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   105040篇
  免费   8741篇
  国内免费   6138篇
耳鼻咽喉   1114篇
儿科学   1565篇
妇产科学   2310篇
基础医学   12443篇
口腔科学   1959篇
临床医学   14057篇
内科学   16664篇
皮肤病学   897篇
神经病学   5679篇
特种医学   3659篇
外国民族医学   42篇
外科学   11251篇
综合类   14800篇
现状与发展   23篇
一般理论   20篇
预防医学   6130篇
眼科学   2868篇
药学   10724篇
  56篇
中国医学   4838篇
肿瘤学   8820篇
  2024年   280篇
  2023年   1503篇
  2022年   3803篇
  2021年   4977篇
  2020年   3522篇
  2019年   3242篇
  2018年   3547篇
  2017年   2928篇
  2016年   2848篇
  2015年   4409篇
  2014年   5622篇
  2013年   5016篇
  2012年   7527篇
  2011年   8273篇
  2010年   4984篇
  2009年   3829篇
  2008年   5271篇
  2007年   5538篇
  2006年   5411篇
  2005年   5707篇
  2004年   3832篇
  2003年   3400篇
  2002年   3009篇
  2001年   2444篇
  2000年   2653篇
  1999年   2710篇
  1998年   1611篇
  1997年   1499篇
  1996年   1331篇
  1995年   1178篇
  1994年   1003篇
  1993年   648篇
  1992年   1002篇
  1991年   811篇
  1990年   695篇
  1989年   620篇
  1988年   621篇
  1987年   541篇
  1986年   435篇
  1985年   344篇
  1984年   219篇
  1983年   166篇
  1982年   94篇
  1981年   102篇
  1980年   94篇
  1979年   118篇
  1978年   56篇
  1977年   64篇
  1976年   50篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
应用酶标法测定58例脑梗塞患者和56例健康对照者血清脂蛋白(a)[LP(a)]含量,并同时测定了其他脂代谢指标,对其中26例脑梗塞患者还测定了血浆纤维蛋白溶解(简称纤溶)指标。结果表明脑梗塞组存在显著的脂代谢和纤溶功能紊乱。LP(a)含量增高,与所测脂代谢、纤溶指标无显著相关,是脑梗塞发病独立的危险因素。  相似文献   
72.
目的:观察体外循环(CPB)对10例瓣膜置换术病人全血细胞胰岛素受体和红细胞ATP含量的影响。方法:利用放射配体结合试验,测定全血细胞胰岛素受体密度和亲和力;用高效液相色谱法测定红细胞ATP含量,同时监测血糖和胰岛素浓度。结果:转流30分钟,血细胞高亲和胰岛素受体(R1)密度明显增加(P<0.01),亲和力(K1)明显降低(P<0.01),低亲和胰岛素受体(R2)密度也明显增加(P<0.01),但亲和力(K2)变化不大(P>0.05);停机30分钟,上述变化有所恢复,但未到转流前的水平。转流30分钟红细胞ATP含量明显降低(P<0.01),并持续到停机后30分钟,同时伴随血糖明显升高(P<0.01),胰岛素/血糖比值明显降低(P<0.01)。结论:CPB可致血细胞胰岛素受体密度增加而亲和力下降,以及红细胞ATP含量下降。  相似文献   
73.
Nephrectomy during operative management of retroperitoneal sarcoma   总被引:4,自引:0,他引:4  
Background: Complete resection of a retroperitoneal sarcoma often requires removal of adjacent organs. In this study we evaluated the role of nephrectomy during operation for retroperitoneal sarcoma. Methods: Between July 1982 and July 1995, 75 of the 371 (20%) patients who underwent resection of retroperitoneal sarcoma at MSKCC underwent concommitant nephrectomy. Data concerning the reasons for nephrectomy, degree of sarcomatous renal involvement, and survival were retrospectively analyzed. Results: Fifty-four patients (72%) underwent nephrectomy during the initial resection, and 21 (28%) during a resection of a recurrent or persistent tumor. The most common reason for nephrectomy was total encasement by sarcoma (n=40; 53%), followed by dense adherence of the tumor to the kidney (n=21; 28%), and the direct invasion of the kidney by tumor (n=2; 3%). Pathology demonstrated an absence of kidney invasion in the majority of cases (55 of 75; 73%). Renal capsular invasion was present in 11 of 75 (15%), renal parenchymal invasion in 7 of 75 (9%), and renal vein invasion in 2 of 75 (3%) of cases. There were no significant differences in survival based on degree of sarcoma involvement of the kidney, tumor grade, or whether the resection was for primary or recurrent disease. The 53 patients who underwent a complete gross resection of all tumor had a significantly improved long-term survival compared to the 20 patients who did not (50% versus 20% DFS at 5 years, respectively; p<0.001). Conclusions: Decisions for concomitant nephrectomy during resection of retroperitoneal sarcoma should be based on whether this maneuver will provide a complete resection of all gross tumor, in which case the long-term disease-free survival of 50% is comparable to the reported 5-year survival of all patients with retroperitoneal sarcoma who are completely resected. Presented at the 49th Annual Cancer Symposium of the Society of Surgical Oncology, Atlanta, Georgia, March 21–24, 1996.  相似文献   
74.
