全文获取类型
收费全文 | 13303篇 |
免费 | 2776篇 |
国内免费 | 143篇 |
专业分类
耳鼻咽喉 | 388篇 |
儿科学 | 347篇 |
妇产科学 | 445篇 |
基础医学 | 876篇 |
口腔科学 | 313篇 |
临床医学 | 3213篇 |
内科学 | 2761篇 |
皮肤病学 | 373篇 |
神经病学 | 1128篇 |
特种医学 | 552篇 |
外科学 | 1681篇 |
综合类 | 411篇 |
现状与发展 | 2篇 |
一般理论 | 2篇 |
预防医学 | 2014篇 |
眼科学 | 156篇 |
药学 | 396篇 |
1篇 | |
中国医学 | 106篇 |
肿瘤学 | 1057篇 |
出版年
2024年 | 81篇 |
2023年 | 428篇 |
2022年 | 153篇 |
2021年 | 330篇 |
2020年 | 540篇 |
2019年 | 237篇 |
2018年 | 658篇 |
2017年 | 665篇 |
2016年 | 691篇 |
2015年 | 786篇 |
2014年 | 843篇 |
2013年 | 1196篇 |
2012年 | 629篇 |
2011年 | 561篇 |
2010年 | 655篇 |
2009年 | 717篇 |
2008年 | 496篇 |
2007年 | 466篇 |
2006年 | 495篇 |
2005年 | 410篇 |
2004年 | 338篇 |
2003年 | 288篇 |
2002年 | 255篇 |
2001年 | 278篇 |
2000年 | 189篇 |
1999年 | 206篇 |
1998年 | 315篇 |
1997年 | 327篇 |
1996年 | 353篇 |
1995年 | 275篇 |
1994年 | 198篇 |
1993年 | 143篇 |
1992年 | 149篇 |
1991年 | 137篇 |
1990年 | 134篇 |
1989年 | 161篇 |
1988年 | 127篇 |
1987年 | 103篇 |
1986年 | 100篇 |
1985年 | 95篇 |
1984年 | 79篇 |
1983年 | 67篇 |
1982年 | 57篇 |
1981年 | 72篇 |
1980年 | 47篇 |
1979年 | 50篇 |
1978年 | 43篇 |
1977年 | 36篇 |
1976年 | 31篇 |
1973年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Summary The effects of personality characteristics on social support and hence risk of depression are explored in a group of 150 largely working-class mothers, a subsample of 400 women who took part in a prospective study. This established that once those with depression at first interview were excluded, practically all of the onsets of depression in the follow-up year occurred among 150 women with a severe event or major difficulty — that is a provoking agent. It was also found that low self-esteem and lack of support from a core tie at the time of the crisis was associated with a considerably increased risk. In the subsample as a whole, measures of dependency and attitudinal constraints to support taken at first interview were not associated with risk of depression. But, it is argued, any enduring personality traits that play a role in the link between lack of support and depression would most likely be seen in a smaller group, namely those who had had early inadequate parenting. And the most promising lead concerning the role of personality characteristics did in fact emerge in relation to a small high risk group with such parenting. Most of them had low self-esteem, and they appeared to confide in inappropriate and unreliable sources of support at time of crisis. 相似文献
102.
Israel Zelikovic Shermine Dabbagh Aaron L. Friedman David T. Uehling Russell W. Chesney 《Pediatric nephrology (Berlin, Germany)》1988,2(4):512-514
A boy aged 4.5 years with prune-belly syndrome (PBS) and associated urethral stenosis, oligohydramnios, imperforate anus and vesicosigmoid fustula is described. In contrast to the anticipated poor prognosis, vesicostomy and divided transverse colostomy performed after birth followed by prophylaxis of infection and bicarbonate supplementation have resulted in a good outcome. The vesicosigmoid fistula might have served in utero as a natural diversion protecting from pressure-induced renal damage. It is suggested that the main determinant of prognosis in PBS is the presence and degree of kidney dysplasia at birth as reflected by the neonatal renal function after performance of an indicated urinary diversion procedure rather than the presence of severe associated anomalies.Supported in part by grants from the National Institute of Health AM 37223-01 and the Medical School and Graduate School Research Committees of the University of Wisconsin and a Research Career Development Award KO4 AM 00421 (RWC), by the Pearl M. Stetler Foundation (SD) and by a National Kidney Foundation fellowship (IZ) 相似文献
103.
Investigation of an outbreak of Salmonella enteritidis gastroenteritis associated with consumption of eggs in a restaurant chain in Maryland 总被引:6,自引:0,他引:6
F Y Lin J G Morris D Trump D Tilghman P K Wood N Jackman E Israel J P Libonati 《American journal of epidemiology》1988,128(4):839-844
Salmonella enteritidis ser. enteritidis was isolated from patrons and employees of three restaurants in a restaurant chain in Maryland during August and September 1985. Isolates from all three restaurants had identical plasmid profiles; this profile was present in 13 of 40 randomly selected S. enteritidis isolates received by the Maryland state health department laboratory during a comparable time period. The outbreak in one restaurant resulted in at least 71 illnesses, with 17 persons known to have been hospitalized. Scrambled eggs served on a "breakfast bar" were implicated as the vehicle of transmission in this restaurant, with eggs a possible vehicle in another of the three restaurants. The data point out the risks associated with improper handling of eggs in food service establishments, provide further evidence for the observed association between S. enteritidis and eggs in the northeastern United States, and demonstrate the utility of plasmid analysis in investigation of outbreaks involving common Salmonella serotypes. 相似文献
104.
