全文获取类型
收费全文 | 5991篇 |
免费 | 421篇 |
国内免费 | 88篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 116篇 |
妇产科学 | 216篇 |
基础医学 | 755篇 |
口腔科学 | 158篇 |
临床医学 | 563篇 |
内科学 | 1149篇 |
皮肤病学 | 94篇 |
神经病学 | 382篇 |
特种医学 | 272篇 |
外科学 | 828篇 |
综合类 | 381篇 |
一般理论 | 2篇 |
预防医学 | 398篇 |
眼科学 | 108篇 |
药学 | 455篇 |
4篇 | |
中国医学 | 125篇 |
肿瘤学 | 454篇 |
出版年
2023年 | 60篇 |
2022年 | 130篇 |
2021年 | 204篇 |
2020年 | 117篇 |
2019年 | 144篇 |
2018年 | 216篇 |
2017年 | 133篇 |
2016年 | 139篇 |
2015年 | 214篇 |
2014年 | 256篇 |
2013年 | 314篇 |
2012年 | 483篇 |
2011年 | 479篇 |
2010年 | 281篇 |
2009年 | 261篇 |
2008年 | 343篇 |
2007年 | 361篇 |
2006年 | 333篇 |
2005年 | 275篇 |
2004年 | 243篇 |
2003年 | 245篇 |
2002年 | 206篇 |
2001年 | 124篇 |
2000年 | 148篇 |
1999年 | 99篇 |
1998年 | 34篇 |
1997年 | 29篇 |
1996年 | 22篇 |
1995年 | 32篇 |
1994年 | 22篇 |
1993年 | 18篇 |
1992年 | 63篇 |
1991年 | 45篇 |
1990年 | 32篇 |
1989年 | 35篇 |
1988年 | 36篇 |
1987年 | 28篇 |
1986年 | 28篇 |
1985年 | 36篇 |
1984年 | 31篇 |
1983年 | 25篇 |
1982年 | 22篇 |
1981年 | 26篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 13篇 |
1977年 | 16篇 |
1976年 | 14篇 |
1975年 | 11篇 |
1974年 | 10篇 |
排序方式: 共有6500条查询结果,搜索用时 15 毫秒
991.
High levels of glucose-6-phosphatase gene and protein expression reflect an adaptive response in proliferating liver and diabetes. 总被引:6,自引:2,他引:6 下载免费PDF全文
B A Haber S Chin E Chuang W Buikhuisen A Naji R Taub 《The Journal of clinical investigation》1995,95(2):832-841
The regenerating liver after partial hepatectomy is one of the few physiologic models of cellular proliferation in the adult animal. During hepatic regeneration, the animal is able to maintain metabolic homeostasis despite the acute loss of two thirds of hepatic tissue. In examining the molecular mechanisms regulating hepatic regeneration, we isolated novel immediate-early genes that are rapidly induced as the remnant liver undergoes the transition from its normal quiescent state into the G1 phase of the cell cycle. One of the most rapidly and highly induced genes which we initially termed RL-1, encodes rat glucose-6-phosphatase (rG6Pase). G6Pase mRNA peaks at 30 min and 36-48 h after hepatectomy correlating with the first and second rounds of cell division. This finding is compatible with studies that showed that G6Pase enzyme activity increases during liver regeneration. However, the increase in G6Pase mRNA is much more dramatic, indicating that it is a more sensitive indicator of this regulation. G6Pase gene expression peaks in the perinatal time period in the liver and remains elevated during the first month of life. The expression of the G6Pase gene is also dramatically elevated in BB diabetic rats, again higher than the enzyme elevation, and its relative induction after partial hepatectomy is blunted in these animals. Insulin treatment of partially hepatectomized diabetic animals downregulates the expression of G6Pase mRNA. Using specific antibodies against G6Pase, we detect a 36-kD G6Pase protein, and its level is elevated in regenerating and diabetic livers. The pattern of G6Pase mRNA expression appears to reflect similar changes in insulin and glucagon levels which accompany diabetes and hepatic proliferation. The elevation of G6Pase expression in these conditions is indicative of its importance as a regulator of glucose homeostasis in normal and abnormal physiologic states. 相似文献
992.
In a fetal variation of circle of Willis (CoW) there is an embryological defect of the primary collateral circulation. Besides the fact that collateral flow cannot develop between anterior and posterior circulation, the tentorium namely prevents cerebellar vessels from connecting to the supra-tentorium territory. Therefore patients with a fetal variation of circle of Willis could be more prone to develop vascular insufficiency. An association between the regional cerebral blood volume (rCBV) inter-hemispheric asymmetry and CoW collateralization was observed with a topographic significance of corona radiate rather than centrum semiovale. An overview of the literature is given. We propose a fetal variation of circle of Willis as a risk factor for stroke should be subject of further investigation. 相似文献
993.
