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   24054篇
  免费   1552篇
  国内免费   161篇
耳鼻咽喉   292篇
儿科学   775篇
妇产科学   714篇
基础医学   2435篇
口腔科学   713篇
临床医学   1953篇
内科学   5155篇
皮肤病学   522篇
神经病学   1099篇
特种医学   957篇
外国民族医学   9篇
外科学   4312篇
综合类   726篇
现状与发展   1篇
一般理论   21篇
预防医学   1633篇
眼科学   707篇
药学   2092篇
中国医学   157篇
肿瘤学   1494篇
  2023年   291篇
  2022年   560篇
  2021年   1401篇
  2020年   741篇
  2019年   937篇
  2018年   1249篇
  2017年   754篇
  2016年   777篇
  2015年   875篇
  2014年   1078篇
  2013年   1332篇
  2012年   1820篇
  2011年   1864篇
  2010年   970篇
  2009年   800篇
  2008年   1175篇
  2007年   1259篇
  2006年   1101篇
  2005年   958篇
  2004年   896篇
  2003年   761篇
  2002年   705篇
  2001年   338篇
  2000年   325篇
  1999年   297篇
  1998年   177篇
  1997年   153篇
  1996年   128篇
  1995年   127篇
  1994年   84篇
  1993年   68篇
  1992年   137篇
  1991年   125篇
  1990年   122篇
  1989年   112篇
  1988年   111篇
  1987年   113篇
  1986年   118篇
  1985年   99篇
  1984年   78篇
  1983年   93篇
  1982年   46篇
  1981年   58篇
  1980年   45篇
  1979年   80篇
  1978年   51篇
  1977年   59篇
  1976年   48篇
  1975年   49篇
  1974年   38篇
排序方式: 共有10000条查询结果,搜索用时 593 毫秒
41.
In this study, the effect of regular khat (Catha edulis Forsk) chewing (200 and 400 g) in humans on plasma leptin, nonesterified fatty acid, triacyglycerol, and total cholesterol levels was investigated. The results presented show that khat chewing increases plasma leptin concentration particularly in individuals who chew 400 g of khat leaves. The significance of increased plasma leptin is in explaining the underlying mechanism of the observed effects associated with khat chewing such as loss of appetite, decreased body weight, and hyperthermia. The decreased body weight was evident from the significantly lower body mass index of the khat leaves chewers group as compared to the non–khat leaves chewers group (control). Moreover, like leptin, the plasma levels of nonesterified fatty acids were significantly higher in those chewing 400 g of khat leaves. On the other hand, the plasma levels of triacylglycerol were significantly lower in the 2 khat-chewers groups (200 and 400 g of khat leaves), whereas plasma cholesterol levels were not affected by the 2 levels of khat leaves used in this study. The significance of these results may suggest that khat leaves may contain a component(s) that has the ability to reduce body weight via decreasing appetite.  相似文献   
42.
S M Y Ahmed  J Singh  M Nicol 《The surgeon》2007,5(6):363-367
There are various methods of reducing anterior shoulder dislocations. The traditionally used methods like Kocher's and Hippocratic are associated with procedural complications and frequently require sedation/muscle relaxants which have their own complications and are associated with longer stay and monitoring requirement in the emergency department. We describe a stepped care approach to shoulder dislocation reduction in the prone position involving four steps and two new manipulation methods taking into consideration the pathological deforming forces in a dislocated shoulder and addressing them in a stepwise fashion. This method does not require sedation/muscle relaxants in the majority of cases, is easy to learn, relatively painless, associated with shorter stay in the emergency department and has fewer complications.  相似文献   
43.
44.
Xanthogranulomatous orchitis is an extremely rare inflammatory non-neoplastic destructive lesion of the testis. We report a 44-year-old man who presented with right scrotal swelling and two discharging sinuses. Testicular tumor markers were normal. Scrotal ultrasound showed heterogeneous testicular areas and irregular margin of the tunica. Surgical exploration revealed infected, unhealthy testicular tissue with necrosis and tumor-like lesion. Orchidectomy was done and histopathology showed xanthogranulomatous orchitis.  相似文献   
45.
46.
Studies on removal of malathion from water by means of activated charcoal   总被引:1,自引:0,他引:1  
The utility of activated charcoal for the removal of malathion from saline waters has been explored. The adsorption capacity of charcoal for malathion has been found to be 117 mg g-1. Adsorption follows the Freundlich adsorption isotherms, the value of k and 1/n for charcoal being 1.6 and 0.60, respectively. Malathion can be eluted with methanol or ethanolic potassium hydroxide.  相似文献   
47.
A case of an odontogenic tumor which invaded the intracranial space from the mandible is reported. Judging from the radiographic images it was similar to a malignant tumor. The patient died 17 years after the first visit. According to the final pathological diagnosis, it was malignant odontogenic mixed tumor of low grade which did not belong to any of the WHO classification.  相似文献   
48.
A new axial skin flap based on the middle cutaneous branch of the medial plantar artery was evaluated in 33 fresh cadaver legs. The vascular pedicle of the skin flap is based on the middle cutaneous artery, its venae comitantes, and segments of the great saphenous vein, if necessary. The middle cutaneous artery is the largest cutaneous branch, arising from the medial plantar artery 2.5 cm distal to its origin. The diameter of its origin is 1.2 mm, and its pedicle is 2 cm long. The midline of the flap runs from the first web space to the heel tip. The upper and lower borders of the flap are 3 to 4 cm on either side of this line. The upper border is medial to the extensor hallucis tendon, and the lower border is medial to the abductor hallucis. Distally, the border begins 2 cm proximal to the metatarsalphalangeal joint; proximally, the border is at the middle of the medial malleolus. The flap diameter can be up to 8 × 12 cm. The middle cutaneous branch of the medial plantar artery was found in all cadaver specimens, except for one with a common trunk. The new flap design leaves the major blood supply to the foot and the plantar aponeurosis intact. It is easy to harvest and may be used either as an island flap or free flap. © 1995 Wiley-Liss, Inc.  相似文献   
49.
50.
Unattached fractions of the radon progeny 218Po and 214Pb, size distributions for both unattached 218Po and 214Pb, and attached 214Pb and 214Bi, along with condensation nuclei (aerosol-particle concentrations), were measured in the open air of the city of El-Minia, Egypt. The measurements were performed with a wire-screen diffusion battery and a low-pressure Berner cascade impactor using standard methodologies. The results for parameters of derived distributions demonstrate that the distributions for the former (unattached 218Po and 214Pb) are nearly similar. The diffusion equivalent diameters (df) of 218Po and 214Pb were determined to be 1.4 and 1.55 nm with relative geometric standard deviations (σg) of 1.65 and 2.1, respectively. The latter distributions (attached 214Pb and 214Bi) are nearly identical. Most of the activities were associated with the aerosol particles of the accumulation mode. The mean activity median aerodynamic diameters (AMAD) of 214Pb and 214Bi have the same value of 380 nm but the relative geometric standard deviation of the log-normal distribution of 214Pb shows a broader activity distribution than 214Bi (σg = 2.2 for 214Pb and σg = 2.05 for 214Bi).  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