全文获取类型
收费全文 | 440649篇 |
免费 | 28383篇 |
国内免费 | 2953篇 |
专业分类
耳鼻咽喉 | 5995篇 |
儿科学 | 9878篇 |
妇产科学 | 11625篇 |
基础医学 | 63213篇 |
口腔科学 | 13411篇 |
临床医学 | 35937篇 |
内科学 | 90525篇 |
皮肤病学 | 9485篇 |
神经病学 | 33022篇 |
特种医学 | 16458篇 |
外国民族医学 | 126篇 |
外科学 | 68501篇 |
综合类 | 10478篇 |
现状与发展 | 1篇 |
一般理论 | 145篇 |
预防医学 | 22259篇 |
眼科学 | 10604篇 |
药学 | 35425篇 |
1篇 | |
中国医学 | 2348篇 |
肿瘤学 | 32548篇 |
出版年
2021年 | 3615篇 |
2019年 | 3623篇 |
2018年 | 5612篇 |
2017年 | 4194篇 |
2016年 | 4407篇 |
2015年 | 5058篇 |
2014年 | 6987篇 |
2013年 | 9615篇 |
2012年 | 12915篇 |
2011年 | 13181篇 |
2010年 | 8344篇 |
2009年 | 7643篇 |
2008年 | 12163篇 |
2007年 | 13124篇 |
2006年 | 13028篇 |
2005年 | 11966篇 |
2004年 | 11493篇 |
2003年 | 11007篇 |
2002年 | 10745篇 |
2001年 | 30254篇 |
2000年 | 30850篇 |
1999年 | 25533篇 |
1998年 | 6002篇 |
1997年 | 4953篇 |
1996年 | 4439篇 |
1995年 | 4123篇 |
1994年 | 3642篇 |
1993年 | 3407篇 |
1992年 | 17434篇 |
1991年 | 16155篇 |
1990年 | 15420篇 |
1989年 | 15237篇 |
1988年 | 13639篇 |
1987年 | 13125篇 |
1986年 | 12112篇 |
1985年 | 11255篇 |
1984年 | 7588篇 |
1983年 | 6234篇 |
1982年 | 3167篇 |
1981年 | 2655篇 |
1979年 | 6094篇 |
1978年 | 3716篇 |
1977年 | 3324篇 |
1975年 | 3008篇 |
1974年 | 3469篇 |
1973年 | 3205篇 |
1972年 | 3159篇 |
1971年 | 3069篇 |
1970年 | 2757篇 |
1969年 | 2767篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
151.
Clinical data of 192 patients with breast cancer with a primary lesion of 2-5 cm (stage II according to the criteria recommended by the UICC) and with histopathologically confirmed positive axillary lymph nodes were analyzed. The patients were divided into three groups: 1) surgical excision alone; 2) surgery plus irradiation; and 3) surgery plus chemotherapy. It was shown that the 5-year survival rates for these groups were 40.5%, 61.0%, and 62.0%, respectively (P less than .05). 相似文献
152.
P A Rittenhouse E A Bakkum L D Van de Kar 《The Journal of pharmacology and experimental therapeutics》1991,259(1):58-65
DOI [(+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCI] is a serotonin (5-HT1C/5-HT2) agonist, with potent cardiovascular effects. The purpose of the present studies was to determine the identity and location of the 5-HT receptor subtype(s) mediating the renin and blood pressure responses to DOI. Injection (i.p.) of DOI to conscious male rats elevated plasma renin activity in a dose-dependent manner. The 5-HT1C/5-HT2 antagonist ritanserin completely blocked the DOI-induced increase in plasma renin activity. In order to distinguish the 5-HT2- from the 5-HT1C- mediated effect of DOI, spiperone was administered before DOI. Low doses of spiperone (0.01 and 0.1 mg/kg, s.c.) significantly reduced the renin response to DOI. Because spiperone has a higher affinity for 5-HT2 than 5-HT1C receptors, these data suggest that DOI stimulates renin secretion through 5-HT2 receptors. To separate central from peripheral 5-HT receptors, we injected DOI into rats pretreated with saline or xylamidine, a 5-HT2 antagonist which does not cross the blood-brain barrier. Xylamidine produced a shift to the right and suppression of the maximal effect of DOI on plasma renin activity, suggesting a role for peripheral 5-HT2 receptors in the effect of DOI. On the other hand, i.c.v. administration of DOI, using doses lower than the peripherally effective doses, caused a significant elevation of plasma renin activity at 200 micrograms/kg. These experiments suggest that DOI's elevation of plasma renin activity has both peripheral and central sites of action.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
153.
D L Renfrew G Y el-Khoury T E Moore M H Kathol C G Whitten C W Walker M A Fraser-Hill 《Investigative radiology》1991,26(11):1019-1023
Although general suggestions have been made regarding a radiology residency curriculum, no specific list of entities has been offered. Over the past ten years, we have developed a resident-run morning conference in musculoskeletal radiology that is supervised by faculty and covers a specific curriculum. We offer our curriculum as an example that may assist other departments in developing their own curricula. 相似文献
154.
