全文获取类型
收费全文 | 1097932篇 |
免费 | 82327篇 |
国内免费 | 2256篇 |
专业分类
耳鼻咽喉 | 16856篇 |
儿科学 | 34352篇 |
妇产科学 | 31848篇 |
基础医学 | 157217篇 |
口腔科学 | 32310篇 |
临床医学 | 92882篇 |
内科学 | 207684篇 |
皮肤病学 | 23802篇 |
神经病学 | 90570篇 |
特种医学 | 46453篇 |
外国民族医学 | 221篇 |
外科学 | 174937篇 |
综合类 | 27032篇 |
现状与发展 | 2篇 |
一般理论 | 323篇 |
预防医学 | 78710篇 |
眼科学 | 27247篇 |
药学 | 81193篇 |
中国医学 | 2197篇 |
肿瘤学 | 56679篇 |
出版年
2018年 | 10662篇 |
2016年 | 10385篇 |
2015年 | 11960篇 |
2014年 | 15789篇 |
2013年 | 23635篇 |
2012年 | 32694篇 |
2011年 | 33341篇 |
2010年 | 19646篇 |
2009年 | 17935篇 |
2008年 | 32056篇 |
2007年 | 35057篇 |
2006年 | 35076篇 |
2005年 | 35144篇 |
2004年 | 34206篇 |
2003年 | 33084篇 |
2002年 | 32003篇 |
2001年 | 46098篇 |
2000年 | 46567篇 |
1999年 | 39568篇 |
1998年 | 11741篇 |
1997年 | 10823篇 |
1996年 | 10341篇 |
1995年 | 9623篇 |
1994年 | 9204篇 |
1992年 | 31454篇 |
1991年 | 30639篇 |
1990年 | 30138篇 |
1989年 | 28904篇 |
1988年 | 26941篇 |
1987年 | 26595篇 |
1986年 | 25255篇 |
1985年 | 24410篇 |
1984年 | 18882篇 |
1983年 | 16039篇 |
1982年 | 10105篇 |
1981年 | 9425篇 |
1980年 | 8770篇 |
1979年 | 19200篇 |
1978年 | 13919篇 |
1977年 | 11668篇 |
1976年 | 10633篇 |
1975年 | 11879篇 |
1974年 | 14458篇 |
1973年 | 13865篇 |
1972年 | 13150篇 |
1971年 | 12259篇 |
1970年 | 11613篇 |
1969年 | 11187篇 |
1968年 | 10188篇 |
1967年 | 9362篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Lesions typical of subacute cutaneous lupus erythematosus developed in an elderly woman after 6 months of PUVA (8-methoxypsoralen and longwave ultraviolet light) therapy for psoriasis. Pancytopenia, antibodies to double-stranded DNA, and hypocomplementemia developed concurrently with the appearance of the cutaneous lesions. With discontinuation of photochemotherapy, the cutaneous lesions disappeared and the pancytopenia improved. 相似文献
962.
C4 concentrations and C4 deficiency alleles in systemic lupus erythematosus. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Annals of the rheumatic diseases》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In a study of 66 patients with systemic lupus erythematosus (SLE) and 80 controls it was found that the presence of two deficiency (null) alleles of C4 had a significant effect on mean C4 concentrations in serum. In six controls who each had two C4 null alleles the mean C4 concentration in serum was 56% lower than in 43 controls without C4 null alleles; the nadir of the C4 concentration in four patients with SLE with two null alleles was also lower by a mean of 55% than in 32 patients who did not have null alleles. Reduced production of C4 allotypes in subjects with two null alleles may be an important determinant of total C4 concentration in patients with SLE. For optimal interpretation of C4 concentrations in SLE, C4 allotyping appears to be indicated, particularly to identify patients who have two null alleles of C4. 相似文献
963.
964.
