全文获取类型
收费全文 | 22592篇 |
免费 | 1021篇 |
国内免费 | 169篇 |
专业分类
耳鼻咽喉 | 275篇 |
儿科学 | 387篇 |
妇产科学 | 344篇 |
基础医学 | 3357篇 |
口腔科学 | 365篇 |
临床医学 | 1979篇 |
内科学 | 4224篇 |
皮肤病学 | 718篇 |
神经病学 | 2837篇 |
特种医学 | 1252篇 |
外科学 | 2923篇 |
综合类 | 155篇 |
一般理论 | 6篇 |
预防医学 | 970篇 |
眼科学 | 507篇 |
药学 | 1767篇 |
中国医学 | 28篇 |
肿瘤学 | 1688篇 |
出版年
2023年 | 95篇 |
2022年 | 156篇 |
2021年 | 280篇 |
2020年 | 235篇 |
2019年 | 283篇 |
2018年 | 383篇 |
2017年 | 300篇 |
2016年 | 428篇 |
2015年 | 479篇 |
2014年 | 663篇 |
2013年 | 825篇 |
2012年 | 1315篇 |
2011年 | 1389篇 |
2010年 | 796篇 |
2009年 | 803篇 |
2008年 | 1466篇 |
2007年 | 1522篇 |
2006年 | 1586篇 |
2005年 | 1599篇 |
2004年 | 1463篇 |
2003年 | 1495篇 |
2002年 | 1424篇 |
2001年 | 283篇 |
2000年 | 243篇 |
1999年 | 321篇 |
1998年 | 335篇 |
1997年 | 278篇 |
1996年 | 221篇 |
1995年 | 179篇 |
1994年 | 202篇 |
1993年 | 155篇 |
1992年 | 130篇 |
1991年 | 134篇 |
1990年 | 124篇 |
1989年 | 105篇 |
1988年 | 107篇 |
1987年 | 76篇 |
1986年 | 84篇 |
1985年 | 86篇 |
1984年 | 92篇 |
1983年 | 88篇 |
1982年 | 88篇 |
1981年 | 98篇 |
1980年 | 77篇 |
1979年 | 73篇 |
1978年 | 53篇 |
1977年 | 69篇 |
1976年 | 69篇 |
1974年 | 61篇 |
1955年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Hoschek Stefan Hoschek-Risslegger Ursula Fiegl Michael Zabernigg August Pall Georg Auberger Thomas Gunsilius Eberhard Schmid Thomas Jamnig Herbert Hilbe Wolfgang 《Wiener Medizinische Wochenschrift》2007,157(21):562-568
Wiener Medizinische Wochenschrift - Aggressives Tumorwachstum, frühe Metastasierung und hohe Assoziation mit intensivem Nikotinkonsum sind die Charakteristika des kleinzelligen... 相似文献
92.
K. Mörike M. Koch Peter Fritz Wolfgang Urban Michel Eichelbaum 《Archives of toxicology》1996,70(5):300-305
In the pathogenesis of isoniazid-induced hepatic injury, cytochrome P450-dependent metabolic activation of the metabolite,
acetylhydrazine (AcHz), is the crucial step. Exhalation of [14C]-carbon dioxide has previously been used to quantify indirectly this pathway. In contrast, according to the current concept
of AcHz bioactivation, molecular nitrogen is produced directly, but has not yet been identified. Here, we measured [15N]-nitrogen and 14CO2 exhalation, after the administration of [15N2]-[14C]-AcHz, in rats. Laser magnetic resonance (LMR) spectroscopy, a new sensitive and specific technique for the measurement
of 15N and 14N in gas samples, was used. To demonstrate the involvement of cytochrome P450, rats were treated with phenobarbital (PB) or
PB + cobalt(II) chloride (CoCl2) (n=3 in each group). Time-dependent 15N2 exhalation differed significantly between treatment groups (p<0.001). At 240 min, cumulative exhalation of 15N was 1.92±0.43% (mean±SE) of the dose in the control group, 2.53±0.23% in the PB group, and 1.00±0.15% in the PB+CoCl2 group (p<0.05 compared to controls, p<0.01 compared to PB). Cumulative exhalation of 14CO2 in 24 h ranged from 15.1 to 21.9%, with no significant difference between treatment groups. In conclusion, N2 is a metabolite of AcHz. N2 formation reflects the cytochrome P450-mediated activation of AcHz and can be used as an index of this pathway. Generally,
LMR spectroscopy is valuable for monitoring any N2-liberating process in vivo.
