全文获取类型
收费全文 | 898657篇 |
免费 | 63412篇 |
国内免费 | 2327篇 |
专业分类
耳鼻咽喉 | 12474篇 |
儿科学 | 28680篇 |
妇产科学 | 26145篇 |
基础医学 | 126583篇 |
口腔科学 | 24684篇 |
临床医学 | 74762篇 |
内科学 | 183151篇 |
皮肤病学 | 18985篇 |
神经病学 | 71391篇 |
特种医学 | 36445篇 |
外国民族医学 | 336篇 |
外科学 | 142124篇 |
综合类 | 19029篇 |
一般理论 | 247篇 |
预防医学 | 64567篇 |
眼科学 | 20083篇 |
药学 | 63809篇 |
中国医学 | 1798篇 |
肿瘤学 | 49103篇 |
出版年
2018年 | 9051篇 |
2017年 | 7161篇 |
2016年 | 7674篇 |
2015年 | 8724篇 |
2014年 | 12368篇 |
2013年 | 19209篇 |
2012年 | 25653篇 |
2011年 | 27260篇 |
2010年 | 16574篇 |
2009年 | 15784篇 |
2008年 | 26129篇 |
2007年 | 27740篇 |
2006年 | 27915篇 |
2005年 | 27446篇 |
2004年 | 26294篇 |
2003年 | 25464篇 |
2002年 | 25059篇 |
2001年 | 41356篇 |
2000年 | 42556篇 |
1999年 | 36265篇 |
1998年 | 9967篇 |
1997年 | 9148篇 |
1996年 | 9082篇 |
1995年 | 8446篇 |
1994年 | 8081篇 |
1993年 | 7584篇 |
1992年 | 28201篇 |
1991年 | 26979篇 |
1990年 | 26410篇 |
1989年 | 25346篇 |
1988年 | 23553篇 |
1987年 | 23174篇 |
1986年 | 22252篇 |
1985年 | 21152篇 |
1984年 | 15806篇 |
1983年 | 13477篇 |
1982年 | 8087篇 |
1979年 | 14589篇 |
1978年 | 10208篇 |
1977年 | 8627篇 |
1976年 | 8147篇 |
1975年 | 8960篇 |
1974年 | 10697篇 |
1973年 | 10182篇 |
1972年 | 9661篇 |
1971年 | 8917篇 |
1970年 | 8584篇 |
1969年 | 8025篇 |
1968年 | 7684篇 |
1967年 | 7087篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
F T McDermott G Whelan D J St John G L Barnes R Elliott R Herrmann G T Schmidt R A Smallwood 《The Medical journal of Australia》1987,146(10):525, 528-525, 529
Information on the relative incidence of Crohn's disease and ulcerative colitis was obtained by a prospective investigation at six Melbourne teaching hospitals. One hundred and eleven patients who presented with chronic inflammatory bowel diseases between 1980-1981 were admitted to the study. Forty (36%) patients were diagnosed as having Crohn's disease and 63 (57%) patients as having ulcerative colitis. The type of chronic inflammatory bowel disease could not be determined in eight (7%) patients. These findings suggest that the relative frequency of Crohn's disease and ulcerative colitis in Melbourne hospitals is within the range that is reported for northern Europe and the United States. 相似文献
993.
M A Bernhisel J F Holman A F Haney D W Schomberg 《The Journal of clinical endocrinology and metabolism》1987,64(6):1251-1256
The role(s) of androgens in the steroidogenic regulation of human granulosa cell production of estrogen and progesterone during monolayer culture was studied. These cells were exposed in vivo to human menopausal gonadotropin and hCG gonadotropin with or without clomiphene citrate. Steroid production rates were compared between cells cultured in control medium and those cultured in medium containing a nonaromatizable androgen [dihydrotestosterone (DHT)] or an aromatizable androgen [androstenedione (A'D)]. Some cultures received A'D from 3-12 days; other cultures received DHT alone for 3, 6, or 9 days before the addition of A'D for 3 days. The effect on steroid production during the culture interval before the addition of A'D also was evaluated. Exposure to A'D increased estrogen production over 50-fold compared with that in control cells or those treated with DHT (P less than 0.001). DHT also failed to alter estrogen production when A'D was added to cultures. Furthermore, the delay in introducing A'D to the cultures for up to 9 days did not decrease subsequent estrogen production compared with that in cultures continually exposed to A'D or DHT plus A'D. Progesterone production was substantial for at least 12 days of culture and was unaffected by the presence of androgen. These results do not confirm previous studies using murine or porcine granulosa cells, which suggested that androgen receptor-dependent mechanisms were involved in increasing estrogen and/or progesterone production in vitro. Rather, they indicate that androgen may not be required to maintain aromatase capability per se in human granulosa-luteal cells previously exposed to ovulation-inducing quantities of gonadotropin. 相似文献
994.
G N Hortobagyi D Frye F A Holmes V Hug G Fraschini A U Buzdar 《Cancer treatment reports》1987,71(12):1193-1196
Thirty patients with progressive metastatic breast cancer and one prior chemotherapy regimen were treated with iproplatin at a starting dose of 300 mg/m2 iv every 3 weeks. After the first 11 patients, the starting dose was decreased to 270 mg/m2. There were one complete remission, three partial remissions, and two minor responses. Responses were observed in soft tissue and osseous and visceral areas. Grade 3 nausea and vomiting were observed in 38% of patients, and grade 3 diarrhea occurred in 31%. The dose-limiting toxicity was thrombocytopenia, which required dose de-escalation in 15 patients. No nephrotoxicity, neurotoxicity, or ototoxicity was observed. Iproplatin has modest antitumor activity in this group of previously treated patients with metastatic breast cancer. 相似文献
995.
996.
997.
998.
999.
1000.
Dipyridamole and RA-642 inhibit the production of superoxide anion and free radical damage to rat lens. 总被引:1,自引:0,他引:1
J P De la Cruz A Sintas A Moreno J Garcia-Campos F Sanchez de la Cuesta 《Pharmacology & toxicology》1991,69(3):201-204
We studied the effects of dipyridamole and RA-642 on the production of superoxide anions and on oxygen radicals-induced lipid peroxidation in lens tissue homogenates from normal rats and rats given dipyridamole or RA-642 intraperitoneally. Superoxide production was evaluated by phenazine methosulphate (PMS)-induced nitroblue tetrazolium (NBT) reduction and lipid peroxidation by ferrous sulfate and ascorbic acid (FeAs)-induced malondialdehyde (MDA) production. Dipyridamole and RA-642 showed an inhibitory effect on both assays in the experiments with lens tissue homogenates from untreated or treated rats. The extent of inhibition, however, was significantly higher in pyrimidopyrimidinic-treated rats (range of inhibition at different times of incubation was 18% versus 23-57% for dipyridamole and 14% versus 73-80% for RA-642 in the assay of MDA production, and 10% versus 33-37% for dipyridamole and 2.5% versus 11-32% for RA-642 in the assay of NBT reduction). Concentrations of dipyridamole and RA-642 in lens tissue from treated animals could not be determined (less than 0.001 micrograms/mg of tissue). Although both compounds inhibited lipid peroxidation induced by oxygen free radicals, the mechanism of action might include the role of adenosine as a mediator. 相似文献