全文获取类型
收费全文 | 8400篇 |
免费 | 481篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 111篇 |
儿科学 | 141篇 |
妇产科学 | 163篇 |
基础医学 | 1347篇 |
口腔科学 | 151篇 |
临床医学 | 739篇 |
内科学 | 1837篇 |
皮肤病学 | 234篇 |
神经病学 | 1060篇 |
特种医学 | 296篇 |
外科学 | 782篇 |
综合类 | 40篇 |
一般理论 | 5篇 |
预防医学 | 556篇 |
眼科学 | 117篇 |
药学 | 774篇 |
中国医学 | 8篇 |
肿瘤学 | 553篇 |
出版年
2023年 | 71篇 |
2022年 | 158篇 |
2021年 | 268篇 |
2020年 | 170篇 |
2019年 | 228篇 |
2018年 | 280篇 |
2017年 | 212篇 |
2016年 | 217篇 |
2015年 | 258篇 |
2014年 | 311篇 |
2013年 | 422篇 |
2012年 | 600篇 |
2011年 | 642篇 |
2010年 | 381篇 |
2009年 | 348篇 |
2008年 | 499篇 |
2007年 | 443篇 |
2006年 | 472篇 |
2005年 | 416篇 |
2004年 | 351篇 |
2003年 | 338篇 |
2002年 | 277篇 |
2001年 | 166篇 |
2000年 | 145篇 |
1999年 | 135篇 |
1998年 | 84篇 |
1997年 | 54篇 |
1996年 | 47篇 |
1995年 | 36篇 |
1994年 | 25篇 |
1993年 | 20篇 |
1992年 | 43篇 |
1991年 | 56篇 |
1990年 | 65篇 |
1989年 | 62篇 |
1988年 | 62篇 |
1987年 | 74篇 |
1986年 | 49篇 |
1985年 | 65篇 |
1984年 | 34篇 |
1983年 | 30篇 |
1982年 | 25篇 |
1981年 | 14篇 |
1980年 | 14篇 |
1979年 | 33篇 |
1977年 | 14篇 |
1974年 | 30篇 |
1973年 | 21篇 |
1972年 | 22篇 |
1971年 | 25篇 |
排序方式: 共有8914条查询结果,搜索用时 0 毫秒
1.
2.
Manuela Kusch Claudia Grundmann Stefanie Keitel Rainer Seitz Herbert K?nig 《Blood coagulation & fibrinolysis》2006,17(7):575-580
A novel assay for factor XIII is described that utilizes exclusively small synthetic peptides as substrates for the cross-linking reaction catalyzed by activated factor XIII (FXIIIa). The acyl donor substrate (selection peptide) is immobilized on a microplate via biotin while the acyl acceptor substrate (detection peptide) is labeled with the fluorochrome Oregon green to allow sensitive detection without the need for secondary enzyme systems for signal amplification. Starting with an amino acid sequence from the fibrin gamma-chain (GQQHHLGGAKQAGDV) as a prototype peptide, the influence of amino acid exchanges were investigated with respect to their impact on the FXIIIa-catalyzed reaction. It was found that FXIIIa readily accepts a broad range of substrate peptides, with a proline neighboring the essential lysine having the most detrimental effect. The assay appears to be valuable for the molecular characterization of factor XIII and may be used for a deeper investigation into the substrate requirements of this final enzyme of wound repair, and eventually also for the characterization of other transglutaminases. 相似文献
3.
4.
5.
Thromboembolic and inflammatory complications of knee joint alloplasty with cemented endoprostheses]
Edward Golec Sebastian Nowak Jaros?aw Wi?niowski Maciej Piatkowski 《Chirurgia narzadów ruchu i ortopedia polska》2004,69(5):315-319
In the presented paper the authors evaluate the long-term results of treatment for inflammatory and thromboembolic complications in knee joint alloplasty with cemented endoprostheses. The clinical material spanning the years 1998-2003 are 15 patients with analysed complications, it determine 9% of all operated. They have evaluated achieved results using the HSS knee rating scale in their own modification. As far as the authors are concerned, venographic examination is a prerequisite for appropriate care of the patients following knee joint alloplasty who might have deep venous thrombosis. It is necessary to provide similar treatment when developing infections are suspected in the perioperative period and in cases of late infections. Consequently, antibiotic therapy and a possible quick bacteriological checkup for healing a postoperative wound is a prerequisite for successful treatment. Achieved results induce statement, that thromboembolic and inflammatory complications caused at most operated chronic vein insufficiency, deficit of range of motion at operated joint and gait insufficiency. Thromboembolic complications was always related with inflammation of knee joint alloplasty in our own material. 相似文献
6.
