首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8922篇
  免费   1019篇
  国内免费   185篇
耳鼻咽喉   80篇
儿科学   23篇
妇产科学   25篇
基础医学   281篇
口腔科学   86篇
临床医学   414篇
内科学   212篇
皮肤病学   23篇
神经病学   123篇
特种医学   103篇
外国民族医学   1篇
外科学   325篇
综合类   1033篇
预防医学   163篇
眼科学   6252篇
药学   705篇
  4篇
中国医学   163篇
肿瘤学   110篇
  2024年   42篇
  2023年   152篇
  2022年   286篇
  2021年   357篇
  2020年   297篇
  2019年   282篇
  2018年   361篇
  2017年   324篇
  2016年   394篇
  2015年   362篇
  2014年   561篇
  2013年   657篇
  2012年   584篇
  2011年   647篇
  2010年   493篇
  2009年   491篇
  2008年   414篇
  2007年   463篇
  2006年   429篇
  2005年   319篇
  2004年   298篇
  2003年   224篇
  2002年   167篇
  2001年   166篇
  2000年   171篇
  1999年   125篇
  1998年   114篇
  1997年   81篇
  1996年   57篇
  1995年   73篇
  1994年   56篇
  1993年   55篇
  1992年   72篇
  1991年   39篇
  1990年   40篇
  1989年   50篇
  1988年   25篇
  1987年   26篇
  1986年   17篇
  1985年   76篇
  1984年   48篇
  1983年   43篇
  1982年   46篇
  1981年   42篇
  1980年   47篇
  1979年   14篇
  1978年   14篇
  1977年   8篇
  1976年   6篇
  1972年   3篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
目的 :观察丝裂霉素C(MMC)在抗青光眼手术中应用的近期及远期效果。方法 :4 2只复发性青光眼在二次手术中一次性应用MMC术后观察及随访。结果 :术前眼压 34.0 5± 4 .0 5mmHg ,明显高于随访半年期 13.13± 3.30mmHg以及随访 2年期 14 .33± 3.30mmHg ,差异有显著性 (P <0 .0 1)。术后近期眼压 6 .75± 1.4 3mmHg ,明显低于随访半年期 (P <0 .0 1)。功能性滤过泡所占比率为 95 .2 %。结论 :术中一次性应用MMC ,远期观察其降压效果明显 ,且无严重并发症发生  相似文献   
52.
目的 研究非穿透性小梁切除术治疗开角型青光眼的手术效果。方法 对20例26眼开角型青光眼行非穿透性小梁切除术,术后观察眼压、结膜滤枕及前房反应等情况,随访1~12个月。结果 术后各期平均眼压均低于术前平均眼压,差异有显著性(P<0.05)术。前平均眼压26.26mmHg,术后3个月、6个月、9个月、12个月平均眼压分别为15.47mmHg、16.89mmHg、19.14mmHg、18.50mmHg。16眼结膜形成滤性手术典型滤过泡,10眼结膜疏松无滤过泡形成。26眼均无前房出血,术后前房反应轻。结论 非穿透性小梁切除术能有效地降低开角型青光眼的眼压,术后并发症少,可作为此类青光眼病人手术的选择。  相似文献   
53.
Summary It is widely accepted that a disturbed blood supply of the optic disc may cause (in addition with an increased intraocular pressure) optic nerve fibre damage. Therefore we measured ocular perfusion pressures in 79 healthy subjects. In 18 patients with low tension glaucoma, in 27 patients suffering from ocular hypertension and in 49 glaucoma (OAG) patients. For measuring perfusion pressures we used the technique of oculooscillo-dynamography (OODG) as described by Ulrich. Additionally we measured intraocular pressure and systemic blood pressure. In OODG the IOP is simultaneously increased in both eyes by application of a suction cup. After increase of the IOP the negative pressure in the suction cup is slowly and linearly decreased. During this decrease the pulse-depending oscillations of each eye are recorded on a strip-chart-recorder. By means of this method retinal and ciliary perfusion pressures can be separated. As a result we could show that mean arterial blood pressure and systolic retinal perfusion pressure were comparable and not statistically significantly different between the groups examined. The systolic ocular perfusion pressures in patients with low tension glaucoma showed a highly statistically significant reduction compared with the other groups. Between healthy subjects, OAG-patients and patients suffering from ocular hypertension there was no difference in systolic ciliary perfusion pressure detectable.  相似文献   
54.
