全文获取类型
收费全文 | 4190篇 |
免费 | 425篇 |
国内免费 | 232篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 54篇 |
妇产科学 | 24篇 |
基础医学 | 620篇 |
口腔科学 | 42篇 |
临床医学 | 541篇 |
内科学 | 702篇 |
皮肤病学 | 75篇 |
神经病学 | 337篇 |
特种医学 | 134篇 |
外国民族医学 | 1篇 |
外科学 | 440篇 |
综合类 | 464篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 318篇 |
眼科学 | 108篇 |
药学 | 371篇 |
中国医学 | 216篇 |
肿瘤学 | 378篇 |
出版年
2024年 | 8篇 |
2023年 | 87篇 |
2022年 | 171篇 |
2021年 | 179篇 |
2020年 | 146篇 |
2019年 | 136篇 |
2018年 | 136篇 |
2017年 | 110篇 |
2016年 | 125篇 |
2015年 | 173篇 |
2014年 | 202篇 |
2013年 | 196篇 |
2012年 | 309篇 |
2011年 | 338篇 |
2010年 | 245篇 |
2009年 | 233篇 |
2008年 | 301篇 |
2007年 | 258篇 |
2006年 | 270篇 |
2005年 | 220篇 |
2004年 | 138篇 |
2003年 | 132篇 |
2002年 | 110篇 |
2001年 | 77篇 |
2000年 | 62篇 |
1999年 | 65篇 |
1998年 | 56篇 |
1997年 | 33篇 |
1996年 | 39篇 |
1995年 | 34篇 |
1994年 | 21篇 |
1993年 | 18篇 |
1992年 | 39篇 |
1991年 | 19篇 |
1990年 | 28篇 |
1989年 | 23篇 |
1988年 | 18篇 |
1987年 | 19篇 |
1986年 | 13篇 |
1985年 | 17篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1971年 | 2篇 |
1966年 | 2篇 |
1935年 | 1篇 |
排序方式: 共有4847条查询结果,搜索用时 15 毫秒
101.
103.
104.
目的观察直丝弓矫治技术联合前方牵引矫治恒牙早期骨性Ⅲ类错患者治疗前、后软硬组织及牙的变化。方法选择符合纳入标准的17例恒牙早期骨性Ⅲ类错患者,采用直丝弓矫治技术联合前方牵引进行治疗,配合快速扩弓,并对治疗前、后头颅侧位片进行测量分析比较。结果矫治结束后覆盖及磨牙关系发生了显著变化,前牙反解除,患者凹面型改善;SNA角平均增加1.37°,A点前移,下颌骨向下向后旋转,ANB角趋于正常。结论恒牙早期骨性Ⅲ类错患者由于生长潜力有限,直丝弓矫治技术联合前方牵引是有效的矫治方法之一。 相似文献
105.
目的检测氧化应激相关基因Nrf2、GST-π、HO1在4NQO小鼠舌癌标本中的表达水平,分析氧化损伤对4NQO诱导的小鼠口腔癌的促进作用。方法 190只8周龄雄性C57BL/6J小鼠随机分为阴性对照组、阳性对照组、6%、15%和30%过氧化氢处理组。阴性对照组不做任何处理,其余4组以0.005%4NQO诱癌16周后,分别用水(阳性对照组)和6%、15%、30%的过氧化氢涂抹小鼠舌部,每周3次,共8周。第24周末处死全部动物,取舌组织进行组织病理学分析及免疫组化染色。结果在粘膜从正常到异常增生、再到癌变的过程中,Nrf2、GST-π和HO1的表达持续升高,并且30%过氧化氢组中重度异常增生和癌变的组织中上述三者的积分光密度值显著高于阳性对照组(P0.01);6%和15%组中,GST-π的积分光密度值均显著高于阳性对照组(P0.05),Nrf2和HO1的积分光密度值与阳性对照组无统计学差异。结论过氧化氢造成的氧化损伤进一步促进了4NQO小鼠口腔癌的发展。 相似文献
106.
