全文获取类型
收费全文 | 785篇 |
免费 | 53篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 9篇 |
妇产科学 | 12篇 |
基础医学 | 88篇 |
口腔科学 | 11篇 |
临床医学 | 63篇 |
内科学 | 173篇 |
皮肤病学 | 6篇 |
神经病学 | 54篇 |
特种医学 | 22篇 |
外科学 | 132篇 |
综合类 | 13篇 |
预防医学 | 23篇 |
眼科学 | 97篇 |
药学 | 90篇 |
中国医学 | 5篇 |
肿瘤学 | 37篇 |
出版年
2023年 | 3篇 |
2022年 | 23篇 |
2021年 | 69篇 |
2020年 | 22篇 |
2019年 | 22篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 26篇 |
2015年 | 26篇 |
2014年 | 43篇 |
2013年 | 33篇 |
2012年 | 58篇 |
2011年 | 58篇 |
2010年 | 36篇 |
2009年 | 21篇 |
2008年 | 40篇 |
2007年 | 45篇 |
2006年 | 58篇 |
2005年 | 48篇 |
2004年 | 29篇 |
2003年 | 27篇 |
2002年 | 20篇 |
2001年 | 8篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1969年 | 2篇 |
1916年 | 1篇 |
排序方式: 共有840条查询结果,搜索用时 15 毫秒
101.
Transmission electron microscope studies of the tegument of the tropical marine fish monogenean parasite Pseudothoracocotyla indica describe surface specialisations and detail the ultrastructure of the tegument and the haptor. The tegument consists of a
syncytium, numerous electron-dense granules, electron-lucent vesicles and large multivesicular bodies. The posterior tegumental
syncytium is infolded to form tegumental ridges that are present on both the ventral and dorsal surfaces. A thin coat of glycocalyx
is present on the tegument surface. In contrast, the tegumental syncytium of the haptor is relatively thin, containing electron-dense
granules and various-sized electron-lucent vesicles. Exocytosis of the electron-dense and electron-lucent vesicles apparently
occurs in the syncytium of the haptor and general body surface. Tegumental damage was observed on the dorsal surface in the
mid-body region and may possibly have been due to natural mechanical forces. The haptor consists of electron-dense clamp sclerites
embedded within a matrix covered by the tegumental syncytium. The sclerites are connected to each other and to the basal lamina
by radially oriented muscle fibres. The haptor is richly supplied with non-myelinated nerve axons. Both uniciliated and non-ciliated
presumed sensory structures are present on the body surface and haptor. Uniciliated sensory structures were found mainly around
the oral sucker. Groups of neurons and nerve processes containing neurosecretory vesicles were frequently observed in the
vicinity of the clamps. Electron immunogold labeling studies demonstrated that neuropeptide F [NPF (Moniezia expansa)] immunoreactivity was confined to electron-dense-cored neurosecretory vesicles in nerve fibres from the posterior and haptor
regions of the fluke.
Received: 8 February 1996 / Accepted: 10 April 1996 相似文献
102.
Independent movement of surface immunoglobulin from Fc receptors on lymphocyte membranes. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The majority of surface immunoglobulin-positive lymph node cells possess Fc receptors detectable by a rosette technique. The movement of surface immunoglobulin to form caps does not alter the distribution of Fc receptors, although Fc rosette-forming indicator cells collect over the immunoglobulin cap under capping conditions. 相似文献
103.
V A Starnes P E Oyer P M Portner N Ramasamy P J Miller E B Stinson J C Baldwin A K Ream J Wyner N E Shumway 《The Journal of thoracic and cardiovascular surgery》1988,96(1):62-71
The electrically driven Novacor implantable left ventricular assist device has been implanted in six patients (four men and two women) since Sept. 7, 1984. In four of the six patients (67%) the device was a successful bridge to cardiac transplantation. One patient died of multiple organ failure and Candida sepsis after 16 days of support with the device. One patient died in the operating room of uncontrollable hemorrhage and biventricular failure caused by severe cardiac rejection. Three patients are alive with cardiac transplants 38, 17, and 10 months after transplantation. One patient died after cardiac transplantation of presumed sepsis. The Novacor left ventricular assist device performed in all cases without mechanical or electrical failure. Excluding the intraoperative death, assist duration ranged from 2 to 16 days. The cardiac index (synonymous with device output) ranged from 2.4 to 3.4 L/min/m2. No embolic events (cerebrovascular or systemic) occurred during assistance with the device. Minimal red cell hemolysis was documented during the period of support. The Novacor left ventricular assist device is a safe and effective bridge to cardiac transplantation in patients with refractory cardiogenic shock. 相似文献
104.
Donald F. Smee Patricia A. McKernan Hassan A. Alaghamandan Karl B. Frank Kandasamy Ramasamy Ganapathi R. Revankar Roland K. Robins 《Antiviral research》1988,10(6):263-277
Eight sugar-modified pyrrolopyrimidine nucleoside analogs related to the antibiotic sangivamycin were evaluated in cell culture against herpes simplex types 1 (HSV-1) and 2 (HSV-2), cytomegalovirus (CMV), adenovirus, and visna virus. Five of the compounds were highly active against most of the viruses with 50% inhibition (ED50) values of 1–10 μM. The selectivity of the agents was low, with inhibition of uninfected cell proliferation occurring within 5-fold that of the virus ED50 for most of the viruses. The compounds did not possess RNA virus-inhibitory activity when evaluated against certain myxo-, paramyxo-, picorna-, reo-, rhabdo-, and togaviruses. Two of the nucleosides were tested further in a cell line persistently infected with Friend leukemia virus where they were inhibitory to both virus yield and cell proliferation at 4–5 μM. Several of the sangivamycin analogs were tested in animal models using a twice-a-day treatment regimen. They proved to be inactive against HSV-1, murine CMV and/or Friend leukemia virus infections in mice. 相似文献
105.