David G Hicks Brian J Yoder Sarah Short Shannon Tarr Nichole Prescott Joseph P Crowe Andrea E Dawson G Thomas Budd Steven Sizemore Muzaffer Cicek Toni K Choueiri Raymond R Tubbs Daniel Gaile Norma Nowak Mary Ann Accavitti-Loper Andra R Frost Danny R Welch Graham Casey 《Clinical cancer research》2006,12(22):6702-6708
PURPOSE: This study aims to determine the effect of loss of breast cancer metastasis suppressor 1 (BRMS1) protein expression on disease-free survival in breast cancer patients stratified by estrogen receptor (ER), progesterone receptor (PR), or HER2 status, and to determine whether loss of BRMS1 protein expression correlated with genomic copy number changes. EXPERIMENTAL DESIGN: A tissue microarray immunohistochemical analysis was done on tumors of 238 newly diagnosed breast cancer patients who underwent surgery at the Cleveland Clinic between January 1, 1995 and December 31, 1996, and a comparison was made with 5-year clinical follow-up data. Genomic copy number changes were determined by array-based comparative genomic hybridization in 47 breast cancer cases from this population and compared with BRMS1 staining. RESULTS: BRMS1 protein expression was lost in nearly 25% of cases. Patients with tumors that were PR negative (P=0.006) or HER2 positive (P=0.039) and <50 years old at diagnosis (P=0.02) were more likely to be BRMS1 negative. No overall correlation between BRMS1 staining and disease-free survival was observed. A significant correlation, however, was seen between loss of BRMS1 protein expression and reduced disease-free survival when stratified by either loss of ER (P=0.008) or PR (P=0.029) or HER2 overexpression (P=0.026). Overall, there was poor correlation between BRMS1 protein staining and copy number status. CONCLUSIONS: These data suggest a mechanistic relationship between BRMS1 expression, hormone receptor status, and HER2 growth factor. BRMS1 staining could potentially be used in patient stratification in conjunction with other prognostic markers. Further, mechanisms other than genomic deletion account for loss of BRMS1 gene expression in breast tumors. 相似文献
7.
K Radon S Huemmer H Dressel D Windstetter G Weinmayr S Weiland E Riu C Vogelberg W Leupold E von Mutius M Goldberg D Nowak 《The European respiratory journal》2006,27(4):774-778
Existing guidelines advise adolescents with asthma and allergies against high-risk occupations. The aim of the current authors' analyses was to investigate the resulting self-selection in a prospective cohort study. The participants of Phase II of the International Study of Asthma and Allergies in Childhood in Germany (aged 9-11 yrs at baseline) were re-contacted after 7 yrs (response rate was 77%) and were asked to complete a questionnaire, which included items on atopic diseases. The subjects were also asked about the type of job they would like to have in the future (preferred job choice). Exposure to agents with potential asthma risk was evaluated using a job exposure matrix. The analyses were restricted to those in school-based vocational training programmes without occupational exposures. A total of 33% of subjects chose jobs with high asthma risk, 23% selected low asthma risk jobs and the remaining adolescents indicated jobs without known asthma risk (reference category). There were no statistically significant associations between asthma, allergic rhinitis or atopic dermatitis and selecting jobs with asthma risk. Participants with allergic rhinitis tended to select high risk jobs less frequently. In conclusion, self-selection into low risk jobs seems to play a minor role in teenagers with asthma or allergies. 相似文献
8.