Angelo Ferrara M.D. Ph.D. Melvin Schwartz M.D. Helen Page R.N. M.P.A. Morton Israel M.A. Yucel Atakent M.D. M.S. C. E. Smith Ph.D. Leon Landovitz Ph.D. 《Journal of community health》1988,13(1):3-18
In the past two decades, there has been a gradual trend to regionalization of perinatal care, categorization of hospitals and transport services for neonatal health care. The literature alludes to both beneficial and deleterious effects of neonatal transport (T) but no controls such as a matched nontransport (NT) population have been utilized to date.The major goal of this study was to evaluate the effect of neonatal transport from Level I and II high risk 2500 gm. neonates (born in NYC in one calendar year, 1979) compared to a cohort nontransported population matched for hospital of birth, weight, race, sex and risk. All transported 2500 gm. from Level I and II (n=328) were studied and a stratified random sample of the nontransported (NT) infants 2500 gm. from these same hospitals (n=2042) was used for comparison. The principle outcome variable was survival. The major conclusion of this study is that in Level I and II hospitals the transport group had a significantly increased survival in infants who were sick (Apgar <6) compared to cohorted nontransported controls. Interhospital differences in survival were noted among Level I and II but not seen in the subdivisions of (A) and (B) hospitals.Angelo Ferrara, M.D., Ph.D., is Professor, Pediatrics, NYU Medical Center, New York, N.Y.: Melvin Schwartz, M.D., was Research Professor, Environmental Medicine, NYU Medical Center, New York, N.Y.; Helen Page, R.N., M.P.A., is Quality Assurance Reviewer, Manhattan Eye, Ear, Throat Hospital, New York, N.Y.: Morton Israel, M.A., is Research Scientist, Health Resources Administration, City of N. Y., New York, N.Y.; Yucel Atakent, M.D., M.S., is Clinical Associate Professor, NYU Medical Center, New York, N.Y.; C.E. Smith, Ph.D., is President, Health Policy Analysis & Accountability Network, Inc. (HPAAN), Edgewood, New Mexico; Leon Landovitz, Ph.D., is Vice President, Management Information Systems, Healthways System Inc., Islin, N.J.Supported by NCHSR Grant #5-R018-HSO3832 相似文献
105.
Mervyn Israel Trevor W. Sweatman Ramakrishnan Seshadri Yoshihiro Koseki 《Cancer chemotherapy and pharmacology》1989,25(3):177-183
Summary
N-Benzyladriamycin-14-valerate (AD 198) is a new lipophilic adriamycin (ADR) analogue that shows marked therapeutic superiority to ADR in murine tumor model systems yet differs mechanistically from ADR in a number of ways. Among its other properties, AD 198 produces a delayed but profound effect on cell-cycle progression and a pattern of continuing DNA damage in cultured cells briefly exposed to the drug. Using radiolabeled drug forms and radioassays combined with HPLC separation and fluorimetric detection techniques, aspects of drug accumulation, biotransformation, and retention in cultured human CEM leukemic lymphocytes were studied, in part to determine a possible pharmacologic basis for the latent effects seen with this drug. In addition, the cellular pharmacology of AD 198 and ADR were comparatively examined under identical experimental conditions. When CEM cells were incubated with drug at equi-growth inhibitory/minimally cytotoxic concentrations (AD 198, 1.0 M; ADR, 0.1 M), a number of differences were apparent. Under conditions of continuous 24-h drug exposure, a slow cellular accumulation and equilibration was observed with ADR (cell: medium equilibrium, 1:11 after 4–6 h), whereas the uptake of AD 198 was rapid and extensive (cell: medium equilibrium, 3:1 within 30 min). In drug-retention studies, when cells were pretreated at the same drug concentrations as before (AD 198 for 1 h; ADR for 4 h) and then transferred to drug-free media, both compounds re-equilibrated their intracellular drug content with the fresh media, losing about 50% of their respective anthracycline levels. Liquid chromatographic analysis of ADR-treated cultures under both sets of conditions showed the parent drug to be the only intracellular anthracycline species, whereas analysis of AD 198-treated cultures revealed two fluorescent signals corresponding to the parent drug and its 14-deesterified biotransformation product,N-benzyladriamycin (AD 288). Levels of AD 288 rose from 2% of the total intracellular anthracycline content immediately on drug admixture to 61% following 24 h continuous drug exposure and to 69% at 24 h in cells exposed to drug for 1 h and then continued in drug-free media for 24 h. At all times, the balance of the intracellular anthracycline fluorescence was attributable to the parent drug; no ADR was detectable in AD 198-treated cells by either fluorescence detection or radioassay. Thus, AD 198 is not a prodrug form of ADR, and the in vitro effects of this agent, including the latent effects on cell-cycle inhibition and DNA damage seen in cells following short-term drug exposure, can be explained on the basis of the high levels of active parent drug and biotransformation product that accumulate and persist in the cells.Abbreviations ADR
adriamycin (doxorubicin)
- AD 198
N-benzyladriamycin-14-valerate
- AD 288
N-benzyladriamycin
- AD 32
N-trifluoroacetyladriamycin-14-valerate
- AD 143
N-trifluoroacetyladriamycin-14-0-hemiadipate
- AD 41
N-trifluoroacetyladriamycin
- [14C]-AD 198
[benzyl]--methylene-14C]-N-benzyladriamycin-14-valerate
- [14C]-ADR
[14-14C]-adriamycin
- HPLC
high-performance liquid chromatography
- TLC
thin-layer chromatography
- DMSO
dimethylsulfoxide
- S-MEM
Eagle's minimum essential medium for suspension culture
- PBS
phosphate-buffered saline (pH 7.0) 相似文献
106.
