全文获取类型
收费全文 | 2164篇 |
免费 | 160篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 140篇 |
妇产科学 | 62篇 |
基础医学 | 324篇 |
口腔科学 | 21篇 |
临床医学 | 146篇 |
内科学 | 325篇 |
皮肤病学 | 45篇 |
神经病学 | 147篇 |
特种医学 | 20篇 |
外国民族医学 | 1篇 |
外科学 | 360篇 |
综合类 | 113篇 |
预防医学 | 165篇 |
眼科学 | 67篇 |
药学 | 192篇 |
中国医学 | 14篇 |
肿瘤学 | 188篇 |
出版年
2023年 | 14篇 |
2022年 | 43篇 |
2021年 | 78篇 |
2020年 | 40篇 |
2019年 | 38篇 |
2018年 | 55篇 |
2017年 | 45篇 |
2016年 | 47篇 |
2015年 | 44篇 |
2014年 | 60篇 |
2013年 | 91篇 |
2012年 | 116篇 |
2011年 | 131篇 |
2010年 | 76篇 |
2009年 | 84篇 |
2008年 | 101篇 |
2007年 | 106篇 |
2006年 | 84篇 |
2005年 | 84篇 |
2004年 | 69篇 |
2003年 | 60篇 |
2002年 | 72篇 |
2001年 | 44篇 |
2000年 | 26篇 |
1999年 | 38篇 |
1998年 | 18篇 |
1997年 | 15篇 |
1995年 | 18篇 |
1994年 | 19篇 |
1993年 | 18篇 |
1992年 | 30篇 |
1991年 | 37篇 |
1990年 | 29篇 |
1989年 | 33篇 |
1988年 | 25篇 |
1987年 | 22篇 |
1986年 | 37篇 |
1985年 | 19篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1981年 | 9篇 |
1979年 | 17篇 |
1978年 | 9篇 |
1975年 | 15篇 |
1974年 | 19篇 |
1973年 | 13篇 |
1972年 | 10篇 |
1971年 | 13篇 |
1970年 | 17篇 |
1966年 | 10篇 |
排序方式: 共有2335条查询结果,搜索用时 15 毫秒
21.
22.
Knowledge-based computer system to aid in the histopathological diagnosis of breast disease.
下载免费PDF全文
![点击此处可从《Journal of clinical pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A knowledge-based computer system, designed to assist pathologists in the histological diagnosis of breast disease, is described. This system represents knowledge in the form of "disease profiles" and uses a novel inference model based on the mathematical technique of hypergraphs. Its design overcomes many of the limitations of existing expert system technologies when applied to breast disease. In particular, the system can quickly focus on a differential problem and thus reduce the amount of data necessary to reach a conclusion. The system was tested on two sets of samples, consisting of 14 retrospective cases and five hypothetical cases of breast disease. Its recommendations were judged "correct" by the evaluating pathologist in 15 cases. This study shows the feasibility of providing "decision support" in histopathology. 相似文献
23.
Tumoral calcium pyrophosphate dihydrate deposition disease (TCPPD, tumoral or tophaceous pseudogout) is a rare nonneoplastic entity which mimics soft-tissue or skeletal malignancy. We present here the fine-needle aspiration cytology findings of a unique case of TCPPD in a 76-yr-old woman, with a large paraischial soft-tissue mass diagnosed as a malignant neoplasm. The difficulty in diagnosing such lesions by fine-needle aspirates is discussed and reviewed in the context of known cases from the literature. 相似文献
24.
目的观察仙荷降脂液对饲料所致高脂血症家兔血脂及血液流变性的影响。方法健康家兔随机分为对照组 (A组 ) ,高脂血症对照组 (B组 )和高脂血症治疗组 (C组 )。A组给予普通饲料 ,B组和C组均给予高脂饲料喂养 ,C组高脂喂养3周后每天加喂仙荷降脂液 ,于实验第0、21、42d分别测定血脂、血液流变学指标。结果C组用药后血清总胆固醇 (TC)、甘油三脂 (TG)、高密度脂蛋白胆固醇(HDL -C)均显著低于B组 (P<0.01) ;全血粘度 (10s-1)、血浆粘度、红细胞刚性指数 (REI)、血小板粘附率均明显降低(P<0.01 ,和P<0.05)。结论仙荷降脂液能降低高脂血症家兔血清TC、TG、HDL -C和改善血液流变性。 相似文献
25.
The rel-associated pp40 protein prevents DNA binding of Rel and NF-kappa B: relationship with I kappa B beta and regulation by phosphorylation 总被引:71,自引:0,他引:71
L D Kerr J Inoue N Davis E Link P A Baeuerle H R Bose I M Verma 《Genes & development》1991,5(8):1464-1476
The product of proto-oncogene Rel associates with a number of cellular proteins. We have studied the effect of one of them, a phosphoprotein of 40 kD (pp40), on the DNA-binding activity of the Rel protein. We demonstrate that purified pp40 not only inhibits the binding of Rel, but also NF-kappa B (p50-p65) heterocomplex to DNA. Additionally, I kappa B beta, but not I kappa B alpha, also prevented the binding of Rel to the kappa B site. I kappa B beta and pp40 are related proteins because (1) they share a number of common tryptic peptides, (2) their inhibitory effect on DNA binding can be abolished by preincubation with pp40-specific antiserum, and (3) labeled I kappa B beta can be immunoprecipitated with pp40 antibodies. pp40 is part of the Rel complex present in the cytoplasm and nuclear extracts of WEHI-231 cells. The activity of pp40 to inhibit the DNA binding of Rel and NF-kappa B is modulated by phosphorylation. 相似文献
26.
