全文获取类型
收费全文 | 3629篇 |
免费 | 190篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 71篇 |
妇产科学 | 271篇 |
基础医学 | 385篇 |
口腔科学 | 54篇 |
临床医学 | 211篇 |
内科学 | 843篇 |
皮肤病学 | 37篇 |
神经病学 | 455篇 |
特种医学 | 177篇 |
外科学 | 469篇 |
综合类 | 10篇 |
预防医学 | 165篇 |
眼科学 | 22篇 |
药学 | 201篇 |
中国医学 | 8篇 |
肿瘤学 | 382篇 |
出版年
2023年 | 22篇 |
2022年 | 30篇 |
2021年 | 56篇 |
2020年 | 43篇 |
2019年 | 57篇 |
2018年 | 72篇 |
2017年 | 51篇 |
2016年 | 75篇 |
2015年 | 86篇 |
2014年 | 92篇 |
2013年 | 144篇 |
2012年 | 205篇 |
2011年 | 227篇 |
2010年 | 134篇 |
2009年 | 113篇 |
2008年 | 205篇 |
2007年 | 185篇 |
2006年 | 225篇 |
2005年 | 182篇 |
2004年 | 197篇 |
2003年 | 188篇 |
2002年 | 154篇 |
2001年 | 107篇 |
2000年 | 94篇 |
1999年 | 79篇 |
1998年 | 48篇 |
1997年 | 44篇 |
1996年 | 40篇 |
1995年 | 30篇 |
1994年 | 35篇 |
1993年 | 25篇 |
1992年 | 71篇 |
1991年 | 60篇 |
1990年 | 68篇 |
1989年 | 63篇 |
1988年 | 49篇 |
1987年 | 42篇 |
1986年 | 38篇 |
1985年 | 15篇 |
1984年 | 26篇 |
1983年 | 17篇 |
1982年 | 18篇 |
1981年 | 14篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1975年 | 14篇 |
1974年 | 11篇 |
排序方式: 共有3838条查询结果,搜索用时 31 毫秒
1.
A new method for protecting intestinal anastomoses in patients at high risk of anastomotic dehiscence or fistula formation is described herein. This method involves raising a seromuscular flap on a pedicle from the stump of the intestine to be anastomosed. The anastomosis is performed, then covered with the seromuscular flap. 相似文献
2.
Tiziano Curti MD Gianandrea Pasquinelli MD Paola Preda BS Antonio Freyrie MD Renzo Laschi MD Massimo D’Addato MD 《Annals of vascular surgery》1989,3(4):351-363
Human adult endothelial cells were enzymatically harvested from adipose tissue. Cell viability was established by Trypan blue exclusion and transmission and scanning electron microscopy. Endothelial cells were identified by immunocytochemical investigation at light microscopy, transmission electron microscopy, and scanning electron microscopy. Isolated cells were positive for actin and vimentin, negative for desmin. Factor VIII RA was mainly expressed at cell surface and occasionally disclosed in the cytoplasm. Reactivity for UEA I and J15 was weak or undetectable. Human endothelial cells were seeded and left to adhere for one hour onto different nonvascular substrates (glass, poly-l-lysine, formvar-carbon, fibronectin, Teflon). Scanning electron microscopy defined surface features, suggesting tenacious cell adhesion on the substrate. Different vascular substrates were tested (preclotted Dacron, albumin Dacron, Hemashield Dacron, Gelseal Dacron, ePTFE, fibronectin-ePTFE). Commercially available coated grafts showed qualitative and quantitative differences in cell adhesion. In particular, Gelseal Dacron provided the best quantitative results, even though a wide variability was observed. In contrast, fibronectin-coated ePTFE gave more reliable results and high spreading efficiency. In the short term, coated grafts do not seem to offer greater advantages than fibronectin-coated ePTFE. However, specific incubation times for each coated graft should be selected and the long-term approach (graft culture) should also be attempted. 相似文献
3.
