全文获取类型
收费全文 | 33139篇 |
免费 | 1747篇 |
国内免费 | 147篇 |
专业分类
耳鼻咽喉 | 350篇 |
儿科学 | 737篇 |
妇产科学 | 581篇 |
基础医学 | 6280篇 |
口腔科学 | 743篇 |
临床医学 | 2618篇 |
内科学 | 6272篇 |
皮肤病学 | 854篇 |
神经病学 | 3405篇 |
特种医学 | 1424篇 |
外科学 | 4591篇 |
综合类 | 151篇 |
一般理论 | 14篇 |
预防医学 | 1660篇 |
眼科学 | 721篇 |
药学 | 2320篇 |
中国医学 | 21篇 |
肿瘤学 | 2291篇 |
出版年
2022年 | 161篇 |
2021年 | 345篇 |
2020年 | 294篇 |
2019年 | 489篇 |
2018年 | 571篇 |
2017年 | 439篇 |
2016年 | 564篇 |
2015年 | 654篇 |
2014年 | 783篇 |
2013年 | 1174篇 |
2012年 | 1628篇 |
2011年 | 1750篇 |
2010年 | 1178篇 |
2009年 | 1127篇 |
2008年 | 1885篇 |
2007年 | 1926篇 |
2006年 | 1795篇 |
2005年 | 1920篇 |
2004年 | 1796篇 |
2003年 | 1763篇 |
2002年 | 1843篇 |
2001年 | 347篇 |
2000年 | 270篇 |
1999年 | 394篇 |
1998年 | 503篇 |
1997年 | 413篇 |
1996年 | 368篇 |
1995年 | 337篇 |
1994年 | 289篇 |
1993年 | 258篇 |
1992年 | 209篇 |
1991年 | 204篇 |
1990年 | 170篇 |
1989年 | 161篇 |
1988年 | 169篇 |
1985年 | 157篇 |
1984年 | 181篇 |
1983年 | 161篇 |
1982年 | 198篇 |
1981年 | 169篇 |
1978年 | 135篇 |
1933年 | 170篇 |
1932年 | 180篇 |
1931年 | 167篇 |
1930年 | 169篇 |
1929年 | 147篇 |
1928年 | 163篇 |
1927年 | 144篇 |
1926年 | 158篇 |
1925年 | 139篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
Azra Raza Harvey D. Preisler Ya Qin Li Richard A. Larson Jack Goldberg George Browman John Bennett Hans Grunwald Ralph Vogler Cathi Kukla 《American journal of hematology》1993,42(4):359-366
A pilot study was conducted of the biological characteristics of the leukemia cells of newly diagnosed patients with poor prognosis acute myelogenous leukemia (AML). This study included measurements of the pretherapy proliferative rate of the leukemia cells in vivo, assessment of differentiation in vivo during remission induction therapy, and the level of expression of the fms, myc, and IL1β genes in pretherapy leukemia cells. Short cell cycle times were characteristic of the best prognostic category and were associated with a rapid reduction in marrow leukemia cells in cytosine arabinoside (araC)-sensitive patients. Expression of c-fms was associated with rapid reduction in marrow leukemia cells during araC therapy and with a successful treatment outcome. Expression of the IL1β gene was associated with short remissions. These studies suggest that when compared to newly diagnosed standard prognosis AML, the leukemia of poor prognosis patients is more likely to exhibit long cell cycle times, low levels of fms expression, and is less likely to be associated with myeloid differentiation during remission induction therapy. © 1993 Wiley-Liss, Inc. 相似文献
94.
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
95.
Pleural mesotheliomas and asbestos exposure in the pulp and paper industries: a new risk group identified by linkage of official registers 总被引:4,自引:0,他引:4
Bengt Jrvholm Hans Malker Birgitta Malker Jan Ericsson Gerd Sllsten 《American journal of industrial medicine》1988,13(5):561-567
Analysis of data obtained by linking the 1960 Swedish Census and the Swedish Cancer Registry has demonstrated an increased risk of pleural mesothelioma among pulp and paper workers. The present study was undertaken with the aim of revealing possible environmental risk factors. The work histories of the 25 cases identified earlier were reviewed. "Certain" or "probable" exposure to asbestos was found among 70% of these workers. The study illustrates how linkage of official registers can be used to identify new risk environments and encourage the establishment of preventive measures. 相似文献
96.
