全文获取类型
收费全文 | 240772篇 |
免费 | 20862篇 |
国内免费 | 14266篇 |
专业分类
耳鼻咽喉 | 2183篇 |
儿科学 | 3040篇 |
妇产科学 | 4895篇 |
基础医学 | 28415篇 |
口腔科学 | 4244篇 |
临床医学 | 30624篇 |
内科学 | 38844篇 |
皮肤病学 | 2845篇 |
神经病学 | 13529篇 |
特种医学 | 8652篇 |
外国民族医学 | 97篇 |
外科学 | 26592篇 |
综合类 | 34483篇 |
现状与发展 | 50篇 |
一般理论 | 45篇 |
预防医学 | 14733篇 |
眼科学 | 6670篇 |
药学 | 24250篇 |
166篇 | |
中国医学 | 11007篇 |
肿瘤学 | 20536篇 |
出版年
2024年 | 492篇 |
2023年 | 3116篇 |
2022年 | 6057篇 |
2021年 | 11402篇 |
2020年 | 8384篇 |
2019年 | 7596篇 |
2018年 | 8026篇 |
2017年 | 7024篇 |
2016年 | 6689篇 |
2015年 | 10172篇 |
2014年 | 12818篇 |
2013年 | 11993篇 |
2012年 | 17695篇 |
2011年 | 19370篇 |
2010年 | 11820篇 |
2009年 | 9471篇 |
2008年 | 12867篇 |
2007年 | 12898篇 |
2006年 | 12495篇 |
2005年 | 12566篇 |
2004年 | 8720篇 |
2003年 | 7759篇 |
2002年 | 6732篇 |
2001年 | 6081篇 |
2000年 | 6209篇 |
1999年 | 6491篇 |
1998年 | 3695篇 |
1997年 | 3695篇 |
1996年 | 2825篇 |
1995年 | 2610篇 |
1994年 | 2251篇 |
1993年 | 1509篇 |
1992年 | 2303篇 |
1991年 | 2005篇 |
1990年 | 1674篇 |
1989年 | 1463篇 |
1988年 | 1271篇 |
1987年 | 1161篇 |
1986年 | 938篇 |
1985年 | 752篇 |
1984年 | 492篇 |
1983年 | 381篇 |
1982年 | 226篇 |
1981年 | 202篇 |
1980年 | 191篇 |
1979年 | 244篇 |
1978年 | 141篇 |
1977年 | 112篇 |
1976年 | 97篇 |
1974年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Antibodies to glutamic acid decarboxylase discriminate major types of diabetes mellitus. 总被引:13,自引:0,他引:13
Insulin-dependent diabetes mellitus (IDDM) is marked by circulating antibodies to a 64,000-M(r) islet cell antigen identified as glutamic acid decarboxylase (GAD). We describe a radioimmunoprecipitation assay with GAD isolated from pig brain. The sera tested were from 80 patients with IDDM including 26 with disease of recent onset and 54 with disease of longer duration (3-42 yr), 20 with non-insulin-dependent diabetes mellitus (NIDDM), and 55 nondiabetic subjects. Conventional assays for islet cell cytoplasmic antibodies were performed concurrently. The level of antibody in serum was expressed in units based on percentage reactivity of a standard reference serum. The frequency of antibody to GAD in IDDM was 69% in short-duration cases and 59% in long-duration cases. The latter was substantially higher than the frequency of islet cell cytoplasmic antibody. Antibodies to GAD were elevated (means +/- 3 SD) in 5% NIDDM cases and in none of the nondiabetic subjects. A simple laboratory test with a defined autoantigen has substantial implications for population screening and early diagnosis of IDDM and for better understanding of its pathogenesis. 相似文献
992.
采用大鼠30%Ⅲ度烫伤模型,应用光镜、电镜、3β-羟甾脱氢酶(3β-HSD)组织化学染色及其相对活性的测定和血清睾酮及黄体生成素(LH)浓度的检测,分不同时相对严重烫伤后30天内大鼠睾丸间质细胞的改变进行了动态观察。结果表明,烫伤后睾丸间质细胞有不同程度的变性、坏死;间质细胞内3β-HSD活性迅速降低,伤后30天仍保持较低水平;血清睾酮水平迅速下降,并持续维持较低水平,伤后30天仍不回升,而血清LH浓度无明显改变。提示烫伤后血清睾酮下降的机理可能与睾丸间质细胞的受损及糖皮质激素升高有关。 相似文献
993.
