全文获取类型
收费全文 | 27804篇 |
免费 | 1945篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 212篇 |
儿科学 | 960篇 |
妇产科学 | 617篇 |
基础医学 | 3754篇 |
口腔科学 | 280篇 |
临床医学 | 4058篇 |
内科学 | 5008篇 |
皮肤病学 | 505篇 |
神经病学 | 2917篇 |
特种医学 | 500篇 |
外科学 | 2844篇 |
综合类 | 253篇 |
一般理论 | 43篇 |
预防医学 | 3669篇 |
眼科学 | 431篇 |
药学 | 1679篇 |
中国医学 | 22篇 |
肿瘤学 | 2046篇 |
出版年
2024年 | 31篇 |
2023年 | 249篇 |
2022年 | 377篇 |
2021年 | 826篇 |
2020年 | 608篇 |
2019年 | 781篇 |
2018年 | 926篇 |
2017年 | 698篇 |
2016年 | 728篇 |
2015年 | 748篇 |
2014年 | 1074篇 |
2013年 | 1557篇 |
2012年 | 2329篇 |
2011年 | 2434篇 |
2010年 | 1289篇 |
2009年 | 1135篇 |
2008年 | 1897篇 |
2007年 | 2000篇 |
2006年 | 1821篇 |
2005年 | 1690篇 |
2004年 | 1526篇 |
2003年 | 1344篇 |
2002年 | 1337篇 |
2001年 | 211篇 |
2000年 | 190篇 |
1999年 | 194篇 |
1998年 | 240篇 |
1997年 | 194篇 |
1996年 | 148篇 |
1995年 | 125篇 |
1994年 | 121篇 |
1993年 | 112篇 |
1992年 | 93篇 |
1991年 | 82篇 |
1990年 | 61篇 |
1989年 | 72篇 |
1988年 | 42篇 |
1987年 | 45篇 |
1986年 | 45篇 |
1985年 | 43篇 |
1984年 | 57篇 |
1983年 | 33篇 |
1982年 | 38篇 |
1981年 | 28篇 |
1980年 | 17篇 |
1979年 | 34篇 |
1976年 | 25篇 |
1975年 | 17篇 |
1974年 | 16篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
73.
Tadashi Nakazawa Yoshiyuki Takami Robert Benkowski Satoshi Ohtsubo Ohashi Yukio Eiki Tayama Goro Ohtsuka Yoshinari Niimi Julie Glueck Akinori Sueoka Helmut Schmallegger Heinrich Schima Ernst Wolner Yukihiko Nosé 《Artificial organs》1997,21(7):597-601
Abstract: To be able to salvage heart failure patients, the need for an economical permanent ventricular assist device is increasing. To meet this increasing demand, a miniaturized centrifugal blood pump has been developed as a permanently implantable device. The Gyro permanently implantable model (PI-601) incorporates a sealless design with a blood stagnation free structure. The pump impeller is magnetically coupled to the driver magnet in a sealless manner. This pump is atraumatic and antithrombogenic and incorporates a double pivot bearing system. A miniaturized actuator was utilized in this system in collaboration with the University of Vienna. The priming volume of this pump is 20 ml. The overall size of the pump actuator package is 53 mm in height and 65 mm in diameter, 145 ml of displacement volume, and 305 g in weight. Testing to date has included in vitro hydraulic performance and hemolysis. This pump can provide 5 L/min against a 110 mm Hg total pressure head at 2,000 rpm and 8 Limin against 150 mm Hg at 2,500 rpm. The normalized index of hemo-lysis (NIH) value of this pump was 0.0028 g/100 L at 5 Limin against 100 mm Hg. A preliminary anatomical study revealed the possibility of the implantability of 2 such systems in biventricular bypass at a preperitoneal location. This system is feasible for use as a permanently implantable biventricular assist device. 相似文献
74.
75.
