全文获取类型
收费全文 | 1643篇 |
免费 | 167篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 22篇 |
儿科学 | 25篇 |
妇产科学 | 22篇 |
基础医学 | 210篇 |
口腔科学 | 75篇 |
临床医学 | 203篇 |
内科学 | 293篇 |
皮肤病学 | 17篇 |
神经病学 | 161篇 |
特种医学 | 124篇 |
外科学 | 206篇 |
综合类 | 41篇 |
一般理论 | 2篇 |
预防医学 | 176篇 |
眼科学 | 37篇 |
药学 | 136篇 |
中国医学 | 1篇 |
肿瘤学 | 62篇 |
出版年
2021年 | 20篇 |
2020年 | 15篇 |
2019年 | 18篇 |
2018年 | 30篇 |
2017年 | 20篇 |
2016年 | 20篇 |
2015年 | 22篇 |
2014年 | 37篇 |
2013年 | 43篇 |
2012年 | 61篇 |
2011年 | 67篇 |
2010年 | 44篇 |
2009年 | 37篇 |
2008年 | 42篇 |
2007年 | 92篇 |
2006年 | 81篇 |
2005年 | 72篇 |
2004年 | 56篇 |
2003年 | 60篇 |
2002年 | 49篇 |
2001年 | 65篇 |
2000年 | 61篇 |
1999年 | 45篇 |
1998年 | 20篇 |
1997年 | 19篇 |
1996年 | 17篇 |
1995年 | 16篇 |
1994年 | 17篇 |
1993年 | 13篇 |
1992年 | 48篇 |
1991年 | 44篇 |
1990年 | 29篇 |
1989年 | 34篇 |
1988年 | 36篇 |
1987年 | 43篇 |
1986年 | 34篇 |
1985年 | 36篇 |
1984年 | 14篇 |
1983年 | 25篇 |
1982年 | 16篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1979年 | 24篇 |
1978年 | 21篇 |
1977年 | 13篇 |
1974年 | 17篇 |
1973年 | 18篇 |
1972年 | 25篇 |
1971年 | 22篇 |
1966年 | 15篇 |
排序方式: 共有1813条查询结果,搜索用时 15 毫秒
1.
2.
OBJECTIVE: Clinical reports over the last 60 years suggest that the amobarbital interview is effective in relieving catatonic symptoms. This has never been substantiated with methodologically sound trials. The authors postulated that a randomized blind comparison of intravenous amobarbital and saline would demonstrate the superiority of amobarbital in relieving catatonic mutism. METHOD: The subjects were 20 inpatients with catatonic mutism. They were randomly assigned to either saline (N = 10) or a 5% amobarbital solution (N = 10), and the infusions were administered intravenously at a rate of 1 cc/min or less over 10 minutes by a blinded physician. A second blinded physician administered a semistructured interview during the infusion to control for the effect of suggestion. A third blinded physician rated patient responsiveness, reactivity, and arousal. Any patient who was unresponsive to the initial infusion was crossed over to the other infusion. Interviews were videotaped for determination of interrater reliability. RESULTS: In the initial infusions, six of 10 patients responded to amobarbital and zero of 10 responded to saline. Four of the saline nonresponders responded when given amobarbital. Response was evident by the 4th minute of the amobarbital infusion. Interrater reliability was high. The responders and nonresponders differed significantly in the variance of the weight-adjusted amobarbital dose, and the responders tended to be older and female. CONCLUSIONS: Intravenous amobarbital is superior to saline in relieving catatonic mutism, although only 50% of these patients responded. The nonresponders were distinguished from the responders by a greater variance in the weight-adjusted dose of amobarbital. 相似文献
3.
Jonathan Koea M.D. F.R.A.C.S. Graeme Taylor F.R.C.P.A. Mary Miller F.R.C.P.A. Michael Rodgers F.R. A.C. S. John McCall M.D. F.R.A.C.S. 《Journal of gastrointestinal surgery》2003,7(5):627-630
Solitary necrotic nodule of the liver is an unusual lesion that is often an incidental finding on abdominal imaging, intraoperative
examination, or post mortem. Most reported cases of solitary necrotic nodule have been in males, and over three quarters of
these lesions have occurred in the right lobe of the liver. Pathologically, solitary necrotic nodule is a benign lesion characterized
by a completely necrotic core that is often partly calcified, surrounded by a dense hyalinized fibrous capsule containing
elastin fibres. The ultrasound appearance of solitary necrotic nodule is usually of a “target” lesion with a hyperechoic center,
while on CT scan they appear as non-enhancing hypodense lesions that are typical of metastatic adenocarcinoma or peripheral
cholangiocarcinoma. The impression of malignancy is further enforced with the finding of necrotic cellular material on biopsy
and the macroscopically hard and “gritty” nature of the nodules. Currently, permanent histopathology of solitary necrotic
nodules is the only accurate method of diagnosis. However, solitary necrotic nodules are usually of a bilobed or lobulated
shape that is unusual for malignant liver lesions, and they often lie in close proximity to hepatic inflow structures. Solitary
necrotic nodule should be suspected in liver lesions with this configuration, location, and on a biopsy showing a large amount
of necrosis. 相似文献
4.