107.
Jide Tian Hoa Dang Zheying Chen Alice Guan Yingli Jin Mark A. Atkinson Daniel L. Kaufman 《Diabetes》2013,62(11):3760-3765
γ-Aminobutyric acid (GABA) has been shown to inhibit apoptosis of rodent β-cells in vitro. In this study, we show that activation of GABAA receptors (GABAA-Rs) or GABAB-Rs significantly inhibits oxidative stress–related β-cell apoptosis and preserves pancreatic β-cells in streptozotocin-rendered hyperglycemic mice. Moreover, treatment with GABA, or a GABAA-R– or GABAB-R–specific agonist, inhibited human β-cell apoptosis following islet transplantation into NOD/scid mice. Accordingly, activation of GABAA-Rs and/or GABAB-Rs may be a useful adjunct therapy for human islet transplantation. GABA-R agonists also promoted β-cell replication in hyperglycemic mice. While a number of agents can promote rodent β-cell replication, most fail to provide similar activities with human β-cells. In this study, we show that GABA administration promotes β-cell replication and functional recovery in human islets following implantation into NOD/scid mice. Human β-cell replication was induced by both GABAA-R and GABAB-R activation. Hence, GABA regulates both the survival and replication of human β-cells. These actions, together with the anti-inflammatory properties of GABA, suggest that modulation of peripheral GABA-Rs may represent a promising new therapeutic strategy for improving β-cell survival following human islet transplantation and increasing β-cells in patients with diabetes.A central focus of research in the type 1 diabetes (T1D) field is to develop ways to safely improve β-cell survival and function and promote their replication. The addition of γ-aminobutyric acid (GABA) or the GABAB receptor (GABAB-R)–specific agonist baclofen to culture media has been shown to inhibit β-cell apoptosis in cultured rodent cell lines and islets (1,2). It remains to be determined whether GABA treatment can inhibit mouse β-cell apoptosis in vivo or, more importantly, whether it can protect human β-cells from stress-induced apoptosis. If GABA can inhibit human β-cell apoptosis, elucidating whether this effect is mediated through the G-protein–coupled GABAB-Rs, and/or the chloride channel GABAA-Rs will enable more specific drug targeting.GABA can promote neurogenesis and neuronal proliferation and is a neuronal survival factor (3–8). GABA has also been shown to promote rodent β-cell replication (1,2). Those studies, however, differentially pointed to GABAA-Rs or GABAB-Rs as modulators of GABA’s effects, making it important to clarify whether one or both types of GABA receptors modulate rodent β-cell replication. While a number of mitogens and growth factors can promote rodent β-cell replication, most fail to promote human β-cell replication (reviewed in refs. 9,10). Therefore, a key question is whether GABA can promote human β-cell replication. Even a small amount of GABA-induced human β-cell replication may be clinically useful by lowering insulin requirements and reducing the risk for long-term complications in T1D patients (11). 相似文献
108.