The purpose of this study was to determine the frequency of pseudocoronary syndromes in persons undergoing cardiac diagnostic tests because of suspected ischaemic heart disease. The study involved 384 subjects, 114 women and 270 men aged 21–75 years, who had been referred for precise cardiac diagnosis with a tentative preliminary diagnosis of ischaemic heart disease. In each subject an exercise stress test was performed, as was an ECG both at rest and during exercise and a coronary angiogram. Subjective sensations (e.g. pain in the chest, dyspnoea) experienced during the tests were also taken into account. Of the 384 patients suffering from pain in the chest area, ischaemic heart disease was excluded in 180 cases. In this subgroup the target HR (submaximal HR) was achieved during the stress test without any significant alterations in the ECG trace (raising or lowering of the ST segment). The subsequent coronary angiography definitively excluded any cardiogenic origin of the pain in the chest. 相似文献
9.
Klaus Herfarth Heinrich Schmidt-Gayk† Stefanie Graf reas Maier† 《Clinical endocrinology》1992,37(6):511-519
OBJECTIVE: We wished to investigate the circadian rhythm and pulsatility of parathyroid hormone (PTH) secretion in man, as conflicting results have been published. DESIGN AND PATIENTS: To investigate the circadian rhythm during daytime, we sampled (a) peripheral blood at hourly intervals in 12 healthy young men from 0900 h until 1700 h. For observation of pulsatility, we sampled (b) peripheral blood at 1-minute intervals for 1 hour in three healthy men and three healthy women (mean 27.7 years, range 21-56 years) and (c) at 1-minute intervals for 30 minutes in 21 patients with surgically confirmed primary hyperparathyroidism (pHPT). MEASUREMENTS: The serum levels of intact PTH were measured by two-site immunoradiometric assay and special care was taken to reduce intra-assay variability, especially at the normal PTH concentration. In series (a), ionized calcium, total calcium and phosphate were also determined. RESULTS: A circadian rhythm during daytime was found for intact PTH in healthy men and women with a nadir at 0930 h and a peak in the afternoon. Ionized calcium and total calcium (protein-adjusted) decreased and phosphate increased in the afternoon. These changes were all statistically significant (P < 0.02). Pulsatility of PTH: Statistical cluster analysis of the data showed no pulsatility either in healthy persons or in patients with primary hyperparathyroidism. In two healthy women and one healthy man slight changes of longer duration were discovered, but no complete pulses. In five patients with primary hyperparathyroidism, larger differences between the highest and lowest concentrations of intact PTH were found, but no complete pulses. CONCLUSIONS: Our data show a significant circadian rhythm during daytime of intact PTH and only minor changes from minute to minute. The alterations in PTH-levels occurred at longer time intervals in healthy persons. In some patients with primary hyperparathyroidism, decreases of PTH-levels were found. The circadian rhythm of PTH may be due to slight changes in calcium or phosphate concentration. 相似文献
10.
In 1984 and at the beginning of 1985 the authors carried out radioimmunoassays (SORIN-CIS kit) the plasma levels of ACTH in 116 multiple sclerosis patients (m-52, f-64) and in 10 cases this radioimmunoassay was done in the cerebrospinal fluid (m-5, f-5). The control group comprised 90 patients with ischialgia and neuroses. The normal value in the plasma was from 0 to 80.86 pg/ml, and in the fluid it was from 0 to 77.08 pg/ml. In multiple sclerosis patients the plasma ACTH level was from 0 to 286.9 pg/ml, in the cerebrospinal fluid from 0 to 89 pg/ml. The values of ACTH were significantly higher in multiple sclerosis patients, mainly in males. In the fluid the level of ACTH was significantly higher in the studied patients. No significant differences in ACTH levels were found between males and females with multiple sclerosis, and in the control group this level was higher in females. Raised ACTH level was found mainly in multiple sclerosis with lung duration of the disease (10 years) at the time of exacerbations. The authors continue studies on the axis hypothalamus-hypophysis-adrenals, on various hormones, prostaglandins, beta-endorphin, biochemical markers, cAMP, cCMP, arylosulphatase A and B MBC etc. 相似文献