全文获取类型
收费全文 | 237403篇 |
免费 | 7155篇 |
国内免费 | 594篇 |
专业分类
耳鼻咽喉 | 3400篇 |
儿科学 | 8642篇 |
妇产科学 | 6616篇 |
基础医学 | 30827篇 |
口腔科学 | 6298篇 |
临床医学 | 19610篇 |
内科学 | 44030篇 |
皮肤病学 | 4988篇 |
神经病学 | 15716篇 |
特种医学 | 12209篇 |
外国民族医学 | 97篇 |
外科学 | 36318篇 |
综合类 | 1918篇 |
现状与发展 | 1篇 |
一般理论 | 41篇 |
预防医学 | 19663篇 |
眼科学 | 4839篇 |
药学 | 16395篇 |
2篇 | |
中国医学 | 197篇 |
肿瘤学 | 13345篇 |
出版年
2021年 | 1243篇 |
2019年 | 1129篇 |
2018年 | 4718篇 |
2017年 | 4674篇 |
2016年 | 4092篇 |
2015年 | 5965篇 |
2014年 | 5782篇 |
2013年 | 5399篇 |
2012年 | 13168篇 |
2011年 | 8165篇 |
2010年 | 4088篇 |
2009年 | 5545篇 |
2008年 | 4930篇 |
2007年 | 5716篇 |
2006年 | 5929篇 |
2005年 | 13989篇 |
2004年 | 15179篇 |
2003年 | 10649篇 |
2002年 | 5675篇 |
2001年 | 4704篇 |
2000年 | 1950篇 |
1999年 | 6193篇 |
1998年 | 986篇 |
1992年 | 7100篇 |
1991年 | 7296篇 |
1990年 | 7522篇 |
1989年 | 7119篇 |
1988年 | 6635篇 |
1987年 | 6371篇 |
1986年 | 6080篇 |
1985年 | 5365篇 |
1984年 | 3725篇 |
1983年 | 3024篇 |
1982年 | 1145篇 |
1980年 | 941篇 |
1979年 | 3906篇 |
1978年 | 2440篇 |
1977年 | 1861篇 |
1976年 | 1620篇 |
1975年 | 2530篇 |
1974年 | 3141篇 |
1973年 | 2799篇 |
1972年 | 2789篇 |
1971年 | 2775篇 |
1970年 | 2588篇 |
1969年 | 2493篇 |
1968年 | 2266篇 |
1967年 | 2193篇 |
1966年 | 1917篇 |
1965年 | 1147篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Gallstones and previous cholecystectomy in 77- to 78-year-old women in an urban population in Sweden 总被引:1,自引:0,他引:1
A randomly selected sample of 120 women, born in 1906-1907 and living in the city of Gothenburg, were invited to an ultrasound examination for gallstone disease. One hundred and nine subjects participated in the study, and among these, 24% gave a history of a previous cholecystectomy, 27% had gallstones, and 49% had no stones in the gallbladder. Among the women with stones in the gallbladder only 35% had associated symptoms. The design of the study enabled a comparison among women with no stones in the gallbladder, with gallstones, and with a previous cholecystectomy. Women with gallstones, previous or present, had a higher body weight, body mass index, skinfold thickness, and serum triglyceride level than subjects without gallstones. 相似文献
992.
993.
Marja Hilska Yrj? Collan Peter J Roberts Jari Ovaska Jyrki K?ssi Hannu Paajanen Matti Laato 《Acta chirurgica》2002,168(2):84-90
OBJECTIVE: To compare the ability of various methods of staging and grading to predict survival in proximal colon cancer. DESIGN: Retrospective study. SETTING: University hospital, Finland. SUBJECTS: 153 patients with primary proximal colon cancer. MAIN OUTCOME MEASURES: Staging by four classification systems, grading by two grading systems, and survival analysis based on Kaplan-Meier survival curves. RESULTS: In all staging systems the survival curves of different stages differed significantly from each other. The modified Dukes' classification was still the best predictor of survival. Grade of tumours had no significant effect on long term survival, but short term survival was affected adversely by the presence of anaplastic tissue. Tumours with no mucin had a worse prognosis than those that produced mucin. All staging methods were superior to either of the histological grading systems tested as prognosticators. Tumour depth correlated with the operator's clinical impression of radicality of operation, and also predicted survival. CONCLUSION: The clinicopathological modified Dukes' staging system was the most powerful prognosticator in proximal colonic cancer and its use in clinical practice should continue. Even a small amount of anaplastic tissue (> or = 5%) had an adverse effect on short term survival. 相似文献
994.
