全文获取类型
收费全文 | 991篇 |
免费 | 44篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 43篇 |
妇产科学 | 16篇 |
基础医学 | 134篇 |
口腔科学 | 15篇 |
临床医学 | 67篇 |
内科学 | 199篇 |
皮肤病学 | 16篇 |
神经病学 | 20篇 |
特种医学 | 160篇 |
外科学 | 72篇 |
综合类 | 127篇 |
预防医学 | 40篇 |
眼科学 | 1篇 |
药学 | 109篇 |
1篇 | |
中国医学 | 2篇 |
肿瘤学 | 40篇 |
出版年
2023年 | 7篇 |
2021年 | 11篇 |
2020年 | 6篇 |
2018年 | 12篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 6篇 |
2014年 | 20篇 |
2013年 | 28篇 |
2012年 | 35篇 |
2011年 | 23篇 |
2010年 | 29篇 |
2009年 | 36篇 |
2008年 | 36篇 |
2007年 | 41篇 |
2006年 | 30篇 |
2005年 | 25篇 |
2004年 | 27篇 |
2003年 | 20篇 |
2002年 | 20篇 |
2001年 | 26篇 |
2000年 | 21篇 |
1999年 | 26篇 |
1998年 | 43篇 |
1997年 | 42篇 |
1996年 | 42篇 |
1995年 | 28篇 |
1994年 | 23篇 |
1993年 | 23篇 |
1992年 | 28篇 |
1991年 | 22篇 |
1990年 | 29篇 |
1989年 | 31篇 |
1988年 | 27篇 |
1987年 | 26篇 |
1986年 | 31篇 |
1985年 | 20篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 17篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1978年 | 8篇 |
1977年 | 10篇 |
1976年 | 10篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1973年 | 6篇 |
1967年 | 5篇 |
1966年 | 5篇 |
排序方式: 共有1063条查询结果,搜索用时 187 毫秒
11.
12.
13.
14.
0 引言 人类免疫缺陷病毒 (human immunodeficiencyvirus,HIV) - 1编码的反式激活蛋白 TAT具有独特的跨膜运转方式 ,而且有转导速度快 ,效率高的特点 ,被称为蛋白转导结构域 (protein transduction domain,PTD) [1 ,2 ] .本研究用PCR扩增了慢性粒细胞白血病慢粒 bcr/ abl融合蛋白的基因片段 ,在其 5′端融合 PTD结构域的编码区后在大肠杆菌中进行了表达 .表达产物经纯化后 ,加入培养的 HL 6 0细胞 ,表达的蛋白可直接进入细胞内 .这一结果为用外源蛋白负载(L oading)免疫细胞提供了新的途径 .1 材料和方法1.1 DNA重组 人工合… 相似文献
15.
Serotonergic mediation of the effects of fluoxetine, but not desipramine, in the rat forced swimming test 总被引:3,自引:3,他引:0
Rationale: The forced swimming test (FST) is a behavioral test in rodents that predicts the clinical efficacy of many types of antidepressant
treatments. Recently, a behavior sampling technique was developed that scores individual response categories, including swimming,
climbing and immobility. Although all antidepressant drugs reduce immobility in the FST, at least two distinct active behavioral
patterns are produced by pharmacologically selective antidepressant drugs. Serotonin-selective reuptake inhibitors increase
swimming behavior, while drugs acting primarily to increase extracellular levels of norepinephrine or dopamine increase climbing
behavior. Distinct patterns of active behaviors in the FST may be mediated by distinct neurotransmitters, but this has not
been shown directly. Objectives: The present study examined the role of serotonin in mediating active behaviors in the forced swimming test after treatment
with two antidepressant drugs, the selective serotonin reuptake inhibitor, fluoxetine and the selective norepinephrine reuptake
inhibitor, desipramine. Methods: Endogenous serotonin was depleted by administering para-cholorophenylalanine (PCPA, 150 mg/kg, IP.) to rats 72 h and 48 h
prior to the swim test. Fluoxetine (10 mg/kg, SC) or desipramine (10 mg/kg, SC) was given three times over a 24-h period prior
to the FST. Behavioral responses, including immobility, swimming and climbing, were counted during the 5-min test. Results: Pretreatment with PCPA blocked fluoxetine-induced reduction in immobility and increase in swimming behavior during the FST.
In contrast, PCPA pretreatment did not interfere with the ability of desipramine to reduce immobility and increase climbing
behavior. Conclusions: Depletion of serotonin prevented the behavioral effects of the selective serotonin reuptake inhibitor fluoxetine in the rat
FST. Furthermore, depletion of serotonin had no impact on the behavioral effects induced by the selective norepinephrine reuptake
inhibitor, desipramine. The effects of antidepressant drugs on FST-induced immobility may be exerted by distinguishable contributions
from different neurotransmitter systems.
Received: 4 February 1999 / Final version: 2 June 1999 相似文献
16.
目的观察小分割分次立体定向放射治疗(fractionated stereotatic radiation therapy,FSRT)脑转移瘤的近期疗效.方法15例病人单纯全脑外照射(WBRT组),中间平面剂量20~40Gy/10~20次/2~4周.17例病人接受FSRT(FSRT组),每次分次剂量为2.5~3.0Gy.其中11病人行单纯FSRT,中心总剂量为30~60Gy/1 0~20次/2~4周;6例病人先行WBRT,然后行FSRT,中心总剂量为46~60Gy/5~6周.结果KSP评分增加10分以上者,WBRT组为5 3.3%,FSRT组为82.4%.(P<0.05).WBRT组有效率(CR PR)为50.0%;FSRT组有效率(CR PR)为80.0%.中位生存率:WBRT组为3.5月,FSRT组为10.0月.结论FSRT能有效地控制脑转移瘤,减轻神经系统症状,提高生存质量,延长病人生存期,而没有增加副作用,值得临床推广应用. 相似文献
17.