The local mean and the average difference of four pairs of test locations within the 26° visual field, situated above and below the horizontal nasal meridian, were used to predict the global field indices MD and CLV of the Gl glaucoma program. Out of 539 examinations (194 eyes suspected of having glaucoma), the local indices NDIFF (describing asymmetrical behavior around the nasal horizontal meridian), ND0 (the mean defect in the nasal region), and the global indices MD and CLV were calculated. Seven hundred fifty-five examinations (446 normal eyes) served as a control group. First and second examinations of 146 glaucoma suspect eyes were used to calculate the retest reliability scores for the indices in question. When analyzing the glaucoma suspects, the local index NDIFF, together with the local mean defect, ND0, yielded highly reliable estimates of the global indices MD and CLV, with a retest correlation r = 0.86 for NDIFF, and r = 0.96 for ND0. The covariance of NDIFF with CLV was r = 0.67, while the co-variance of MD with ND0 was r = 0.95.The ranges of the local indices ND0 and NDIFF were each classified into normal range and range of suspected pathology, in analogy to the normal and pathological ranges of the global field indices. Equivalence of the local indices with the corresponding ranges of MD and CLV was investigated and the results are shown. The establishment of local indices may prove to be a powerful tool in early detection of glaucomatous damage.  相似文献   
55.
目的分析白内障伴青光眼患者术后胰岛素抵抗及炎症因子水平变化与视觉质量的关系。 方法选取47例(47眼)白内障伴青光眼患者为研究对象,均接受超声乳化+小梁切除术治疗。术前、术后7天、术后3个月检测患者客观散射指数(OSI)、点扩散函数(PSF)、调制传递函数截止频率(MTF cutoff)、胰岛素敏感指数及白细胞介素(IL)-1β、IL-10、IL-2水平。采用Pearson法分析视觉质量参数与胰岛素抵抗情况及炎症因子的相关性。 结果与术前比较,术后7天和术后3个月最佳校正视力、MTF cutoff及胰岛素敏感指数升高,且术后3个月更高(P<0.05);与术前比较,术后7天和术后3个月眼压、角膜内皮细胞计数、PSF、OSI及血清IL-1β、IL-2、IL-10水平降低,且术后3个月更低(P<0.05)。Pearson分析显示,术前、术后7天和术后3个月,白内障伴青光眼患者OSI与胰岛素敏感指数呈负相关(P<0.05),与血清IL-1β、IL-2、IL-10水平呈正相关(P<0.05);MTF cutoff与胰岛素敏感指数呈正相关(P<0.05),与血清IL-1β、IL-2、IL-10水平呈负相关(P<0.05);PSF与血清IL-1β水平呈负相关(P<0.05)。术后7天和3个月,PSF与胰岛素敏感指数呈正相关(P<0.05),与血清IL-2、IL-10水平呈负相关(P<0.05)。 结论超声乳化联合小梁切除术对视觉质量的改善可能与胰岛素抵抗及炎症因子变化密切相关。  相似文献   
56.
One hundred cases of recalcitrant glaucoma were operated with a long tube single-plate Molteno implant (LSMI). At the median follow-up of 15 months an intraocular pressure of 19 mm Hg was obtained in 64 of the 87 eyes (73%) which have a minimum follow-up of 6 months (secondary non-neovascular glaucomas=19; congenital glaucomas=26; secondary neovascular glaucomas=12). The interval probability (percentage±standard error) of obtaining a successful result (IOP19 mmHg) was 79% (±13) at twelve months from surgery, and 53% (±24) at the eighteen month interval. The least favorable results were obtained in the secondary non-neovascular glaucomas. Complications observed included choroidal detachment (24%), tube exposure (4%), tube-endothelium contact (6%), plus band keratopathy, fibrous ingrowth, traction retinal detachment and corneal ulcers.Seventeen cases needed repeate surgery for the management of complications. In order to decrease the post-operative hypotony, we have been using a tourniquet suture around the tube at the time of implantation to occlude it temporarily and limit the outflow.  相似文献   
57.
目的探讨高眼压状态下青光眼手术方法的安全性和效果。方法对32例药物降压无效的青光眼患者进行青光眼手术,术后观察出血、滤过泡、前房、眼压及视力的变化。结果术后1月视力提高的21只眼(65.63%);保持不变的11只眼(34.38%);眼压术后≤21mmHg者28只眼(87.5%);用药物控制的4只眼(12.5%)。结论高眼压状态采取手术治疗是安全有效的。  相似文献   
58.
