全文获取类型
收费全文 | 324135篇 |
免费 | 29083篇 |
国内免费 | 22880篇 |
专业分类
耳鼻咽喉 | 2986篇 |
儿科学 | 3422篇 |
妇产科学 | 4925篇 |
基础医学 | 39947篇 |
口腔科学 | 5493篇 |
临床医学 | 45255篇 |
内科学 | 49700篇 |
皮肤病学 | 3082篇 |
神经病学 | 18364篇 |
特种医学 | 11977篇 |
外国民族医学 | 213篇 |
外科学 | 33211篇 |
综合类 | 49856篇 |
现状与发展 | 76篇 |
一般理论 | 20篇 |
预防医学 | 19614篇 |
眼科学 | 9570篇 |
药学 | 32793篇 |
334篇 | |
中国医学 | 17397篇 |
肿瘤学 | 27863篇 |
出版年
2024年 | 1002篇 |
2023年 | 5013篇 |
2022年 | 13045篇 |
2021年 | 16388篇 |
2020年 | 12035篇 |
2019年 | 10843篇 |
2018年 | 11410篇 |
2017年 | 9915篇 |
2016年 | 9357篇 |
2015年 | 14350篇 |
2014年 | 17797篇 |
2013年 | 15342篇 |
2012年 | 22803篇 |
2011年 | 25805篇 |
2010年 | 15902篇 |
2009年 | 12249篇 |
2008年 | 17014篇 |
2007年 | 17017篇 |
2006年 | 17051篇 |
2005年 | 16774篇 |
2004年 | 10664篇 |
2003年 | 9758篇 |
2002年 | 8438篇 |
2001年 | 7465篇 |
2000年 | 8276篇 |
1999年 | 9017篇 |
1998年 | 5475篇 |
1997年 | 5499篇 |
1996年 | 4332篇 |
1995年 | 3922篇 |
1994年 | 3213篇 |
1993年 | 2097篇 |
1992年 | 2827篇 |
1991年 | 2415篇 |
1990年 | 2117篇 |
1989年 | 1861篇 |
1988年 | 1563篇 |
1987年 | 1352篇 |
1986年 | 1107篇 |
1985年 | 912篇 |
1984年 | 526篇 |
1983年 | 373篇 |
1982年 | 242篇 |
1981年 | 238篇 |
1980年 | 188篇 |
1979年 | 221篇 |
1978年 | 82篇 |
1977年 | 89篇 |
1974年 | 102篇 |
1973年 | 83篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
We detected the presence and distribution of HBcAg in the liver by immunohistochemistry (ABC method) and the presence of HBV-DNA in serum (spot hybridization) and anti-HBe in serum (ELISA) from 59 cases of hepatitis B hospitalized in our hospital, including 47 cases of CAH, 5 cases of CPH, and 7 cases of subacute fulminant hepatitis. 1. HBcAg in the liver was detected in 25 out of 47 cases (53%) of CAH, in 2 out of 5 cases of CPH and in 4 out of 7 cases of subacute fulminant hepatitis. The total percentage was 53% (31/59). 2. There was no positive correlation between HBV replication activity and liver disease activity (P greater than 0.05). Our results did not support the hypothesis that suggests a direct cytopathic effect of HBV. Oppositely, the fact was that the presence, the amount and the patterns of HBcAg in the liver, and the presence of HBV-DNA in serum were predominant in mild CAH compared with those in severe CAH, predominant in CAH without cirrhosis compared with those in CAH with cirrhosis. There was a tendency of inverse correlation between HBV replication activity and liver disease activity. The results above were in line with the concept that HBcAg expressed on the surface of infected hepatocytes may be relevant target for T lymphocyte cytotoxicity. The results have suggested that an immune response to HBV is present, leading to the destruction of most infected cells. 3. There was a positive correlation between HBV-DNA in serum and HBcAg in the liver (P less than 0.005), indicating that HBV-DNA in serum can represent HBV replication.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
992.
An elevated serum cholesterol level is a well known major risk factor for developing atherosclerosis in general, and for coronary heart disease in particular. There are many lipid lowering agents currently available. We used gemfibrozil in twenty hyperlipidemic cases who failed to response to diet control for three months. They were thirteen males and seven females with their ages ranging from thirty to eighty-one year-old. They included ten diabetes, one nephrotic syndrome and nine pure hyperlipidemic patients. All cases received gemfibrozil 600mg twice daily for 4-12 weeks. Gemfibrozil caused an increase in HDL cholesterol. The reductions in serum level of total cholesterol, total cholesterol/HDL cholesterol, and triglyceride were found. Only one case developed mild gastrointestinal side effect. There was no other major side effects. 相似文献
993.
994.
目的探讨交叉韧带重建术中可吸收挤压螺钉的使用方法和疗效。方法总结53例交叉韧带重建病例使用可吸收挤压螺钉的情况,在术中、术后并发症、术后康复、膝关节功能状况等方面进行回顾性分析。结果三例出现韧带切割现象。两例股骨侧螺钉拧入后导引针无法拔出。一例挤压螺钉断裂。术后Lysholm评分平均92.4±4.1。结论交叉韧带重建术中使用可吸收挤压螺钉固定的方法固定牢固,术后恢复快,利于早期康复。 相似文献
995.
