全文获取类型
收费全文 | 3871篇 |
免费 | 392篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 67篇 |
儿科学 | 248篇 |
妇产科学 | 52篇 |
基础医学 | 532篇 |
口腔科学 | 52篇 |
临床医学 | 367篇 |
内科学 | 794篇 |
皮肤病学 | 70篇 |
神经病学 | 261篇 |
特种医学 | 263篇 |
外科学 | 372篇 |
综合类 | 122篇 |
一般理论 | 7篇 |
预防医学 | 383篇 |
眼科学 | 132篇 |
药学 | 250篇 |
中国医学 | 2篇 |
肿瘤学 | 325篇 |
出版年
2021年 | 56篇 |
2020年 | 38篇 |
2019年 | 41篇 |
2018年 | 65篇 |
2017年 | 47篇 |
2016年 | 37篇 |
2015年 | 73篇 |
2014年 | 74篇 |
2013年 | 124篇 |
2012年 | 154篇 |
2011年 | 165篇 |
2010年 | 112篇 |
2009年 | 87篇 |
2008年 | 139篇 |
2007年 | 173篇 |
2006年 | 133篇 |
2005年 | 151篇 |
2004年 | 146篇 |
2003年 | 126篇 |
2002年 | 132篇 |
2001年 | 134篇 |
2000年 | 131篇 |
1999年 | 119篇 |
1998年 | 67篇 |
1997年 | 71篇 |
1996年 | 80篇 |
1995年 | 64篇 |
1994年 | 57篇 |
1993年 | 61篇 |
1992年 | 97篇 |
1991年 | 109篇 |
1990年 | 103篇 |
1989年 | 117篇 |
1988年 | 118篇 |
1987年 | 96篇 |
1986年 | 90篇 |
1985年 | 94篇 |
1984年 | 57篇 |
1983年 | 48篇 |
1982年 | 38篇 |
1981年 | 35篇 |
1980年 | 29篇 |
1979年 | 42篇 |
1978年 | 30篇 |
1976年 | 38篇 |
1975年 | 25篇 |
1974年 | 28篇 |
1973年 | 27篇 |
1972年 | 27篇 |
1971年 | 29篇 |
排序方式: 共有4299条查询结果,搜索用时 15 毫秒
101.
Leukocyte recruitment in the subcutaneous sponge implant model of acute inflammation in the rat is not mediated by leukotriene B1 总被引:2,自引:0,他引:2
The subcutaneous sponge implant model of acute inflammation in the rat has been evaluated as a suitable test system for evaluating the potential anti-inflammatory efficacy of 5-lipoxygenase inhibitors. The inflammatory parameters measured were exudate volume and leukocyte recruitment. Specific radioimmunoassays were used to measure (1) 5-lipoxygenase (LPO) and cyclo-oxygenase (CO) activity in exudate leukocytes stimulated ex vivo with A23187, and (2) the LTB4 and PGE2 content of inflammatory exudate. The NSAIDs flurbiprofen and indomethacin inhibited cell recruitment, exudate volume and CO activity with ED50S of approximately 1 mg per kg p.o. but failed to inhibit LPO activity at 10 mg per kg p.o. Nafazatrom (Bayer 6575), quercetin and NDGA, which inhibit LPO activity in vitro, were inactive against all parameters when dosed at 100 mg per kg p.o. The "mixed inhibitors" BW755C and phenidone were approximately equipotent inhibitors of LPO activity but BW755C was 10 times more potent than phenidone against CO activity. BW755C was also greater than 10 times more potent at inhibiting cell recruitment and exudate volume than phenidone suggesting that the anti-inflammatory efficacy of the mixed inhibitors reflect their potency against CO rather than LPO activity. Time course studies demonstrated that the inhibitor effects of BW755C and phenidone on leukocyte recruitment reflected a reduction in the PGE2 but not the LTB4 content of the inflammatory exudate. Polyester sponges soaked in high concentrations of LTB4 caused only a modest (2-fold) increase in leukocyte recruitment whilst physiological levels were inactive. The results taken together suggest that CO products make a major contribution to leukocyte recruitment in this model whilst the LPO product LTB4 has little role. This model therefore is of little value for evaluating the anti-inflammatory efficacy of 5-lipoxygenase inhibitors. Moreover, the rat would appear to be unsuitable for evaluating the role of LTB4 in acute inflammation. 相似文献
102.
Suspensions of washed human red blood cells were treated with nine synthetic putative metabolic derivatives of primaquine (PQ'), and their individual effects on activity of the hexose monophosphate shunt (HMS) were quantitated by radiometric analysis of 14CO2 from [14C] glucose. The most potent HMS stimulant was 5-hydroxy-6-methoxy-8-aminoquinoline (5H6MQ), which caused 10-fold elevation of HMS activity at an estimated concentration of 0.004 mM. Ten millimolar primaquine (PQ) was required to achieve the same effect. Thus, 5H6MQ was approximately 2500-fold more reactive with the HMS than PQ. Other analogs achieved less than 0.4- to 154-fold increases in HMS reactivity. Patterns of effects on HMS activity indicated that 5-hydroxylation and/or N-dealkylation of PQ strongly enhanced HMS reactivity. In contrast, none of the putative metabolites of PQ activated the proteolytic system known to degrade oxidized protein in red cells, indicating that stimulation of the HMS by the PQ analogs was not related to an injurious oxidative stress. Red cells pretreated with 1.0 mM N-ethylmaleimide (NEM) or with 1.0% (w/v) sodium nitrite to cause glutathione sulfhydryl blockage and conversion of red cell hemoglobin to methemoglobin (metHb), respectively, also showed elevation of HMS activity when exposed to 5H6MQ. These observations suggested that 5H6MQ-induced elevation of HMS activity was at least partially independent of glutathione redox reactions, hydrogen peroxide accumulation and reaction with oxyhemoglobin. The relevance of these observations to proposed mechanisms of hemolytic toxicity of PQ is discussed. 相似文献
103.
