全文获取类型
收费全文 | 47522篇 |
免费 | 1948篇 |
国内免费 | 589篇 |
专业分类
耳鼻咽喉 | 168篇 |
儿科学 | 1291篇 |
妇产科学 | 761篇 |
基础医学 | 3651篇 |
口腔科学 | 1166篇 |
临床医学 | 2818篇 |
内科学 | 12658篇 |
皮肤病学 | 413篇 |
神经病学 | 2675篇 |
特种医学 | 730篇 |
外国民族医学 | 1篇 |
外科学 | 7200篇 |
综合类 | 3188篇 |
一般理论 | 1篇 |
预防医学 | 4560篇 |
眼科学 | 393篇 |
药学 | 4755篇 |
28篇 | |
中国医学 | 2150篇 |
肿瘤学 | 1452篇 |
出版年
2024年 | 96篇 |
2023年 | 802篇 |
2022年 | 1215篇 |
2021年 | 1908篇 |
2020年 | 1465篇 |
2019年 | 3427篇 |
2018年 | 2680篇 |
2017年 | 1937篇 |
2016年 | 975篇 |
2015年 | 885篇 |
2014年 | 1828篇 |
2013年 | 1687篇 |
2012年 | 1546篇 |
2011年 | 1804篇 |
2010年 | 1313篇 |
2009年 | 1227篇 |
2008年 | 1222篇 |
2007年 | 1092篇 |
2006年 | 852篇 |
2005年 | 687篇 |
2004年 | 544篇 |
2003年 | 487篇 |
2002年 | 357篇 |
2001年 | 270篇 |
2000年 | 233篇 |
1999年 | 192篇 |
1998年 | 165篇 |
1997年 | 156篇 |
1996年 | 141篇 |
1995年 | 138篇 |
1994年 | 143篇 |
1993年 | 107篇 |
1992年 | 104篇 |
1991年 | 88篇 |
1990年 | 58篇 |
1989年 | 68篇 |
1986年 | 50篇 |
1985年 | 1443篇 |
1984年 | 2479篇 |
1983年 | 2301篇 |
1982年 | 1716篇 |
1981年 | 1802篇 |
1980年 | 1500篇 |
1979年 | 1311篇 |
1978年 | 1135篇 |
1977年 | 652篇 |
1976年 | 1100篇 |
1975年 | 971篇 |
1974年 | 808篇 |
1973年 | 777篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
本文探讨食管胃腔内弹力环扎吻合术的力学机理。这是一种不用任何缝合材料或吻合器进行胃食管吻合的新技术,我们已成功应用于临床。取临床所用的乳胶管按该材料多向异性特征、实验条件以及弹力环数目分为8组,每组3个样品进行各种体外力学试验。通过应力—应变(拉力—伸长)关系曲线和定伸长松驰试验确定它的力学特性是一种粘弹性材料。根据实验所得的应力换算为弹力环对食管和胃组织所施加的最佳压力(压强)是4.23±0.23Kg/cm~2,这样才能保证这一种新颖的吻合术可达到简便、安全、可靠的目的。 相似文献
52.
神经网络分析方法用于心脏病诊断的研究 总被引:2,自引:1,他引:1
神经网络可以很好的拟合任意的非线性函数。我们从 QRS波群的高频三维频谱中提取出一些定量的特征参数 ,用神经网络的方法对这些参数进行有监督的学习训练 ,最终能在由这些特征参数张成的 m维空间中构建出一个 m维的曲面来区分病人和健康人的 QRS波群高频三维频谱 ,从而使得训练后的网络能基于 QRS波群的高频三维频谱自行诊断出病人和健康人 相似文献
53.
54.
Takashi Toyonaga Eisei Nishino Toshio Dozaiku Chie Ueda Tomoomi Hirooka 《Digestive endoscopy》2007,19(Z1):S14-S18
The gastric vasculature responsible for intraoperative bleeding in endosocpic submucosal dissection (ESD) is the ramified vascular network occupying the middle of the submucosal layer and large vessels penetrating the muscle layer. Appropriate management for these vessels must be addressed. The trimming of the ramified vascular network can be safely performed with coagulation mode following shallow mucosal cutting. A large penetrating vessel usually requires precoagulation prior to dissection. These procedures are effectively performed with the water jet short needle knife (Flush knife). 相似文献
55.
56.
Paolo R. Salvalaggio Katie Neighbors Susan Kelly Karan M. Emerick Kishore Iyer Riccardo A. Superina Peter F. Whitington Estella M. Alonso 《American journal of transplantation》2005,5(8):1868-1874
The Pediatric End-Stage Liver Disease (PELD) score was designed to reduce subjectivity in liver allocation and to advantage patients with a higher probability of waiting list mortality. The aims of this study were to determine the impact of PELD implementation for children with chronic liver disease and to assess whether PELD met its goal of standardization of liver allocation for children. This study used data reported to the United Network for Organ Sharing (UNOS) registry for children with chronic liver disease receiving primary cadaveric liver transplant between January 2000 and December 2001 (pre-PELD) and March 2002 and July 2003 (PELD). PELD reduced the percentage of children transplanted while in an intensive care unit and as status 1. A calculated PELD score was used for allocation in only 52% of recipients. Thirty percent were status 1 at transplant and PELD scores granted by exception were used for allocation in 18% of patients. There was regional variation in PELD score at allocation and use of exception scores with a significant relationship between PELD score and percentage of exception cases. Regional variation suggests that PELD has not resulted in standardization of listing practices in pediatric liver transplantation. 相似文献
57.
