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   14282篇
  免费   674篇
  国内免费   153篇
耳鼻咽喉   104篇
儿科学   269篇
妇产科学   137篇
基础医学   1560篇
口腔科学   385篇
临床医学   1030篇
内科学   4024篇
皮肤病学   193篇
神经病学   955篇
特种医学   512篇
外科学   2634篇
综合类   47篇
预防医学   346篇
眼科学   174篇
药学   1156篇
中国医学   22篇
肿瘤学   1561篇
  2023年   87篇
  2022年   148篇
  2021年   334篇
  2020年   193篇
  2019年   228篇
  2018年   317篇
  2017年   242篇
  2016年   312篇
  2015年   329篇
  2014年   435篇
  2013年   542篇
  2012年   820篇
  2011年   900篇
  2010年   508篇
  2009年   430篇
  2008年   777篇
  2007年   812篇
  2006年   833篇
  2005年   880篇
  2004年   887篇
  2003年   824篇
  2002年   795篇
  2001年   294篇
  2000年   264篇
  1999年   288篇
  1998年   228篇
  1997年   160篇
  1996年   153篇
  1995年   111篇
  1994年   109篇
  1993年   97篇
  1992年   152篇
  1991年   159篇
  1990年   141篇
  1989年   144篇
  1988年   115篇
  1987年   113篇
  1986年   98篇
  1985年   102篇
  1984年   75篇
  1983年   77篇
  1981年   40篇
  1980年   36篇
  1979年   73篇
  1978年   46篇
  1977年   41篇
  1975年   32篇
  1971年   38篇
  1970年   32篇
  1969年   35篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
5.
6.
A case of cystadenocarcinoma of the liver is reported. The patient was a 73-year-old woman in whom a tumor was detected in the lateral segment of the liver during a health examination. Ultrasonograms and computed tomograms showed a multilocular cystic mass. Magnetic resonance imaging (MRI) showed a multilocular lowintensity mass, including a high-intensity portion and a portal branch compressed by the tumor. MRI with gadolinium showed an enhanced cyst wall. The cystic part of the tumor became smaller and the solid part became larger over a 1-month period, indicating that the tumor was malignant. Subsegmentectomy (S3) was performed and cystadenocarcinoma with cystadenoma was diagnosed by histopathological examination. Identification of changes in the appearance of a tumor should be helpful for the differential diagnosis of cystadenoma and cystadenocarcinoma.  相似文献   
7.
A series of 5-hydroxy and 5-benzyloxy analogs of the antiarrhythmic and multidrug resistance (MDR) modulating drug propafenone was synthesized and the MDR-modulating activity of the compounds was evaluated using a daunomycin efflux assay system. The key step of the synthesis is the selective reduction of the double bond in 1 without cleavage of the benzyl group thus leading to the phenol 3 . Alkylation with epichlorohydrine followed by nucleophilic epoxide ring opening gave the benzylated target compounds 5a–d . Subsequent cleavage of the benzyl group gave the 5-hydroxy analogs 6a–d . Structure activity relationship studies showed, that the 5-hydroxy derivates 6a–d fit the log P/log potency correlation line previously established for a series of propafenone analogs. In contrast, all four 5-benzyloxy analogs 5a–d showed almost identical EC50 values, independent of their log P value.  相似文献   
8.
The surgical treatment of 100 cases with congenital dilatation of bile duct with special reference to late complications was analyzed. There were no deaths nor occurrences of malignancy. Among 91 patients who had undergone the standard operation, namely total excision of the dilated extrahepatic bile duct and reconstruction after Roux-en-Y hepaticojejunostomy, there were one early complication (pancreatic juice leakage) and five late complications (four intrahepatic gallstones and one liver abscess). The cause of intrahepatic gallstone formation after a total excisional operation was attributed to the remaining intrahepatic bile duct dilatation and the stenosis located between the intrahepatic bile duct dilatation and the common hepatic duct. Accordingly, these results support the total excisional procedure for this condition; however, with regard to the cases associated with cystic dilatation of intrahepatic bile ducts, completely free bile drainage from the dilated intrahepatic biliary system should be performed at the radical operation.  相似文献   
9.
The present study was undertaken to evaluate the role and possible interaction of the endogenous opioid peptide (EOP) and corticotropin-releasing factor (CRF) in the acute stress-induced suppression of gonadotropin secretion in ovariectomized estrogen-primed rats. An intravenous (i.v.) injection of naloxone (10 or 20  mg/kg), an EOP antagonist, significantly elevated serum luteinizing hormone (LH) levels within 10  min in non-stressed animals. The naloxone-induced LH release was completely eliminated when tested 30  min after the onset of acute immobilization. In a subsequent study, it was found that suppression of the naloxone-induced LH release occurred as early as 5  min after the stress onset, and was still evident 60  min after the end of a 30-min period of immobilization. The effect of naloxone was restored 3  h after liberation of the animal from the 30-min immobilization. An intraventricular (i.c.v.) injection of CRF (1 or 5  μg) also significantly suppressed, in a dose-related manner, the effect of a subsequent i.v. injection of naloxone. However, an i.c.v. injection of α -helical CRF(9-41) (25 or 50  μg), a CRF antagonist, prior to immobilization, could not interfere with the suppressive effect of stress on naloxone-induced LH release. These results suggest that both acute immobilization stress and CRF can inhibit the LH secretory activity without mediation by EOP neurons. However, the stress-related suppression may involve non-CRF mechanism(s).  相似文献   
10.
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