Received: 14 March 1995/Accepted: 15 August 1995 相似文献
93.
94.
Klaus-Dietmar Merboldt Gunnar Krüger Wolfgang Hnicke Andreas Kleinschmidt Jens Frahm 《Magnetic resonance in medicine》1995,34(4):639-644
Functional mapping of human brain activation has been accomplished at high spatial and temporal resolution (voxel size 4.9 μl, temporal increment 100 ms). The approach was based on oxygenation-sensitive long-echo time FLASH MRI sequences synchronized to multiply repeated cycles of visual stimulation in a CINE acquisition mode. This high temporal resolution revealed that stimulus-related signal intensity changes in human visual cortex display an initial latency followed by increases extending over several seconds. Furthermore, the temporal characteristics of the complete CINE MRI signal time course depended on the absolute and relative durations of activation and control periods and, for example, caused an apparent absence of a poststimulation “undershoot” phenomenon. Complementing hyperoxygenation due to rapid hemodynamic adjustments, these results suggest signal intensity modulation by enhanced oxygen consumption and concomitant deoxygenation during prolonged and/or repetitive stimulation. 相似文献
95.
Zhao Canxi Wu Yan Lei Ying Ruan Heqiu Wolfgang Voelter Albrecht Jung Miriam Schick 《华中科技大学学报(医学英德文版)》1996,16(4):203-204
Zusammenfassung Die Wirkung des ?thylazetatextraktes von Chrysanthemum morifolium auf P. falciparum wurde in vitro untersucht. W?hrend sich
die Parasit?mie bei der Kontrollgruppe bis zu 10. 90 % entwickelte, wurde bei dem mit ?thylazetatextrakt in einer Konzentration
von 100 μg/ml Medium am 5. Tag der Kultur eine signifikante Hemmwirkung auf die Parasiten beobachtet. Die Parasit?mie blieb
bei 1. 00 %.
Diese Arbeit wurde durch die Stiftung von “National Nature Science Foundation of China” finanziert (No. 39260066) 相似文献
96.
97.
Michael Fromm Wolfgang E. Berdel Hans D. Schick Susanne Danhauser-Riedl Ulrich Fink Wolfgang Remy Anneliese Reichert Anke Ankele Heinz W. Präuer Jörg R. Siewert Johann Rastetter 《Investigational new drugs》1988,6(3):189-194
Summary Carbetimer, a new synthetic low molecular weight polyelectrolyte with a novel structure displayed antitumor activiy in a number of animal tumor model systems and in vitro investigations. Based on these findings it was brought to a phase I clinical trial in patients with advanced malignant disease after failure of conventional treatment or with no conventional treatment available. Forty-eight patients received 98 courses. The schedule was a one hour i.v. infusion every four weeks. The starting dose was 180 mg/m2 and dose escalation was performed according to a modified Fibonacci formula up to 16,690 mg/m2. At least three patients were treated at each dose level and each patient was eligible to receive repeat courses at the same dose, until progressive disease or dose-limiting toxicity intervened. No hematological toxicity was encountered. Some adverse effects such as reversible proteinuria, hypercalcaemia, pain at infusion site, nausea and vomiting and fatigue were seen partly in a dose-related manner but did not represent the maximum tolerated dose (MTD). The limiting toxicity at the highest dose level of 16,690 mg/m2 consisted of ocular symptoms (light flashes) accompanied by a modest decrease of blood pressure and nausea or vomiting during a one hour infusion. 16,690 mg/m2/1 hour was considered the MTD. There were four deaths on study, all considered diseaserelated. Fourteen patients had stable disease for more than two courses, which, however, could also be explained by the natural course of disease. No clear-cut antitumor responses were noted in our study center.The recommended dose for phase II trials derived from our results is 12,550 mg/m2/2 hours. However, with regard to experiences in other phase I studies, the subsequent phase II studies will be performed with a dose of 6,500 mg/m2. 相似文献
98.
