全文获取类型
收费全文 | 1004篇 |
免费 | 71篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 14篇 |
妇产科学 | 9篇 |
基础医学 | 110篇 |
口腔科学 | 32篇 |
临床医学 | 113篇 |
内科学 | 228篇 |
皮肤病学 | 3篇 |
神经病学 | 72篇 |
特种医学 | 99篇 |
外科学 | 174篇 |
综合类 | 3篇 |
一般理论 | 1篇 |
预防医学 | 78篇 |
眼科学 | 13篇 |
药学 | 67篇 |
中国医学 | 2篇 |
肿瘤学 | 51篇 |
出版年
2022年 | 14篇 |
2021年 | 41篇 |
2020年 | 20篇 |
2019年 | 21篇 |
2018年 | 34篇 |
2017年 | 19篇 |
2016年 | 22篇 |
2015年 | 32篇 |
2014年 | 39篇 |
2013年 | 48篇 |
2012年 | 75篇 |
2011年 | 66篇 |
2010年 | 54篇 |
2009年 | 39篇 |
2008年 | 62篇 |
2007年 | 51篇 |
2006年 | 45篇 |
2005年 | 47篇 |
2004年 | 45篇 |
2003年 | 37篇 |
2002年 | 27篇 |
2001年 | 9篇 |
2000年 | 16篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1979年 | 4篇 |
1976年 | 7篇 |
1975年 | 11篇 |
1974年 | 5篇 |
1973年 | 8篇 |
1971年 | 8篇 |
1965年 | 4篇 |
1960年 | 3篇 |
1959年 | 3篇 |
1958年 | 5篇 |
1933年 | 9篇 |
1932年 | 4篇 |
1930年 | 7篇 |
排序方式: 共有1078条查询结果,搜索用时 296 毫秒
121.
E. Schlicker J. Timm J. Zentner M. Göthert 《Naunyn-Schmiedeberg's archives of pharmacology》1997,356(5):583-589
We examined the question of whether cannabinoid receptors modulating noradrenaline release are detectable in the brain of
humans and experimental animals. For this purpose, hippocampal slices from humans, guinea-pigs, rats and mice and cerebellar,
cerebrocortical and hypothalamic slices from guinea-pigs were incubated with [3H]noradrenaline and then superfused. Tritium overflow was evoked either electrically (0.3 or 1Hz) or by introduction of Ca2+ ions (1.3μM) into Ca2+-free, K+-rich medium (25μM) containing tetrodotoxin 1μM. Furthermore, the cAMP accumulation stimulated by forskolin 10μM was determined
in guinea-pig hippocampal membranes. We used the following drugs: the cannabinoid receptor agonists (–)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol
(CP-55,940) and R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazin-yl]-(1-naphthalenyl)methanone (WIN 55,212-2), the inactive S(–)-enantiomer of the latter (WIN 55,212-3) and the CB1 receptor antagonist N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxamide (SR 141716). The electrically evoked tritium overflow from guinea-pig hippocampal slices was reduced by WIN 55,212-2 (pIC30% 6.5) but not affected by WIN 55,212-3 up to 10μM. The concentration-response curve of WIN 55,212-2 was shifted to the right
by SR 141716 (0.032μM) (apparent pA2 8.2), which by itself did not affect the evoked overflow. WIN 55,212-2 1μM also inhibited the Ca2+-evoked tritium overflow in guinea-pig hippocampal slices and the electrically evoked overflow in guinea-pig cerebellar, cerebrocortical
and hypothalamic slices as well as in human hippocampal slices but not in rat and mouse hippocampal slices. SR 141716 (0.32μM)
markedly attenuated the WIN 55,212-2-induced inhibition in guinea-pig and human brain slices. SR 141716 0.32μM by itself increased
the electrically evoked tritium overflow in guinea-pig hippocampal slices but failed to do so in slices from the other brain
regions of the guinea-pig and in human hippocampal slices. The cAMP accumulation stimulated by forskolin was reduced by CP-55,940
and WIN 55,212-2. The concentration-response curve of CP 55,940 was shifted to the right by SR 141716 (0.1μM; apparent pA2 8.3), which by itself did not affect cAMP accumulation. In conclusion, cannabinoid receptors of the CB1 subtype occur in the human hippocampus, where they may contribute to the psychotropic effects of cannabis, and in the guinea-pig
hippocampus, cerebellum, cerebral cortex and hypothalamus. The CB1 receptor in the guinea-pig hippocampus is located presynaptically, is activated by endogenous cannabinoids and may be negatively
coupled to adenylyl cyclase.
Received: 5 June 1997 / Accepted: 6 August 1997 相似文献
122.