Pre-targeted immunoscintigraphy of murine tumors with indium-111-labeled bifunctional haptens 总被引:6,自引:0,他引:6
D A Goodwin C F Meares M J McCall M McTigue W Chaovapong 《Journal of nuclear medicine》1988,29(2):226-234
A method of tumor imaging utilizing the nonspecific accumulation of antibody through leaky capillaries is described, in which the antibody and the radiolabel are administered separately. Nonradioactive antibody is given first (pre-targeted), and allowed adequate time to reach maximum tumor concentration. Depending on the antibody, this may take several days. At the time of maximum tumor concentration of nonradioactive antibody, the blood is quickly cleared of excess circulating nonradioactive antibody using a special i.v. "chase". The radiolabel then is given and imaging done in 1 to 3 hr. The use of short lived tracers (hours) to image antibodies that localize slowly (days) in-vivo is made possible by this method. 相似文献
5.
Neutrophil responses to platelet-activating factor 总被引:5,自引:0,他引:5
J. T. O'Flaherty C. H. Miller J. C. Lewis R. L. Wykle D. A. Bass C. E. McCall M. Waite L. R. DeChatelet 《Inflammation》1981,5(3):193-201
1-O-Alkyl-2-O-acetyl-sn-glyceryl-3-phosphorylcholine (i.e., platelet-activating factor) was prepared and confirmed to possess potent platelet aggregating activity. It was also potent in aggregating and degranulating rabbit and human neutrophils. When injected into rabbits, the lipid induced profound neutropenia, thrombocytopenia, and anaphylactic symptoms. The lyso derivative of this lipid, 1-O-alkyl-sn-glyceryl-3-phosphorylcholine, was inactive or several orders of magnitude weaker in inducing these responses. The acetylated lipid appears to be a potent stimulator of both platelets and neutrophils. Its anaphylactic-like toxicity may be related, at least in part, to its ability to aggregate or otherwise stimulate these cells.This work was supported by NIH grants AI09169, AI10732, AI14929, HL16769, HL14164, and AMI1799. 相似文献
6.
Evaluation of PCR testing of ethanol-fixed nasal swab specimens as an augmented surveillance strategy for influenza virus and adenovirus identification
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Krafft AE Russell KL Hawksworth AW McCall S Irvine M Daum LT Connoly JL Reid AH Gaydos JC Taubenberger JK 《Journal of clinical microbiology》2005,43(4):1768-1775
Viral culture isolation has been widely accepted as the "gold standard" for laboratory confirmation of viral infection; however, it requires ultralow temperature specimen storage. Storage of specimens in ethanol at room temperature could expand our ability to conduct active surveillance and retrospective screenings of viruses with rapid and inexpensive real-time PCR tests, including isolates from remote regions where freezing specimens for culture is not feasible. Molecular methods allow for rapid identification of viral pathogens without the need to maintain viability. We hypothesized that ethanol, while inactivating viruses, can preserve DNA and RNA for PCR-based methods. To evaluate the use of ethanol-stored specimens for augmenting surveillance for detection of influenza viruses A and B and adenoviruses (AdV), paired nasal swab specimens were collected from 384 recruits with febrile respiratory illness at Fort Jackson, S.C., in a 2-year study. One swab was stored at ambient temperature in 100% ethanol for up to 6 months, and the other swab was stored at -70 degrees C in viral medium. For viral detection, frozen specimens were cultured for a variety of respiratory viruses, and ethanol-fixed specimens were tested with TaqMan (TM) probe and LightCycler SYBR green (SG) melting curve assays with at least two different PCR targets for each virus. The sensitivities of the TM and SG assays on specimens stored in ethanol for 1 month were 75% and 58% for influenza A, 89% and 67% for influenza B, and 93 to 98% and 57% for AdV, respectively. Lower specificities of the real-time assays corresponded to the increased detection of PCR-positive but culture-negative specimens. Influenza virus RNA was detected as well or better after 6 months of storage in ethanol. 相似文献
7.
