全文获取类型
收费全文 | 3230266篇 |
免费 | 227399篇 |
国内免费 | 9087篇 |
专业分类
耳鼻咽喉 | 43694篇 |
儿科学 | 105241篇 |
妇产科学 | 89311篇 |
基础医学 | 452878篇 |
口腔科学 | 88530篇 |
临床医学 | 291846篇 |
内科学 | 637052篇 |
皮肤病学 | 75239篇 |
神经病学 | 266242篇 |
特种医学 | 125358篇 |
外国民族医学 | 1025篇 |
外科学 | 486440篇 |
综合类 | 65192篇 |
现状与发展 | 7篇 |
一般理论 | 1288篇 |
预防医学 | 246320篇 |
眼科学 | 72944篇 |
药学 | 234836篇 |
10篇 | |
中国医学 | 6559篇 |
肿瘤学 | 176740篇 |
出版年
2021年 | 25197篇 |
2019年 | 26093篇 |
2018年 | 36456篇 |
2017年 | 28233篇 |
2016年 | 32333篇 |
2015年 | 36421篇 |
2014年 | 50745篇 |
2013年 | 75994篇 |
2012年 | 101799篇 |
2011年 | 107812篇 |
2010年 | 65155篇 |
2009年 | 62292篇 |
2008年 | 101187篇 |
2007年 | 107259篇 |
2006年 | 108832篇 |
2005年 | 105213篇 |
2004年 | 100940篇 |
2003年 | 97548篇 |
2002年 | 94174篇 |
2001年 | 149433篇 |
2000年 | 152641篇 |
1999年 | 129645篇 |
1998年 | 38380篇 |
1997年 | 34079篇 |
1996年 | 34052篇 |
1995年 | 32648篇 |
1994年 | 30077篇 |
1993年 | 28354篇 |
1992年 | 100660篇 |
1991年 | 96739篇 |
1990年 | 93781篇 |
1989年 | 90741篇 |
1988年 | 83245篇 |
1987年 | 81627篇 |
1986年 | 76904篇 |
1985年 | 73290篇 |
1984年 | 54956篇 |
1983年 | 46735篇 |
1982年 | 28161篇 |
1979年 | 48813篇 |
1978年 | 34587篇 |
1977年 | 29350篇 |
1976年 | 27393篇 |
1975年 | 29243篇 |
1974年 | 34577篇 |
1973年 | 33042篇 |
1972年 | 30977篇 |
1971年 | 28605篇 |
1970年 | 26709篇 |
1969年 | 25547篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
G.E. ORLANDINI S. ZECCHI ORLANDINI A.F. HOLSTEIN R. EVANGELISTI and R. PONCHIETTI 《Andrologia》1987,19(3):315-321
The human prostatic urethra has been investigated by means of scanning electron microscopy. On the posterior wall of the urethra, the seminal colliculus with the orifices of the ejaculatory ducts is clearly detectable. The upper portion of the prostatic urethra shows a typical transitional epithelium with large superficial cells of a ruffled appearance. In the lower portion of the organ (underneath the openings of the ejaculatory ducts), the apical pattern of the cells varies considerably. Four main aspects are recognizable: apices provided with microvilli, dome-shaped apices with an almost smooth surface, large apices with labyrinthic microplicae and ciliated apices. Also, apices showing intermediate characteristics can be noted. The functional significance of the morphological patterns as well as the possibility of a transition among the various types of surface structures are discussed. 相似文献
995.
996.