D. Trainer P.R. Pehrsson D.B. Haytowitz J.M. Holden K.M. Phillips A.S. Rasor N.A. Conley 《Journal of food composition and analysis》2010,23(8):843-851
The National Food and Nutrient Analysis Program (NFNAP) was implemented in 1997 to update and improve the quality of food composition data maintained by the United States Department of Agriculture (USDA). NFNAP was designed to sample and analyze frequently consumed foods in the U.S. food supply using statistically rigorous sampling plans, established sample handling procedures, and qualified analytical laboratories. Methods for careful handling of food samples from acquisition to analysis were developed to ensure the integrity of the samples and subsequent generation of accurate nutrient values. The infrastructure of NFNAP, under which over 1500 foods have been sampled, mandates tested sample handling protocols for a wide variety of foods. The majority of these foods were categorized into several major areas: (1) frozen foods; (2) fresh produce and/or highly perishable foods requiring refrigeration; (3) fast foods and prepared foods; (4) shelf-stable foods; (5) specialized study and non-retail (point of production) foods; and (6) foods from remote areas (e.g. American Indian reservations). This paper describes the sample handling approaches, from the collection and receipt of the food items to the preparation of the analytical samples, with emphasis on the strategies developed for those foods. It provides a foundation for developing sample handling protocols of foods to be analyzed under NFNAP and for other researchers working on similar projects. 相似文献
58.
观察329块(男193,女136)国人成年跟骨的距关节面形态。其中A型出现率,男为45.08±3.58%,女为41.18±4.22%;B型出现率男为53.89±3.59%,女为58.82±4.22%;C型仅男性出现2例,占1.04±0.73%。成套标本中,距关节面左右对称的,男性90例中有81例,占90.00±3.16%;女性67例中有59例,占88.06±3.96%。经统计学处理,侧别间及性别间均无明显差异。文内结合观察结果提出自己的分型标准及类型,并与以往资料进行了比较。 相似文献
59.
JOHN CHALMERS 《British journal of clinical pharmacology》1996,42(1):29-35
1 A 'retrospective' of the development of the drug treatment of hypertension is presented from the early days of ganglion blockers to the present time together with a review of the evidence of benefit from treatment.
2 Current issues and debates are summarised including shortfalls in the control of hypertension in populations, difficulties surrounding the measurement of blood pressure, disagreement on the levels of blood pressure to treat, the goal blood pressures to aim at, issues surrounding lifestyle measures such as the low salt diet and low intensity exercise, and treatment with diuretics and with calcium antagonists.
3 A 'perspective' is presented on some avenues for progress in the years ahead. These will include the identification of genetic markers to determine the hypertensive individuals with the greatest risk of death and of cardiovascular complications. 相似文献
2 Current issues and debates are summarised including shortfalls in the control of hypertension in populations, difficulties surrounding the measurement of blood pressure, disagreement on the levels of blood pressure to treat, the goal blood pressures to aim at, issues surrounding lifestyle measures such as the low salt diet and low intensity exercise, and treatment with diuretics and with calcium antagonists.
3 A 'perspective' is presented on some avenues for progress in the years ahead. These will include the identification of genetic markers to determine the hypertensive individuals with the greatest risk of death and of cardiovascular complications. 相似文献
60.
Yoshifumi Kawarada Kouji Takahashi Masami Tabata Shuji Isaji Yoshifumi Ogura Ryuji Mizumoto 《Journal of Hepato-Biliary-Pancreatic Surgery》1993,1(1):8-13
Eighty of 89 patients who underwent radical resection (resectability 89.9%) for carcinoma of the papilla of Vater between 1976 and 1992 were retrospectively reviewed. Seventy-three patients underwent pancreaticoduodenectomy (PD) and 7 underwent pylorus-preserving pancreaticoduodenectomy (PPPD). The postoperative mortality rate was only 3.8% (3 patients). The 3- and 5-year survival rates were 63.6% and 57.4%, respectively. Important factors influencing long-term survival were Stage (clinical stage = Stage), microscopic lymph node metastasis (n), duodenal wall invasion (d), vascular invasion (v), and the epithelium of origin. Early carcinoma of the papilla of Vater is defined as tumor in which invasion is limited within the papilla of Vater; in particular, carcinomatous invasion is within the muscle of Oddi (d0) with n0. PD and/or PPPD with radical lymph node dissection should be performed for carcinoma of the papilla of Vater, as these procedures can be performed with low morbidity and mortality. 相似文献