全文获取类型
收费全文 | 1361篇 |
免费 | 63篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 48篇 |
妇产科学 | 4篇 |
基础医学 | 349篇 |
口腔科学 | 24篇 |
临床医学 | 123篇 |
内科学 | 208篇 |
皮肤病学 | 12篇 |
神经病学 | 72篇 |
特种医学 | 204篇 |
外科学 | 143篇 |
综合类 | 42篇 |
预防医学 | 37篇 |
眼科学 | 29篇 |
药学 | 53篇 |
中国医学 | 3篇 |
肿瘤学 | 75篇 |
出版年
2022年 | 11篇 |
2021年 | 19篇 |
2020年 | 20篇 |
2019年 | 21篇 |
2018年 | 22篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 27篇 |
2014年 | 27篇 |
2013年 | 39篇 |
2012年 | 38篇 |
2011年 | 43篇 |
2010年 | 30篇 |
2009年 | 39篇 |
2008年 | 42篇 |
2007年 | 45篇 |
2006年 | 39篇 |
2005年 | 38篇 |
2004年 | 38篇 |
2003年 | 39篇 |
2002年 | 34篇 |
2001年 | 23篇 |
2000年 | 29篇 |
1999年 | 26篇 |
1998年 | 45篇 |
1997年 | 38篇 |
1996年 | 25篇 |
1995年 | 21篇 |
1994年 | 18篇 |
1993年 | 20篇 |
1992年 | 13篇 |
1991年 | 20篇 |
1990年 | 27篇 |
1989年 | 25篇 |
1988年 | 24篇 |
1987年 | 27篇 |
1986年 | 18篇 |
1985年 | 26篇 |
1984年 | 14篇 |
1982年 | 11篇 |
1978年 | 14篇 |
1943年 | 15篇 |
1942年 | 19篇 |
1941年 | 23篇 |
1940年 | 10篇 |
1939年 | 31篇 |
1938年 | 36篇 |
1937年 | 32篇 |
1936年 | 37篇 |
1935年 | 36篇 |
排序方式: 共有1438条查询结果,搜索用时 15 毫秒
1.
2.
3.
W. Küker I. Mader T. Nägele M. Uhl C. Adolph U. Klose U. Herrlinger 《European journal of neurology》2006,13(8):819-826
Progressive multifocal leukoencephalopathy (PML) is caused by the replication of JC virus in oligodendrocytes of immunocompromised patients. Diagnosis usually relies on the polymerase chain reaction (PCR)-based demonstration of JC virus DNA in the cerebrospinal fluid. As previous reports have suggested that some patients may benefit from antiviral therapy, non-invasive early diagnosis is highly desirable. Repetitive magnetic resonance imaging (MRI) examinations (two to nine) were obtained in seven patients (aged 40–67 years, six males, one female) with classical clinical and imaging findings of PML. Five patients had underlying hematological disorders and two acquired immune deficiency syndrome. PCR of the cerebrospinal fluid (CSF) specimen was positive for JC virus DNA in six patients. MRI sequences included T2-, T1- and diffusion-weighted (DW) images in all patients and diffusion-tensor imaging (DTI) in four cases. DTI was once performed at 3T, in the remaining patients at 1.5T. All patients received antiviral treatment with cidofovir in addition to the treatment of the underlying disorder. MRI showed areas of T2 hyperintensity with involvement of the subcortical U-fibers and restricted diffusion in all patients. Areas of diffusion abnormality correlated with disease progress. Contrast enhancement was encountered once after successful treatment and heralded clinical remission with virus elimination from the CSF. Hence, MRI including DW and contrast-enhanced images may be used to evaluate disease activity. Contrast enhancement may indicate an inflammatory response and thus herald immunologic virus elimination. 相似文献
4.
Imaging of activated microglia with PET and [11C]PK 11195 in corticobasal degeneration. 总被引:3,自引:0,他引:3
Karsten Henkel Jochen Karitzky Michaela Schmid Irina Mader Gerhard Glatting Jürgen W Unger Bernd Neumaier Albert C Ludolph Sven N Reske G Bernhard Landwehrmeyer 《Movement disorders》2004,19(7):817-821
Positron emission tomography (PET) using [(11)C]PK 11195, a ligand for peripheral benzodiazepine receptor binding sites, offers the opportunity to image activated microglia in vivo. This tool may therefore be used to display the occurrence of microglial activation in the course of neurodegeneration. A patient with the clinical diagnosis of corticobasal degeneration (CBD) and left-sided symptoms was studied using fluorodeoxyglucose (FDG) and [(11)C]PK 11195 PET. We found a marked right hemispheric hypometabolism and asymmetric microglial activation in corresponding areas of the basal ganglia and right temporal and parietal cortex. [(11)C]PK 11195 PET suggests involvement of microglial activation in the pathogenesis of CBD. 相似文献
5.
Brandon JC; Teplick SK; Haskin PH; Sammon JK; Muhr WF; Hofmann AF; Gambescia RA; Zitomer N 《Radiology》1988,166(3):665-667
The authors describe their experience with methyl tertiary butyl ether (MTBE) in a larger series of patients than previously reported in order to acquaint physicians with both its effectiveness for dissolution of common bile duct calculi and the limitations of its use. Ten patients with 13 biliary calculi underwent percutaneous stone dissolution treatment with the experimental cholesterol solvent, MTBE. Three stones completely dissolved within 30 minutes, seven were reduced in size, and three were visibly unaffected. All stones not completely dissolved were easily extracted by means of a stone basket except for one in a patient taken to surgery. Although MTBE perfusion is an effective technique for management of biliary calculi, practitioners should be aware that its use is quite time consuming and its odor difficult to control. 相似文献
6.
