全文获取类型
收费全文 | 3261篇 |
免费 | 144篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 30篇 |
妇产科学 | 32篇 |
基础医学 | 375篇 |
口腔科学 | 41篇 |
临床医学 | 302篇 |
内科学 | 649篇 |
皮肤病学 | 45篇 |
神经病学 | 489篇 |
特种医学 | 106篇 |
外科学 | 674篇 |
综合类 | 31篇 |
预防医学 | 142篇 |
眼科学 | 34篇 |
药学 | 228篇 |
中国医学 | 4篇 |
肿瘤学 | 205篇 |
出版年
2021年 | 34篇 |
2020年 | 24篇 |
2019年 | 26篇 |
2018年 | 34篇 |
2017年 | 40篇 |
2016年 | 42篇 |
2015年 | 49篇 |
2014年 | 76篇 |
2013年 | 114篇 |
2012年 | 167篇 |
2011年 | 168篇 |
2010年 | 96篇 |
2009年 | 80篇 |
2008年 | 140篇 |
2007年 | 134篇 |
2006年 | 146篇 |
2005年 | 151篇 |
2004年 | 149篇 |
2003年 | 151篇 |
2002年 | 116篇 |
2001年 | 155篇 |
2000年 | 130篇 |
1999年 | 134篇 |
1998年 | 43篇 |
1997年 | 47篇 |
1996年 | 25篇 |
1995年 | 23篇 |
1994年 | 19篇 |
1993年 | 18篇 |
1992年 | 61篇 |
1991年 | 48篇 |
1990年 | 52篇 |
1989年 | 58篇 |
1988年 | 44篇 |
1987年 | 42篇 |
1986年 | 46篇 |
1985年 | 40篇 |
1984年 | 26篇 |
1983年 | 21篇 |
1982年 | 18篇 |
1981年 | 17篇 |
1979年 | 19篇 |
1978年 | 21篇 |
1977年 | 21篇 |
1976年 | 32篇 |
1975年 | 36篇 |
1974年 | 29篇 |
1973年 | 35篇 |
1972年 | 18篇 |
1971年 | 22篇 |
排序方式: 共有3422条查询结果,搜索用时 0 毫秒
11.
12.
Zusammenfassung Verglichen mit phänotypisch normalen Kontrolltieren fanden sich bei NMRI-Mäusen mit kongenitaler Thymusaplasie nur wenige Peyersche Plaques, die zudem nur aus diffusen Lymphocytenansammlungen bestanden. Auch die Milzfollikel waren erheblich verkleinert, wobei die periarteriolären Follikelbereiche gelegentlich zellärmer erschienen. Das wei\e Blutbild der thymuslosen Tiere war durch eine mä\ige Lymphopenie charakterisiert. Obwohl die Milzen der Mäuse mit kongenitaler Thymusaplasie keine Verringerung der Zahlen an präexistenten 19S-Hämolysin-bildenden Zellen aufweisen, waren nach Erstimmunisierung mit 4·108 Schaferythrocyten nur minimale Zahlen an 19S-Produzenten und 7 S-Produzenten nachweisbar. Die sekundäre antigene Stimulierung mit 4·108 Schaferythrocyten führte zu keiner nennenswerten Gedächtnisreaktion, was anzeigt, da\ die Bildung von Gedächtniszellen ein thymusabhängiger Proze\ ist. Die alleinige intraperitoneale Injektion abgetöteter Zellen von B. pertussis führte zu Hypersplenie, Leukozytose und Vermehrung der präexistenten Zahlen an 19S-Hämolysin-bildenden Zellen. Im Gegensatz zu Normaltieren, wo die Leukocytose durch eine Vermehrung von Granulocyten und Lymphocyten charakterisiert ist, fehlte bei den thymuslosen Tieren die Lymphocytenvermehrung. Der Zunahme der Blutgranulocyten entsprach eine verstärkte Granulopoese in Leber und Milz. Bei Normaltieren fand sich nach Erstimmunisierung durch simultane Applikation von 4·108 Schaferythrocyten und 3·109 abgetöteten Zellen vonB. pertussis eine verstärkte und verlängerte Produktion von 19S- und besonders 7S-Hämolysin-bildenden Zellen, verbunden mit einer verstärkten Präparation des lymphoretikulären Gewebes für die anamnestische Reaktion. Bei den Mäusen mit kongenitaler Thymusaplasie beschränkte sich der Adjuvanseffekt allem auf die Frühphase der immunologischen Primärreaktion, was seinen Ausdruck in einer deutlichen Vermehrung der 19S-Produzenten und einer nur geringgradigen Vermehrung der 7S-Produzenten fand.