T W Findley M G Stineman 《American journal of physical medicine & rehabilitation / Association of Academic Physiatrists》1989,68(5):240-251
The process of data entry and initial analysis to locate data errors is described. Basic terms are defined and a simple method of entering data by using word processing software is illustrated. Data checking is done by using visual check of the raw data. Statistical programs are then used to locate possible data errors by finding data points (outliers) that are very different from the average. Special graphic output of statistical programs, scatterplots and box and whisker plots can be used to further locate questionable data. Examples of data entry forms and annotated step by step data cleaning with the use of inexpensive programs for personal computers are presented. 相似文献
965.
A Goldfarb J Weinreb W G Daniel I Kronzon 《Journal of the American Society of Echocardiography》1989,2(5):350-353
A patient who had right and left atrial membranes was examined. The diagnosis and the hemodynamic significance of both membranes were detailed by transesophageal echocardiography and were confirmed by magnetic resonance imaging. Transesophageal imaging was found to be superior to routine echocardiography in visualization of these atrial structures. 相似文献
966.
Prospective randomized comparison of mezlocillin therapy alone with combined ampicillin and gentamicin therapy for patients with cholangitis 总被引:3,自引:0,他引:3
W B Gerecht N K Henry W W Hoffman S M Muller N F LaRusso J E Rosenblatt W R Wilson 《Archives of internal medicine》1989,149(6):1279-1284
Forty-six patients with cholangitis were randomized to receive therapy with mezlocillin sodium (24 patients) or a combination of ampicillin sodium--gentamicin sulfate (22 patients). The biliary concentration of mezlocillin was 112 times higher than that of ampicillin and 778 times higher than that of gentamicin. The ratio of the concentration in serum or bile over the minimum inhibitory concentration against aerobic gram-negative bacilli (therapeutic index) was higher for mezlocillin than for either ampicillin or gentamicin. Twenty (83%) of 24 patients were cured following mezlocillin therapy compared with 9 (41%) of 22 patients after ampicillin-gentamicin therapy. The 3 patients with superinfection were in the ampicillin-gentamicin arm of the study. Fewer toxic or adverse effects occurred in association with mezlocillin treatment than with ampicillin-gentamicin treatment. Mezlocillin therapy was more effective, less toxic, and less expensive than treatment with ampicillin and gentamicin for patients with cholangitis. 相似文献
967.
In the first 100 patients operated on for C T-E PH, three were referred with the diagnosis of UPAA having been made elsewhere. We found that many features of these two conditions are so similar that differential diagnosis is very difficult. Shared features may include findings on chest x-ray film, pulmonary angiography, CT scan and MRI studies. Since the two conditions vary substantially with respect to the methods of potential surgical correction, recognition of this possible differential diagnostic dilemma is important. 相似文献
968.
Preclinical and clinical investigations currently underway are employing novel strategies for combining vaccines with conventional and experimental anticancer therapies. To date, the FDA has not approved a therapeutic cancer vaccine. However, the results of recent investigations suggest an increasing role for vaccines in new models of combination therapy for many types of cancer. This article reviews and discusses therapeutic cancer strategies that employ vaccines in combination with local radiation, chemotherapy, hormone therapy, and anti-CTLA-4 mAb. Preclinical studies have shown that certain anticancer agents have immune modulatory effects that result in up-regulation of surface expression of MHC molecules, tumor-associated antigens, or Fas on malignant cells, rendering them more susceptible to immune destruction. Preliminary results of clinical studies using combination strategies have demonstrated a postvaccination antigen cascade, prolonged time to disease progression, and improved overall survival. Several larger randomized trials are ongoing, and more are required to support these findings. 相似文献
969.
