全文获取类型
收费全文 | 532943篇 |
免费 | 28597篇 |
国内免费 | 498篇 |
专业分类
耳鼻咽喉 | 6715篇 |
儿科学 | 17034篇 |
妇产科学 | 12612篇 |
基础医学 | 93167篇 |
口腔科学 | 12503篇 |
临床医学 | 48893篇 |
内科学 | 95916篇 |
皮肤病学 | 11928篇 |
神经病学 | 34241篇 |
特种医学 | 19851篇 |
外国民族医学 | 53篇 |
外科学 | 78624篇 |
综合类 | 7705篇 |
现状与发展 | 2篇 |
一般理论 | 110篇 |
预防医学 | 38848篇 |
眼科学 | 11949篇 |
药学 | 41624篇 |
1篇 | |
中国医学 | 1128篇 |
肿瘤学 | 29134篇 |
出版年
2019年 | 3950篇 |
2018年 | 5809篇 |
2017年 | 4180篇 |
2016年 | 4908篇 |
2015年 | 5417篇 |
2014年 | 7200篇 |
2013年 | 10640篇 |
2012年 | 15757篇 |
2011年 | 17556篇 |
2010年 | 10048篇 |
2009年 | 8894篇 |
2008年 | 15862篇 |
2007年 | 17595篇 |
2006年 | 17100篇 |
2005年 | 16411篇 |
2004年 | 16027篇 |
2003年 | 15390篇 |
2002年 | 14922篇 |
2001年 | 22541篇 |
2000年 | 23095篇 |
1999年 | 19044篇 |
1998年 | 5293篇 |
1997年 | 4417篇 |
1996年 | 4438篇 |
1995年 | 4167篇 |
1992年 | 14492篇 |
1991年 | 15917篇 |
1990年 | 16041篇 |
1989年 | 15717篇 |
1988年 | 14394篇 |
1987年 | 14264篇 |
1986年 | 13248篇 |
1985年 | 12748篇 |
1984年 | 9441篇 |
1983年 | 8042篇 |
1982年 | 4203篇 |
1979年 | 8988篇 |
1978年 | 6418篇 |
1977年 | 5170篇 |
1976年 | 5540篇 |
1975年 | 6637篇 |
1974年 | 7447篇 |
1973年 | 7207篇 |
1972年 | 6640篇 |
1971年 | 6349篇 |
1970年 | 5918篇 |
1969年 | 5502篇 |
1968年 | 5188篇 |
1967年 | 4657篇 |
1966年 | 3982篇 |
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
221.
Surgical management of 100 consecutive esophageal strictures 总被引:1,自引:0,他引:1
R D Henderson R F Henderson G V Marryatt 《The Journal of thoracic and cardiovascular surgery》1990,99(1):1-7
We report our experience with 100 consecutive patients with reflux-induced esophageal structure managed surgically. Preoperative dilatation, total fundoplication gastroplasty, and postoperative dilatation were used in 98 patients. Only two required resection of the esophageal structure. We have identified preoperative factors that adversely affect the results. These include scleroderma; previous operation, either esophageal or gastric, and the severity of the esophageal stricture. Results of nonresectional operations are excellent in uncomplicated cases or with the addition of only one complicating factor. The more complicating factors, the worse the results. Those patients with three preoperative complicating factors do poorly and may benefit from esophageal resection. We conclude that results obtained from this conservative nonresectional management program justify continuance of the use of total fundoplication gastroplasty with preoperative and postoperative dilatation in the management of such patients. 相似文献
222.
