全文获取类型
收费全文 | 7857篇 |
免费 | 382篇 |
国内免费 | 364篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 175篇 |
妇产科学 | 34篇 |
基础医学 | 535篇 |
口腔科学 | 12篇 |
临床医学 | 843篇 |
内科学 | 2025篇 |
皮肤病学 | 18篇 |
神经病学 | 50篇 |
特种医学 | 338篇 |
外国民族医学 | 2篇 |
外科学 | 1833篇 |
综合类 | 1253篇 |
现状与发展 | 3篇 |
预防医学 | 240篇 |
眼科学 | 15篇 |
药学 | 706篇 |
3篇 | |
中国医学 | 274篇 |
肿瘤学 | 238篇 |
出版年
2024年 | 14篇 |
2023年 | 99篇 |
2022年 | 173篇 |
2021年 | 237篇 |
2020年 | 207篇 |
2019年 | 150篇 |
2018年 | 187篇 |
2017年 | 207篇 |
2016年 | 220篇 |
2015年 | 206篇 |
2014年 | 405篇 |
2013年 | 494篇 |
2012年 | 355篇 |
2011年 | 396篇 |
2010年 | 376篇 |
2009年 | 374篇 |
2008年 | 415篇 |
2007年 | 380篇 |
2006年 | 372篇 |
2005年 | 402篇 |
2004年 | 288篇 |
2003年 | 247篇 |
2002年 | 258篇 |
2001年 | 213篇 |
2000年 | 186篇 |
1999年 | 141篇 |
1998年 | 172篇 |
1997年 | 159篇 |
1996年 | 143篇 |
1995年 | 118篇 |
1994年 | 145篇 |
1993年 | 109篇 |
1992年 | 82篇 |
1991年 | 77篇 |
1990年 | 92篇 |
1989年 | 48篇 |
1988年 | 76篇 |
1987年 | 51篇 |
1986年 | 42篇 |
1985年 | 25篇 |
1984年 | 43篇 |
1983年 | 22篇 |
1982年 | 35篇 |
1981年 | 16篇 |
1980年 | 21篇 |
1979年 | 20篇 |
1978年 | 19篇 |
1977年 | 14篇 |
1975年 | 18篇 |
1974年 | 16篇 |
排序方式: 共有8603条查询结果,搜索用时 15 毫秒
21.
22.
Richard Bost MD Jean Hostein MD Maria Valenti Bruno Bonaz MD Nicole Payen Henri Faure Jacques Fournet MD 《Digestive diseases and sciences》1990,35(2):193-199
A quantitatively and/or qualitatively abnormal duodenogastric reflux (DGR) could be involved in the pathogenesis of nonulcer dyspepsia (NUD). The aims of this prospective study were to look for (1) a pathological DGR profile during fasting and (2) an eventual correlation between DGR profile and clinical symptoms. Twenty-six NUD patients were investigated. Seven other operated patients with a surgical procedure facilitating DGR episodes and 27 healthy volunteers served as control groups. A clinical score was determined for each patient from a standardized questionnaire. Gastric aspiration was performed for 6 hr in fasting subjects. The aspirates were pooled into 17 samples. In each sample the concentration and the output of total bile acids was determined. If the concentration was larger than 30 mol/liter in pooled samples, the concentrations of free bile acids and the distribution of the conjugated bile acids was determined. The percentage of aliquots with a total bile acid concentration larger than 50 mol/liter (without upper limit), and the percentage with a concentration larger than 2500 mol/liter was also obtained. No significant difference was demonstrated between the healthy volunteers and NUD patients, whatever the parameter considered. However, there was a significant increase in each of the quantitative parameters for the group of operated patients in comparison with the NUD patient group. No significant correlation was found between the clinical score and the DGR profile in NUD patients. Apparently, DGR episodes do not play a primary role in the pathogenesis of NUD.Part of this work was presented at the 4th European Symposium on Gastrointestinal Motility, Krakow, Poland. September 22–24, 1988.Hepatogastroenterology, 35:178, 1988 (abstract). 相似文献
23.