Heiko Sch?der Diane L Carlson Dennis H Kraus Hilda E Stambuk Mithat G?nen Yusuf E Erdi Henry W D Yeung Andrew G Huvos Jatin P Shah Steven M Larson Richard J Wong 《Journal of nuclear medicine》2006,47(5):755-762
(18)F-FDG PET has a high accuracy in staging head and neck cancer, but its role in patients with clinically and radiographically negative necks (N0) is less clear. In particular, the value of combined PET/CT has not been determined in this group of patients. METHODS: In a prospective study, 31 patients with oral cancer and no evidence of lymph node metastases by clinical examination or CT/MRI underwent (18)F-FDG PET/CT before elective neck dissection. PET/CT findings were recorded by neck side (left or right) and lymph node level. PET/CT findings were compared with histopathology of dissected nodes, which was the standard of reference. RESULTS: Elective neck dissections (26 unilateral, 5 bilateral; a total of 36 neck sides), involving 142 nodal levels, were performed. Only 13 of 765 dissected lymph nodes harbored metastases. Histopathology revealed nodal metastases in 9 of 36 neck sides and 9 of 142 nodal levels. PET was TP in 6 nodal levels (6 neck sides), false-negative in 3 levels (3 neck sides), true-negative in 127 levels (23 neck sides), and false-positive in 6 levels (4 neck sides). The 3 false-negative findings occurred in metastases smaller than 3 mm or because of inability to distinguish between primary tumor and adjacent metastasis. TP and false-positive nodes exhibited similar standardized uptakes (4.8 +/- 1.1 vs. 4.2 +/- 1.0; P = not significant). Sensitivity and specificity were 67% and 85% on the basis of neck sides and 67% and 95% on the basis of number of nodal levels, respectively. If a decision regarding the need for neck dissection had been based solely on PET/CT, 3 false-negative necks would have been undertreated, and 4 false-positive necks would have been overtreated. CONCLUSION: (18)F-FDG PET/CT can identify lymph node metastases in a segment of patients with oral cancer and N0 neck. A negative test can exclude metastatic deposits with high specificity. Despite reasonably high overall accuracy, however, the clinical application of PET/CT in the N0 neck may be limited by the combination of limited sensitivity for small metastatic deposits and a relatively high number of false-positive findings. The surgical management of the N0 neck should therefore not be based on PET/CT findings alone. 相似文献
970.
P B Schneider U Denk M Breitenbach K Richter P Schmid-Grendelmeier S Nobbe M Himly A Mari C Ebner B Simon-Nobbe 《Clinical and experimental allergy》2006,36(12):1513-1524
BACKGROUND: Alternaria alternata is one of the most important allergenic fungi worldwide. Mannitol dehydrogenase (MtDH) has previously been shown to be a major allergen of Cladosporium herbarum and cross-reactivity has been demonstrated for several fungal allergens. OBJECTIVE: The present study's objective was to clone the MtDH from an A. alternata cDNA library, express and purify the recombinant non-fusion protein and test its IgE-binding properties. Methods A cDNA library prepared from A. alternata hyphae and spores was screened for mannitol dehydrogenase by DNA hybridization with the radioactively labelled C. herbarum homologue as a probe. The resulting clone was sequenced and heterologously expressed in Escherichia coli as a recombinant non-fusion protein, which was purified to homogeneity and analysed for its IgE-binding capacity. RESULTS: The coding sequence of the full-length cDNA clone comprises 798 bp encoding a protein with a molecular mass of 28.6 kDa and a predicted pI of 5.88. Protein sequence analysis revealed an identity of 75% and a homology of 86% between the MtDHs of A. alternata and C. herbarum. The functional mannitol dehydrogenase was expressed in the E. coli strain BL21(DE3) transformed with the vector pMW172 and purified to homogeneity. The enzyme catalyses the NADPH-dependent conversion of d-fructose to d-mannitol. In IgE-ELISA and immunoblots, MtDH is recognized by 41% of A. alternata-allergic patients. In vivo immunoreactivity of the recombinant MtDH was verified by skin prick testing. Finally, inhibition-ELISA experiments confirmed cross-reactivity between the MtDHs of A. alternata and C. herbarum. CONCLUSION: Mannitol dehydrogenase (Alt a 8) represents an important new allergen of the ascomycete A. alternata that might be suitable for improving diagnostic and therapeutic procedures. 相似文献