Sanjay Sisodiya J Helen Cross Ingmar Blümcke David Chadwick John Craig Peter B Crino Paul Debenham Norman Delanty Frances Elmslie Mark Gardiner Jeffrey Golden David Goldstein David A Greenberg Renzo Guerrini Michael Hanna John Harris Paul Harrison Michael R Johnson George Kirov Dimitri M Kullman Andrew Makoff Carla Marini Rima Nabbout Lina Nashef Jeffrey L Noebels Ruth Ottman Munir Pirmohamed Asla Pitk?nen Ingrid Scheffer Simon Shorvon Graeme Sills Nicholas Wood Sameer Zuberi 《Epileptic Disord》2007,9(2):194-236
The Sixth Epilepsy Research Foundation workshop, held in Oxford in March 2006, brought together basic scientists, geneticists, epidemiologists, statisticians, pharmacologists and clinicians to consider progress, issues and strategies for harnessing genetics to improve the understanding and treatment of the epilepsies. General principles were considered, including the fundamental importance of clear study design, adequate patient numbers, defi ned phenotypes, robust statistical data handling, and follow-up of genetic discoveries. Topics where some progress had been made were considered including chromosomal abnormalities, neurodevelopment, hippocampal sclerosis, juvenile myoclonic epilepsy, focal cortical dysplasia and pharmacogenetics. The ethical aspects of epilepsy genetics were reviewed. Principles and limitations of collaboration were discussed. Presentations and their matched discussions are produced here. There was optimism that further genetic research in epilepsy was not only feasible, but might lead to improvements in the lives of people with epilepsy. 相似文献
4.
Angelo M. Carella Sandro Nati Paolo Carlier Daniela Pierluigi Domenico Giordano Angela Congiu Gino Santini Daniele Scarpati Salvina Barra Renzo Corvo Vito Vitale Maria R. Raffo Raffaella Cerri Marco Risso Mauro Spriano Renato Vimercati Ester Pungolino Andrea Bacigalupo Eugenio Damasio 《Leukemia & lymphoma》1991,5(1):43-47
Forty consecutive adult patients under the age of 50 with acute non-lymphoblastic leukemia (ANLL) in first complete remission, underwent autologous bone marrow transplantation (ABMT) between March 1984 and April 1990. The conditioning regimen employed included cyclophosphamide and total body irradiation, followed by the administration of unpurged ABMT. The median time from diagnosis to transplant was 7 months (3-15 months), and the median time from complete remission to ABMT was 4 months (range 3-9 months). Twenty-two (51%) patients remain in complete remission 6-81 months (median 24 months) after ABMT.
The causes of death were, recurrent leukemia (11 patients), parenchymal toxicities such as acute respiratory distress syndrome and veno-occlusive disease (3 patients), hemorrhage (2 patients) and infection (2 patients). Eleven patients relapsed after 3-12 months (median 5 months). This study has produced survival data comparable to those of other institutions employing TBI for either allo or autotransplants. 相似文献
The causes of death were, recurrent leukemia (11 patients), parenchymal toxicities such as acute respiratory distress syndrome and veno-occlusive disease (3 patients), hemorrhage (2 patients) and infection (2 patients). Eleven patients relapsed after 3-12 months (median 5 months). This study has produced survival data comparable to those of other institutions employing TBI for either allo or autotransplants. 相似文献
5.
Francesco Bertoni Giovanni Cazzaniga Giovanna Bosshard Enrico Roggero Renzo Barbazza Michele De Boni Carlo Capella Ennio Pedrinis Franco Cavalli rea Biondi & Emanuele Zucca 《British journal of haematology》1997,97(4):830-836
Gastric MALT lymphoma usually develops from chronic gastritis, the vast majority of which (>90%) is associated with Helicobacter pylori infection. We sequenced the third complementarity determining region (CDR3) of immunoglobulin heavy chain genes in 19 gastric MALT lymphoma clones to determine the pattern of variable (V), diversity (D) and joining (J) gene utilization during immunoglobulin gene rearrangement.
