全文获取类型
收费全文 | 1695622篇 |
免费 | 140413篇 |
国内免费 | 2749篇 |
专业分类
耳鼻咽喉 | 22565篇 |
儿科学 | 55591篇 |
妇产科学 | 48281篇 |
基础医学 | 242751篇 |
口腔科学 | 50031篇 |
临床医学 | 149219篇 |
内科学 | 333574篇 |
皮肤病学 | 35697篇 |
神经病学 | 139622篇 |
特种医学 | 68576篇 |
外国民族医学 | 479篇 |
外科学 | 255435篇 |
综合类 | 40124篇 |
现状与发展 | 4篇 |
一般理论 | 636篇 |
预防医学 | 134137篇 |
眼科学 | 37977篇 |
药学 | 127104篇 |
2篇 | |
中国医学 | 3150篇 |
肿瘤学 | 93829篇 |
出版年
2018年 | 16775篇 |
2016年 | 14804篇 |
2015年 | 17168篇 |
2014年 | 23603篇 |
2013年 | 35207篇 |
2012年 | 48494篇 |
2011年 | 50844篇 |
2010年 | 29539篇 |
2009年 | 28588篇 |
2008年 | 48249篇 |
2007年 | 50710篇 |
2006年 | 51236篇 |
2005年 | 49571篇 |
2004年 | 48232篇 |
2003年 | 46083篇 |
2002年 | 44901篇 |
2001年 | 78542篇 |
2000年 | 81172篇 |
1999年 | 69009篇 |
1998年 | 18976篇 |
1997年 | 17325篇 |
1996年 | 17340篇 |
1995年 | 16836篇 |
1994年 | 15842篇 |
1993年 | 14917篇 |
1992年 | 57256篇 |
1991年 | 55371篇 |
1990年 | 54145篇 |
1989年 | 52325篇 |
1988年 | 48574篇 |
1987年 | 47764篇 |
1986年 | 45493篇 |
1985年 | 43954篇 |
1984年 | 32844篇 |
1983年 | 28304篇 |
1982年 | 16534篇 |
1981年 | 14789篇 |
1980年 | 13866篇 |
1979年 | 31113篇 |
1978年 | 21465篇 |
1977年 | 18098篇 |
1976年 | 16943篇 |
1975年 | 17853篇 |
1974年 | 21829篇 |
1973年 | 21009篇 |
1972年 | 19163篇 |
1971年 | 18076篇 |
1970年 | 16524篇 |
1969年 | 15507篇 |
1968年 | 14210篇 |
排序方式: 共有10000条查询结果,搜索用时 85 毫秒
991.
The relationship between the immunoglobulin kappa light chain allotypes and autoantibodies was studied in a series of seven human monoclonal kappa-bearing IgM antibodies with Rheumatoid Factor (RF) activity, two IgM anti-low density lipoprotein (LDL) antibodies, and one IgM anti-intermediate filament (IF) antibody. Residues at amino acid positions 153 and 191 related to the Km allotypes in human kappa chains were determined by an HPLC tryptic fingerprint and corroborated by amino acid sequence analysis. All the autoantibodies shared similar variable regions derived from the V kappa IIIb gene(s). The seven RF and the anti-IF were associated with the Km(3) constant region allotype whereas the two anti-LDL were associated with the Km(1,2) allotype. Thus, monoclonal autoantibodies showed the same Km allotypic distribution as the normal population. However, although the number of samples is small, it seems likely that a preferential association may exist between particular V kappa genes and Km alleles in the generation of autoantibodies with different specificities. 相似文献
992.
R W Wulkan L Zwang T L Liem B G Blijenberg B Leijnse 《Zeitschrift für klinische Chemie und klinische Biochemie》1987,25(10):719-722
An expert system for evaluation of X-ray diffraction patterns of urinary calculi is described and evaluated. The software was developed using the PERSONAL CONSULTANT expert system shell from Texas Instruments. 相似文献
993.
994.
Use of the appropriateness evaluation protocol for estimating the incremental costs associated with nosocomial infections 总被引:1,自引:0,他引:1
Existing methods for estimating additional days of hospital stay due to nosocomial infections (NI) have a number of documented limitations. An alternative method described in this paper uses the Appropriateness Evaluation Protocol (AEP) to determine whether each day of acute inpatient care is appropriate based on the need for care of the NI, original cause of hospitalization (OC), or combined NI-OC requirements. Using this method to identify specific days of hospitalization due to Staphylococcus aureus nosocomial infection, we find: 1) length of stay is increased for only a minority of patients (38%); 2) an average of 20 additional days of stay occurred for patients with 1 or more days attributed to NI; and 3) an average of 52% of length of stay of patients with 1 or more days attributed to NI can be attributed to the NI. Application of the AEP-based method is a useful alternative for identifying additional days of stay due to NI. 相似文献
995.
Activity of newer beta-lactam agents against clinical isolates of Bacteroides fragilis and other Bacteroides species. 总被引:7,自引:4,他引:3
下载免费PDF全文
![点击此处可从《Antimicrobial agents and chemotherapy》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J P O''''Keefe F R Venezio C A DiVincenzo K L Shatzer 《Antimicrobial agents and chemotherapy》1987,31(12):2002-2004
The in vitro activities of beta-lactam antibiotics against Bacteroides fragilis and B. fragilis group isolates are presented. Clinical isolates from 1986 were compared with strains from 1979 to 1982. Imipenem, ticarcillin-clavulanic acid, and ceftizoxime were the most active agents. Cefotetan was equivalent to cefoxitin against B. fragilis but less active against B. fragilis group isolates. Enhancement of cefotaxime by its desacetyl metabolite was minimal. 相似文献
996.
997.
998.
999.
Mo Weijtens Anke van Spronsen Anton Hagenbeek Eric Braakman Anton Martens 《Human gene therapy》2002,13(2):187-198
Graft-versus-host disease (GvHD), a major complication of allogeneic bone marrow transplantation, has been ascribed to mature T cells in the graft. Because T cells play an important role in engraftment of the bone marrow and decrease the probability of relapse of leukemia, a treatment strategy was developed to preserve the benefits of T cells in the graft and to control the severe complications of GvHD. This can be accomplished by the genetic modification of donor T cells with a suicide gene that allows their selective in vivo elimination and subsequently the abrogation of GvHD. For clinical benefit the alloreactivity of herpes simplex virus thymidine kinase (HSV-TK) gene-transduced T cells should be retained. Therefore, we investigated the influence of gene transduction and the selection procedure on T cells. We demonstrated that activation and culturing of T cells reduce their capacity to induce lethal GvHD in an allogeneic rat bone marrow transplantation model. Furthermore, positive immunomagnetic selection of gene-transduced T cells resulted in loss of the GvHD-inducing capacity of HSV-TK(+) T cells directly after MACS (magnetic cell sorting) selection; this loss could be recovered by a 1-day expansion of the selected T cells. No effect on alloreactivity was observed to be caused by the gene transduction procedure. Our study resulted in the development of an optimized culture and gene transduction protocol with preservation of T cell alloreactivity. Treatment of transplanted rats with ganciclovir resulted in a rapid reduction in the number of HSV-TK(+) T cells in the peripheral blood and in increased survival of the animals. 相似文献
1000.