104.
Primary acquired nasolacrimal duct obstruction. A clinicopathologic report and biopsy technique 总被引:11,自引:0,他引:11
Primary acquired nasolacrimal duct obstruction (PANDO) of adults is a clinical syndrome of unknown cause, and the histopathology of the nasolacrimal duct has not been substantially studied. A technique of excisional biopsy of the soft tissue contents within the nasolacrimal canal during external dacryocystorhinostomy (DCR) is presented. No complications were associated with the biopsy technique in 14 cases. Two cases of lacrimal obstruction secondary to sarcoidosis and leukemia were discovered in biopsies of patients with the clinical syndrome of PANDO, demonstrating the value of routine biopsy during DCR. Biopsies revealed a spectrum of changes that correlated with duration of symptoms. Early cases revealed active chronic inflammation along the entire length of the narrowed nasolacrimal duct. Intermediate cases revealed focal resolution of the inflammatory process with fibrosis, while late cases showed fibrous obliteration of the entire duct. Although the first event in primary acquired nasolacrimal duct obstruction remains uncertain, clinicopathologic correlation suggests that compression of the duct by inflammatory infiltrates and edema precedes clinical chronic dacryocystitis. 相似文献
105.
106.
单克隆抗体博来霉素A6偶联物对白血病细胞特异性结合与内化 总被引:2,自引:0,他引:2
抗CCT2单克隆抗体博来霉素A6偶联物可吸附胶体金颗粒(McAb-A6-Au)。电镜观察表明,在4℃,1h,表面有McAb-A6-Au颗粒的CEM细胞最高达78%;在37℃,4h,内化McAb-A6-Au颗粒的CEM细胞高达72%。而抗原性无关的U937细胞仅为14%。并且McAb-A6-Au颗粒能直接穿过细胞膜、核膜进入细胞浆和细胞核。37℃,1h已有10~18%的CEM细胞核内有McAb-A 6-Au颗粒。实验结果提示了单抗与博来霉素A6的偶联物与选择性地结合靶细胞,而且进入细胞速度快、穿透力强,有可能成为治疗白血病药物。 相似文献
107.
Secretion of matrix metalloproteinase‐3 by co‐cultured pigmented and non‐pigmented human trabecular meshwork cells following selective laser trabeculoplasty
下载免费PDF全文
![点击此处可从《Clinical & experimental ophthalmology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
108.
M.D.Carol L. Carraccio M.D. Sc.D.Marie C. McCormick Ph.D.Susan C. Weller 《The Journal of pediatrics》1987,110(6):982-987
An assessment of health cognition and health locus of control (HLOC) was obtained in 85 healthy and 81 chronically ill children, using instruments adapted from Piaget's work and standard HLOC measures. A relationship between HLOC and compliance was sought in a subset of children with spina bifida taught self-catheterization. Evidence of the developmental nature of health cognition and HLOC was documented. Contrary to the effect of experience in formal learning, experience with chronic disease did not alter developmental progression in these health-related areas. Our results suggest that in communicating with children about illness, the pediatrician's approach should not be altered by an appearance of superficial sophistication that some children may acquire as part of their experience with chronic disease. 相似文献
109.
David W. McCormick Sara L. Rassoulian-Barrett Daniel R. Hoogestraat Stephen J. Salipante Dhruba SenGupta Elizabeth A. Dietrich Brad T. Cookson Grace E. Marx Joshua A. Lieberman 《Emerging infectious diseases》2023,29(3):467
Molecular methods can enable rapid identification of Bartonella spp. infections, which are difficult to diagnose by using culture or serology. We analyzed clinical test results of PCR that targeted bacterial 16S rRNA hypervariable V1–V2 regions only or in parallel with PCR of Bartonella-specific ribC gene. We identified 430 clinical specimens infected with Bartonella spp. from 420 patients in the United States. Median patient age was 37 (range 1–79) years; 62% were male. We identified B. henselae in 77%, B. quintana in 13%, B. clarridgeiae in 1%, B. vinsonii in 1%, and B. washoensis in 1% of specimens. B. quintana was detected in 83% of cardiac specimens; B. henselae was detected in 34% of lymph node specimens. We detected novel or uncommon Bartonella spp. in 9 patients. Molecular diagnostic testing can identify Bartonella spp. infections, including uncommon and undescribed species, and might be particularly useful for patients who have culture-negative endocarditis or lymphadenitis. 相似文献
110.
保证输血时血清学方面的安全,首要的是对受血者与献血者ABO血型定型,血清学检查通常分两个步骤.正定型通常使用鼠源单克隆抗体检测红细胞表面是否存在A或B抗原.互补的实验即反定型,利用当红细胞上缺乏A或B抗原时,人群可天然产生相对应的抗体的原理,检测血清中是否存在抗-A或者抗-B抗体.确定了受血者红细胞表面的ABO抗原以及血浆中的抗体,便能确定血型,为其提供相合的血液. 相似文献