Manohar M. Panjabi Gweneth Henderson Yue James Jens Peter Timm 《European spine journal》2007,16(12):2159-2165
Rationale behind motion preservation devices is to eliminate the accelerated adjacent-level effects (ALE) associated with spinal fusion. We evaluated multidirectional flexibilities and ALEs of StabilimaxNZ® and simulated fusion applied to a decompressed spine. StabilimaxNZ® was applied at L4–L5 after creating a decompression (laminectomy of L4 plus bilateral medial facetectomy at L4–L5). Multidirectional Flexibility and Hybrid tests were performed on six fresh cadaveric human specimens (T12–S1). Decompression increased average flexion–extension rotation to 124.0% of the intact. StabilimaxNZ® and simulated fusion decreased the motion to 62.4 and 23.8% of intact, respectively. In lateral bending, corresponding increase was 121.6% and decreases were 57.5 and 11.9%. In torsion, corresponding increase was 132.7%, and decreases were 36.3% for fusion, and none for StabilimaxNZ® ALE was defined as percentage increase over the intact. The ALE at L3–4 was 15.3% for StabilimaxNZ® versus 33.4% for fusion, while at L5–S1 the ALE were 5.0% vs. 11.3%, respectively. In lateral bending, the corresponding ALE values were 3.0% vs. 19.1%, and 11.3% vs. 35.8%, respectively. In torsion, the corresponding values were 3.7% vs. 20.6%, and 4.0% vs. 33.5%, respectively. In conclusion, this in vitro study using Flexibility and Hybrid test methods showed that StabilimaxNZ® stabilized the decompressed spinal level effectively in sagittal and frontal planes, while allowing a good portion of the normal rotation, and concurrently it did not produce significant ALEs as compared to the fusion. However, it did not stabilize the decompressed specimen in torsion. 相似文献
123.
124.
Die Onkologie - Der Begriff „neuroendokrine Tumoren“ (NET), oder allgemeiner „neuroendokrine Neoplasien“ (NEN), umfasst eine sehr heterogene Gruppe seltener Tumoren mit... 相似文献
125.
Assessing the optimal preparation strategy to minimize the variability of cardiac pyruvate dehydrogenase flux measurements with hyperpolarized MRS
下载免费PDF全文
![点击此处可从《NMR in biomedicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kerstin N. Timm Andrew Apps Jack J. Miller Vicky Ball Cher‐Rin Chong Michael S. Dodd Damian J. Tyler 《NMR in biomedicine》2018,31(9)
Hyperpolarized [1‐13C] pyruvate MRS can measure cardiac pyruvate dehydrogenase (PDH) flux in vivo through 13C‐label incorporation into bicarbonate. Using this technology, substrate availability as well as pathology have been shown to modulate PDH flux. Clinical protocols attempt to standardize PDH flux with oral glucose loading prior to scanning, while rodents in preclinical studies are usually scanned in the fed state. We aimed to establish which strategy was optimal to maximize PDH flux and minimize its variability in both control and Type II diabetic rats, without affecting the pathological variation being assessed. We found similar variances in the bicarbonate to pyruvate ratio, reflecting PDH flux, in fed and fasted/glucose‐loaded animals, which showed no statistically significant differences. Furthermore, fasting/glucose loading did not alter the low PDH flux seen in Type II diabetic rats. Overall this suggests that preclinical cardiac hyperpolarized magnetic resonance studies could be performed either in the fed or in the fasted/glucose‐loaded state. Centres planning to start new clinical studies with cardiac hyperpolarized magnetic resonance in man may find it beneficial to run small proof‐of‐concept trials to determine whether metabolic standardizations by oral or intravenous glucose load are beneficial compared with scanning patients in the fed state. 相似文献
126.
Validation of a novel CARTOSEG™ segmentation module software for contrast‐enhanced computed tomography‐guided radiofrequency ablation in patients with atrial fibrillation
下载免费PDF全文
![点击此处可从《Pacing and clinical electrophysiology : PACE》网站下载免费的PDF全文](/ch/ext_images/free.gif)
127.
Orpheus Kolokythas Thomas Gauthier Anna T Fernandez Hua Xie Brian A Timm Carlos Cuevas Manjiri K Dighe Lee M Mitsumori Matt F Bruce Daniel A Herzka Gaurav K Goswami R Torrance Andrews Kelly M Oas Theodore J Dubinsky Bill H Warren 《Journal of ultrasound in medicine》2008,27(6):935-946
OBJECTIVE: The purpose of this study was to evaluate the technical feasibility of ultrasound-based elastography as a tool for assessing the size and shape of the coagulation necrosis caused by radio frequency ablation (RFA) probes using expandable electrodes ex vivo as well as in a patient with a liver metastasis. METHODS: A commercially available expandable RFA probe was used to create a 3-cm ablation in a piece of bovine liver. The ablation probe was used in situ to induce tissue deformation for elastography before and after ablation. Ultrasonic radio frequency data were processed to generate elasticity strain images. The appearance of the ablation zone was compared with magnetic resonance imaging and a gross section specimen. One patient with malignant metastatic disease to the liver and a clinical indication for RFA was investigated for the feasibility of percutaneous elastography of RFA using the same technique. Sonographic strain images were compared with the appearance of the nonenhancing ablation zone on contrast-enhanced computed tomography. RESULTS: Ex vivo, the ablation zone on ultrasound-based elastography was represented by an area of increased stiffness and was well demarcated from the nonablated surrounding tissue. The size and shape of the ablated zone on the strain image correlated well with the gross specimen and the magnetic resonance imaging appearance. Strain images obtained from the patient showed results similar to those of the ex vivo experiment and correlated well with the nonenhancing area of ablation on contrast-enhanced computed tomography. CONCLUSIONS: Ultrasound-based elastography may be a promising tool for displaying the ablation zone created by expandable RFA probes. 相似文献
128.