Dr. Julie A. Porter Pharm.D. Dr. Barry L. Carter Pharm.D. FCCP Dr. Thomas P. Johnston Ph.D. Dr. Warren K. Palmer Ph.D. 《Pharmacotherapy》1995,15(1):92-98
A new animal model of hyperlipidemia is being developed using the nonionic surfactant poloxamer 407 (P-407). We investigated the impact of pravastatin on P-407-induced hyperlipidemia. Twenty rats received P-407 300 mg intraperitoneally to induce hyperlipidemia, and 20 control rats received saline injection. Pravastatin was administered orally to an equal number of rats in both groups using three different regimens. A fourth group did not receive pravastatin. At 24 hours after injection, total cholesterol levels in two of the pravastatin groups were 28% and 34% lower than those in animals that did not receive pravastatin (p≤0.01). At 48 hours, triglyceride levels were significantly lower in all pravastatin groups (21–44%) versus animals not receiving pravastatin. Pravastatin diminished the effects of P-407 on lipoproteins. This new animal model may be useful in screening for investigational antihyperlipidemic agents. 相似文献
76.
Daniel L. Rubin Karen L. Falk Malcolm J. Sperling Michael Ross Sanjay Saini Barry Rothman Frank Shellock Elias Zerhouni David Stark Eric K. Outwater Udo Schmiedl Louis C. Kirby Judith Chezmar Terry Coates Miles Chang Jeffery M. Silverman Neil Rofsky Keith Burnett Julie Engel Stuart W. Young 《Journal of magnetic resonance imaging : JMRI》1997,7(5):865-872
The purpose of this study was to assess the effectiveness and safety of Gadolite Oral Suspension as a gastrointestinal (GI) contrast agent for MRI in a phase II and two phase III multicenter clinical trials. Gadolite was administered to 306 patients with known or suspected abdominal and/or pelvic disease. MRI with T1- and T2-weighted sequences was performed before and after ingestion. Efficacy was evaluated by having two masked readers rate the certainty of their MR diagnosis (0 = uncertain, 1 = probable, 2 = definite) on randomly presented pre- and post-Gadolite Oral Suspension enhanced images. Principal investigators also evaluated the images and established the final diagnosis. Vital signs, clinical chemistries, and adverse events were documented. Blood and urine samples were analyzed for gadolinium content to determine whether Gadolite Oral Suspension was absorbed systemically. Certainty in MR diagnosis increased significantly (P < .001) for both blinded readers between pre- and post-Gadolite images (.49–1.18 for reader 1; .46–1.53 for reader 2). Sensitivity, specificity, and accuracy also increased for both masked readers. No gadolinium was detected in blood or urine samples. There were no serious adverse events and no apparent drug-related trends in mean vital signs or laboratory values. Gadolite is a highly effective, safe, and well tolerated contrast agent for clinical use with MRI. 相似文献
77.
78.
Multiply Recurrent Trichilemmal Carcinoma With Perineural Invasion and Cytokeratin 17 Positivity 总被引:4,自引:0,他引:4
Julie E. Allee MD George Cotsarelis MD Benjamin Solky MD Jonathan L. Cook MD 《Dermatologic surgery》2003,29(8):886-889
BACKGROUND: Trichilemmal carcinoma is an uncommon cutaneous malignancy that is thought to be the malignant counterpart of the trichilemmoma. Despite histologic features such as pronounced cytologic atypia, trichilemmal carcinoma is often described as having a rather benign clinical course. Cases of tumor recurrence after therapy are uncommon, and tumor neurotropism has never been described. OBJECTIVE: A case of multiply recurrent trichilemmal carcinoma with perineural invasion is described. The outer root sheath differentiation of this neoplasm is confirmed with the use of novel antibodies directed toward cytokeratins that are expressed in this area of the hair follicle. METHODS: The trichilemmal carcinoma was excised using the Mohs surgical technique. Tissue obtained during the extirpation of the tumor was subjected to immunohistochemical staining for cytokeratin 15, cytokeratin 17, and c-erb-B2. RESULTS: Tumor neurotropism was noted. The trichilemmal carcinoma demonstrated abundant cytoplasmic staining for cytokeratin 17 and c-erb-B2. CONCLUSIONS: In distinction to previous reports, this case reveals that trichilemmal carcinoma can demonstrate significant biological aggression, as reflected by tumor neurotropism and by failure to respond to multiple surgical excisions. The purported outer root sheath differentiation of this neoplasm is confirmed with the use of novel immunohistochemical staining. This immunohistochemical staining may be useful in differentiating trichilemmal carcinoma from other clear cell neoplasms. 相似文献
79.
80.