A 1975 report stated that a schizophrenic genotype may be manifested in infants by a neurointegrative defect called pandysmaturation. Recent evidence supports this: (1) 12 studies found delayed development in schizophrenics' infants and in preschizophrenics; (2) "blind" psychometric evaluations favored an adult schizotypal disorder in four to six of seven high-risk subjects with pandysmaturation in the New York study; and (3) finally, in a partial replication of this method using the Jerusalem data, blind diagnoses of "probable" and "possible" pandysmaturation were significantly related to a parental diagnosis of schizophrenia and to cognitive and motor neurointegrative deficits at 10 years. Obstetrical complications were unrelated to diagnosis, pandysmaturation, or outcome in the overall sample. However, we found a small subgroup of schizophrenic offspring in whom the most severe motor deficits at follow-up were related to obstetrical complications, pandysmaturation, and low birth weight. 相似文献
97.
98.
Individual differences in adult human sleep and wakefulness: Leitmotif for a research agenda 总被引:9,自引:0,他引:9
This paper reviews the literature on interindividual variability in human sleep parameters, sleepiness, responses to sleep deprivation, and manifestations of sleep disorders. Variability among individuals in sleep/wake biology and behavior is pervasive. The magnitude of such individual differences is often considerable and comparable to the effect sizes of many experimental and clinical interventions. Evidence is accumulating that certain aspects of sleep/wake-related variability--such as sleep duration, daytime sleepiness, and vulnerability to the effects of sleep loss--involve trait characteristics in healthy populations and among sleep-disordered patients. Establishing the trait-specific nature of variability in sleep/wake parameters is a prerequisite for elucidating the corresponding neurophysiologic and/or genetic mechanisms. At present, it remains largely unknown what underlies or predicts sleep/wake-related traits, what relationships these traits may have to each other, and what functional significance may be associated with specific traits. Scientific studies addressing these issues are warranted, as understanding the basis of trait variability may yield new insights into sleep/wake regulation and sleep pathology. Understanding individual differences in sleep and wakefulness may also have provocative but important implications for health economics and clinical care, as well as for safety, productivity, and general well-being. This paper gives suggestions for a research agenda focusing on individual differences in sleep research and sleep medicine. 相似文献
99.
Polontchouk LO Valiunas V Haefliger JA Eppenberger HM Weingart R 《Pflügers Archiv : European journal of physiology》2002,443(5-6):676-689
Gap junctions were assayed during re-differentiation of adult rat cardiomyocytes in long-term culture to gain insight into the processes of remodeling. Double immunostaining allowed the localization of connexins Cx40, Cx43, and Cx45 between myocytes and demonstrated co-expression and co-localization in individual cells and gap junction plaques, respectively. Immunoblots showed differential time-dependent changes in connexin expression and phosphorylation. The total amount of connexins and the ratio of phosphorylated/non-phosphorylated isoforms gradually increased during the re-establishment of intercellular communication. Dual voltage-clamp studies showed the involvement of several types of gap junction channels. Multichannel currents yielded diverse spectra of g(j,inst)=f( V(j)) and g(j,ss)=f( V(j)) relationships ( g(j,inst): instantaneous gap junction conductance; g(j,ss): conductance at steady state; V(j): transjunctional voltage), indicative of homotypic and heterotypic channels. Single-channel currents revealed two prominent conductances reflecting gamma(j,main) and gamma(j,residual). The histograms of gamma(j,main) showed four discrete peaks (41-44, 59-61, 70-76, and 100-107 pS) attributable to a combination of Cx45-Cx45, Cx40-Cx45 and Cx43-Cx45 channels (1st peak), Cx43-Cx43 and Cx40-Cx43 channels (2nd peak), Cx43-Cx43 channels (3rd peak) and Cx40-Cx40 and Cx40-Cx43 channels (4th peak). However, the presence of heteromeric channels cannot be excluded. The data are consistent with an up-regulation of Cx45 and Cx43 during re-differentiation. 相似文献
100.
Zusammenfassung Das gesunde Neugeborene bildet seinen eigenen Haptoglobintyp innerhalb der 1. Lebenswoche aus. Unreife (Frühgeborene) und starke Hämolyse können das Auftreten verzögern. Am Ende des 3. Monats war der eigene Typ bei allen untersuchten Säuglingen (865) nachweisbar. 相似文献