The magnitude and breadth of hepatitis C virus-specific CD8+ T cells depend on absolute CD4+ T-cell count in individuals coinfected with HIV-1
下载免费PDF全文
![点击此处可从《Blood》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kim AY Lauer GM Ouchi K Addo MM Lucas M Schulze Zur Wiesch J Timm J Boczanowski M Duncan JE Wurcel AG Casson D Chung RT Draenert R Klenerman P Walker BD 《Blood》2005,105(3):1170-1178
CD8(+) T-cell responses are an essential antiviral host defense in persistent viral infections, and their sustained effectiveness is thought to be critically dependent on CD4(+) T-helper cells. To determine the relationship between HIV-1-induced CD4(+) T-cell depletion and hepatitis C virus (HCV)-specific CD8(+) T-cell responses during viral persistence, we studied 103 persons positive for HCV, 74 coinfected with HIV-1. CD8(+) T-cell responses to the entire HCV polyprotein were determined by using an interferon-gamma enzyme-linked immunospot (ELISpot) assay. Although HIV-1 infection by itself was not associated with a diminished HCV-specific response, HIV-1-associated CD4(+) depletion was associated with significantly lower HCV-specific CD8(+) T cells (R = 0.48, P < .0001). In contrast, declining CD4(+) counts over the same range were not associated with diminished Epstein-Barr virus (EBV)- (R = 0.19, P = .31) or HIV-1-specific (R = -0.13, P = .60) CD8(+) T-cell responses in persons infected with all viruses. These data indicate that frequencies of circulating HCV-specific CD8(+) T-cell responses are sensitive to absolute CD4(+) T-cell counts and provide a possible explanation for the accelerated HCV disease course in persons coinfected with HIV-1 and HCV. 相似文献
129.
Andreas Andreou Safak Gül Andreas Pascher Wenzel Sch?ning Hussein Al-Abadi Marcus Bahra Fritz Klein Timm Denecke Benjamin Strücker Gero Puhl Johann Pratschke Daniel Seehofer 《HPB : the official journal of the International Hepato Pancreato Biliary Association》2015,17(2):168-175
Background
Patients with hepatocellular carcinoma (HCC) beyond the Milan criteria are not considered for liver transplantation (LT) in many centres; however, LT may be the only treatment able to achieve long-term survival in patients with unresectable HCC. The aim of this study was to assess the role of recipient age and tumour biology expressed by the DNA index in the selection of HCC patients for LT.Patients
Clinicopathological data of 364 patients with HCC who underwent LT between 1989 and 2010 were evaluated. Overall survival (OS) was analysed by patient age, tumour burden based on Milan criteria and the DNA index.Results
After a median follow-up time of 78 months, the median survival was 100 months. Factors associated with OS on univariate analysis included Milan criteria, patient age, hepatitis C infection, alpha-fetoprotein (AFP) level, the DNA index, number of HCC, diameter of HCC, bilobar HCC, microvascular tumour invasion and tumour grading. On multivariate analysis, HCC beyond Milan criteria and the DNA index >1.5 independently predicted a worse OS. When stratifying patients by both age and Milan criteria, patients ≤60 years with HCC beyond Milan criteria had an OS comparable to that of patients >60 years within Milan criteria (10-year OS: 33% versus 37%, P = 0.08). Patients ≤60 years with HCC beyond Milan criteria but a favourable DNA index ≤1.5 achieved excellent long-term outcomes, comparable with those of patients within Milan criteria.Conclusions
Patients ≤60 years may undergo LT for HCC with favourable outcomes independently of their tumour burden. Additional assessment of tumour biology, e.g. using the DNA index, especially in this subgroup of patients can support the selection of LT candidates who may derive the most long-term survival benefit, even if Milan criteria are not fulfilled. 相似文献130.
Randomised clinical study of plaque removal efficacy of a power toothbrush in a paediatric population
下载免费PDF全文
![点击此处可从《International journal of paediatric dentistry / the British Paedodontic Society [and] the International Association of Dentistry for Children》网站下载免费的PDF全文](/ch/ext_images/free.gif)