Diese Arbeit wurde durch die Deutsche Forschungsgemeinschaft gefördert. 相似文献
Influence ofBordetella pertussis on the lymphatic tissue of miceVIII. The influence ofBordetella pertussis on the primary and secondary immune potential of thymusless (nude) mice
As compared to phenotypically normal controls, in the intestine of NMRI mice with congenital aplasia of the thymus (nude) only small numbers of Peyer's patches could be detected, which consisted of relatively diffuse accumulations of lymphocytes. The splenic follicles were likewise considerably reduced in size, whereby the thymus-dependent areas occasionally appeared to be deficient in lymphocytes. Furthermore, the thymusless mice were found to have blood lymphopenia. Although the spleens of nude mice contained rather enhanced numbers of pre-existing 19S hemolysin forming cells, only small numbers of 19S producers and very poor numbers of 7S hemolysin-forming spleen cells were demonstrable after the primary immunization with 4·108 sheep erythrocytes. Secondary antigenic stimulation with an equal dose of the erythrocyte antigen did not result in a noteworthy secondary immune response. This evidently indicates that the production of memory cells is a thymus-dependent process. A single intraperitoneal injection of 3·109 pertussis organisms led to splenomegaly, blood leukocytosis and augmentation of the pre-existing 19S hemolysin-forming spleen cells. Whilst in normal controls the blood leukocytosis was found to be due to an increase in both lymphocytes and granulocytes, in nude mice the leukocytosis was solely caused by the increase in granulocytes, this being associated with increased granulopoiesis in spleen and liver. The primary immunization of normal controls with 4·108 sheep erythrocytes and 3·109 pertussis organisms led to an increased and prolonged development of both 19S and 7S hemolysin-producing spleen cells. Furthermore, the bacterial adjuvant increased the process of priming for the secondary immune response. Unlike to this, in mice with congenital aplasia of the thymus adjuvancy of pertussis organisms was restricted to the early phase of the primary immune response, as is documented by the distinct augmentation of 19S producers and a poor increase in the numbers of 7S hemolysin-forming spleen cells.
Diese Arbeit wurde durch die Deutsche Forschungsgemeinschaft gefördert. 相似文献
13.
Growth inhibition and transformation of a human fetal tracheal epithelial cell line by long-term exposure to diethylnitrosamine 总被引:2,自引:0,他引:2
In order to obtain more information on the in vitro transformationof human cells, a human fetal tracheal epithelial cell line(FHET16/5) was exposed for a long time to diethylnitrosamine(DEN). In 20 passages, this cell line (diploid, male) maintainedstrong immunohistochemical reactivity for carcino-embryonnicantigen and wool merokeratin; it was negative for vimentin.The cells contained PAS-positive mucous substances and ultrastructurallywere found to have desmosomelike attachments. Treatment of thecells was with 0.3% dimethyl sulphoxide (DMSO), or DMSO with150, 450, 1000 or 2000 µg/ml of DEN. It was started atthe ninth passage and continued for six passages over 9 weeksfor the control (DMSO) and the three lowest control doses ofDEN, and for three passages over 9 weeks for the 2000 µg/mlDEN group. Cells grown for 13 days after the end of treatmentwere plated in soft agar and injected subcutaneously in nudemice. The frequency of anchorage-independent colonies grownin soft agar was directly related to DEN dose. Colony-formingefficiency, as an expression of toxic effect, was also dosedependent. Autoradiographically detected unscheduled DNA synthesisindicated an association between anchorage-independent transformationand DNA alterations induced by DEN. Cells injected into nudemice did not produce tumours during a 6-month period, but invasivenesswas observed when cells from the 2000 µg/ml DEN groupwere transplanted on the dermis of cultured chick embryo skin.The results indicate that DEN causes anchorage-independent transformationaccompanied by unscheduled DNA synthesis in a fetal human trachealepithelial cell line. 相似文献
14.
Variations of core-temperature rhythms occurring during a "normal" day (24-hour period without extraordinary challenges for organism) were studied in 5 male sheep. To record the influence of the metabolic processes in different organic systems, core temperatures were measured at various locations at the same time. To minimise any influences due to measurement or behavior (e.g., effects of isolation), a telemetric system was used for registration and animals were kept without restraint in their habitual herd. Particularly biphasic circadian rhythms were found, and feeding schedule as zeitgeber is discussed. Beyond that, independent from point of measurement short-time rhythms with wavelengths of 140 and 90 min were found. Therefore, an origin in the central nervous system can be supposed. Rhythms with wavelengths of 3 hours, 75 min and 1 hour were not stable throughout a whole 24-hour period and did not occur at all measurement points in the same intensity. A comparison of anatomical placements of the various measurement points leads to the realization of distinct organic functions as sources for these rhythms. 相似文献
15.
