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   8431篇
  免费   496篇
  国内免费   55篇
耳鼻咽喉   128篇
儿科学   213篇
妇产科学   219篇
基础医学   1024篇
口腔科学   434篇
临床医学   633篇
内科学   1907篇
皮肤病学   166篇
神经病学   842篇
特种医学   319篇
外科学   1130篇
综合类   23篇
预防医学   373篇
眼科学   117篇
药学   702篇
中国医学   15篇
肿瘤学   737篇
  2023年   84篇
  2022年   197篇
  2021年   362篇
  2020年   197篇
  2019年   281篇
  2018年   308篇
  2017年   236篇
  2016年   292篇
  2015年   331篇
  2014年   374篇
  2013年   478篇
  2012年   677篇
  2011年   668篇
  2010年   358篇
  2009年   309篇
  2008年   518篇
  2007年   482篇
  2006年   484篇
  2005年   446篇
  2004年   410篇
  2003年   278篇
  2002年   281篇
  2001年   86篇
  2000年   78篇
  1999年   98篇
  1998年   54篇
  1997年   40篇
  1996年   23篇
  1995年   32篇
  1994年   23篇
  1993年   18篇
  1992年   42篇
  1991年   38篇
  1990年   30篇
  1989年   42篇
  1988年   32篇
  1987年   28篇
  1986年   32篇
  1985年   21篇
  1984年   20篇
  1983年   25篇
  1982年   13篇
  1981年   12篇
  1979年   14篇
  1978年   11篇
  1975年   11篇
  1972年   13篇
  1970年   10篇
  1969年   10篇
  1968年   10篇
排序方式: 共有8982条查询结果,搜索用时 9 毫秒
11.
Keratodermia is an incurable genetic and regional disease located in the palmar and plantar regions. The author reports his experience with five cases of palmoplantar keratodermia that were treated by grafting onto the soles and the palms skin taken from the calves and the thighs.  相似文献   
12.
The compound IBI-P-05006, 2-(6'-carboxyhexyl)-3-n-hexylcyclohexylamine, is an antiaggregating agent under development. IBI-P-05006 is an in vitro inhibitor of platelet aggregation. The biotransformation of this compound has been studied in the dog and rat. We present here a study on the metabolites of IBI-P-05006 found in dog and rat urine, and in dog plasma. Analyses were done by gas chromatography-mass spectrometry. In dog urine 15 metabolites were identified. Some of them were also found in dog plasma and in rat urine. The unmetabolized drug was found only in plasma. 10 different hydroxylated metabolites were characterized. The hydroxyl groups were introduced in the hexyl chain in positions omega-4, omega-3, omega-2, omega-1 and omega.  相似文献   
13.
Slightly elevated values of homocysteine are commonly associated with thromboembolic diseases, while high values can be found in patients with congenital metabolic defects or nutritional problems. The clinical use of homocysteine as an independent marker of cardiovascular disease was limited in the past by technical problems with its measurement, the instrumentation (HPLC, radioenzymatic assays, gas chromatography-mass spectrometry, etc.) and the necessary skills required. Commercially available immunoassays now permit a simpler and more rapid measurement of homocysteine, that is more suitable for routine clinical laboratories; in this paper we analyze the results obtained by using three fully automated methods for homocysteine determination (Abbott IMx immunoassay, Abbott AxSYM immunoassay and Immulite 2000 homocysteine immunoassay) and their correlation with the widely used HPLC method. The results clearly indicate that all three automated immunochemical methods correlate well with the HPLC method (slope 0.97-1.03; intercept 0.95-1.91 with a recovery above 95% for all three methods).  相似文献   
14.
