全文获取类型
收费全文 | 2349篇 |
免费 | 99篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 97篇 |
妇产科学 | 22篇 |
基础医学 | 436篇 |
口腔科学 | 78篇 |
临床医学 | 265篇 |
内科学 | 572篇 |
皮肤病学 | 112篇 |
神经病学 | 49篇 |
特种医学 | 272篇 |
外国民族医学 | 4篇 |
外科学 | 176篇 |
综合类 | 52篇 |
预防医学 | 102篇 |
眼科学 | 32篇 |
药学 | 162篇 |
中国医学 | 1篇 |
肿瘤学 | 46篇 |
出版年
2016年 | 27篇 |
2015年 | 31篇 |
2014年 | 29篇 |
2013年 | 78篇 |
2012年 | 31篇 |
2011年 | 28篇 |
2010年 | 51篇 |
2009年 | 40篇 |
2008年 | 31篇 |
2007年 | 50篇 |
2006年 | 51篇 |
2005年 | 32篇 |
2004年 | 24篇 |
2003年 | 30篇 |
2002年 | 26篇 |
2001年 | 35篇 |
2000年 | 24篇 |
1999年 | 39篇 |
1998年 | 84篇 |
1997年 | 95篇 |
1996年 | 107篇 |
1995年 | 70篇 |
1994年 | 75篇 |
1993年 | 79篇 |
1992年 | 45篇 |
1991年 | 39篇 |
1990年 | 49篇 |
1989年 | 67篇 |
1988年 | 64篇 |
1987年 | 52篇 |
1986年 | 58篇 |
1985年 | 38篇 |
1984年 | 56篇 |
1983年 | 27篇 |
1982年 | 32篇 |
1981年 | 39篇 |
1980年 | 49篇 |
1979年 | 23篇 |
1978年 | 27篇 |
1977年 | 35篇 |
1976年 | 38篇 |
1975年 | 36篇 |
1972年 | 24篇 |
1970年 | 23篇 |
1965年 | 50篇 |
1964年 | 50篇 |
1963年 | 47篇 |
1962年 | 41篇 |
1961年 | 40篇 |
1960年 | 65篇 |
排序方式: 共有2481条查询结果,搜索用时 15 毫秒
21.
Evaluation of maternal plasma creatine kinase activity as a marker of abnormal early pregnancy 总被引:1,自引:0,他引:1
Zorn JR; Cherruau B; Abi-Rached F; Dehee A; Danoy X; Le Blond J; Ekindjian O 《Human reproduction (Oxford, England)》1997,12(11):2534-2537
We have tested the value of maternal plasma creatine kinase activity for
diagnosing ectopic pregnancies obtained after in-vitro fertilization and
embryo transfer. Plasma creatine kinase was assayed in 57 patients: 20
normal, 23 miscarriages and 14 ectopic pregnancies, for a total of 240
samples. All values were in the lower part of the normal range except only
one in a miscarrying patient. A statistically significant difference was
observed for a cut-off value of 45 IU/l between normal and ectopic
pregnancies. However, for this cut-off point, the measurement of plasma
creatine kinase activity had a sensitivity of 0.50 and a specificity of
0.76 for the diagnosis of ectopic pregnancy. The positive predictive value
was 0.69. Creatine kinase activity measurements are thus of no practical
value in this particular population, in which an early and specific marker
of ectopic implantation would be of paramount interest. The association of
human chorionic gonadotrophin (HCG) determinations and ultrasound scanning
of the pelvis still remain the best paraclinical support for an early
diagnosis of ectopic implantation.
相似文献
22.
