on oxygen tension (PO2), little data exist concerning the influence of PO2 on the viscoelasticity of individual HbSS RBC. We have used micropipette aspiration techniques to test the deformation response of both HbSS and control HbAA RBC over a wide range of PO2 at 23 degrees C. Sickled, spiculed HbSS cells were present for PO2 approximately less than 35 mm Hg; for a number of these cells, the deformation response was essentially elastic and an effective membrane rigidity (EMR) was calculated. EMR increased with decreasing PO2 and was approximately 5 to 50 times higher than the equivalent rigidity of oxygenated HbSS RBC. In addition, the rate of membrane deformation was very slow for sickled cells; the half-time for the deformation process increased as PO2 was lowered and was about two orders of magnitude longer than the equivalent time for normal RBC. Other sickled cells exhibited plastic deformation when subjected to comparable deforming forces and experienced irreversible membrane deformation and budding. At all PO2 levels tested, some HbSS RBC remained as discocytes; these cells had normal membrane elasticity and membrane viscosity. Furthermore, changes in PO2 did not affect the membrane properties of HbAA RBC. Thus, gross abnormalities in the deformation response of HbSS RBC were only detected after morphological sickling had occurred. These abnormalities most likely arose from changes in the cytoplasmic HbS viscoelasticity and, if present in vivo, would be expected to impair the flow of HbSS cells in the microcirculation. 相似文献