Serum p55 and p75 tumour necrosis factor receptors as markers of disease activity in juvenile chronic arthritis. 总被引:4,自引:1,他引:3 下载免费PDF全文
M Gattorno P Picco A Buoncompagni F Stalla P Facchetti M P Sormani V Pistoia 《Annals of the rheumatic diseases》1996,55(4):243-247
OBJECTIVE: To determine the expression of tumour necrosis factor alpha (TNF alpha) and its soluble receptors (p55 and p75) in the sera and synovial fluid of patients with juvenile chronic arthritis (JCA), and their correlation with disease activity parameters. METHODS: Ninety eight sera from 45 patients with JCA (14 systemic, 12 polyarticular, 19 pauciarticular), 20 sera from age matched healthy controls, and five synovial fluids from five antinuclear antibody (ANA) positive pauciarticular JCA patients were tested for the presence of TNF alpha, soluble TNF receptors p55 and p75 (sTNFRp55, sTNFRp75), and interleukin-6 (IL-6) by an enzyme amplified sensitivity immunoassay. Physician global estimate of disease activity, weekly fever score and joint score, C reactive protein (CRP), erythrocyte sedimentation rate (ESR), and haemoglobin concentration were evaluated as parameters of disease activity. The expression of p55 and p75 on peripheral mononuclear cells (MNCs) from five patients with systemic JCA and synovial MNCs from five ANA positive patients with pauciarticular JCA was evaluated by flow cytometry. RESULTS: TNF alpha serum concentrations did not differ significantly between the patients with active JCA and the control group. No correlation was found between TNF alpha and parameters of disease activity, but both p55 and p75 showed a significant positive correlation with the physician global estimate of disease activity (p < 0.001), ESR (p < 0.001), CRP (p < 0.001), and serum concentrations of IL-6 (p < 0.001). Serum concentrations of haemoglobin correlated inversely with the concentrations of p55 and p75 (p < 0.001). Synovial lymphocytes selectively expressed the p75 surface receptor. CONCLUSIONS: sTNFRp55 and sTNFRp75 each represent a sensitive marker of disease activity in JCA. Their increased expression in biological fluids may support the hypothesis that TNF alpha has a role in the pathogenesis of JCA. 相似文献
223.
OBJECTIVE: To determine the most frequent clinical causes of a prolonged activated partial thromboplastin time (APTT) result, and to determine whether a new heparin-removal device (the Hepchek, Pall Biomedical, Glen Cove, NY 11542) is capable of efficiently detecting the causes of these values. DESIGN: A combination of chart review and laboratory testing comparing the criterion standard--the heparin chromogenic substrate assay--with the Hepchek. Laboratory investigations were blinded and controlled. SETTING: Inpatient, acute-care hospital. PATIENTS: A total of 1,000 hospital patients with a variety of hemostatic disorders. MAIN OUTCOME MEASURE: The extent to which the Hepchek accurately identified the etiology of a prolonged APTT result. RESULTS: The APTT was prolonged in 25.2% of samples. The presence of heparin in the sample was confirmed by chromogenic assay or by using the Hepchek heparin-removal filter. The presence of heparin was confirmed in 12.8% of all samples and in more than 50% of all abnormal samples. The cause of the abnormal APTT was often unappreciated by the clinician. Bayesian analysis of the Hepchek's ability to diagnose heparin correctly as the cause of the abnormal APTT showed a sensitivity of 100% and specificity of 99.9%. CONCLUSION: Use of the Hepchek in the routine clinical laboratory is an efficient and rapid method of detecting heparin as a cause of isolated prolonged APTT results, and should reduce demands for unwarranted coagulation analyses and inappropriate treatment with blood products. 相似文献
224.
J. de Pedro-Cuesta V. Abraira G.-X. Jiang G. Solders S. Fredrikson 《Acta neurologica Scandinavica》1996,93(2-3):175-183
Using hierarchical cluster analysis, applied to 47 cases of Guillain-Barre Syndrome (GBS) incident in South-West Stockholm (SWS) during the period from January 1973 to June 1992, we identified three major clinicoepidemiological subgroups. The first subgroup, 25.5% of the cases (26.7 ± 6.7 years), recorded a peak incidence at ages 20–29 years and presented significant differences from other subgroups, a high proportion of cases with onset at low age preceded by respiratory infection (83.3%) and with normal motor conduction velocity (50.0%). Also found, were less affected biological parameters, a rapidly progressive course and independence in gait at one month after onset. A second subgroup, 27.7% of cases, was severely affected, clinically and functionally. It consisted predominantly of young individuals (22.7 ± 11.1 years), with a high incidence (69.2% of cases) in autumn. A third subgroup, comprising 40.47; of cases, was older (61.1 ± 11.0 years) and, in general, also severely affected. The incidence of this form appeared to be invariant with time. 相似文献
225.
226.
