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   250278篇
  免费   19629篇
  国内免费   13700篇
耳鼻咽喉   2238篇
儿科学   3102篇
妇产科学   4913篇
基础医学   28911篇
口腔科学   4297篇
临床医学   31773篇
内科学   40736篇
皮肤病学   2934篇
神经病学   13959篇
特种医学   8690篇
外国民族医学   96篇
外科学   27345篇
综合类   34534篇
现状与发展   48篇
一般理论   45篇
预防医学   15314篇
眼科学   6810篇
药学   24507篇
  245篇
中国医学   11242篇
肿瘤学   21868篇
  2024年   2992篇
  2023年   4650篇
  2022年   8991篇
  2021年   11686篇
  2020年   9079篇
  2019年   8157篇
  2018年   8055篇
  2017年   7081篇
  2016年   6789篇
  2015年   10137篇
  2014年   12761篇
  2013年   11932篇
  2012年   17577篇
  2011年   19224篇
  2010年   11745篇
  2009年   9395篇
  2008年   12763篇
  2007年   12854篇
  2006年   12370篇
  2005年   12456篇
  2004年   8608篇
  2003年   7649篇
  2002年   6621篇
  2001年   6006篇
  2000年   6119篇
  1999年   6420篇
  1998年   3683篇
  1997年   3719篇
  1996年   2825篇
  1995年   2619篇
  1994年   2263篇
  1993年   1522篇
  1992年   2305篇
  1991年   2004篇
  1990年   1686篇
  1989年   1486篇
  1988年   1284篇
  1987年   1193篇
  1986年   956篇
  1985年   762篇
  1984年   500篇
  1983年   393篇
  1982年   236篇
  1981年   214篇
  1980年   198篇
  1979年   251篇
  1978年   147篇
  1977年   123篇
  1976年   110篇
  1974年   122篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Three cases of proved peritoneal carcinomatosis were examined by magnetic resonance imaging (MRI). Air was used to distend the entire gastrointestinal tract via an antegrade method. The findings included seedings along the small intestine, transverse and sigmoid colon, stellate pattern in the mesentery, plaque-like and bulky tumor masses in the mesentery and greater omentum, and focal thickenings along the right subdiaphragmatic parietal peritoneum. Stenosis caused by tumor encasement at the duodenojejunal junction and ileocolic anastomosis were first detected by MRI and later confirmed by barium studies. Ascites was present in all cases. One case showed ascites located only along the left paracolic gutter. This report shows that MRI is also able to demonstrate peritoneal carcinomatosis by using air as a gastrointestinal contrast medium.  相似文献   
82.
Gastric cancer is unusual during pregnancy. Also, because of the physiologic changes that occur with pregnancy, it is rare to see a worsening of peptic ulcers during pregnancy. A patient with an exacerbation of peptic ulcers presented with gastric carcinoma during pregnancy.  相似文献   
83.
84.
Seventy-two patients of chronic obstructive pulmonary disease (COPD) of Qi deficiency syndrome with abnormal immune indices were treated with Yiqi Mianyi Granule (YQMYG) and the efficacy was compared with that of 30 cases treated with Zhenqi fuzheng Granule (ZQFZG) for control. Results showed that the markedly effective rate of symptomatic improvement of Qi deficiency in YQMYG group was 65.3%, the total effective rate 93.1%. 88.6% of the immune indices lower than normal were corrected and 43. 7% of them were normalized, while for indices that were higher than normal the rate were 78.2% and 52.9% respectively. These results suggested that YQMYG could improve symptom of Qi Deficiency markedly, strengthen cellular immunity and regulate immune dysfunction. Its therapeutic efficacy was obviously superior to ZQFZG (P<0.Q5).  相似文献   
85.
Abstract: In the commercially available intravenous formulation of Cyclosporin A (Sandimmun®), polyoxyethylated castor oil (Cremophor®EL) is used as a solubilizing agent. We have recently reported that the acute nephrotoxic effect of this preparation was alleviated by replacing Cremophor®EL with a soybean oil-based fat emulsion in a rat model. To further explore the potential of fat emulsions as carriers for cyclosporin A, data on the in vivo pharmacokinetics and tissue distribution are required. In this study in pigs, the pharmacokinetics of soybean oil-cyclosporin A was compared to that of Sandimmun®. The two formulations seemed bioequivalent, as there were no significant differences in the systemic clearances, volumes of distribution or elimination half-lives. Moreover, the tissue distributions of soybean oil-cyclosporin A and Sandimmun® were compared in rats. These studies also included two additional lipid-based carriers: one based on iodized ester of poppy seed oil and the other on a liposomal preparation. The tissue distributions were found to be similar regardless of the carriers used. Fat emulsion carriers seem to offer possibilities for preparing better tolerated intravenous formulations of cyclosporin A while maintaining the same characteristics concerning pharmacokinetics and tissue distribution.  相似文献   
86.
The posterior tibial flap is a type C fasciocutaneous flap from the medial calf with the posterior tibial vascular bundle as its pedicle. Most of the skin perforators, 1 to 3 in number, can be found in the middle third of the leg, with an average diameter of 0.8 mm and an average length of 22 mm. The posterior tibial artery ranges between 1.5 and 2.0 mm in diameter, although it is absent in 8 percent of limbs. Since the saphenous nerve is taken with the flap, this is an innervated flap. The flap can be transferred as a free flap or a pedicled flap. The reversed-flow pedicled flap has an average pedicle length of 8 cm. The posterior tibial flap is a reliable, large, thin, innervated flap and can be raised with the patient supine. Case reports are presented of six patients who received a free flap transfer and of one patient who received a reversed-flow pedicled flap. There were two cases of heel ulcerations, two crushed hands, one chronic ulceration and osteomyelitis of the tibia, one burn contracture of the neck, and one salvage flap for diabetic gangrene of the hand.  相似文献   
87.
88.
Bloodflowvariationandenergymetabolisminthegastricmucosafollowing7.5%hypertonicsalineresuscitationWangJunyi(王俊义);WuGuosheng;(吴...  相似文献   
89.
90.
Hypothermia and preservative perfusates have been used to decrease ischemic renal injury. This study was performed to identify the preservative function of perfusates independent of the effects of hypothermia. Rats underwent 45 minutes of renal ischemia. Rectal and renal parenchyma temperatures were monitored and maintained within 1° C of normal. Perfusates were University of Wisconsin solution (UW), Euro-Collins solution, normal saline solution, and Ringer's lactate solution. A nonperfused ischemic control and a nonischemic control group were also evaluated. Parameters evaluated included serum creatinine and blood urea nitrogen levels, renal ischemic injury grade, renal weight, and gross appearance of the injured kidney. Rats treated with UW solution were found to have a significantly lower creatinine, blood urea nitrogen, and injury grade than the other three perfused groups. The external gross appearance of the UW-treated kidneys was normal, whereas that of the other groups demonstrated moderate to severe injury. Although the mean right/left renal weight difference of the UW-treated group was lower than that of the other three groups, this was not statistically significant. Under normothermic conditions in rats, UW solution affords significant renal protection from ischemia. Euro-Collins, normal saline, and Ringer's lactate solutions display no significant protective effect.Presented at the Twentieth Annual Meeting of the Peripheral Vascular Surgery Society, New Orleans, La., June 10, 1995.  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