MARTIN J. BOHN JR JOYCE L. CARBONELL EDWIN I. MEGARGEE 《Criminal behaviour and mental health : CBMH》1995,5(1):14-33
This study investigated the applicability and utility of Megargee and Bohn's MMPI-based offender classification system in correctional mental health units (MHUs). Previous studies found that 11 MHU samples (n = 1723) had substantially more offenders classified in the more pathological MMPI types than did 21 samples (n = 5881) drawn from general male populations in US prisons. In this study of 63 severely disturbed felons, 43% belonged to the most pathological type (‘group How’). Comparing MHU patients with general offenders from the same IvfIvIPI types on staff ratings and case history variables, we found that the MHU patients were significantly poorer in adjustment. Within the MHU sample, there was no difference in case history variables or adjustment ratings between those in the most and least severe MMPI types. These findings differed from those of studies using less severely disturbed, more heterogeneous, MHU populations. It was concluded that, in settings in which the entire population is flagrantly disturbed, the MMPI-based system is more useful in screening potential admissions than it is in making meaningful distinctions among those already admitted. 相似文献
23.
MUNSON A. E.; WHITE K. L. JR.; BARNES D. W.; MUSGROVE D. L.; LYSY H. H.; HOLSAPPLE M. P. 《Toxicological sciences》1988,10(4):691-700
An Immunotoxicological Evaluation of 4,4'-Thiobis-(6-t-butyl-m77-cresol)in Female B6C3F1 Mice. 1. Body and Organ Weights, Hematology,Serum Chemistries, Bone Marrow Cellularity, and Hepatic MicrosomalParameters. MUNSON, A. E., WHITE, K. L., JR., BARNES, D. W.,MUS-GROVE, D. L., LYSY, H. H., AND HOLSAPPLE, M. P. (1988).Fundam. Appl. Toxicol. 10, 691700. Adult female B6C3F1mice were gavaged with 4,4'-thiobis-(6-t-butyl-m-cresol) (TBBC)in corn oil at doses of 10, 100, or 200 mg/kg daily for 14 consecutivedays. There was no overt toxicity, as manifested by grosslyobservable behavioral changes, decreased growth rate over theexposure period, or mortality. There were also no marked effectson serum chemistries or hematology, with the exception of asignificant increase (41%) in the number of leukocytes at thehighest dose. Absolute differential counts indicated that significantincreases occurred in the number of lymphocytes (31%) and neutrophils(177%). Studies with bone marrow indicated a significant 30%increase in the number of cells/femur from animals treated withthe highest dose of TBBC. The number of macrophage progenitors(CFU-M)/femur was significantly increased by 28%, while thenumber of granulocyte-monocyte progenitors (CFU-GM)/femur wasnonsig-nificantly increased by 20% in the high dose animals.The weight of both the spleen and liver was increased in a dose-relatedfashion, although the histopathology of the spleen of TBBC-treatedmice was not different from control. The livers of mice receivingthe high dose showed mild focal hydropic degeneration, mildhepatitis, and a slight increase in the number of Kupffer cells.No other organs were affected. Liver microsomal protein andcytochrome P-450 levels were increased in a dose-related fashion.Enzyme activities of aminopyrine demethylase and aniline hydroxylase,but not arylhydrocarbon hydroxylase, were also increased ina dose-related fashion. 相似文献
24.