Limited-field-of-view radio-frequency receiver antennas provide improved near-field sensitivity for magnetic resonance imaging by decreasing the antenna volume. The Helmholtz-type surface coil, consisting of two flat rings, is an organ-encompassing antenna that takes advantage of this principle to yield an improved signal-to-noise ratio (S/N). The coil was tested in a group of 50 patients and 16 healthy volunteers. Images obtained with the Helmholtz coil demonstrated quantitatively superior S/N of 2.2-fold or greater than that of comparison body coil images, as well as qualitatively superior anatomic resolution. 相似文献
7.
Postpartal increase in the plasma potassium concentration of asphyxiated newborn infants is a very rare complication with possibly deleterious outcome. In a group of 98 asphyxiated and 87 healthy infants we have not seen either a case of severe hyperkalemia or rhythm disturbances. We found lower reference-ranges for plasma potassium concentration in the group of healthy infants than previously published, which we would like to introduce. The pathogenesis of hyperkalemia in hypoxia is not yet fully understood. Further experimental investigations will be necessary. 相似文献
8.
Genotype-phenotype correlation for nucleotide substitutions in the IgII- IgIII linker of FGFR2 总被引:6,自引:3,他引:3
9.
Uroscopy in the 21st century: high-field NMR spectroscopy 总被引:1,自引:1,他引:0
Neild GH; Foxall PJ; Lindon JC; Holmes EC; Nicholson JK 《Nephrology, dialysis, transplantation》1997,12(3):404-417
From the experiments described, it can be seen that there are different
research approaches that can be taken and these are summarized in Table 1.
Whereas much scientific research is principally hypothesis led, there
remains, nevertheless, an important place for exploratory research. High
resolution NMR can measure, directly and simultaneously, a wide range of
endogenous metabolites in biological fluids and has the unique capability
of providing structural information on the metabolites detected. It has
proved to be a powerful research tool with which to study inherited
metabolic diseases, renal disease, drug metabolism, and toxicity, and can
be used to monitor the effects of drug therapy. For instance, by using a
library of experimental toxins one can map the metabolic profile of
site-specific nephron injury. With this approach in man one could
eventually take an unknown disease such as Balkan nephropathy and predict
the initial site of tubular injury, the mode of injury and therefore the
kind of toxin capable of producing that injury. NMR spectroscopic
techniques are still advancing rapidly, with ever increasing sensitivity
and sophistication of NMR pulse sequences to enhance structural elucidation
in complex mixtures. Given the advances in directly coupled HPLC-NMR and
even HPLC-NMR-mass spectroscopy it is likely that these technologies in
conjunction with pattern recognition will make major contribution to our
understanding of renal processes and provide new diagnostic insights in the
21st century.
相似文献
10.
Stereospecific pharmacokinetics of rac-5-methyltetrahydrofolic acid in patients with advanced colorectal cancer.
下载免费PDF全文
![点击此处可从《British journal of clinical pharmacology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
R M Mader G G Steger B Rizovski M P Djavanmard W Scheithauer R Jakesz H Rainer 《British journal of clinical pharmacology》1995,40(3):209-215
1. The pharmacokinetics and toxicity of racemic 5-methyltetrahydrofolic (rac-5-MTHF) acid after i.v. infusion were investigated in 18 patients with advanced colorectal cancer. Doses of 100-600 mg rac-5-MTHF/m2 were administered over 2 h together with a bolus of 500 mg/m2 5-fluorouracil (5-FU) as a midpoint injection. 2. The pharmacokinetics of both diastereoisomers were linear in the range from 100-600 mg 5-MTFH/m2. Independent of the administered dose, the maximal plasma concentration of [R]-5-MTHF was nearly twice that of [S]-5-MTHF. The elimination of [S]-5-MTHF from plasma was considerably faster than that of the [R]-isomer (elimination half-life: 3.1 +/- 1.0 h vs 8.3 +/- 3.2 h). No metabolites were detected in plasma and in urine samples. 3. The plasma protein binding was stereoselective ([R]-5-MTHF bound: 88.2 +/- 2.7%; [S]-5-MTHF bound: 59.9 +/- 6.8%; P < 0.001), causing a significantly higher renal clearance for [S]-5-MTHF when compared with the [R]-isomer (37.5 +/- 23.7 ml min-1 vs 12.7 +/- 11.2 ml min-1, P < 0.001). There was no dose dependence, but gender influenced renal clearance (CLren[R]-5-MTHF: male vs female: 20.5 +/- 14.5 ml min-1 vs 7.8 +/- 4.7 min-1, P = 0.03; CLren [S]-5-MTHF: male vs female: 57.2 +/- 21.7 ml min-1 vs 25.7 +/- 16.2 ml min-1, P = 0.006). 4. Toxic side effects of the combination 5-FU/5-MTHF were rare and generally mild, and included stomatitis, nausea/emesis, diarrhoea, anaemia, leukopenia, and thrombocytopenia. 5. In combination with 500 mg 5-FU/m2 a single dose of 600 mg rac-5-MTHF/m2 can safely be administered to patients with colorectal cancer. A similar therapeutic benefit of 5-MTHF to folinic acid in the biochemical modulation of 5-FU is supported by the comparison of in vitro and in vivo data. 相似文献