用顶空气相色谱法测定醋酸烯诺孕酮埋植剂中环氧乙烷的残留量,结果表明,线性试验与精密度良好,平均回收率为99.8%,残留量为0.93%。样品在灭菌后,室温放置3天,其环氧乙烷残留量均在0.0001%以下,符合环氧乙烷残留量应不大于0.001%的规定。表明采用顶空气相色谱法测定醋酸烯诺孕酮理植剂中环氧乙烷残留量,方法简便,结果准确,适用于对该产品中环氧乙烷残留量的检测与控制。  相似文献   
59.
Interstitial Stress and Fluid Pressure Within a Growing Tumor   总被引:1,自引:0,他引:1  
A solid tumor is composed of a population of cells that is expanding as a result of cell division. With dense cell packing, the solid matrix of the interstitial tissue is subject to residual stress. In addition, elevated interstitial fluid pressure (IFP) has been reported by researchers for a number of solid tumors. These features were incorporated into a mathematical model that predicts the mechanical response of a solid tumor within its host environment. A theoretical framework accounting for volumetric expansion, transvascular exchange and extravascular transport of fluids was developed using poroelastic theory, and applied to a spherical, vascularized, alymphatic tumor undergoing small growth increments. Simulations of tumor IFP were similar to those predicted by Jain and Baxter (Ref. 23), showing elevated IFP that is driven by microvascular fluid pressure. Tumor growth, tissue stiffness, and IFP contribute to the compressive stresses predicted in the solid tumor interior. Tensile and compressive stresses were predicted in adjacent host tissues corresponding to radial and circumferential directions, respectively. An application of this model includes a solid stress-based framework for predicting regions of vascular collapse within the tumor interior. © 2003 Biomedical Engineering Society. PAC2003: 8717Ee, 8710+e, 8719Rr, 8719Xx  相似文献   
60.
In crucial cases the diagnosis of non-Hodgkin's lymphoma (NHL) still represents a challenge to the pathologist since morphological criteria do not always help to distinguish between reactive and malignant lymphoproliferations. Clonality assays are a useful supplement since monoclonal cell proliferation is strong evidence for malignancy. The polymerase chain reaction (PCR) can be utilized to establish the clonal origin of B-or T-cell lymphocyte populations by amplification of rearranged immunoglobulin and T-cell receptor (TCR) genes. In the present study DNA was isolated from a variety of neoplastic and nonneoplastic formalin-fixed, paraffin-embedded lymph nodes (n=62), cutaneous tissue (n=9), samples of miscellaneous origin (n=11), and, reported here for the first time, decalcified bone marrow samples (n=35). These samples were submitted to PCR-based assays directed against the immunoglobulin heavy-chain (IgH), immunoglobulin light-chain (IgL), and TCR chain genes. The impact of various decalcifying agents on the ability to amplify DNA was investigated by PCR-based amplification of a single copy gene. Buffered and nonbuffered EDTA was found not to impede amplification of DNA fragments up to 300 bp in length. In lymph node and cutaneous specimens monoclonality was detected in 83% of B-NHL cases using a seminested PCR approach for the amplification of IgH, whereas the same approach gave rise to monoclonal bands in 80% of bone marrow samples. The subsequent amplification of IgL helped to raise the sensitivity of detection to 94%. Monoclonality was detected in seven of nine T-cell NHLs by amplification of TCR. Most of the false-negative results were related to DNA extracted from centroblastic-centrocytic lymphoma and lymphoplasmocytic immunocytoma (37% negative each). PCR-based rearrangement analysis of immunoglobulin and TCR chain genes should be used in diagnostic pathology for cases which are histopathologically and immunohistochemically questionable. The application of clonality assays to bone marrow samples previously decalcified with EDTA provides a new tool for the detection of minimal residual disease.Abbreviations BALT bronchus-associated lymphoid tissue - dNTP deoxynucleoside triphosphate - Ig immunoglobulin - IgH immunoglobulin heavy chain - IgL immunoglobulin light chain - MALT mucosa-associated lymphoid tissue - NHL non-Hodgkin's lymphoma - PCR polymerase chain reaction - TCR T-cell receptor  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号