M Aschner 《Pharmacology & toxicology》1987,60(2):81-85
It was established by means of SDS polyacrylamide gel electrophoresis that direct injections of methyl mercury (10 micrograms Hg) into the mature rat vitreous body of the eye decrease protein synthesis in the retina and optic nerve at 4 hours after injection. Although the global spectrum of polypeptides did not change, a specific decrease in the volume of polypeptides of 20-23 K daltons molecular weight was evident. Conversely, systemic exposure to methyl mercury resulted in increased protein synthesis of polypeptides of 20-23 K molecular weight both in adult (8 mgHg/kg/day for 8 days) and neonatal rats (2 mgHg/kg/day for 10 days). In addition, specific changes in the volume of polypeptides 75-90 K molecular weight were noted in sciatic nerves of neonatal rats. These data are consistent with a bimodal response in protein synthesis following MeHg treatment. Local presence of MeHg following direct injection into the eye causes a reduction in protein synthesis, while chronic systemic exposure results in increased synthesis and transport of proteins in both mature and developing optic nerves and neonatal sciatic nerves. Thus, these systems possess the capacity to attempt regenerative processes through induction of a small subset of proteins known as GAPs (Growth-Associated Proteins) during the early stages of systemic methyl mercury exposure. These wide spread and system-specific changes are consistent with growth-specific functions during the early stages of methyl mercury exposure. 相似文献
997.
N Watanabe Y Niitsu H Umeno H Kuriyama H Neda N Yamauchi M Maeda I Urushizaki 《Gan to kagaku ryoho. Cancer & chemotherapy》1987,14(12):3337-3343
Effects of human recombinant TNF on the tumor blood vessels and on the thrombus formation were investigated in relation to its mode of antitumor action against Meth-A sarcoma transplanted in BALB/c mice. The extent of the blood vessel lesion was evaluated by using transparent chamber placed in the mouse skin. Bleeding, hyperemia and congestion were observed at 1-2h, 4-6h and 24h after TNF (1 X 10(4)U/mouse) administration, respectively. In contrast, no histological changes in the normal blood vessels were observed microscopically following TNF injection. Thrombus formation was evoked in the tumor vessels 4h after TNF injection. However, when thrombus formation was prevented by heparin, no difference was observed among antitumor action of TNF against Meth-A fibrosarcoma necrotic response and the rate of complete cure. These results suggest that the direct effects of TNF causing lesions in the tumor blood vessels plays an important role in its antitumor action. 相似文献
998.
F Mandelli G De Rossi P Mancini A Alberti A Cajozzo F Grignani P Leoni V Liso M Martelli A Neri 《Journal of clinical oncology》1987,5(3):398-406
Clinical and biological data were evaluated using Desu univariate analyses or Cox multivariate analyses in a series of 1,777 chronic lymphocytic leukemia (CLL) patients from an Italian Cooperative Group. In univariate analyses, age and sex of patients, presence of bone marrow (BM; greater than or equal to 50%), and peripheral blood (PB; greater than or equal to 60,000/microL) lymphocytosis, anemia (hemoglobin [Hb] less than 11 g/dL), thrombocytopenia (less than 100,000/microL), direct Coombs' test positivity, hepatomegaly, splenomegaly, and extent of lymph node involvement were shown to be of significant prognostic value. Multivariate analyses, through a stepwise procedure, showed that the most important prognostic variables are Hb, hepatomegaly, lymph node involvement, PB lymphocytosis, and age and sex of patients. Further covariates would produce an improvement having a nonsignificant P value. Based on the results of multivariate analyses, a four-step staging using the significant variables of the Cox model is proposed. 相似文献
999.
The records of 29 consecutive patients treated by a pure, open, anterior acromioplasty were reviewed retrospectively. Excluded from consideration were patients with the following pathologic diagnoses or histories: (1) previously attempted acromioplasty on the same shoulder; (2) intraoperatively confirmed rotator cuff tear; (3) any surgically treatable biceps tendon or acromioclavicular abnormality; (4) lost to follow-up study. Three different techniques were employed to perform the acromioplasties. The first technique required partial deltoid origin detachment with an osteotome. The second technique spared the deltoid origin, while again using an osteotome to perform the acromioplasty. The third technique also spared the deltoid origin but used a high-speed burr to perform the acromioplasty. Evaluated in terms of patient satisfaction, residual pain, length of convalescence, suboptimal results, and complications, the first technique proved to be the least effective. The second technique produced early, excellent results. The third technique, in which a burr was employed through an intact deltoid origin, was most effective; technically, the method was also relatively simple and reliable. 相似文献
1000.