G M Nordstr?m E Borglund C R Nyman 《Scandinavian journal of urology and nephrology》1990,24(2):117-122
Sixty-six patients with uretero-ileostomy were investigated with special regards to local status of the urinary stoma, i.e. stomal site, length, size/shape, and peristomal skin. Each variable was defined. In reports from other centres there has been a lack of definitions making it difficult to compare results from different studies. One fifth of our patients had inadequately located stomas and 85% had stomas shorter than 1 cm. The peristomal skin status was assessed according to CPS, Classification of Peristomal Skin. Eight per cent of the patients exhibited severe erythematous/erosive lesions and one fifth pseudoverrucose lesions. The relation between skin lesions and local status of the urinary stoma was analyzed. Patients with inadequately located stomas were more likely to show severe erythematous/erosive lesions and there was a tendency towards patients with stomas shorter than 1 cm, more frequently exhibiting pseudoverrucose lesions. 相似文献
995.
M E Senocak G Kale N Büyükpamuk?u A Hi?s?nmez M Ca?lar 《Journal of pediatric surgery》1990,25(6):681-684
Gastric teratoma is a very rare benign tumor. Fifty-three cases, only two of which were females, have previously been reported. This report concerns two cases of teratoma arising from stomach. One of them is the third female case described in the literature. 相似文献
996.
S S S?rensen T K Glud P J S?rensen A Amdisen E B Pedersen 《Nephrology, dialysis, transplantation》1990,5(4):247-257
Renal tubular sodium and water handling determined by the lithium clearance technique, plasma concentrations of atrial natriuretic peptide (ANP), angiotensin II, aldosterone, arginine vasopressin (AVP), and urinary excretion of prostaglandin E2 (PGE2) were determined both during basal conditions and before and after intravenous sodium loading with a 2.5% sodium chloride solution in patients with polycystic kidney disease (PKD), ten with normal or slightly reduced kidney function (PKDN) and seven with moderately reduced kidney function (PKDR), and in 15 healthy controls. In PKDN tubular function was normal, whereas in PKDR both proximal and distal reabsorption of sodium and water were reduced. Angiotensin II and aldosterone were normal in both groups of patients. During basal conditions ANP was higher in PKDR than in PKDN. PGE2 was significantly higher in PKDR than in PKDN. For all patients significant correlations were found between GFR and both ANP (rho = -0.51, n = 17, P less than 0.05) and PGE2 (rho = -0.53, n = 17, P less than 0.05). It is concluded that renal sodium handling is normal in the early stages of PKD. With deterioration of kidney function both proximal and distal tubular reabsorption of sodium is reduced and the accompanying changes in ANP and PGE2 may be compensatory phenomena counteracting declining glomerular filtration rate. 相似文献
997.
998.
A. E. van Leeuwen-Stok G. J. Schuurhuis A. M. Dr?ger A. W. Visser-Platier G. J. Teule P. C. Huijgens 《British journal of cancer》1996,74(4):619-624
Gallium-67 is a radionuclide that accumulates in haematological malignancies and is used for diagnostic purposes. Uptake of 67Ga into the cell occurs via the transferrin receptor, which is differentially expressed during the various cell cycle phases. With the aim of selectively increasing 67Ga uptake, we studied whether the transferrin receptor (TfR) expression could be modulated in the U937 and U715 lymphoma cell lines by cytostatic drugs inducing cell cycle phase accumulation. We tested clinically relevant drugs such as 1-beta-D-arabinofuranosylcytosine (Ara-C), hydroxyurea and methotrexate. Cytotoxicity was determined by testing the clonogenic capacity of the lymphoma cell lines. All three drugs induced an increase in S-phase content, TfR expression and 67Ga uptake in U937 and U715 single cells. The combinations of drugs and 67Ga resulted in an additive effect on the clonogenic capacity. In U937 spheroids, cultured by the fibrin clot technique, we found an accumulation in the S-phase too as well as an increase of the transferrin receptor expression after Ara-C preincubation. As in single cells 67Ga uptake was increased without synergistic effects on the clonogenic capacity. In conclusion, priming with drugs induces increased transferrin receptor expression and 67Ga uptake. Inhibition of clonogenic capacity was additive rather than synergistic. 相似文献
999.
1000.
Six direct radioimmunoassays of estradiol evaluated 总被引:1,自引:0,他引:1
We evaluated the analytical performance of six commercial direct radioimmunoassays of 17 beta-estradiol, those from Radioassay Systems Laboratories, IRE Medgenix, Biotecx Laboratories, Farmos Spectria, International CIS, and Diagnostic Products Corp. The mean value for estradiol (E2) and the within- and between-run CVs were determined for serum pools and control materials, measured in seven to 10 runs with each method. Mean values for E2 in pooled sera deviated by 75% to 350% from the means measured with our routinely used extraction method. Between-run CVs ranged from 4% to 14% for the direct assays as compared with 10% for the extraction assay. We also investigated, for two of the direct assays, the effect of extraction with diethyl ether before radioimmunoassay, with respect to improvement in the agreement with our extraction method. All of the assays were easy to perform and results were obtained within 4-5 h, but we conclude that matrix effects may be expected in direct assays of estradiol. 相似文献