We compared the tumor-initiating activities toward mouse skin of two
structurally related polycyclic aromatic hydrocarbon diol epoxides: racemic
anti-1,2,3,4-tetrahydro-5,6-dimethylchrysene-1,2-diol-3,4- epoxide
(5,6-diMeCDE) and racemic anti-1,2,3,4-tetrahydro-5-
methylchrysene-1,2-diol-3,4-epoxide (5-MeCDE). Tumors induced by these diol
epoxides were analysed for mutations in the Ha-ras gene. 5,6- diMeCDE is
derived from the non-planar parent compound 5,6- dimethylchrysene, and
reacts to approximately equal extents with dA and dG in DNA, whereas
5-MeCDE is derived from a nearly planar parent compound, 5-methylchrysene,
and reacts mainly with dG in DNA. 5,6- diMeCDE, at initiating doses of 33,
100 or 400 nmol per mouse, induced 1.2, 2.2 and 6.2 skin tumors per mouse,
respectively. It was significantly less tumorigenic than 5-MeCDE which
induced 3.1, 7.5 and 9.1 skin tumors per mouse at the same doses. Tumors
induced by 5,6- diMeCDE had a large number of CAA-->CTA mutations in
codon 61 of the Ha- ras gene: 50, 55 and 75% of the tumors analysed had
this mutation at the 33, 100 and 400 nmol doses. No mutations were found in
codons 12 and 13 in the tumors induced by 5,6-diMeCDE. In contrast,
CAA-->CTA mutations in codon 61 were rarely seen in tumors induced by
5-MeCDE. At the highest dose of 5-MeCDE, 20% of the tumors analysed had
mutations at G of codons 12 and 13. The results of this comparative study
support the hypothesis that mutations in the Ha-ras gene in mouse skin
tumors induced by PAH diol epoxides occur as a result of their direct
reaction with the gene. However, pathways other than the commonly observed
Ha- ras codon 61 mutations are clearly important in mouse skin
tumorigenesis by these diol epoxides.
相似文献
18.
H O Goyal T D Braden C S Williams P Dalvi M Mansour J W Williams 《Toxicological sciences》2005,87(1):242-254
We previously reported that diethylstilbestrol (DES) or estradiol valerate (EV) exposure at a dose of 0.10-0.12 mg/kg, or higher, per day, on alternate days, from postnatal days 2-12, resulted in abnormal penis development and infertility (H. O. Goyal et al., 2005, J. Androl. 26, 32-43). The objective of this study was to identify a critical developmental period(s) during which EV exposure results in the observed penile abnormalities. Male pups received EV at a dose of 0.10-0.12 mg/kg on postnatal day(s) 1, 1-3, 4-6, 1-6, 7-12, 13-18, 19-24, or 25-30. Fertility was tested at 102-115 days of age and tissues were examined at 117-137 days. Both penile morphology and fertility were unaltered in rats treated with EV after 12 days of age. Conversely, except in rats treated on postnatal day 1 only, none of the males treated prior to 12 days of age sired pups, and all had abnormal penises, including varying degrees of abnormal accumulation of fat cells and loss of cavernous spaces and smooth muscle cells in the corpora cavernosa penis, which were maximal in the 1-6-day group. Also, the preputial sheath was partially released or its release was delayed, and the weight of the bulbospongiosus muscle was significantly reduced. Plasma testosterone (T) in the 1-6- and 4-6-day groups and intratesticular T in the 4-6-day group were significantly lower. The testosterone surge, characteristic of controls in the first week of life, was suppressed in the 1-3-day group. Estrogen receptor alpha mRNA expression was enhanced in the body of the penis in the 1-3-day group, but not in the 13-18-day group. Hence, EV exposure prior to 12 days of age (as short as 1-3 days postnatal), but not after 12 days of age, results in long-term abnormal penile morphology, characterized by abnormal accumulation of fat cells in the corpora cavernosa penis and, consequently, loss of fertility. 相似文献
19.
20.
Anil Kumar Gvalani Samir Deolekar Jignesh Gandhi Abhay Dalvi 《The Indian journal of surgery》2014,76(1):56-60
Restoration of swallowing in a patient with dysphagia due to nondilatable corrosive stricture of esophagus remains a surgical challenge. Organs available for replacement are stomach, jejunum, or colon. Jejunum is useful to replace a small segment, whereas stomach and colon are required for a long-segment replacement. In cases where the stomach is also injured, colon remains the only option. The route of colonic interposition has also been a subject of debate over the years. Antesternal, retrosternal, or esophageal bed passage are the routes described. In the present series, the data of antesternal colonic interposition (ACI) performed for nondilatable benign esophageal strictures in 32 patients (1988–2011) have been retrospectively analyzed. The results indicate that ACI for corrosive strictures is a quick and simple procedure. Thoracotomy is avoided and anastomosis is easily performed in the neck, and mortality rate due to anastomotic failure or graft failure is diminished. This retrospective analysis discusses the ease, effectiveness, quality of life, morbidity, and mortality of ACI and compares the pros and cons of ACI with other procedures described in the literature. 相似文献