CD14, a lipopolysaccharide (LPS) receptor, is present on the surface membrane of phagocytic leukocytes; it is also present in a soluble form in serum. Recently published results confer to this molecule novel functions that are linked to T-cell activation and to apoptosis. We report here that we have defined and characterized a novel lymphocyte population in human peripheral blood, a population that expresses an intracellular antigen detectable with MO2, a monoclonal antibody directed against the human CD14 molecule. This population is composed primarily of CD8-positive T-cells. We found surprisingly that this novel MO2-positive population of lymphocytes was greatly enhanced in asymptomatic, untreated HIV-positive individuals. 相似文献
107.
Viral abrogation of lymphocyte mitogenesis: induction of a soluble factor inhibitory to cellular proliferation. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
PHA and Con A-driven mitogenesis of mouse C3H lymphocytes can be inhibited by co-incubation with a variety of different virus particles. These effects appear independent of infection, and can be obtained using UV-inactivated virus. Viruses may be added to spleen cell cultures as late as 46 h after co-incubation with mitogen, and still achieve significant inhibition of proliferative responsiveness. The described inhibition is apparently mediated, in part at least, by a soluble factor which is induced in splenic cultures following interaction with virus particles. This factor is apparently a product of macrophages. It does not posess interferon activity, but does have the ability to inhibit lectin- and alloantigen-driven mitogenesis, as measured in fresh cultures of splenic lymphocytes and in the mixed lymphocyte culture (MLC) reaction, respectively. Moreover, addition of virus to splenic cultures can apparently activate suppressor lymphocytes with the ability to inhibit proliferative responsiveness of fresh lymphocyte suspensions in the presence of Con A. 相似文献
108.
V Israel 《Virology》1967,33(2):317-322
109.
Celia I. Kaye Alice O. Martin Beverly R. Rollnick R. Rollnick Konrad Nagatoshi Jeannette Israel Mark Hermanoff Brad Tropea Joan T. Richtsmeier Newton E. Morton 《American journal of medical genetics. Part A》1992,43(6):913-917
Seventy-four families of probands with oculoauriculovertebral anomaly were evaluated, including 116 parents and 195 off-spring. Relatives were examined to identify ear malformations, mandibular anomalies, and other craniofacial abnormalities. For segregation analysis using POINTER, selection of the sample was consistent with single as-certainment. Different population liabilities were used for probands and relatives, because affection was narrowly defined for probands and broadly defined for relatives. The hypothesis of no genetic transmission was rejected. The evidence favored autosomal dominant inheritance; recessive and polygenic models were not distinguishable. © 1992 Wiley-Liss, Inc. 相似文献
110.
Tibor Hortobágyi Joseph A. Houmard Richard G. Israel John W. Carpenter Judy Heath Hisham A. Barakat 《European journal of applied physiology》1993,67(3):226-230
Summary The purpose of this study was to determine the effects of short-term exercise cessation on lipid and lipoprotein profile and insulin sensitivity in highly trained runners (n=12; mean age 19.9 years) and power athletes (n=12; mean age 24.4 years). Following 14 days of exercise cessation, running time to exhaustion and maximal oxygen uptake decreased by 9.2% and 4.8% (P < 0.05) in the runners, while in the power athletes one repetition maximum squat and bench press did not change (P>0.05). No changes occurred in body composition. Data from a 2-h oral glucose tolerance test revealed an impairment of the glycemic state in all athletes (P<0.05). In contrast, exercise cessation did not significantly (P>0.05) alter plasma levels of cholesterol, triglycerides, and low density (LDL) and high density lipoprotein (HDL). No changes were observed in HDL2, HDL2b, and HDL3 subfractions, LDL diameter, and qualitative LDL pattern (P>0.05). These data thus suggest that despite a decrease in insulin sensitivity, short-term exercise cessation, independent of exercise mode, was insufficient to alter plasma lipid and lipoprotein profiles in well-trained athletes. 相似文献