Jia XL Li SY Dang SS Cheng YA Zhang X Wang WJ Hughes CE Caterson B 《World journal of gastroenterology : WJG》2012,18(30):3962-3976
AIM: To investigate the expression of chondroitin sulphate proteoglycans (CSPGs) in rat liver tissues of hepatocellular carcinoma (HCC).METHODS: Thirty male Sprague Dawley rats were randomly divided into two groups: control group (n = 10) and HCC model group (n = 20). Rats in the HCC model groups were intragastrically administrated with 0.2% (w/v) N-diethylnitrosamine (DEN) every 5 d for 16 wk, whereas 0.9% (w/v) normal saline was administered to rats in the control group. After 16 wk from the initiation of experiment, all rats were killed and livers were collected and fixed in 4% (w/v) paraformaldehyde. All tissues were embedded in paraffin and sectioned. Histological staining (hematoxylin and eosin and Toluidine blue) was performed to demonstrate the onset of HCC and the content of sulphated glycosaminoglycan (sGAG). Immunohistochemical staining was performed to investigate the expression of chondroitin sulphate (CS)/dermatan sulphate (DS)-GAG, heparan sulphate (HS)-GAG, keratan sulphate (KS)-GAG in liver tissues. Furthermore, expression and distribution of CSPG family members, including aggrecan, versican, biglycan and decorin in liver tissues, were also immunohistochemically determined.RESULTS: After 16 wk administration of DEN, malignant nodules were observed on the surface of livers from the HCC model group, and their hepatic lobule structures appeared largely disrupted under microscope. Toluidine blue staining demonstrated that there was an significant increase in sGAG content in HCC tissues when compared with that in the normal liver tissues from the control group [0.37 ± 0.05 integrated optical density per stained area (IOD/area) and 0.21 ± 0.01 IOD/area, P < 0.05]. Immunohistochemical studies demonstrated that this increased sGAG in HCC tissues was induced by an elevated expression of CS/DS (0.28 ± 0.02 IOD/area and 0.18 ± 0.02 IOD/area, P < 0.05) and HS (0.30 ± 0.03 IOD/area and 0.17 ± 0.02 IOD/area, P < 0.01) but not KS GAGs in HCC tissues. Further studies thereby were performed to investigate the expression and distribution of several CSPG components in HCC tissues, including aggrecan, versican, biglycan and decorin. Interestingly, there was a distinct distribution pattern for these CSPG components between HCC tissues and the normal tissues. Positive staining of aggrecan, biglycan and decorin was localized in hepatic membrane and/or pericellular matrix in normal liver tissues; however, their expression was mainly observed in the cytoplasm, cell membranes in hepatoma cells and/or pericellular matrix within HCC tissues. Semi-quantitative analysis indicated that there was a higher level of expression of aggrecan (0.43 ± 0.01 and 0.35 ± 0.03, P < 0.05), biglycan (0.32 ± 0.01 and 0.25 ± 0.01, P < 0.001) and decorin (0.29 ± 0.01 and 0.26 ± 0.01, P < 0.05) in HCC tissues compared with that in the normal liver tissues. Very weak versican positive staining was observed in hepatocytes near central vein in normal liver tissues; however there was an intensive versican distribution in fibrosis septa between the hepatoma nodules. Semi-quantitative analysis indicated that the positive rate of versican in hepatoma tissues from the HCC model group was much higher than that in the control group (33.61% and 21.28%, P < 0.05). There was no positive staining in lumican and keratocan, two major KSPGs, in either normal or HCC liver tissues.CONCLUSION: CSPGs play important roles in the onset and progression of HCC, and may provide potential therapeutic targets and clinical biomarkers for this prevalent tumor in humans. 相似文献
109.
Manav Nayeni Arpit Dang Alex J. Mao Monali S. Malvankar-Mehta 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》2021,56(3):151-157
ObjectiveQuality of vision plays an important role in everyday living, and low vision (LV) can take a toll on individual's quality of life (QOL). The objective of this paper is to evaluate the impact of LV on QOL and depressive symptoms in LV patients compared with healthy controls.DesignSystematic review and meta-analysis.MethodsLiterature was systematically searched to obtain all relevant records. Covidence software was used to conduct the systematic review. Duplicate records were removed, and 2 independent reviewers screened records for relevance. After screening, risk of bias assessment was carried out. Data were extracted and meta-analysis was performed using STATA 15.0. Fixed-effect and random-effect models were computed based on heterogeneity.ResultsIn total, 2870 records were retrieved from database and grey literature searches. Twelve articles (35 341 subjects) were included for quantitative analysis. Overall, the QOL of LV patients was significantly lower compared with healthy individuals. Common QOL questionnaires, including 25-item visual function questionnaire (VFQ-25) (standard mean difference [SMD] = 0.91, confidence interval [CI]: [0.42–1.40]), 36-item short form survey (SMD = 0.53, CI: [0.26–0.80]), VFQ-14 (SMD = 0.58, CI: [0.42–0.74]), and visual function QOL questionnaire (SMD = 0.68, CI: [0.54–0.82]), demonstrated a poor QOL in LV patients compared with healthy controls. Additionally, odds of depressive symptoms were significantly greater (odds ratio = 2.25, CI: [1.58–3.21]) in LV patients compared with controls.ConclusionLV patients demonstrated a poor QOL and higher odds of depressive symptoms compared with healthy controls. 相似文献
110.