75.
Ten cases of pediatric fulminant hemophagocytic syndrome, encountered between 1986 and 1989, are described. They occurred in the summer, and the patients presented with fever, jaundice, hepatosplenomegaly, pancytopenia, coagulopathy, and abnormal liver function. Bone marrow studies revealed infiltration by atypical T-lymphoid cells, rare B immunoblasts, and mature histiocytes with hemophagocytosis. Initially, histiocytic medullary reticulosis was suspected in six cases. The clinical course was characterized by rapid deterioration, with a mean period of 16 days from onset of fever to death. The main causes of death were coagulopathy with multiple organ failure and opportunistic infection. In seven of eight cases studied by serologic assay and Southern blot hybridization, acute or active Epstein-Barr virus (EBV) infection was documented. It is suggested that an atypical or fulminant form of primary EBV infection distinct from classic infectious mononucleosis was prevalent in previously healthy children in Taiwan. Younger age involvement and seasonal clustering were characteristic of the disorder described.  相似文献   
76.
PURPOSE: To study the diagnostic ability of scanning laser polarimetry with variable corneal compensation (GDx VCC) for early glaucomatous (EG) eyes and glaucoma-suspect (GS) eyes in a Taiwan Chinese population. METHODS: This prospective cross-sectional study included 82 EG eyes (mean deviation, MD: -3.32 +/- 2.20 dB), 45 GS eyes (MD: -2.43 +/- 2.16 dB), and 62 normal eyes. Retinal nerve fiber layer thickness of each subject was measured using GDx VCC and Humphrey Field Analyzer visual field testing. Measured GDx VCC parameters were compared among groups. The area under the receiver operating characteristic (AROC) curve of each parameter was used to differentiate normal from EG eyes or GS eyes. The correlation between MD and each parameter was also evaluated. RESULTS: For both normal versus EG and normal versus GS, the largest AROC values were for nerve fiber indicator, superior average thickness, and inferior average thickness. There was no significant correlation between MD and GDx-VCC-measured parameters either in EG or GS eyes. CONCLUSIONS: GDx VCC shows only moderate ability to distinguish normal eyes from eyes with early glaucoma. However, its diagnostic role in eyes with suspicious discs and normal visual fields is uncertain at this moment in the Taiwan Chinese population. Further studies are needed to address this issue.  相似文献   
77.
To determine the single- and multiple-dose ceftazidime kinetics, we administered ceftazidime, 2 gm intravenous bolus every 12 hours, to 14 infected Chinese patients with various degrees of renal function. Blood samples were drawn in serial after the first and 7th dose and serum ceftazidime concentrations were measured by high pressure liquid chromatography. Ceftazidime concentration-time data were fitted to a two-compartment model with a nonlinear regression program. Ceftazidime kinetics was unaltered by repeated dosing. Both total body clearance and elimination rate constant of ceftazidime decrease significantly in proportion to the creatinine clearance estimated by Bjornsson's method. Renal insufficiency did not modify the steady-state volume of distribution (Vdss) of ceftazidime which, however, appeared to be larger than those reported previously. This larger Vdss may be explained by acute infection process, confinement to bed, and increased extracellular fluid volume as a result of hypoalbuminemia. Our study indicates the estimated creatinine clearance as a useful guide to ceftazidime dosage adjustment and also emphasizes the clinical relevance of conducting kinetic studies of antibiotics in infected patients.  相似文献   
78.
To assess the rationale of intraarterial (i.a.) 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea chemotherapy, distribution of 14C-labeled 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)- 3-nitrosourea in rat glioma was studied after i.a. or i.v. infusion. Immediately after infusion, the tumor located in the hemisphere of intracarotid infusion received 4.6-fold higher radioactivity than the tumor located contralaterally to intracarotid infusion and 2.8-fold higher radioactivity than i.v. infusion. The difference was kept up to 30 min after i.a. infusion. Autoradiographic observation indicated rather uniform distribution of the tracer in the central portion of i.a. infusion. However, in the periphery of i.a. infusion, distribution of the tracer was nonhomogenous. The results indicate that i.a. 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea chemotherapy is useful when the tumor has high blood flow and is located in the center of an infused area.  相似文献   
79.
Forty patients with symptoms of internal derangement of the knee were examined arthroscopically under local anesthesia using a continuous irrigation solution of 0.2% lidocaine. Serum levels were measured during and following the procedure to determine peak levels obtained and to assure that toxic levels were not exceeded. The procedure was well tolerated by all patients and found to be adequate by the surgeon. No procedure was terminated because of discomfort. Lidocaine levels ranged from undetectable to 2.5 micrograms/ml with an average of 0.6 microgram/ml. No complications of lidocaine toxicity were noted by the anesthesiologist or the operating surgeon. This technique provides a safe and efficient method of meeting the demands for diagnostic and therapeutic arthroscopy in ambulatory patients.  相似文献   
80.
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