J P Aston H M Kingston I Ramasamy E G Walters D Stansbie 《Journal of the neurological sciences》1984,65(3):307-314
Plasma creatine kinase (CK) and pyruvate kinase (PK) were measured in 31 obligate carriers of Becker muscular dystrophy (BMD), 36 BMD patients and appropriate controls. Mean plasma CK was 108 U/l in obligate carriers and 62 U/l in 43 age- and sex-matched controls (P less than 0.001 carriers vs controls). Control CK reference range was 31-125 U/l (mean +/- 2 SD of log transformed values). Mean plasma PK was 40 U/l in obligate carriers and 34 U/l in 56 controls (P less than 0.02 carriers vs controls). Control PK reference range was 18-61 U/l. Values of CK above the reference range upper limit were found in 13 of 31 BMD obligate carriers but only 2 showed elevated PK values. The sensitivity of CK in determining BMD carrier status, although only 42%, was markedly better than PK at 6.5%. Mean plasma CK in BMD patients was 2366 U/l, a 19-fold increase over the control value of 127 U/l (P less than 0.001 patients vs controls). Control CK reference range was 40-316 U/l. In contrast, mean plasma PK in BMD patients was 353 U/l, only 7-fold higher than the mean control value of 57 U/l (P less than 0.001 patients vs controls). Control PK reference range was 22-126 U/l. Clearly, the estimation of plasma PK as a means of determining BMD carrier status is markedly inferior to CK. Previous reports of increased sensitivity of PK compared with CK may have been due to artefactually elevated PK levels produced during sample preparation. 相似文献
106.
PURPOSE: To study the effect of piperine, an alkaloid, on thyroid hormones and apolipoproteins in high-fat-diet (HFD) and antithyroid drug-induced hyperlipidemic rats. EXPERIMENTAL: Male Wistar rats were first divided into two groups, control diet and high-fat diet (HFD) and then subdivided into four subgroups of ten animals each. The animals were treated with the following regimens for 10 weeks: 1% carboxymethyl cellulose; 10 mg carbimazole (CM)/kg body weight; 10 mg CM + 40 mg piperine/kg body weight, and 10 mg CM + 2 mg atorvastatin /ATV//kg body weight. Lipid profiles, hormone levels, and apolipoprotein levels were studied in all groups. RESULTS: HFD and/or CM administration significantly elevated the plasma levels of total cholesterol, VLDL, LDL, triglycerides, free fatty acids, and phospholipids, but significantly reduced the HDL levels. Moreover, CM administration significantly reduced apo A-I levels and T3, T4 and testosterone levels while significantly elevating plasma apo B, thyroid stimulating hormone (TSH) and insulin levels. The simultaneous administration of piperine and HFD significantly reduced plasma lipids and lipoproteins levels, except for HDL, which was significantly elevated. Piperine supplementation also improved the plasma levels of apo A-I, T3, T4, testosterone, and I and significantly reduced apo B, TSH, and insulin to near normal levels. CONCLUSIONS: The data presented here provide evidence that piperine possesses thyrogenic activity, thus modulating apolipoprotein levels and insulin resistance in HFD-fed rats, opening a new view in the management of dyslipidemia by dietary supplementation with nutrients. 相似文献
107.
The allele and genotype frequencies of MDR1 C3435T polymorphism were determined in 185 unrelated healthy Tamilians. The genomic DNA was extracted from peripheral leucocytes using phenol chloroform method and genotyped by PCR-RFLP method. The frequencies of MDR1 C3435 and T3435 alleles in Tamilian population were 0.46 and 0.54 respectively. The distribution of T3435 in this population was found to be greater than Africans and almost similar to Caucasians and Orientals. The distribution of CC, CT and TT genotypes was 0.18, 0.56 and 0.26 respectively. The frequency distribution of the CC genotype was lower in them when compared with Chinese and Africans whereas CT genotype was higher in comparison with all the major ethnic groups. 相似文献
108.
A 26-year-old woman presented with sudden defective vision in the right eye following lifting a heavy bucket of water. Examination showed a dense premacular subhyaloid haemorrhage associated with arteriovenous communications of the retina (AVCRs). Spontaneous absorption of the premacular haemorrhage with consequent improvement in the visual acuity was seen after two months. The possible aetiopathogenesis of the case is also discussed. 相似文献
109.
Perumal Nagarajan Arindkar Shailendra Ramasamy Venkatesan M. Jerald Mahesh Kumar Subeer S Majumdar Ramesh C Juyal 《Comparative clinical pathology》2012,21(6):1577-1585
The aim of the study was to evaluate baseline data of mutant strain of mice and to compare haematological parameters with their background strains. Almost all mutant strains of either sex had statistically significant changes in relation to their background strains. These findings will be useful for researchers in designing experiments on mutant strains for various disease models and interpreting data obtained from those strains. 相似文献
110.