本文用显微分光光度计对39例手术切除的不同组织学类型的人体肺癌标本癌细胞核的DNA含量进行了测量。其中高、中、低分化的鳞癌分别为3、6和5例;高、中、低分化的腺癌分别为3、5和5例;未分化癌大细胞型和小细胞型各为3例和6例。结果发现各类型肺癌的DNA含量均有统计学上的差异(P<0.01)。各DNA含量直方图的峰值部位及分布范围亦不同。从而提示了根据DNA含量的不同,可能有助于肺癌组织学类型及其分化程度的判别:而DNA含量直方图对肺癌类型的判别亦可能是有益的。 相似文献
996.
997.
998.
本文通过分析近5年来我院18例女性直肠癌全直肠系膜切除术后直肠阴道痿的临床资料。发现直肠阴道痿多发生于中低位直肠癌行全直肠系膜切除保肛手术的患者。痿的发生与肿瘤的位置、肿瘤的分期、肿瘤距肛门口的距离.以及手术技巧、手术难度、引流方法有关。而与是否进行预防性造口,以及是否采用腹腔镜手术无关。预防上强调应重视术中直肠前壁的锐性分离、结肠直肠吻合以及术后盆腔的负压引流。治疗上应首先进行保守治疗,即肠内营养,阴道冲洗。早期配合肠外营养、及全身或局部抗炎治疗,大部分直肠阴道痿通过保守治疗可以治愈。保守治疗无效时考虑结肠或回肠末端造口。若长期不愈应考虑吻合口肿瘤复发的可能。 相似文献
999.
Hongbo Wang Songyun Li Laurent Givalois & Georges Pelletier 《Journal of neuroendocrinology》1998,10(3):193-198
Recently, an 86-amino acid polypeptide with high affinity for diazepam binding sites, termed diazepam-binding inhibitor (DBI), has been found in the rat brain. DBI, as well as a peptide derived from DBI, the octadecaneuropeptide DBI[33–50] (ODN), interacts with the GABAA receptor complex. To investigate the role of these endogenous ligands for GABAA receptors on prolactin gene expression, we studied the effects of acute intracerebroventricular administration (4 h before sacrifice) of ODN on prolactin mRNA levels in the male rat. Because, in some neuropeptidergic systems, glucocorticoids play a role in the response to ODN, we also studied the influence of adrenal glands and the effect of dexamethasone administration in the response of prolactin gene expression to ODN. ODN injection produced an increase in prolactin mRNA levels. Adrenalectomy performed 5 days before sacrifice resulted in an increase in prolactin gene expression and also potentiated the stimulating effect of ODN. Because castration has been shown to decrease prolactin gene expression in the male rat, we used castrated and adrenalectomized animals to study the role of dexamethasone in the response of lactotrophs to ODN. In these steroid-deprived animals, dexamethasone treatment (for 4 days) decreased prolactin mRNA levels but did not modify the response to ODN. These data indicate that an endogenous neuropeptide interacting with the GABAA receptor complex can stimulate prolactin gene expression and suggest that the adrenal glands may produce factor(s) capable of decreasing prolactin mRNA. On the other hand, it does not appear that glucocorticoid hormones play a role in the effect of ODN on lactotroph activity. 相似文献
1000.
R. Grant Steen Wilburn E. Reddick Raymond K. Mulhern James W. Langston Robert J. Ogg Andrea A. Bieberich Peter B. Kingsley Winfred C. Wang 《Journal of magnetic resonance imaging : JMRI》1998,8(3):535-543
Conventional MRI (cMRI) has shown that brain abnormalities without clinical stroke can manifest in patients with sickle cell disease (SCD). We used quantitative MRI (qMRI) and psychometric testing to determine whether brain abnormalities can also be present in patients with SCD who appear normal on cMRI. Patients 4 years of age and older with no clinical evidence of stroke were stratified by cMRI as normal (n = 17) or abnormal (n = 13). Spin-lattice relaxation time (T1) of gray and white matter structures was measured by the precise and accurate inversion recovery (PAIR) qMRI method. Patient cognitive ability was assessed with a standard psychometric instrument (WISC-III or WISC-R). In all 30 patients with SCD, qMRI T1 was lower than in 24 age- and race-matched controls, in cortical gray matter (P < .0006) and caudate (P < .0009), as well as in the ratio of gray-to-white matter T1 (P < .008). In the 17 patients who were shown to be normal by cMRI, qMRI T1 was still lower than in controls, in both cortical gray matter (P < .02) and caudate (P < .004). Histograms of voxel T1 show that the proportion of voxels with T1 values intermediate between gray and white matter (ie, consistent with encephalomalacia) was 9% higher than controls in patients shown to be normal by cMRI (P < .05) and 15% higher than controls in patients shown to be abnormal by cMRI (P < .0005). The full scale intelligence quotient (FSIQ) of all patients with SCD was 75, compared to the FSIQ of 88 in a historical control group of patient siblings (P < .001). The FSIQ of patients shown to be normal by cMRI was 79, significantly lower than the FSIQ of patient siblings (P < .04). The FSIQ of 71 in patients shown to be abnormal by cMRI was significantly lower than both the patient siblings (P < .005) and the patients shown to be normal by cMRI (P < .04). Patients shown to be abnormal by cMRI scored lower than patients shown to be normal by cMRI, specifically on the subtests of vocabulary (P = .003) and information (P = .03). Cognitive impairment is thus significant, even in patients with SCD who were shown to be normal by cMRI, suggesting that cMRI may be insensitive to subtle neurologic damage that can be detected by qMRI. Because cognitive impairment can occur in children normal by cMRI, our findings imply that prophylactic therapy may be needed earlier in the course of SCD to mitigate neurologic damage. 相似文献