DNA was extracted from paraffin-embedded sections and the rearranged CDR3 regions were amplified using a semi-nested polymerase chain reaction (with primers complementary to the conserved framework-three segment of the variable region [FR3A] and J regions). The DNA used for cloning and sequencing was obtained after purification of monoclonal bands excised from polyacrylamide gels. The N-D-N region specific to each clone was compared with known germline D sequences.
Similarly to that observed in normal and leukaemic B cells, our series of gastric MALT lymphomas showed apparent preferential utilization of genes from the DXP family. In two cases no similarity between the CDR3 nucleotide sequences of the neoplastic clones and the known germline D sequences could be found. In 10/19 analysed alleles the lymphoma B-cell clones appeared to contain two D gene segments (D-D recombination), a rare occurrence in normal individuals but one which has been described as a significant event in the determination of idiotype expression and antigen-binding affinity. Remarkably, despite the use of different D and J segments, the resultant amino acid sequences matched in two patients, suggesting the presence of a common selecting antigen.
The observed pattern of D gene rearrangement suggests that MALT lymphoma B-cell clones have undergone antigen selection, which seems to indicate that the antigen stimulation plays a pivotal role in the development of the lymphoma. 相似文献
DNA was extracted from paraffin-embedded sections and the rearranged CDR3 regions were amplified using a semi-nested polymerase chain reaction (with primers complementary to the conserved framework-three segment of the variable region [FR3A] and J regions). The DNA used for cloning and sequencing was obtained after purification of monoclonal bands excised from polyacrylamide gels. The N-D-N region specific to each clone was compared with known germline D sequences.
Similarly to that observed in normal and leukaemic B cells, our series of gastric MALT lymphomas showed apparent preferential utilization of genes from the DXP family. In two cases no similarity between the CDR3 nucleotide sequences of the neoplastic clones and the known germline D sequences could be found. In 10/19 analysed alleles the lymphoma B-cell clones appeared to contain two D gene segments (D-D recombination), a rare occurrence in normal individuals but one which has been described as a significant event in the determination of idiotype expression and antigen-binding affinity. Remarkably, despite the use of different D and J segments, the resultant amino acid sequences matched in two patients, suggesting the presence of a common selecting antigen.
The observed pattern of D gene rearrangement suggests that MALT lymphoma B-cell clones have undergone antigen selection, which seems to indicate that the antigen stimulation plays a pivotal role in the development of the lymphoma. 相似文献
6.
Synergistic antiproliferative activity of quercetin and cisplatin on ovarian cancer cell growth 总被引:1,自引:0,他引:1
G Scambia F O Ranelletti P Benedetti Panici G Bonanno R De Vincenzo M Piantelli S Mancuso 《Anti-cancer drugs》1990,1(1):45-48
It has been demonstrated that the flavonoid quercetin (3,3',4',5-7-pentahydroxyflavone) (Q) inhibits the growth of several cancer cell lines and that the antiproliferative activity of this substance is mediated by a so-called type II estrogen binding site (type II EBS). We investigated the effects of quercetin and cisplatin (CDDP) alone and in combination on the proliferation of the ovarian cancer cell line OVCA 433. Both drugs exhibited a dose-related growth inhibition in a range of concentrations between 0.01 and 2.5 microM and 0.01 and 2.5 micrograms/ml for Q and CDDP respectively. The combination of the two drugs resulted in a synergistic antiproliferative activity. Two other flavonoids tested, i.e., rutin (3-rhamnosylglucoside of quercetin) and hesperidin [7-b rutinoside of hesperetin (3'-5-3-hydroxy-4-methoxyflavone)] were ineffective both alone and in combination with CDDP. Since both rutin and hesperidin do not bind to type II EBS it can be hypothesized that Q synergizes with CDDP by acting through an interaction with these binding sites. 相似文献
7.
8.
