全文获取类型
收费全文 | 513393篇 |
免费 | 44626篇 |
国内免费 | 33165篇 |
专业分类
耳鼻咽喉 | 4704篇 |
儿科学 | 5883篇 |
妇产科学 | 8600篇 |
基础医学 | 61584篇 |
口腔科学 | 8924篇 |
临床医学 | 69065篇 |
内科学 | 79985篇 |
皮肤病学 | 5323篇 |
神经病学 | 28782篇 |
特种医学 | 18673篇 |
外国民族医学 | 277篇 |
外科学 | 53884篇 |
综合类 | 77174篇 |
现状与发展 | 105篇 |
一般理论 | 64篇 |
预防医学 | 31931篇 |
眼科学 | 14857篇 |
药学 | 51834篇 |
436篇 | |
中国医学 | 26337篇 |
肿瘤学 | 42762篇 |
出版年
2024年 | 1483篇 |
2023年 | 7313篇 |
2022年 | 18857篇 |
2021年 | 24167篇 |
2020年 | 17827篇 |
2019年 | 16146篇 |
2018年 | 17071篇 |
2017年 | 15033篇 |
2016年 | 14246篇 |
2015年 | 21524篇 |
2014年 | 27097篇 |
2013年 | 24417篇 |
2012年 | 35941篇 |
2011年 | 40434篇 |
2010年 | 25142篇 |
2009年 | 19723篇 |
2008年 | 27122篇 |
2007年 | 27190篇 |
2006年 | 27091篇 |
2005年 | 26831篇 |
2004年 | 17682篇 |
2003年 | 16026篇 |
2002年 | 13944篇 |
2001年 | 12646篇 |
2000年 | 13522篇 |
1999年 | 14469篇 |
1998年 | 8602篇 |
1997年 | 8575篇 |
1996年 | 6702篇 |
1995年 | 6137篇 |
1994年 | 5156篇 |
1993年 | 3383篇 |
1992年 | 4853篇 |
1991年 | 4157篇 |
1990年 | 3591篇 |
1989年 | 3144篇 |
1988年 | 2667篇 |
1987年 | 2397篇 |
1986年 | 1970篇 |
1985年 | 1590篇 |
1984年 | 968篇 |
1983年 | 728篇 |
1982年 | 443篇 |
1981年 | 419篇 |
1980年 | 367篇 |
1979年 | 450篇 |
1978年 | 220篇 |
1977年 | 201篇 |
1974年 | 217篇 |
1973年 | 175篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Welson Wen-Shang Wang Dipankar Das Stephen A McQuarrie Mavanur R Suresh 《European journal of pharmaceutics and biopharmaceutics》2007,65(3):398-405
We have developed a universal ovarian cancer cell targeting vehicle that can deliver biotinylated therapeutic drugs. A single-chain antibody variable domain (scFv) that recognizes the CA125 antigen of ovarian cancer cells was fused with a core-streptavidin domain (core-streptavidin-VL-VH and VL-VH-core-streptavidin orientations) using recombinant DNA technology and then expressed in Escherichia coli using the T7 expression system. The bifunctional fusion protein (bfFp) was expressed in a shaker flask culture, extracted from the periplasmic soluble protein, and affinity purified using an IMAC column. The two distinct activities (biotin binding and anti-CA125) of the bfFp were demonstrated using ELISA, Western blot and confocal laser-scanning microscopy (CLSM). The ELISA method utilized human NIH OVCAR-3 cells along with biotinylated bovine serum albumin (B-BSA) or biotinylated liposomes, whereas, the Western blot involved probing with B-BSA. The CLSM study has shown specificity in binding to the OVCAR-3 cell-line. ELISA and Western blot studies have confirmed the bifunctional activity and specificity. In the presence of bfFp, there was enhanced binding of biotinylated antigen and liposome to OVCAR-3 cells. In contrast, the control EMT6 cells, which do not express the CA125 antigen, showed minimal binding of the bfFp. Consequently, bfFp based targeting of biotinylated therapeutic drugs, proteins, liposomes, or nanoparticles could be an alternative, convenient method to deliver effective therapy to ovarian cancer patients. Peritoneal infusion of the bfFp-therapeutic complex could also be effective in locally targeting the most common site of metastatic spread. 相似文献
53.
Qualls E J Stevens Jason M Seibly Ying H Chen Rob D Dickerman Jerry Noel Keith A Kattner 《Journal of clinical neuroscience》2007,14(6):585-589
The adequate treatment of methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis has intrigued clinicians for some time. As the resistance of these pathogens, coupled with the increase in community-acquired cases, continues steadily to rise, clinicians are finding it useful to employ multi-modal approaches for efficacious treatment. The authors present a single case report of a patient with recurrent MRSA osteomyelitis, lumbar paraspinal and epidural abscess. He was found to have decreased muscle strength and was hyporeflexic in the involved extremity. Serum testing demonstrated MRSA bacteremia. Neuroimaging studies revealed evidence of paraspinal abscess and a presumed herniated nucleus pulposus at the L5/S1 interspace with significant nerve root compromise. Despite antimicrobials, his symptoms persisted, necessitating surgical exploration. At surgery, paraspinal and epidural abscesses were encountered and debrided; however, no herniated disc was visualized. This case demonstrates the diagnostic and therapeutic dilemmas with which these lesions present. We postulate that the MRSA osteomyelitis/discitis pathogens were walled off in the disc space and subsequently inoculated the soft tissues with ensuing bacteremia. We concur that antimicrobial treatment should be the first line of therapy for these patients; however, surgical debridements and cautious spinal instrumentation should be employed where appropriate. 相似文献
54.