The Effects of Permeation Enhancers on the Surface Morphology of the Rat Nasal Mucosa: A Scanning Electron Microscopy Study 总被引:2,自引:0,他引:2
A rat model has been developed to compare relative morphological changes in the nasal mucosa after exposure to potential membrane permeation enhancers. Scanning electron microscopy was used to characterize gross structural and specific cellular changes following exposure. Micrographs of the rat nasal mucosa were scored in four categories: (1) mucosal surface integrity, (2) ciliary morphology, (3) mucus/extracellular debris, and (4) presence of red blood cells. The order of increasing morphological damage resulting from a 5-min exposure to each surfactant was 0.5% Solulan C-24 0.5% Solulan C-24/0.5% sodium tauro-24,25-dihydrofusidate (STDHF) < 0.5% STDHF < 1.0% STDHF 1.0% Laureth-9 < 1.0% sodium taurodeoxycholate 1.0% sodium deoxycholate. The changes observed in the mucosal morphology after exposure to the various surfactants are in general agreement with data in the literature. This model is able to compare rapidly the relative morphological effects on the mucosal membrane of different nasal formulations. 相似文献
24.
Fibrous remnants from the porta hepatis and wedge biopsies of the liver were studied in 60 patients with biliary atresia. The patients were divided into three groups on the basis of bile duct diameter — I: no ducts; II: <50 m; III: >50 m. The liver damage was classified into three grades on the basis of ductular and parenchymal histopathologic changes and extent of inflammatory pathology. There was no correlation between severity of hepatic damage and duct diameter, although the levels of serum bilirubin and alkaline phosphatase varied in direct proportion to the degree of hepatic damage. There was an inverse relationship between age and duct diameter, but neither correlated with bile flow at surgery or in the postoperative period. The data suggest that Indian children with biliary atresia follow a different clinical course compared to those from Japan and Western countries.
Correspondence to: V. Bhatnagar 相似文献
25.
Moazzem Hossain Osamu Murahashi Hisami Ando Kentiro Kaneko Takahiro Ito 《Pediatric surgery international》1996,11(2-3):126-129
Proliferating cell nuclear antigen (PCNA) and transforming growth factor (TGF) are considered as markers of cell proliferation. The expression of PCNA and TGF was evaluated immunohistochemically using anti-PCNA antibody and TGF in 31 patients with biliary atresia (BA) (15 jaundice-free and 16 with persistent jaundice) and 6 control infants. The labeling indices (LI) for PCNA- and TGF-positive bile-duct epithelium in BA were 14.1±14.0% and 51.4±33.7%, respectively, which was significantly higher than in the controls (P <0.01). In BA, the number of PCNA-immunoreactive cells was higher in the peripheral bile ductules than in the central bile ducts of the portal tract (P <0.01). LI was not related to patient age at the time of hepatic portoenterostomy in two groups divided at the age of 60 days. Patients in the persistent jaundice group had greater expression of PCNA and TGF (21.7±16.0% and 76.9±20.7%, respectively) compared to those in the jaundice-free group (6.0±2.7% and 24.3±20.9%, P <0.001). PCNA and TGF expression in the bile-duct epithelium of the portal tract was closely related to prognosis in BA patients, and thus could be useful as a prognostic marker. 相似文献
26.
Dr. Alphonse E. Sirica PhD Lynne W. Elmore BA Nobuya Sano MD 《Digestive diseases and sciences》1991,36(4):494-501
A novel intrahepatic biliary cell culture/in vivo transplantation system has been developed with an essentially pure population of bile ductular epithelial cells isolated from rat liver 6–12 weeks after bile duct ligation. In primary culture, these cells retain staining strongly for -glutamyltranspeptidase and glutathione S-transferase P. The cytoplasm of cultured bile ductular cells reacts with an anti-laminin antibody, but loses immunoreactivity with a monoclonal anti-cytokeratin 19 antibody. Semiconservative DNA synthesis in the cultured cells was dependent upon the continued presence of 10% fetal calf serum in the medium. Replicating bile ductular cells could be subcultured for a finite number of passages. In addition, freshly isolated bile ductular epithelial cells gave rise to well differentiated bile ductular structures when transplanted into the interscapular fat pads of syngeneic recipient rats.Presented at the Proceedings of the International Meeting on Normal and Neoplastic Growth in Hepatology, Bari, Italy, June 1989.This work was supported by USPHS Grant RO1 CA39225 to Dr. Sirica by the National Cancer Institute, Department of Health and Human Services. 相似文献
27.