An avidin–biotin enzyme-linked immunosorbent assay (ELISA) is described for h-endorphin (h-EP). Microtiter plates coated with commercially available antibodies were used together with h-EP tracer derivatives that were biotinylated in positions 24, 28, and 29 via a C6 spacer arm. Nonspecific binding of biotinylated derivatives to the microtiter plates was blocked with a mixture of 1% casein and 10% ethanolamine in 0.1 M NaHCO3. A sequential saturation procedure using a high-affinity antiserum in combination with an avidin–alkaline phosphatase complex matched the sensitivity of reported radioimmunoassays (RIAs), with a detection limit of 0.5 fmol/assay. The intra- and interassay coefficients of variation were 5 and 12%, respectively. Results obtained by ELISA and RIA showed good correlations (r = 0.95). The -EP concentration in extracted rat plasma after high-performance liquid chromatographic (HPLC) fractionation was determined by this method to be 1600 fmol/ml. 相似文献
99.
Dr Jonas Hähnel MD Wolfgang Friesdorf MD Bernhard Schwilk MD Thomas Marx MD Silvia Blessing 《Journal of clinical monitoring and computing》1992,8(1):1-6
The technical equipment of today's intensive care unit (ICU) workstation has been characterized by a gradual, incremental accumulation of individual devices, whose presence is dictated by patient needs. These devices usually present differently designed controls, operate under different alarm philosophies, and cannot communicate with each other. By contrast, ICU workstations could be equipped permanently and in a standardized manner with electronically linked modules if the attending physicians could reliably predict, at the time of admission, the patient's equipment needs. Over a period of 3 1/2 months, the doctors working in our 20-bed surgical ICU made 1,000 predictions concerning outcome, equipment need, duration of artificial ventilation, and duration of hospitalization for 300 recently admitted patients. The interviews were made within the first 24 hours after admission. The doctors being interviewed were usually (i.e., in over 90% of cases) unfamiliar with the patient. Information concerning the patient's general state of health, special pre-ICU events, and complications was offered to the interviewed clinician because this information represents standard admission data. It was found that the equipment need (represented by two different setups, high tech and low tech) could be predicted most reliably (96.4% correct predictions) compared with a prediction on outcome of ICU treatment (94.5%), on duration of artificial ventilation (75.4%), and on duration of stay (43.4%). There was no significant (p>0.05) difference in the reliability of predictions between residents and consultants. Factors influencing the postoperative equipment need varied with surgical specialty. The general state of health, as indicated by the ASA classification (p<0.001), and the specific intervention (all multiple-valve replacements needed the high-level equipment standard) appeared to be most important in cardiac surgery, while a state of septicemia was important in general surgery (p<0.001). Our findings suggest that ICU workstations may be standardized into at least two types. 相似文献
100.
The "tension reduction hypothesis" of ethanol was investigated with respect to stress- and ethanol-induced changes of plasma catecholamines and their relations to changes in emotional state and performance. Twenty-two healthy male volunteers were tested under the influence of 0.8 g/kg ethanol and compared to 22 matched controls receiving a placebo drink. Stress was induced by mental arithmetic applied prior to and 45 min after fluid consumption. Plasma epinephrine (E) and norepinephrine (NE) obtained from an indwelling cannula inserted 50 min prior to stress application were determined prior to and after each stress session. Percentage changes were compared within and between groups and correlated with respective changes of emotional states and performance in mental arithmetic. While ethanol decreased performance and stress-related emotional arousal, it did not affect stress-induced changes in plasma catecholamines. Rather, the fluid (ethanol as well as placebo) increased NE levels. Emotional tension reduction was associated with low resting or average levels of E in the placebo group but this relationship was disrupted by ethanol. High NE resting levels and drink induced increases predicted emotional tension reduction with placebo but an increase in stress induced depression with alcohol. "Biochemical tension reduction" (represented by both reduced E and NE stress response) may be predicted from generally lower levels of activation and elation by alcohol but not with the placebo condition. Although performance was positively related to low NE resting levels and stress responses, no influence of alcohol on this relationship was observed.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献