OBJECTIVES: To evaluate the accuracy of sonographic identification of the site of umbilical cord insertion (CI) at 18-20 weeks of gestation, to compare the sensitivities for detection of a velamentous cord insertion (VCI) secondary to a CI into the anterior, posterior or fundal wall, and to compare the intrapartum complications secondary to VCI into the upper, middle or lower third of the uterus. METHODS: As part of the routine ultrasound scan at 18-20 weeks' gestation we evaluated abnormal CI (VCI and marginal CI) and the location of the CI in the uterus in 3446 pregnancies. In cases of abnormal CI, the location of the CI was further classified as being in the upper, middle or lower third of the uterus. After delivery, the placenta and the umbilical cord were examined and intrapartum complications were compared with the location of the CI. RESULTS: The values for antenatal detection of VCI were: sensitivity, 25 of 40 (62.5%); positive predictive value, 25 of 25 (100%); and negative predictive value, 3406 of 3421 (99.6%). The sensitivity for cases in which the CI was located on the anterior wall was 12 of 13 (92.3%); when it was located on the posterior wall, the sensitivity was 11 of 22 (50.0%); and when it was fundal the sensitivity was 2 of 5 (40.0%). Variable decelerations were frequently observed with a VCI. In lower VCI cases, non-reassuring fetal heart rate patterns and emergency Cesarean sections occurred with a higher frequency than in cases with upper or middle VCI (P < 0.01). After delivery, the length of the aberrant vessels in cases of VCI by pathologic examination was 3.9 +/- 3.3 cm in the upper third, 4.7 +/- 4.6 cm in the middle third, and 10.6 +/- 6.8 cm in the lower third; thus, the aberrant vessel length was significantly greater when the CI was in the lower third of the uterus (P = 0.024). CONCLUSION: We have demonstrated that VCI with a lower CI site and with longer aberrant vessels is associated with various intrapartum complications. This finding has the potential for improving perinatal outcome.  相似文献   
15.
Sinotubular junction reconstruction in reimplantation type of valve-sparing aortic procedure can present some problem when a Valsalva graft is used. Since in the Valsalva graft the sinotubular junction height is predetermined, correct matching with native commissures height can be difficult. We propose a method by which it is possible to create a new sinotubular junction in Valsalva graft without altering its original configuration.  相似文献   
16.
We present 2 cases of superficial siderosis of the central nervous system secondary to chronic subarachnoid bleeding. The diagnosis was made with MR and cerebrospinal fluid (CSF) examination. MR showed, in T2-weighted images, superficial hypointensity of the cervical cord, brainstem, cerebellum, and basal cisterns due to hemosiderin deposits. CSF was xanthochromic, with increased protein content. In 1 of the 2 cases also the CT examination was positive, showing a hyperdense rim around the brainstem. A complete neuroradiological evaluation (MR, CT, angiography and myelography) did not permit to detect the source of the bleeding.  相似文献   
17.
Toxic pustuloderma associated with azithromycin   总被引:1,自引:0,他引:1  
  相似文献   
18.
19.
Technetium-99m methoxyisobutylisonitrile (MIBI), like thallium-201, has recently been introduced as a myocardial perfusion agent and is now also showing very promising results in parathyroid scintigrapy. The results of 201Tl/99mTc-pertechnetate and 99mTc-MIBI/99mTc-pertechnetate subtraction scintigraphy, ultrasonography and computed tomography are presented in a series of 43 patients operated on for hyperparathyroidism. All four imaging modalities were confirmed to be reliable, scintigraphy being the most accurate. Sensitivities ranged from 81% to 95%, that of 99mTc-MIBI being the highest. Moreover this tracer, which has more favourable physical and also biochemical properties, yielded images of superior quality. This allowed localization of the lesion by visual inspection only in as many as 86% of the patients with positive 99mTc-MIBI/99mTc-pertechnetate subtraction scintigraphy. We believe that the higher sensitivity, superior image quality and lower cost of 99mTc-MIBI imaging will make 99mTc-MIBI the new radiopharmaceutical of choice for parathyroid scintigraphy (when one takes into account the stability of labelling with large activities it is possible to perform three or four cardiac studies together with one parathyroid scintigraphic examination using one lyophililzed vial).  相似文献   
20.
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