The adjuvant disease of the rat is an experimental disease, not only important as an arthritis model, but also as an "urethritis model" in clinical and therapeutical respects. The polyarthritic syndrome in rats following injection of Freund's adjuvant also shows regularly involvement of the genitourinary system. Urethritis, cavernitis, and balanitis are common inflammatory manifestations of the penis, which can mostly be observed. In the peritesticular and periepididymal fat, granulomata and nonspecific inflammatory reactions do occur. Prostata, bladder, kidneys, testes, and epididymis are seldom involved in the inflammatory process. This therapeutical study demonstrated clearly that acetylsalicylic acid (dosage: 80 mg/kg BW/day) cannot be of benefit for these changes. However, it was possible to significantly influence the inflammatory changes by using prednisolone (dosage: 1.5 mg/kg BW/day). 相似文献
16.
Matching patients with etiologically distinct but clinically overlapping cognitive disorders on performance of a regionally specific neuropsychological task is a novel and potentially powerful approach to highlighting differences in the pathophysiological mechanisms of impaired cognition. We used this strategy to compare patients with Huntington's disease (HD) and schizophrenia (SC), disorders that share similarities in cognitive impairment. Patients were matched on the basis of performance on the Wisconsin Card Sorting test of "prefrontal" function, after which neuropsychological test data and regional cerebral blood flow data were determined while patients who performed the Wisconsin Card Sorting test were examined. Patients with HD performed worse on visuospatial tasks and recall memory than did patients with SC, although Wechsler Adult Intelligence Scales-Revised IQ and Wechsler Memory Scale memory quotients were equivalent. These differences could not be attributed to differences on the index task, the Wisconsin Card Sorting Test. Patients with HD and SC exhibited a double dissociation in regional cerebral blood flow. The patients with SC had relatively low frontal and high parietal flows, while patients with HD exhibited the reverse of this pattern. Thus, the regional cerebral blood flow and neuropsychological findings in this study appeared to demonstrate that the single final common cognitive impairment of executive function in HD and SC is associated with two markedly dissimilar pathophysiological states. 相似文献
17.
The Flow-Fluorescence Cytometric Method (FCM) was applied to investigate the DNA content and the ploidy outlines of each of 96 glioblastomas. No specific DNA pattern was detected, possibly because of the tangle morphology of these variable tumors. Due to their capricious growth the DNA distribution proved to fluctuate greatly. Thus, the series, arranged according to increased PI (proliferation index) values, exhibited a wide spread within a total range from 7.1–97.15% (mean 39.3%) PI. A threefold subdivision of main types (I–III) appears to be of practical use for clinical prognostic assessment: diploid tumors with a PI range up to 10% (N=7) are followed by abnormal chiefly tretra- and hyper-tetraploid tumors up to PI values about 30% (N=21). The third category includes cases showing excessive aneuploidy combined more and more with polyploidy and valid stemlines, up to the PI maximum of about 97 rel.% (N=68). Thus, in 89 tumors clear pathological changes of DNA content can be decoded; of these 68 (76.4%) express a considerable aneuploidy and polyploidy respectively.Dedicated to Prof. Dr. HJ Bauer for his 75th birthday, March 31, 1989 相似文献
18.
Batalden PB Mohr JJ Nelson EC Plume SK Baker GR Wasson JH Stoltz PK Splaine ME Wisniewski JJ 《Quality management in health care》1997,5(3):41-51
Today's primary care provider faces the challenge of caring for individual patients as well as caring for populations of patients. This article offers a model--the panel management process--for understanding and managing these activities and relationships. The model integrates some of the lessons learned during the past decade as we have worked to gain an understanding of the continual improvement of health care after we have understood that care as a process and system. 相似文献
19.
20.
Walther T Falk V Schneider J Walther C Mohr FW 《The Annals of thoracic surgery》1999,68(5):1858-9; discussion 1860
Stentless tricuspid valve replacement was performed in a 21-year-old patient with severe destructive tricuspid valve endocarditis resistant to medical therapy. Postoperative recovery was uneventful. Stentless atrioventricular valves are considered an additional treatment option besides stented valves or homograft implantations for severe right-sided endocarditis. Transvalvular hemodynamics are excellent, and right ventricular function can be preserved by suspending the valve at the papillary muscles. 相似文献