全文获取类型
收费全文 | 1599638篇 |
免费 | 133563篇 |
国内免费 | 2577篇 |
专业分类
耳鼻咽喉 | 21656篇 |
儿科学 | 52932篇 |
妇产科学 | 46226篇 |
基础医学 | 227768篇 |
口腔科学 | 47198篇 |
临床医学 | 140904篇 |
内科学 | 314766篇 |
皮肤病学 | 34090篇 |
神经病学 | 130111篇 |
特种医学 | 64724篇 |
外国民族医学 | 474篇 |
外科学 | 243792篇 |
综合类 | 39716篇 |
现状与发展 | 3篇 |
一般理论 | 549篇 |
预防医学 | 122866篇 |
眼科学 | 36470篇 |
药学 | 121268篇 |
3篇 | |
中国医学 | 2974篇 |
肿瘤学 | 87288篇 |
出版年
2018年 | 14766篇 |
2016年 | 12900篇 |
2015年 | 15028篇 |
2014年 | 20646篇 |
2013年 | 31352篇 |
2012年 | 42547篇 |
2011年 | 44751篇 |
2010年 | 26338篇 |
2009年 | 25304篇 |
2008年 | 43003篇 |
2007年 | 45246篇 |
2006年 | 46058篇 |
2005年 | 44673篇 |
2004年 | 44092篇 |
2003年 | 42180篇 |
2002年 | 41293篇 |
2001年 | 75684篇 |
2000年 | 78326篇 |
1999年 | 66388篇 |
1998年 | 17731篇 |
1997年 | 16335篇 |
1996年 | 16314篇 |
1995年 | 16020篇 |
1994年 | 15070篇 |
1993年 | 14217篇 |
1992年 | 55427篇 |
1991年 | 53776篇 |
1990年 | 52566篇 |
1989年 | 50832篇 |
1988年 | 47224篇 |
1987年 | 46561篇 |
1986年 | 44284篇 |
1985年 | 42844篇 |
1984年 | 32035篇 |
1983年 | 27565篇 |
1982年 | 16144篇 |
1981年 | 14436篇 |
1980年 | 13564篇 |
1979年 | 30462篇 |
1978年 | 21068篇 |
1977年 | 17764篇 |
1976年 | 16697篇 |
1975年 | 17575篇 |
1974年 | 21487篇 |
1973年 | 20672篇 |
1972年 | 18854篇 |
1971年 | 17770篇 |
1970年 | 16289篇 |
1969年 | 15269篇 |
1968年 | 13950篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
912.
Actions of phencyclidine on the action potential and membrane currents of single guinea-pig myocytes 总被引:2,自引:0,他引:2
The direct actions of phencyclidine (PCP) on mammalian sarcolemma were examined by determination of the drug's effects on the action potentials of isolated guinea-pig ventricular cells, and on the underlying ionic currents. PCP (10(-6) to 10(-4) M) did not alter the resting membrane potential but produced a dose-dependent prolongation of the duration of the action potential, and a reduction of the rate of depolarization of phase 0 (Vmax) of the action potential. Voltage clamp experiments revealed that PCP blocks both myocardial Ca++ channels and myocardial time-dependent K+ channels. The K+ channel blockade was shown to exhibit an apparent voltage-dependence. The effects of PCP on these ionic channels could explain previous reports of it prolonging myocardial action potentials and conflicting reports of positive and negative inotropism. 相似文献
913.
914.
915.
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
916.
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
917.
918.
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
919.
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
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
920.