Cyclosporin A induced internalization of the bile salt export pump in isolated rat hepatocyte couplets. 总被引:2,自引:0,他引:2
Irene D Román M Dolores Fernández-Moreno Jesús A Fueyo Marcelo G Roma Roger Coleman 《Toxicological sciences》2003,71(2):276-281
Isolated rat hepatocyte couplets were used to perform the comparative study of two widely used immunosuppressors, cyclosporin A (CsA) and tacrolimus (FK506) on hepatocanalicular function. We assessed canalicular function by counting the percentage of couplets that were able to accumulate the fluorescent cholephile, cholyl-lysyl-fluorescein (CLF), into the canalicular vacuole between the two cells, i.e., canalicular vacuole accumulation (CVA) of CLF. Compared to controls (DMSO-treated cells), CsA, in the approximate range of concentrations used therapeutically, caused inhibition of CVA of CLF, disorganization of the bile salt export pump (Bsep) localization at canalicular level resulting in its relocation into the cell, and disruption of the pericanalicular F-actin cytoskeleton. In contrast, FK506, at both approximately therapeutic and supratherapeutic concentrations, had no deleterious effect upon CVA of CLF, upon the localization of the bile salt transporter at the canalicular membrane, or on the organization of the pericanalicular F-actin cytoskeleton. These results point to transporter and cytoskeletal disorganization as contributors or determinants of CsA-induced cholestasis at canalicular level, whereas FK506 does not appear to produce these cholestasis-determining responses even at supratherapeutic concentrations. 相似文献
28.
肝内胆管癌30例的临床病理特征及预后分析 总被引:1,自引:0,他引:1
目的 :探讨肝内胆管癌 (intra hepaticcholangiocarcinoma ,ICC)的临床病理特征及治疗与预后的关系。方法 :回顾性分析 1991~ 1999年山东省立医院、济宁医学院附属医院 3 0例ICC患者病理、临床资料。结果 :ICC比肝细胞癌少见且预后不良 ,手术切除是目前较理想治疗方式 ,影响预后的因素是肿瘤边缘、淋巴结转移与组织病理情况。根治切除术后 1年生存率 5 3 3 % ,3年生存率 3 3 3 %。结论 :根治性切除是最有效的治疗方法。 相似文献
29.
Langerhans' cell histiocytosis (LCH) of the liver is uncommon. When seen, it is part of multifocal disease and can present as biliary obstruction. We present a case of sclerosing biliary disease with a solitary LCH lesion and no evidence of systemic disease. We postulate that the LCH is a secondary phenomenon, arising against a background of a complex, familial liver disease. This case also raises the possibility that some instances of idiopathic sclerosing cholangitis may follow cryptic LCH of the bile ducts. 相似文献
30.
This study illustrates the local spread of lower bile duct cancer with thin-section helical CT in correlation with the surgical
and pathological findings. Pathologically, 16 patients had pancreatic invasion, 4 had small bowel mesentery invasion, 7 had
extrapancreatic nerve plexus invasion, and 3 patients had vascular invasion. On thin-section helical CT, pancreatic invasion
was correlated to the clarity or non-clarity of the bile duct mass-pancreas border and the presence of an intrapancreatic
mass. Cases with small bowel mesentery and extrapancreatic nerve plexus invasion showed mass or stranding around the superior
mesenteric artery and/or inferior pancreatoduodenal artery. Vascular invasion was seen as tumor contiguity to these vessels.
Received: 28 September 1998; Revised: 30 December 1998; Accepted: 2 April 1999 相似文献