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   24187篇
  免费   1278篇
  国内免费   129篇
耳鼻咽喉   260篇
儿科学   321篇
妇产科学   323篇
基础医学   3226篇
口腔科学   753篇
临床医学   1647篇
内科学   6256篇
皮肤病学   372篇
神经病学   1465篇
特种医学   752篇
外科学   4035篇
综合类   120篇
一般理论   1篇
预防医学   799篇
眼科学   557篇
药学   1618篇
中国医学   66篇
肿瘤学   3023篇
  2023年   108篇
  2022年   230篇
  2021年   405篇
  2020年   228篇
  2019年   295篇
  2018年   418篇
  2017年   323篇
  2016年   406篇
  2015年   406篇
  2014年   527篇
  2013年   645篇
  2012年   990篇
  2011年   1118篇
  2010年   607篇
  2009年   525篇
  2008年   951篇
  2007年   1069篇
  2006年   1049篇
  2005年   1087篇
  2004年   1037篇
  2003年   1067篇
  2002年   960篇
  2001年   892篇
  2000年   912篇
  1999年   869篇
  1998年   291篇
  1997年   236篇
  1996年   253篇
  1995年   199篇
  1994年   178篇
  1993年   163篇
  1992年   683篇
  1991年   616篇
  1990年   572篇
  1989年   648篇
  1988年   552篇
  1987年   508篇
  1986年   520篇
  1985年   472篇
  1984年   303篇
  1983年   233篇
  1982年   132篇
  1980年   109篇
  1979年   219篇
  1978年   172篇
  1977年   135篇
  1974年   109篇
  1971年   119篇
  1969年   126篇
  1968年   99篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The in vitro and in vivo effects of 3-formylamino-7-methylsulfonylamino-6-phenoxy-4H-1-benzopyran-4-on e (T-614, CAS 123663-49-0), a new antiinflammatory agent, on arachidonic acid metabolism were investigated in comparison with those of reference drugs. Although the inhibitory effect of T-614 on the synthesis of prostaglandins by rabbit renal microsomes was very weak (IC50 of 58 micrograms/ml), T-614 effectively inhibited the prostaglandin E2 (PGE2) generation by mouse fibroblasts stimulated with bradykinin with an IC50 value of 0.47 micrograms/ml. The suppressive effect of T-614 on the PGE2 generation in fibroblasts was also found when cells were stimulated with Ca ionophore A23187, but not when induced with arachidonic acid. T-614 suppressed the A23187-induced PGE2 generation by rat macrophages, but not the leukotriene B4 production. In addition, 5-lipoxygenase activities in guinea-pig peritoneal exudated cells were not inhibited. In in vivo experiments, at doses of more than 1 mg/kg, T-614 reduced the PGE2 contents in inflammatory exudate of rat carrageenin-sponge type inflammation, but it was almost inactive in inhibiting gastric prostaglandins production up to 100 mg/kg. T-614 also did not affect the urinary PGE2 excretion in rats, and slightly inhibited the thromboxane synthesis in rat blood. Furthermore, the convulsion-induced increase of PGE2 in mouse brain was inhibited by T-614. These data suggest that T-614 inhibits the production of cyclooxgenase-mediated products with apparently different mode from classical non-steroidal antiinflammatory drugs, and may partly explain the discrepancy in pharmacological properties between this compound and other drugs.  相似文献   
92.
93.
94.