Alveolar hydatid disease of the liver: computed tomography and transabdominal ultrasound with histopathological correlation. 总被引:5,自引:0,他引:5
K Choji N Fujita M Chen A S Spiers Y Morita M Shinohara T Nojima G Irie 《Clinical radiology》1992,46(2):97-103
The appearances of alveolar hydatid disease of the liver (AHDL) on computed tomography (CT) and ultrasound (US) were retrospectively compared with histopathological appearances in 67 patients with 100 separate lesions. The radiological features were correlated directly with the pathological specimens obtained from each patient. We conclude that the CT appearances are more specific, but that US has a role to play in mass screening in endemic areas, and intraoperatively. 相似文献
994.
用YAG、CO_2激光按不同功率照射家兔眼,观察对角膜、虹膜、晶状体的损伤和修复过程,探索两种激光对角膜的最小损伤和使其穿孔的有效功率。结果发现:YAG激光用230~250mW(1~2秒)时,可使角膜上皮呈灰白色混浊,1~2W(5~6秒)时角膜穿孔;CO_2激光用340~380mW(0.2~2秒)时,同样使角膜上皮灰白色混浊,1.3~1.4W(1秒)时角膜穿孔,在功率、照射时间、光斑相同的条件下,CO_2激光对角膜损伤重,YAG激光则对虹膜、晶状体损伤重。 相似文献
995.
996.
胃癌单克隆抗体-丝裂霉素C结合物的制备及其细胞毒特征 总被引:1,自引:1,他引:0
作者报道胃癌单克隆抗体MG11-丝裂霉素C(MMC)结合物的制备及其对肿瘤细胞的杀伤作用。首先用戊二酐处理MMC,于MMC上引入羧基,MMC衍生物与N羟基琥珀酰亚胺及2,2′-二环已基碳二亚胺反应,得到MMC活性酯,后者与抗体反应将MMC引入抗体中。经测定,每克分子抗体中引入约6~7克分子药物,结合物对人胃癌细胞KATⅢ具有较强的选择性杀伤作用,在0.56μg/ml水平(药物浓度)对肿瘤细胞杀伤牢达60%,优于游离药物(51%)及无关抗体结合物(9.3%),提示选用的胃癌单抗对MMC具有较好的导向作用。 相似文献
997.
S Y Yousufzai A L Chen A A Abdel-Latif 《The Journal of pharmacology and experimental therapeutics》1988,247(3):1064-1072
Comparative studies on the effects of prostaglandins (PGs) on 1,2-diacylglycerol, measured as phosphatidic acid (PA), and inositol trisphosphate (IP3) production, cyclic AMP (cAMP) formation, myosin light chain (MLC) phosphorylation and contraction in the iris sphincter smooth muscle of rabbit, bovine and other mammalian species were undertaken and functional and biochemical relationships between the IP3-Ca++ and cAMP second messenger systems were demonstrated. The findings obtained from these studies can be summarized as follows: 1) all PGs investigated, including PGE2, PGF2 alpha, PGF2 alpha-ester, PGE1 and PGA2 increased IP3 accumulation and PA formation, and the extent of stimulation was dependent on the animal species. Thus, PGF2 alpha-ester (1 microM), the most potent of the PGs, increased IP3 accumulation in rabbit and bovine sphincters by 33 and 58%, respectively, and increased PA formation by 67 and 56%, respectively. The PG increased IP3 accumulation in both rabbit and bovine sphincters very rapidly (T1/2 values about 26 sec) and in a dose-dependent manner. 2) The PG had no effect on MLC phosphorylation in the rabbit sphincter, but it increased that of the bovine by 36%. 3) The PG increased cAMP formation by 75% in the rabbit sphincter but it had no effect on that of the bovine. 4) The PG induced a maximal contractile response in the bovine sphincter but it had no effect on that of the rabbit. 5) In the bovine, PGA2 induced IP3 accumulation and contraction, without an effect on cAMP formation; however, in the rabbit, cat and dog it increased cAMP formation and had no effect on IP3 accumulation and contraction.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
998.
999.
陈永昌 《江苏大学学报(医学版)》1995,(1)
以氨基比林聚集为间接的泌酸指标,本实验观察了急性分离的大鼠胃粘膜壁细胞对EGF的反应。结果表明:1.急性分离后30分钟左右,壁细胞对较大剂量的EGF(100nM)的反应为胃酸分泌的减少;2.急性分离后60分钟左右,壁细胞对EGF(0.1-100nM)的反应为泌酸活动的加强。结果提示壁细胞被分离后经历一功能恢复的过程,EGF对壁细胞的生理作用可能是加强其泌酸活动。 相似文献
1000.
本文报道19例外伤或手术后膜性白内障行后房型人工晶体植入联合囊膜切开术或Nd:YAG激光囊膜切开,收到较好的效果,12例视力≥0.3,9例≥0.5。对手术及YAG激光治疗的并发症及预防措施作简要论述。 相似文献