An indirect enzyme-linked immunosorbent assay (ELISA) for the detection of hexoestrol (HES) was developed, optimized and validated for the analysis of HES in pork. Many parameters, such as the volume ratio of solution A and solution B, colour developing time, pH value, incubation time, the volume ratio of the standard solution and diluted antiserum, blocking solution, blocking condition, coating solution and coating condition were studied and optimized in the paper. The regression equation of the final inhibition curve is y = - 0.3345x + 1.4955, R2=0.9913. The linear range is 0.1-8.1 ng/ml, and the IC50 is 0.671 ng/ml. The specificity of the assay was evaluated by the cross-reactivity rates of six compounds, of which two structurally related compounds had a relatively higher cross-reactivity rate of 25% and 6%. HES was added into a pork sample at 5 ng/g level and then the sample was extracted. The recovery is between 49.6% and 79.2%, and the variation coefficient is 0.164. 相似文献
55.
近年来,伴随着药物治疗的快速发展.以药理活性非常强的药物为代表,开发出许多用药时必须给予足够关注的药物,“用药最适化”这一概念逐渐成为人们非常关注的问题。这主要是为了实现用药时的最佳形式。尽可能地根据选择或者需要控制药物的浓度.时间模式。输送到药物的作用表达部位。实现治疗用药的安全性。但是,历来的方法却很难实现这一点,通过利用新的技术和方法调控药物在体内的动态变化,以获得最好治疗效果为中心的药物使用方法和药剂正在开发之中。这就是给药系统,使用可以表达自身概念的语言来命名。虽然都是以各种药物在体内的动态过程作为调控对象,但是还分为①controlled release(调控释放给药);②开发新的给药途径、克服药物吸收障碍;③靶向给药(targeting)等三个途径。 相似文献
56.
Chee-Yueh Angie Ho Chun-Yu Chen Min-Wen Yang Hung-Ping Liu 《European journal of cardio-thoracic surgery》2005,28(1):174-175
Functional separation of the lungs may be accomplished by several methods. Patient with restricted mouth opening has limited options for one-lung ventilation. We report the use of wire-guided endobronchial blockade, a new tool for achieving one-lung ventilation in a patient with restricted mouth opening requiring nasotracheal, fiberoptic intubation for esophagectomy and reconstruction with gastric tube substitution. 相似文献
57.
Huimin Wang Changyuan Wang Jihong Yao Kexin Liu 《Blood coagulation & fibrinolysis》2007,18(6):555-558
Fully soluble hemostatic fiber (FHF) is made from cotton yarn through a series of chemical reactions with NaOH and chloroacetic acid. The major component of FHF is carboxymethylcellulose. FHF is a kind of biodegradation macromolecule material that can disassociate into a low-molecular-weight compound or a simple substance by hydrolytic and enzymatic courses. The purpose of the present study is to investigate the hemostatic mechanism of FHF. The study indicated that FHF can stop bleeding by physical, chemical and physiological routes. In the physical route, expansion of carboxymethylcellulose in FHF stops bleeding by forming a mechanical clog after contacting with the blood. In the chemical route, the platelets can quickly aggregate around FHF and stimulate releasing and disaggregating reactions, after contacting with the rough surface of FHF, producing thrombus and hemostasis. In the physiological route, gluey particles with negative charges can activate intrinsic coagulation systems by activating the blood coagulation factor XII after FHF dissolution. 相似文献
58.
59.
60.
To study the pathological and histochemical characteristics of lesions in piglet livers infected with Taenia saginata asiatica (T. saginata asiatica) throughout the different stages, piglets were fed with eggs of T. saginata asiatica and raised in isolation in an animal center to establish the T. saginata asiatica infection model with normal piglets as control. The pathological changes in the piglet livers were observed after the infection
using liver sections stained with hematoxylin and eosin. Histochemical methods were used to check the changes in lipid, glycogen
and protein content in the liver. The data collected by image analysis were analyzed statistically with Statistical Package
for the Social Science. The results show that T. saginata asiatica-exposed piglets were indeed infected. Inflammatory reactions began on the fourth day and progressed rapidly. Kupffer cell
hyperplasia, hepatic hydropic degeneration and ballooning degeneration were found in the 10th–20th days after infection. Hepatic
central veins and hepatic sinusoids were dilated and congested. Spotty necrosis occurred in some local liver tissues. In the
40th–60th days, granulomatous reactions and mild hepatocirrhosis were the main lesions. In the 70th–80th days, hepatocirrhosis
and bile duct proliferation were observed in the liver. In the different stages, lipid drops were increased while glycogen
and protein levels were decreased to some degree. There was a significant difference in metabolism between the infected group
and the control group (P < 0.01). It is concluded that pigs are the favorable intermediate host of T. saginata asiatica and its infection can result in serious pathological and histochemical lesions in host organs.
Translated from Journal of Guiyang Medical College, 2006, 31(4): 296–300 [译自: 贵阳医学院学报] 相似文献