李黄恩 王勇 陈茂盛 李雪婷 徐艳雪 唐琼燕 周衍文 武哲明 司马晶 巫雷 曾庆森 曹向荣 高岩 党秀红 邱志方 李莉 李志强 单明华 祖皮丽娅 徐惠芳 李海祥 《中华眼科杂志》2021,(1):56-62
目的分析中国18家医院的14万例年龄相关性白内障患者角膜前表面散光的分布特征。方法回顾性系列病例研究。连续性收集2015年7月至2018年10月于中国18家爱尔眼科医院就诊的40岁以上年龄相关性白内障患者143889例(143889只右眼)的眼部生物学参数资料。角膜前表面散光度数和轴向、前房深度、角膜屈光力、眼轴长度等眼球参数采用IOLMaster 500测量,获取3次测量结果的平均值。各医院将资料整理分析后提交给武汉爱尔眼科医院进行总体分析。非正态分布数据以M(P25~P75)表示;采用Mann-Whitney检验、Kruskal-Wallis检验、χ2检验等分析角膜前表面散光度数和轴向在不同性别、年龄、前房深度、角膜屈光力、眼轴长度中的分布差异。结果143889例患者中女性84319例,男性59570例;年龄为72(65~78)岁;角膜散光度数为0.84(0.51~1.33)D,散光度数≥0.75 D者80895例(56.22%),散光度数≥1.00 D者57304例(39.83%)。女性角膜散光度数为0.87(0.53~1.37)D,男性为0.82(0.50~1.29)D(U=-14.891);女性顺规散光比例为33.26%(28046/84319),逆规散光比例为49.08%(41385/84319);男性顺规散光比例为34.26%(20408/59570),逆规散光比例为46.91%(27945/59570)(χ2=70.913),差异均有统计学意义(均P<0.05)。随年龄增加,角膜散光度数先由0.94(0.57~1.48)D减少至0.75(0.46~1.18)D,后又增大至1.19(0.74~1.79)D,差异有统计学意义(H=1263.438,P<0.05),变化的转折在61~70岁。随着年龄的增大,顺规散光比例减小[由77.50%(396/511)减少至12.50%(3/24)],逆规散光比例增大[由11.15%(57/511)增大至79.07%(34/43)],斜向散光比例变化不大[17.02%(16/94)至19.92%(245/1230)],分布差异有统计学意义(χ2=10174.496,P<0.05)。前房越浅,角膜散光度数越大,由0.82(0.51~1.31)D增大至1.05(0.61~1.56)D;逆规散光比例越大,由47.32%(60207/127227)增大至51.69%(184/356),差异均有统计学意义(H=409.961,χ2=120.995;均P<0.05)。平均角膜屈光力越大,角膜散光度数越大,由0.80(0.49~1.33)D增大至0.95(0.58~1.53)D;逆规散光比例越小,由52.84%(4963/9392)减小至39.97%(9023/22577),差异均有统计学意义(H=808.562,χ2=752.147;均P<0.05)。不同眼轴长度相比,当眼轴长度>25.00 mm时,角膜散光度数最大,为1.04(0.62~1.65)D;逆规散光比例最大,为49.00%(10964/22376),差异均有统计学意义(H=2071.198,χ2=131.130;均P<0.05)。结论年龄相关性白内障患者角膜前表面散光轴向以逆规散光为主。随着年龄的增大,角膜散光度数有先减小后增加的趋势。65岁为顺规散光向逆规散光变化的转折点。前房越浅,角膜前表面散光度数以及逆规散光比例越大。当眼轴长度>25.00 mm时,角膜前表面散光度数和逆规散光比例最大。 相似文献