全文获取类型
收费全文 | 575篇 |
免费 | 56篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 21篇 |
妇产科学 | 18篇 |
基础医学 | 118篇 |
口腔科学 | 16篇 |
临床医学 | 45篇 |
内科学 | 103篇 |
皮肤病学 | 17篇 |
神经病学 | 51篇 |
特种医学 | 61篇 |
外科学 | 50篇 |
综合类 | 13篇 |
预防医学 | 35篇 |
眼科学 | 9篇 |
药学 | 35篇 |
中国医学 | 1篇 |
肿瘤学 | 15篇 |
出版年
2021年 | 8篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 15篇 |
2015年 | 15篇 |
2014年 | 19篇 |
2013年 | 33篇 |
2012年 | 21篇 |
2011年 | 19篇 |
2010年 | 15篇 |
2009年 | 21篇 |
2008年 | 11篇 |
2007年 | 16篇 |
2006年 | 23篇 |
2005年 | 29篇 |
2004年 | 30篇 |
2003年 | 23篇 |
2002年 | 12篇 |
2001年 | 23篇 |
2000年 | 13篇 |
1999年 | 15篇 |
1998年 | 15篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 12篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1975年 | 8篇 |
1972年 | 9篇 |
1971年 | 5篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1968年 | 6篇 |
1967年 | 6篇 |
1966年 | 5篇 |
1963年 | 3篇 |
1962年 | 4篇 |
1957年 | 3篇 |
1956年 | 3篇 |
1955年 | 4篇 |
1900年 | 3篇 |
排序方式: 共有633条查询结果,搜索用时 15 毫秒
1.
Neuroimaging in Pineal Tumors 总被引:4,自引:0,他引:4
F Reis MD AV Faria MD PhD VA Zanardi MD PhD JR Menezes MD F Cendes MD PhD LS Queiroz MD PhD 《Journal of neuroimaging》2006,16(1):52-58
BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread. 相似文献
2.
3.
Replacement of cholesterol gallstones by murideoxycholyl taurine gallstones in prairie dogs fed murideoxycholic acid 总被引:1,自引:0,他引:1
B I Cohen N Ayyad E H Mosbach C K McSherry N Matoba A F Hofmann H T Ton-Nu Y Peng C D Schteingart R J Stenger 《Hepatology (Baltimore, Md.)》1991,14(1):158-168
The effect of two hydrophilic bile acids, murideoxycholic acid (3 alpha,6 beta-dihydroxy-5 beta-cholanoic acid) and ursodeoxycholic acid, on cholesterol and bile acid metabolism and hepatic pathology and gallstone composition was studied in the prairie dog. Cholesterol gallstones were induced by feeding a diet containing 1.2% cholesterol for 75 days. The animals were divided into six groups, and gallstone regression was studied as follows: groups 2 and 5, chow plus 0.2% cholesterol; groups 3 and 6, chow plus 0.2% cholesterol plus 0.15% ursodeoxycholic acid; groups 4 and 7, chow plus 0.2% cholesterol plus 0.15% murideoxycholic acid. Animals in groups 2 to 4 were killed after an additional 6 wk; animals in groups 5 to 7 were killed after an additional 12 wk. Gallstone dissolution did not occur in any group. The gallstones in groups 2, 3, 5 and 6 were typical cholesterol aggregates, as determined by polarized light microscopy and Fourier transform infrared spectrometry. The gallstones of the murideoxycholic acid group were large, solitary, dark stones that appeared radiopaque under 22 kVp x-ray examination. Scanning electron microscopy showed that in these stones the cholesterol crystals had been replaced by an amorphous material, both within the stone and on the stone surface. Chemical analysis indicated that at the end of 12 wk the calcium/sodium salt of the taurine conjugate of murideoxycholic acid (murideoxycholyl taurine) comprised 70% of the stones; protein, cholesterol and small amounts of other bile salts were also present. In vitro studies confirmed the insolubility of the sodium and calcium salts of murideoxycholyl taurine. These studies indicate that the hydrophilic bile acids, murideoxycholic acid and ursodeoxycholic acid, did not achieve gallstone dissolution under the conditions used. In the animals fed murideoxycholic acid, an insoluble calcium salt of murideoxycholyl taurine replaced cholesterol as the major constituent of gallbladder stones. This is the first example of an insoluble dihydroxy taurine-conjugated bile acid; administration of the unconjugated bile acid induced precipitation of a kind of gallstone not previously reported. The final result was transformation of cholesterol stones to bile salt stones. 相似文献
4.
Chronic food restriction has been shown to enhance glucose metabolism in adipocytes from lean Zucker rats at 10, 26, and 52 weeks of age compared to ad libitum-fed lean rats. Only adipocytes from food restricted 10-week-old obese rats demonstrated this response. In this study, lean and obese rats were food restricted from 5 until 14 weeks of age to determine the age at which adipocytes from obese rats were no longer affected by this intervention. Effects of 1 week of refeeding were also determined. When the rats were killed, body weights were highest in control rats followed by restricted/refed and then restricted rats within each genotype. Epididymal pad weights of lean rats were resistant to dietary intervention, while those of obese-restricted and obese-restricted/refed rats weighed less than pads of obese-control rats. Retroperitoneal pad weight was lowered by food restriction in both genotypes; but only that of lean-restricted/refed rats totally recovered with refeeding. Adipocytes of lean-restricted rats had the highest conversion of glucose to CO2. Glyceride-glycerol production was higher in obese compared to lean rats, but restricted rats had elevated conversion of glucose to fatty acids. In general, these results indicate that by 14 weeks of age obese Zucker rats no longer respond to food restriction with an elevated rate of glucose metabolism in adipocytes. 相似文献
5.