Food cravings in relation to body mass index, restraint and estradiol levels: a repeated measures study in healthy women. 总被引:7,自引:3,他引:4
The study considered the nature and extent of cravings in 108 healthy women between the ages of 20 and 37 who were tested at four time points over a 2-year period. There was substantial consistency over the four widely separated time points (3 months-1 year) in the types of foods craved, with chocolate and ice cream highest on the list, followed by fatty and spicy foods, and sweets. Women with a higher body mass index reported more consistent cravings for salty foods, especially those with high flavor intensity. There were no significant relationships between dietary restraint and the number, frequency or types of cravings. There were also no strong relationships between estradiol levels and the number, frequency or types of cravings women reported in the whole sample. The data suggest that women have a stable core of foods for which they experience cravings, relatively independent of estradiol levels, BMI or degree of dietary restraint. 相似文献
9.
S Amoroso G F Di Renzo F Maurano P Maida M Taglialatela L Annunziato 《Experimental aging research》1987,13(1-2):85-87
Circulating prolactin (PRL) levels, dopamine (DA) content, in vitro basal and stimulus-evoked endogenous DA release from arcuate-periventricular nuclei median-eminence fragments were studied in young (4 months) and old (24-25 months) male rats of Sprague-Dawley strain. Serum PRL levels did not differ in young and aged animals. In addition DA tissue content, basal and K+- or d-amphetamine evoked endogenous DA release did not show age-related differences. These results suggest that in male rats of the Sprague-Dawley strain the activity of tuberoinfundibular dopaminergic (TIDA) neurons does not change during senescence, unlike what happens in other strains of rats. 相似文献
10.
The significance of associated pre-invasive lesions in patients resected for primary lung neoplasms. 总被引:2,自引:0,他引:2
E Ruffini M Bongiovanni A Cavallo P L Filosso R Giobbe M Mancuso M Molinatti A Oliaro 《European journal of cardio-thoracic surgery》2004,26(1):165-172
OBJECTIVE: To evaluate the prevalence and clinico/prognostic significance of the presence of pre-invasive lesions in patients resected for primary lung neoplasm. METHODS: From 1993 to 2002, 1090 patients received resection for primary lung carcinomas. Of these, 73 presented an associated pre-invasive lesion in the surgical specimen distant from the primary tumour. Classification of pre-invasive lesions included Atypical Adenomatous Hyperplasia (AAH); Carcinoma In Situ (CIS) either diffuse or at the bronchial resection margin; Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH). Correlation between the presence of pre-invasive lesion and the following variables were calculated by logistic regression analysis: sex, age, median tumour size, histology, histologic differentiation, histologic evidence of invasiveness (vascular and perineural invasion), peritumoural lymphocytic infiltrate, pTNM, lobe location, history of previous malignancy. Survival rates were computed using Kaplan-Meier method and survival differences with the total patient population of resected lung carcinomas were tested using the log-rank method. RESULTS: There were 28 AAH, 42 CIS (5 at the bronchial resection margin) and 3 DIPNECH. Histology of the primary tumor included bronchioloalveolar carcinoma (9 patients), adenocarcinoma (19), squamous cell carcinoma (39), typical carcinoid tumour (3) and adenosquamous carcinoma (3). Overall prevalence of pre-invasive lesion was 6.7%. A strong correlation was found between the presence of AAH and the co-existence of either adenocarcinoma, bronchioloalveolar carcinoma or mixed adenocarcinoma-containing tumours (P = 0.00002) between CIS and squamous cell carcinoma (P = 0.009) and between DIPNECH and carcinoid tumours (P = 0.001). No significant correlation was found between the presence of any type of pre-invasive lesion and sex, age, median tumour size, histologic differentiation, histologic evidence of invasiveness, pTNM, lobe location and history of previous malignancy or the probability to develop a second primary lung carcinoma in the remaining lobe(s) after resection. Survival rates in the patients with AAH and CIS were not significantly different from those of patients without pre-invasive lesion (P = 0.3 and P = 0.1). CONCLUSIONS: Associated pre-invasive lesions in patients resected for primary lung neoplasms are not infrequent. AAH is associated with adenocarcinoma, CIS with squamous cell carcinoma, DIPNECH with typical carcinoid tumours. Our experience indicates that in these patients histology, stage distribution and survival do not differ from the total population of resected patients with lung tumors. 相似文献