CT- or sonography-guided biopsy of the liver in the presence of ascites: frequency of complications 总被引:1,自引:0,他引:1
F B Murphy K P Barefield H V Steinberg M E Bernardino 《AJR. American journal of roentgenology》1988,151(3):485-486
The presence of ascites has been considered a contraindication to percutaneous biopsy of the liver. To determine the validity of this assumption, we performed percutaneous biopsies of the liver under CT or sonographic guidance in 28 patients who had ascites and in 28 patients who did not have ascites and compared the complication rates in the two groups. Twenty-two patients (79%) in the group with ascites and 19 patients (68%) in the group without ascites had biopsies to determine the cause or extent of chronic liver disease. The remainder were oncologic patients who had biopsies to determine the cause of a focal hepatic mass. The complication rate in the patients who had ascites (32%) was less than that in the patients who did not have ascites (43%) (the difference did not reach statistical significance, p less than .30). In the ascites group, complications included transient hypotension (five patients), a mild-to-moderate fall in hematocrit (three patients), and a small leak of ascites from the biopsy site (one patient). In the control group, minor complications included transient hypotension (three patients), a mild-to-moderate fall in hematocrit (seven patients), and a small subcapsular hematoma (one patient). One major complication occurred in the control group: a patient required a blood transfusion because of the fall in his hematocrit. We conclude that the complication rate in liver biopsies guided by CT or sonography in the presence of ascites is not higher than similar biopsies done in the absence of ascites. Ascites should not be considered a contraindication for performing such biopsies. 相似文献
227.
In experiments on albino rats it was established that three administrations of indomethacin in a dose of 0.01 g/kg body weight induced a severe damage of the liver characterized by disturbances of hepatocytic membranes, bile-producing and protein-producing functions of the liver, an enhancement of lipid peroxidation, a decrease of reduced glutathione pool. Antioxidants (tocopherol acetate, essentiale, legalon, flacumin) limit manifestations of indomethacin, hepatotoxicity, as a result of which tha functional-biochemical disorders in the liver show up to a lesser degree. During the combined use of antioxidants in indomethacin-induced lesions of the liver their hepatoprotective activity increases. 相似文献
228.
Two oral liquid dosage forms of acetazolamide have been developed. Using the solubility profiles, polyethylene glycol 400 (7%, v/v) was used as the solubilizing agent and propylene glycol (53%, v/v) as the cosolvent to keep acetazolamide in solution. Because of the bitter taste of acetazolamide, sweetening agents (simple syrup, sorbitol solution, and artificial sweeteners) and flavors (raspberry, sweet, and menthol) were added to the final formulations. A buffer (either phosphate or citrate) solution was used to maintain a pH value of 4 (pH of maximum stability as reported earlier) to minimize hydrolysis. The final dosage forms were stable for at least 90 days at 37 degrees C (loss of potency of 5%). According to FDA guidelines, a tentative expiry date of 2 years at 25 degrees C is justifiable. 相似文献
229.
L R?stam R V Luepker M B Mittelmark D M Murray J S Slater H Blackburn 《American journal of preventive medicine》1988,4(5):249-254
To determine the potential effect of screening on referral patterns, an adult population sample (4,404 men, 5,164 women, 20-69 years of age) was systematically recruited and screened for hypercholesterolemia and then analyzed by different cholesterol referral recommendations. Using levels suggested by the Lipid Research Clinics Coronary Primary Prevention Trial (greater than or equal to 265 mg/dL), 7.3% of men and 5.8% of women would be referred for follow-up. With the suggested recommendations of the National Cholesterol Education Program (NCEP), (greater than or equal to 200 mg/dL), 49.2% of men and 40.2% of women would be referred. The use of age-related definitions of the NIH Consensus Conference on Lipid Lowering results in 28.0% referrals in men and 21.8% in women. From this population, hypercholesterolemia subjects (greater than or equal to 265 mg/dL at screening; n = 624) were invited for a second cholesterol determination (58% returned), which found 36% below the 265 mg/dL level. Population screening for cholesterol is likely to produce large numbers of patients for follow-up, with the actual numbers strongly dependent on cutoff levels and age-sex distributions. Referral and follow-up of these patients may place a significant load on an unprepared health care community. 相似文献
230.