The anticonvulsive properties of a new compound: F1933 (Dulozafone) were investigated in the amygdala kindling model and compared with those of diazepam. Both drugs protected fully kindled rats against generalized seizures but failed to suppress partial ictal events (amygdala afterdischarges and limbic seizures). The anticonvulsive action of F1933, administered at the ED100, was nearly reversed by the specific antagonist of benzodiazepines receptors; R015-1788 (Flumazenil), suggesting that the effect of F1933 is mediated by this receptor. These results also emphasize the usefulness of kindling to test antiepileptic drugs and to confirm their supposed profile of action. 相似文献
6.
An 82-year-old woman developed a well-differentiated squamous cell carcinoma that apparently arose in two discrete congenital cysts of the liver. Both cysts were lined predominantly by stratified squamous epithelium with extensive areas of dysplasia and foci of transition to in situ carcinoma and overt exophytic and infiltrating squamous cell carcinoma. A third intrahepatic cyst was lined entirely by bile duct-type epithelium and contained no tumor. The liver was massively infiltrated by the carcinoma, and there were metastases to the lymph nodes, lung, and bone marrow. Since a search for an alternative primary tumor site was unrevealing, the authors interpret this as a unique case of primary squamous cell carcinoma originating in congenital cysts of the liver. 相似文献
7.
8.
Steffen Stenger Werner Solbach Martin Rllinghoff Christian Bogdan 《European journal of immunology》1991,21(7):1669-1675
Tumor necrosis factor-alpha (TNF-alpha) strongly activates murine peritoneal macrophages (M phi) for killing of amastigotes from Leishmania major in the presence of low amounts of interferon-gamma (IFN-gamma). Recently, we found that IFN-gamma and interleukin 4 (IL 4) also synergistically enhance the antileishmanial potential of M phi. In this report, evidence is provided that the synergism of IFN-gamma and IL 4 is based on the ability of the lymphokines to induce the endogenous production of TNF-alpha. First, both IFN-gamma and IL 4 as single agents and in combination were potent inducers of TNF-alpha production by M phi infected with L. major amastigotes. Second, the synergistic effect of IFN-gamma and IL 4 on parasite killing by M phi strongly correlated with their synergistic effect on the release of TNF-alpha. Third, the IFN-gamma/IL 4-mediated parasite elimination was completely abrogated not only in the presence of antibodies to IFN-gamma and IL 4, but also with an antibody specific for TNF-alpha. Consistent with the conclusion that endogenously produced TNF-alpha accounts for the synergism of IL 4 with IFN-gamma is the finding that N omega-monomethyl-L-arginine, an inhibitor of the L-arginine-dependent generation of microbicidal nitrogen intermediates, totally blocked the M phi activation induced by IFN-gamma combined with IL 4 as well as by IFN-gamma combined with TNF-alpha. These results underline the complex interplay of cytokines derived from lymphocytes and M phi and the role of TNF-alpha as pivotal factor for the induction of antileishmanial effector functions. 相似文献
9.
Is the outcome of in-vitro fertilization and embryo transfer treatment improved by spontaneous or surgical drainage of a hydrosalpinx? 总被引:4,自引:7,他引:4
Sowter MC; Akande VA; Williams JA; Hull MG 《Human reproduction (Oxford, England)》1997,12(10):2147-2150
A pilot study was designed to examine whether the outcome of embryo
transfer in women with a hydrosalpinx might be improved by surgical
drainage of the hydrosalpinx at the time of oocyte collection for in- vitro
fertilization treatment. A comparative, controlled but retrospective
analysis of the results was performed of all women with infective tubal
damage aged <40 years old, who had ovulatory cycles, a normal uterus and
a partner with normal spermatozoa. A standardized treatment regimen was
used. A maximum of three embryos were transferred. Hydrosalpinx was defined
by prior hysterosalpingography and/or laparoscopy with transcervical dye
injection. A total of 237 embryo transfer cycles in women with
hydrosalpinges (tubal distension not visible in 151, visible but not
drained in 30 and drained in 56) were compared with 705 embryo transfer
cycles in women with tubal disease but no hydrosalpinx. Results were
analysed in the first three cycles but also separately in the first cycle
to check for bias. Success rates were higher in the first cycle, but did
not significantly influence overall differences. Implantation rates were
significantly reduced overall in the hydrosalpinx group (8.0 versus 13.2%
for controls; P < 0.001), being 8.3% (P < 0.01) in the subgroup
without evident tubal distension and 7.5% (not significant) in the drained
hydrosalpinx group. This study shows that tubal damage with distal
occlusion is associated with a marked reduction in embryo implantation,
even in the absence of obvious fluid distension. Surgical drainage of
distended hydrosalpinges appears to offer no benefit.
相似文献
10.
H Zaun D Stenger S Zabransky M Zankl 《Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und verwandte Gebiete》1984,35(3):162-165
Two children with abnormally long eyelashes and bushy brows ("trichomegaly") present at birth and associated with pigmentary degeneration of the retina and general growth retardation are described. This combination of findings has been observed previously in three cases. Mental retardation, sparse scalp hair, endocrinologic deficiencies and (in one of our cases) koilonychia may be found in addition, but not necessarily. 相似文献