We examined the effects of angiotensin II (Ang II) on inward rectifier K+ currents (IK1) in rat atrial myocytes. [125I]Ang II-binding assays revealed the presence of both Ang II type 1 (AT1) and type 2 (AT2) receptors in atrial membrane preparations. Ang II inhibited IK1 in isolated atrial myocytes with an IC50 of 46 nmol/l. This inhibition was abolished by the AT, antagonist RNH6270 but not at all by the AT2 antagonist PD123319. Treatment of cells with pertussis toxin or a synthetic decapeptide corresponding to the carboxyl-terminus of Gialpha-3 abolished the inhibition by Ang II, indicating the role of a Gi-dependent signaling pathway. Accordingly, Ang II failed to inhibit IK1 in the presence of forskolin, dibutyryl-cAMP or protein kinase A catalytic subunits. In spite of the increased binding capacities for [125I]Ang II, Ang II failed to affect IKI in cells from spontaneously hypertensive rats (SHR). AT, immunoprecipitation from atrial extracts revealed decreased amounts of Gialpha-2 and Gialpha-3 proteins associated with this receptor in SHR as compared with controls. The reduced coupling of AT, with Gialpha. proteins may underlie the unresponsiveness of atrial IK1 to Ang II in SHR cells.  相似文献   
95.
Cysts and tumors of the seminal vesicle are uncommon, and their coexistence is extremely rare. We report a case of multiple papillary tumors inside a seminal vesicle cyst associated with ipsilateral renal agenesis in a 17-year-old man. Surgical excision of the cyst and tumors was performed without any morbidity and histology revealed well differentiated papillary adenocarcinoma.  相似文献   
96.
97.
98.
99.
PURPOSE: To evaluate the treatment results of low-dose-rate (LDR) and high-dose-rate (HDR) interstitial brachytherapy (ISBT) for T3 mobile tongue cancer. MATERIAL AND METHODS: Between 1974 and 1992, 61 patients with T3 mobile tongue cancer were treated with LDR ISBT using (192)Ir hairpins with or without single pins. In addition, between 1991 and 1999, 14 patients were treated with HDR ISBT. For nine patients treated with ISBT alone, the total dose was 59-94 Gy (median 72 Gy) within one week in LDR ISBT and 60 Gy/10 fractions/5 days in HDR ISBT. For 66 patients treated with a combination therapy of external beam radiotherapy (EBRT) and ISBT, the total dose was 12.5-60 Gy (median 30 Gy) of EBRT and 50-112 Gy (median 68 Gy) within 1 week in LDR ISBT or 32-60 Gy (median 48 Gy)/8-10 fractions/5-7 days in HDR ISBT. RESULTS: The 2- and 3-year local control rates of all patients were both 68%. The 2- and 3-year local control rates of patients treated with LDR ISBT were both 67%, and those with HDR ISBT were both 71%. The local control rate of patients treated with HDR ISBT was similar to those with LDR ISBT. CONCLUSIONS: ISBT for T3 mobile tongue cancer is effective and acceptable. The treatment result of HDR ISBT is almost similar to that of LDR ISBT for T3 mobile tongue cancer.  相似文献   
100.
Objective. Employing [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) to assess the correlation between the effect of deep brain stimulation (DBS) on the subthalamic nucleus (STN) and the regional cerebral metabolic rate of glucose (rCMRGlc) in advanced Parkinson's disease patients (N = 8). Materials and Methods. On the basis of patients’ diary records, we performed FDG‐PET during the off‐period of motor activity with on‐ or off‐stimulation by STN‐DBS on separate days and analyzed the correlation between changes in motor symptoms and alterations in the rCMRGlc. Result. When FDG‐PET was performed, the motor score on the unified Parkinson's disease rating scale (UPDRS) was 64% lower with on‐stimulation than with off‐stimulation (p < 0.001, Wilcoxon single‐rank test). STN‐DBS increased the rCMRGlc in the posterior part of the right middle frontal gyrus, which corresponded to the premotor area, and the right anterior lobe of the cerebellum (p < 0.005, paired t‐test). No region exhibited a decrease in rCMRGlc. Among the items of the UPDRS motor score, the changes in resting tremor and rigidity of the left extremities showed a significant correlation with the changes in rCMRGlc observed in the right premotor area (p < 0.02 and p < 0.05, respectively, Spearman's rank correlation). Conclusions. STN‐DBS either activates the premotor area or normalizes the deactivation of the premotor area. These FDG‐PET findings obtained are consistent with the idea that STN‐DBS modifies the activities of neural circuits involved in motor control.  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