西藏自治区精神障碍流行病学调查I:重型精神障碍 总被引:4,自引:2,他引:4
WEI Geng LIU Shanming ZHANG Wei XIANG Yun HUANG Xiaoqi YANG Chuang HUANG Wenjun XIE Weijue HE Xia SU Xiaofan Wang Jia Ciren Pingcuo Baima Zuoga Ci Pu Zha Sang LIU Xiehe 《中国神经精神疾病杂志》2008,(10)
目的调查西藏精神障碍患病率,为政府制订西藏卫生工作规划提供科学依据。方法参考两次全国精神障碍流行病学调查的方法,使用美国精神障碍诊断与统计手册轴I障碍用临床定式检查执行手册/研究版(SCID-I)作为定式检查工具,并以美国精神障碍诊断与统计手册-第四版(DSM-IV)为诊断标准,对西藏具有代表性的4个地市进行精神障碍流行病学抽样调查。结果在西藏≥15岁人口中实际调查5375人,心境障碍、精神分裂症、器质性精神障碍和急性短暂精神病性障碍的时点患病率分别为0.48%,0.34%,0.17%和0.037%;终生患病率分别为0.56%,0.37%,0.17%和0.037%。结论西藏4类重型精神障碍总的终生患病率为1.14%,如何妥善解决全自治区1%人口中重型精神障碍患者的诊治问题,在政府制订卫生工作规划时有必要特别加以关注。 相似文献
994.
The role of hepatitis B and C viruses in hepatocellular carcinoma in a hepatitis B endemic area. A case-control study. 总被引:5,自引:0,他引:5
W L Chuang W Y Chang S N Lu W P Su Z Y Lin S C Chen M Y Hsieh L Y Wang S L You C J Chen 《Cancer》1992,69(8):2052-2054
To investigate the role of hepatitis B (HBV) and C viruses (HCV) in hepatocellular carcinoma (HCC) in an HBV endemic area and elucidate the interaction of these two viruses, a case-control study of 128 patients with HCC and 384 age-matched and sex-matched control subjects was done. The positive rates of hepatitis B surface antigen (HBsAg, 77.3%, 99 of 128) and anti-HCV (19.5%, 25 of 128) in patients with HCC were significantly higher than in control subjects (P less than 0.001). Both HBsAg and anti-HCV were important risk factors for HCC (relative risks, 13.96 and 27.12, respectively), and the risk for HCC was elevated significantly to 40.05 (95% confidence interval, 12.57 to 127.6) when HBsAg and anti-HCV were considered simultaneously. These results suggested that HBV and HCV were associated highly with HCC in an HBV endemic area and that these two viruses might contribute independent but synergistic effects to the pathogenesis of HCC. 相似文献
995.
自噬是细胞清除胞质中受损、缺陷或无用的细胞器、长寿命蛋白质和脂质,并回收其成分以满足生物新陈代谢的营养和能量需要的主要分解代谢过程。急性胰腺炎(AP)是常见临床急症,其发病率也逐年升高。研究显示,自噬在AP的发病过程中起到重要作用,可以导致胰腺腺泡细胞内胰蛋白酶原的激活,腺泡细胞内大液泡积聚,诱发促炎介质的释放,引起胰腺炎症细胞浸润和全身性炎症反应。笔者就自噬的分子机制以及自噬在AP发生、发展中作用机制的研究进展进行综述。 相似文献
996.
沙苑子本草考证 总被引:1,自引:0,他引:1
沙苑子为我国常用中药,药用历史悠久。通过查阅本草文献,对沙苑子名称、基原、功效、产地及伪品5个方面进行考证,得知其名称演变大致经过"白蒺藜""沙苑蒺藜""沙苑子"3个阶段;历代本草记载沙苑子基原为扁茎黄芪的干燥成熟种子,古今应用品种基本一致;沙苑子补肾固精功效的记载自宋《本草衍义》起逐渐清晰明确;沙苑子道地产区自宋时起为陕西沙苑,明清时期产地逐渐转到陕西潼关、山西等地,建国后以陕西省为主向北扩散,以陕西潼关为佳;沙苑子建国前有马薸子、色微绿伪品及紫云英子等混伪品,建国后有紫云英、猪屎豆、华黄芪和直立黄芪的种子等混伪品。为沙苑子正本清源,并为其进一步深入开发提供参考。 相似文献
997.