Therapy of human cervical carcinoma with monoclonal antibody-Pseudomonas exotoxin conjugates. 总被引:1,自引:0,他引:1
Pseudomonas exotoxin A (PE) linked to the F(ab')2 fragment of 1H10, a murine monoclonal antibody recognizing a carbohydrate epitope of a glycoconjugate expressed on the surface of human cervical carcinoma tumor cells, was evaluated for in vitro and in vivo activity. PE can kill cells by ADP-ribosylating elongation factor 2 thus inhibiting protein synthesis. Disulfide- as well as thioether-linked immunotoxins (1H10-PE) killed cervical carcinoma cells in vitro and were 20-160 times more inhibitory to target than to control cells. Cell killing was antibody mediated as demonstrated by the reduction of 1H10-PE growth inhibition to target CaSki cells by free 1H10 F(ab')2. In addition, a control antibody immunotoxin was nontoxic to CaSki cells. Thioether-linked 1H10-PE administered either i.v. or i.p. suppressed the growth of established solid s.c. cervical carcinoma tumors xenografted in nude mice for over 30 days. Treatment with antibody alone or a control immunotoxin had no significant effect on tumor growth. Administration of immunotoxin i.p. was associated with less toxicity than administration i.v., but i.v. injections were more effective at suppressing the growth of established solid tumors. 相似文献
155.
156.
157.
5-Amino-4-imidazolecarboxamide (AICA) riboside, the nucleoside corresponding to AICA ribotide (AICAR or ZMP), an intermediate of the de novo pathway of purine biosynthesis, was found to exert a dose-dependent inhibition on gluconeogenesis in isolated rat hepatocytes. Production of glucose from lactate-pyruvate mixtures was half-maximally inhibited by approximately 100 microM and completely suppressed by 500 microM AICA riboside. AICA riboside also inhibited the production of glucose from all other gluconeogenic precursors investigated, i.e., fructose, dihydroxyacetone, and L-proline. Measurements of intermediates of the glycolytic-gluconeogenic pathway showed that AICA riboside provoked elevations of triose phosphates and fructose-1,6-bisphosphate and decreases in fructose-6-phosphate and glucose-6-phosphate. The effects of AICA riboside persisted when the cells were washed 10 min after its addition but were suppressed by 5-iodotubercidin, an inhibitor of adenosine kinase. AICA riboside provoked a dose-dependent buildup of normally undetectable Z nucleotides. After 20 min of incubation with 500 microM AICA riboside, ZMP, ZTP, and ZDP reached 3, 0.3, and 0.1 mumol/g cells, respectively. Concentrations of ATP were not significantly modified by addition of up to 500 microM AICA riboside when the cells were incubated with lactate-pyruvate but decreased with fructose or dihydroxyacetone. The activity of rat liver fructose-1,6-bisphosphatase was inhibited by ZMP with an apparent Ki of 370 microM. It is concluded that AICA riboside exerts a suppressive effect on gluconeogenesis because it provokes an accumulation of ZMP, which inhibits fructose-1,6-bisphosphatase.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
158.
Prognostic factors in the treatment of hepatocellular carcinoma with transcatheter arterial embolization and arterial infusion. 总被引:8,自引:0,他引:8
Y Yamashita M Takahashi Y Koga R Saito S Nanakawa Y Hatanaka N Sato K Nakashima J Urata K Yoshizumi 《Cancer》1991,67(2):385-391
From January 1986 to December 1988, a prospective trial of transcatheter arterial treatment was carried out for hepatocellular carcinoma (HCC). Two hundred seventy-five patients were included. Okuda's staging system was employed. Patients with Stage I and II HCC were treated by transcatheter arterial embolization (TAE) with a gelatin sponge containing an anti-cancer agent (protocol 1a); a gelatin sponge and iodized oil mixed with an anti-cancer agent (protocol 1b); or iodized oil mixed with an anti-cancer agent (protocol 2). Patients with Stage III HCC were treated with iodized oil with anti-cancer agent (protocol 2). As an exception, patients with an unsuccessful superselective catheterization into the proper hepatic artery by Seldinger technique or obstruction of the main trunk of the portal vein were treated with percutaneous transcatheter arterial infusion into the common hepatic artery regardless of stage (protocol 3). Tumor type and extension, area of tumor involvement, portal vein involvement, method of treatment, and presence of ascites and icterus were found to be the significant factors for an initial response to therapy. Treatment method was the most important factor. Respective survival rates at 1 and 2 years were 70.9% and 55.3% for protocol 1a; 62.3% and 43.8% for protocol 1b; 37.8% and 18.3% for protocol 2; and 16.5% and 0% for protocol 3. Many factors proved to significantly influenced prognosis; however, tumor type had the most important prognostic significance followed by AFP value, ascites, treatment protocol, and area of tumor involvement. 相似文献
159.
T Uno M Takamatsu Y Inoue Y Kawahata K Iuchi G Tsukamoto 《Journal of medicinal chemistry》1987,30(12):2163-2169
A series of 6-fluoro- and 6,8-difluoro-7-(azole substituted)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids were prepared. Structure-activity relationship studies indicated that the antibacterial potency was better when the 6,8-substituents were fluorine atoms and the 7-substituent was either 1-imidazolyl, 20, or 4-methyl-1-imidazolyl, 25. From the results of studies on pharmacokinetic profile and toxicity, 20 and 25 were found to possess excellent antibacterial activities and to show high blood levels after oral administration to mice with low toxicity. 相似文献
160.