Strain variation in glycosaminoglycan recognition influences cell-type-specific binding by lyme disease spirochetes
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)
Lyme disease, a chronic multisystemic disorder that can affect the skin, heart, joints, and nervous system is caused by Borrelia burgdorferi sensu lato. Lyme disease spirochetes were previously shown to bind glycosaminoglycans (GAGs). In the current study, the GAG-binding properties of eight Lyme disease strains were determined. Binding by two high-passage HB19 derivatives to Vero cells could not be inhibited by enzymatic removal of GAGs or by the addition of exogenous GAG. The other six strains, which included a different high-passage HB19 derivative (HB19 clone 1), were shown to recognize both heparan sulfate and dermatan sulfate in cell-binding assays, but the relative efficiency of binding to these two GAGs varied among the strains. Strains N40, CA20-2A, and PBi bound predominantly to heparan sulfate, PBo bound both heparan sulfate and dermatan sulfate roughly equally, and VS461 and HB19 clone 1 recognized primarily dermatan sulfate. Cell binding by strain HB19 clone 1 was inhibited better by exogenous dermatan sulfate than by heparin, whereas heparin was the better inhibitor of binding by strain N40. The GAG-binding preference of a Lyme disease strain was reflected in its cell-type-specific binding. Strains that recognized predominantly heparan sulfate bound efficiently to both C6 glioma cells and EA-Hy926 cells, whereas strains that recognized predominantly dermatan sulfate bound well only to the glial cells. The effect of lyase treatment of these cells on bacterial binding was consistent with the model that cell-type-specific binding was a reflection of the GAG-binding preference. We conclude that the GAG-binding preference varies with the strain of Lyme disease spirochete and that this variation influences cell-type-specific binding in vitro. 相似文献
27.
Influence of lectins, hexoses, and neuraminidase on the association of purified elementary bodies of Chlamydia trachomatis UW-31 with HeLa cells. 总被引:2,自引:5,他引:2
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)
Using highly purified elementary bodies of Chlamydia trachomatis UW-31 (serotype K), we found that HeLa 229 monolayer cultures bound more 32P-labeled chlamydiae after pretreatment with the lectin wheat germ agglutinin. The lectin, on the other hand, inhibited competitively when chlamydial association was assayed in the presence of polycations. The two effects of wheat germ agglutinin were abolished when N-acetylneuraminic acid (NeuNAc)- or N-acetylglucosamine (GlcNAc)-preincubated wheat germ agglutinin was used. Brief exposure of HeLa cells to neuraminidase abolished the ability to bind the elementary bodies, whether or not polycations were present. Furthermore, at 5 degrees C but not at 37 degrees C, NeuNAc, GlcNAc and N-acetylgalactosamine inhibited chlamydial association only in the absence of the polycation DEAE-dextran. The results suggest that NeuNAc residues on the plasma membrane are the principal, but not the only, receptors for this strain of C. trachomatis. 相似文献
28.
In rats with adjuvant-induced arthritis the effects of prednisolone andl-thyroxine on the changes in collagen metabolism were investigated both in the skin and tendon during the acute and chronic phase of the arthritis. In untreated animals with adjuvant-induced arthritis, a decrease in the collagen synthesis accompanied by an increase in the catabolism of collagen and a retardation in the conversion of soluble to insoluble collagen were noted both in the skin and tendon during the course of the disease. Prednisolone was found to accelerate the conversion of soluble to insoluble collagen and to inhibit the enhanced catabolism of collagen in rats with adjuvant-induced arthritis.l-Thyroxine accelerated the conversion of soluble to insoluble collagen in adjuvant-induced arthritic rats more effectively than prednisolone but was less effective with regard to the inhibition of enhanced catabolism of collagen. However, the synthesis of collagen in adjuvant-induced arthritis was improved by both prednisolone andl-thyroxine. 相似文献
29.
Neonatal back-transport. Cost-effectiveness 总被引:1,自引:0,他引:1
This study examines the cost-effectiveness of returning previously ill neonates to community hospitals after treatment in a tertiary center, a concept known as "back-transport." The authors compared the charges for medical care during convalescence of a group of back-transported infants (BT infants; n = 20) with a similar group of infants who remained in a tertiary center for convalescence (NT infants; n = 20). The total charges for convalescent care (inpatient plus transport charges) for 20 representative BT infants was $61,840, compared with $68,240 for 20 matched NT infants, an average savings of $320 per BT infant. The average daily bed charge and charges for laboratory tests and medications were significantly less for BT infants compared with NT infants, and these reductions offset the transport charges for BT infants. The authors conclude that back transport decreases the charges for medical care for most infants. Therefore, the decision to back-transport an individual infant usually can be based on factors other than cost. 相似文献
30.