Conscious rats were exposed to acute hypovolemic-hypotension by bleeding (5 ml/300 g body weight). Treatment with the opiate antagonist naloxone (7 mg/kg intra-arterial) following hemorrhage resulted in an increase of systolic blood pressure but not heart rate. Changes in plasma catecholamine levels did not differ between control and naloxone-treated animals. From these results we suggest that the ability of naloxone to improve blood pressure after hemorrhage is not due to increased sympatho-adrenomedullary activity. 相似文献
998.
A graded dose assessment of the efficacy of beclomethasone dipropionate aerosol for severe chronic asthma. 总被引:7,自引:0,他引:7
J H Toogood N M Lefcoe D S Haines B Jennings N Errington L Baksh L Chuang 《The Journal of allergy and clinical immunology》1977,59(4):298-308
In a 26-wk double-blind controlled study of 34 patients whose asthma had been poorly controlled despite oral steroids, valuable clinical and pulmonary function improvement was derived by adding beclomethasone aerosol to the prednisone regimen. The amount of improvement correlated linearly with beclomethasone dosage over the range 200 to 1,600 microng/day. These patients required relatively high dosage. Success in achieving asymptomatic status was only 26% with the conventional 400 microng/day and 60% at 1,600 microng/day. Oropharyngeal candidiasis was also dose-related but did not prohibit the use of high-dosage beclomethasone. Respiratory infections, physical signs, blood glucose, and electrolytes were unaffected by the drug. A dose-related suppression of cortisol secretion was demonstrated, but about 1/4 of the group had normal plasma cortisol even at 1,600 microng/day plus the oral prednisone. An individualized risk-benefit assessment seems a better basis for choosing an optimal beclomethasone regimen for each patient than adherence to a conventionalized fixed dosage of 400 microng/day. This requires definition of: (1) a specific goal of treatment in the individual patient and the beclomethasone dosage required to achieve it; (2) the adrenocortical functional response of that particular patient to the desired dose of beclomethasone; and (3) the presence and degree of any dose-limiting constraints such as preexisting complications of steroid use. 相似文献
999.
Nerve transfer (or nerve crossover) is a well established technique for achieving reinnervation of a valuable sensory or motor territory by reconnection using a functional nerve of lesser value. Patients with lower spinal cord lesions causing neurogenic bladder dysfunction could theoretically benefit from such an approach for return of useful micturition. Based on the known anatomical details of the spinal nerve, a new reconstructive method was created to provide intradural ventral root transfer for pure motor-to-motor reinnervation and extradural postganglionic spinal nerve transfer for pure sensory-to-sensory reinnervation. Experimental studies in rats were performed, demonstrating the feasibility of this approach. A modified method is further suggested that would use nerve grafts for extradural approaches to pure motor and sensory transfers, without the need for extensive laminectomy and dura opening. This proposed approach is anticipated to minimize the associated morbidity and mortality with such spinal nerve reconstruction. 相似文献
1000.
刘鑫宇|贺彦宇|彭创|彭沙勇|刘苏来|杨平洲 《中国普通外科杂志》2018,27(2):193-198
目的:探讨黏蛋白3(MUC3)和黏蛋白4(MUC4)在结石相关肝内胆管细胞癌(ICC)组织中的表达及临床意义。方法:用免疫组化法检测MUC3、MUC4在24例正常胆管组织、44例肝内肝管结石胆管组织、38例结石相关ICC组织中的表达,分析两者表达与ICC患者临床病理因素及预后的关系。结果:MUC3与MUC4在3种组织中的表达均有统计学差异(均P0.05),在正常胆管组织、结石患者胆管组织,结石相关ICC组织中MUC3的表达阳性率依次降低(79.2%、56.8%、36.8%),而MUC4的表达阳性率则相反(29.2%、79.5%、86.8%)。两者的表达均与结石相关ICC患者的肿瘤组织学分级、有无淋巴结转移有关,且MUC4的表达与门静脉有无浸润有关(均P0.05)。结石相关ICC患者中,MUC3阳性表达者术后生存率明显高于阴性患者,MUC4阳性表达患者术后生存率明显低于阴性表达患者(均P0.05)。结论:在结石相关ICC组织中,MUC3表达降低,而MUC4的表达升高,两者表达的变化与结石相关ICC的进展、侵袭及转移紧密相关。 相似文献