Previous literature presents discordant results on the relationship between physiological and subjective sexual arousal in women. In this study, the use of hierarchical linear modeling (HLM) revealed a significant concordance between continuous measures of physiological and subjective sexual arousal as assessed during exposure to erotic stimuli in a laboratory setting. We propose that past studies that have found little or no association between the two measures may have been in part limited by the methodology and statistical analyses employed. 相似文献
8.
Phagocytosis of Live Versus Heat-Killed Bacteria by Human Polymorphonuclear Leukocytes 总被引:1,自引:5,他引:1
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lawrence R. DeChatelet Debra Mullikin Pamela S. Shirley Charles E. McCall 《Infection and immunity》1974,10(1):25-29
Heat-killed Pseudomonas aeruginosa are phagocytized much more slowly by human polymorphonuclear leukocytes than are the live organisms. The post-phagocytic increase in hexose monophosphate shunt activity (HMS) parallels the ingestion of the bacteria. The addition of serum to the live organisms causes a marked increase in both ingestion and cellular HMS activity; serum actually causes an inhibition of both uptake and HMS activity when added to the heat-killed organisms. Differences in postphagocytic HMS activity between live and heat-killed organisms were observed with three different species of bacteria, indicating that the phenomenon is not restricted to P. aeruginosa. These data emphasize that the influence of the particle on the phagocytic process is considerable. 相似文献
9.
Genetic association of defects in macrophage larvicidal activity and vaccine-induced resistance to Schistosoma mansoni in P strain mice.
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S L James R Correa-Oliveira A Sher L A Medvitz R D McCall 《Infection and immunity》1987,55(8):1884-1889
In contrast to most inbred strains, P mice fail to develop significant resistance to Schistosoma mansoni infection as a result of vaccination with irradiated cercariae. Vaccinated P mice also exhibit a defect in macrophage activation for killing of larval schistosomes upon specific-antigen challenge in vivo. To examine the genetic basis of these defects in vaccine-induced immunity, inheritance of the two traits was examined in (C57BL/6 X P)F1, F2, and reciprocal backcross generations. The defect in macrophage function which characterizes the P strain parent was found to be inherited in a fully recessive manner and to be controlled by only one or two major genetic loci. Moreover, a highly significant correlation (P less than 0.0025) was observed between the level of macrophage larvicidal activity and the level of resistance to challenge infection in segregating generations. Such an association is consistent with a cause-and-effect relationship, providing strong in vivo evidence implicating activated macrophages as immune effector cells of resistance to S. mansoni in the mouse-irradiated-vaccine model. 相似文献
10.
J. T. O'Flaherty M. J. Thomas C. J. Lees C. E. McCall 《The American journal of pathology》1981,104(1):55-62
The following oxidative derivatives of arachidonic acid were prepared and assayed for their ability to aggregate cytochalasin-B-pretreated human neutrophils: 5-, 8-, 9-, 11-, 12-, and 15-hydroxyeicosatetraenoic acids. The compounds were prepared by oxidation of arachidonic acid and purified by direct and reverse phase high performance liquid chromatography. Each lipid was racemic at the hydroxy residue and had a cistrans conjugated double bond adjacent to the hydroxy residue. Except for racemization, therefore, they were identical to hydroxyeicosatetraenoic acids generated by neutrophils exposed to diverse aggregating stimuli. In addition, 15-L-hydroxyeicosatetraenoic acid was prepared from soybean lipoxygenase. Of these 7 fatty acid preparations, only 5- and 12-hydroxyeicosatetraenoic acid aggregated the cells. Thus, the bioactions of these lipids are crucially dependent upon the position of the hydroxy residue. The 5- and 12-hydroxy derivatives were potent aggregating agents, inducing half-maximal responses at 200 and 40 nM, respectively. Their bioactions required extracellular calcium and magnesium. And the response to both fatty acids was effectively blocked by three inhibitors of cellular arachidonic acid metabolism: nordihydroguaiaretic acid, 5,8,11,14-eicosatetraynoic acid, and indomethacin. The 5- and 12- hydroxyeicosatetraenoic acids, therefore, may induce neutrophils to metabolize their endogenous arachidonate. Alternatively, the two hydroxy acids themselves may be further metabolized through pathways inhibited by arachidonate antimetabolites into a final mediator(s) of aggregate formation. 相似文献