SIKORSKI E. E.; MCCAY J. A.; WHITE K. L. JR.; BRADLEY S. G.; MUNSON A. E. 《Toxicological sciences》1989,13(4):843-858
The effects of gallium arsenide (GaAs) exposure on immunocompetenceof B6C3F1 female mice were investigated. GaAs was administeredas a single intratracheal instillation at doses of 50, 100,and 200 mg/kg. Fourteen days after exposure, various cellularand humoral immune parameters were assessed. GaAs exposure increasedspleen cellularity in a dose-dependent manner. However, thepercentages of Thy 1.2 positive and 1g positive cells were decreasedand that of F4/80 positive cells was increased dose dependency.The IgM and IgG antibody-forming cell response of the spleento the T-dependent antigen sheep erythrocytes was reduced by66 and 48%, respectively, at 200 mg/kg. Levels of the serumcomplement protein, C3, were increased by as much as 16% withno significant change in CH50 levels. The mitogenic responseof splenic T cells to Con A and PHA was unaffected by GaAs,but that of B cells to LPS was increased by 52%. The delayedhypersensitivity response to keyhole limpet hemocyanin and mixedlymphocyte response were significantly reduced in a dose-dependentmanner by GaAs exposure. Natural killer cell activity againstthe YAC-1 mouse lymphoma was enhanced in treated mice. Analysisof peritoneal exudate cells (PEC) revealed a dose-dependentdecrease in number and a shift in the composition of PECs. Thepercentage of PEC monocytes increased from 53% of the populationto 81%, while the lymphocytes decreased from 46 to 20%. Theadherent PEC population demonstrated decreased phagocytosisof covaspheres and increased phagocytosis of chicken erythrocytes(CRBC). GaAs exposure had no effect on host resistance to Plasmodiumyoelii or Streptococcus pneumoniae, but dose dependency increasedresistance of the mouse to Listeria monocytogenes Treated micedemonstrated a significantly decreased resistance to the B16F10melanoma with a sevenfold increase in tumor burden at 200 mg/kg.GaAs affects both humoral and cellular immune parameters inmice and impairs the ability of the immune system to protectagainst B16F10 tumor challenge. 相似文献
25.
26.
J. R. NEEFE JR. H. BALNER A. D. BARNES C. FORD G. N. ROOENTINE JR. W. VAN VREESWIJK F. E. WARD 《Tissue antigens》1975,6(2):77-79
The Second International Nonhuman Primate Histocompatibility Workshop permitted comparison of rhesus monkey alloantisera developd in various laboratories on a single common panel of related and unrelated monkeys. Analysis of the data permits the conclusion that at least nine specificities are recognized by more than one laboratory, including six at the first locus and three at the second locus. 相似文献
27.
The Gm-Pi linkage heterogeneity in view of Pi M subtypes 总被引:1,自引:3,他引:1
T. GEDDE-DAHL JR R. R. FRANTS† B. OLAISEN† A. W. ERIKSSON† E. VAN LOGHEM§ L. LAMM¶ 《Annals of human genetics》1981,45(2):143-153
In this study linkage between the loci for Gm (γ-type heavy-chain immunoglobulin markers) and Pi (α1 -antitrypsin/α1 -protease inhibitor) has been shown in families segregating for the Pi M subtypes (Ml, M2, M3 and Msal) as identified by separator isoelectric focusing. The estimate for the Gm-Pi (M-type) recombination is 0-29 (95% limits 0-24-O37) at a peak lod score of 4-31 and with no sex difference. This value is not significantly different from updated recombination frequency estimates for Gm-Pi in Pi MS (0-26) and Pi MZ, SZ and FZ families (0 21). The overall Gm-Pi recombination fraction estimate of 0 26 (95 % limits O23-0-30) at a peak lod score of 20-75 must now be considered as solid. There is a significant heterogeneity within the male Pi MZ families in that the new Finnish families show a higher recombination between Gm and Pi. There is also a possible segregation distortion (Z:M = 23:8). The heterogeneity is discussed in terms of haplotypes, the behaviour of which could be determined by linked genes or chromosomal rearrangements. The possibility that the α1 -antitrypsin level influences recombination frequency has not been ruled out, but cannot explain the heterogeneity within Pi MZ families. 相似文献
28.
The ramification of the portal vein at the porta hepatis was studied by anatomic dissection performed in 32 formalin fixed human livers. In all the specimens there were branches which ran towards the caudate lobe, arising from the portal vein and either from the left or the right portal branches. Tri-and quadrifurcation of the portal vein was observed. In 5 cases (16%) there were branches arising from left portal branch or portal vein and directed anteriorly to the quadrate lobe or to the region of the gall-bladder sulcus. These branches ranged from 1.0 to 6.0 mm in diameter. The portal caudate branches were divided into 3 groups.Group 1: Branches to the papillary process; 1 or 2 branches in 26 cases (82%), 3 or 5 branches in 3 cases (9%) and no branches in 3 cases (9%); 相似文献
29.
30.