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   12035篇
  免费   746篇
  国内免费   42篇
耳鼻咽喉   162篇
儿科学   708篇
妇产科学   249篇
基础医学   1652篇
口腔科学   131篇
临床医学   883篇
内科学   2629篇
皮肤病学   256篇
神经病学   707篇
特种医学   192篇
外科学   1382篇
综合类   445篇
一般理论   2篇
预防医学   767篇
眼科学   376篇
药学   1212篇
中国医学   113篇
肿瘤学   957篇
  2023年   95篇
  2022年   189篇
  2021年   379篇
  2020年   192篇
  2019年   248篇
  2018年   319篇
  2017年   240篇
  2016年   291篇
  2015年   345篇
  2014年   462篇
  2013年   600篇
  2012年   836篇
  2011年   855篇
  2010年   495篇
  2009年   438篇
  2008年   658篇
  2007年   605篇
  2006年   516篇
  2005年   509篇
  2004年   425篇
  2003年   395篇
  2002年   376篇
  2001年   271篇
  2000年   254篇
  1999年   212篇
  1998年   111篇
  1997年   75篇
  1996年   83篇
  1995年   74篇
  1994年   62篇
  1993年   73篇
  1992年   143篇
  1991年   148篇
  1990年   145篇
  1989年   112篇
  1988年   112篇
  1987年   115篇
  1986年   90篇
  1985年   114篇
  1984年   70篇
  1983年   70篇
  1979年   74篇
  1978年   63篇
  1977年   50篇
  1976年   53篇
  1975年   53篇
  1974年   60篇
  1973年   60篇
  1972年   66篇
  1971年   54篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Intussusception is a very rare cause of intestinal obstruction in neonates. It is of extremely rare occurrence among premature neonates. We present a case of 11-day-old premature neonate who presented with abdominal distension, intolerance to feeds, vomiting, significant bilious aspirate and bleeding per rectum. The initial diagnosis of necrotizing enterocolitis (NEC) led to a delay in the diagnosis. On exploratory laparotomy, it turned out to be a case of ileo-colic intussusception with Meckel''s diverticulum as a lead point. This site of intussusception (ileo-colic) and presence of a lead point among premature neonate is of exceedingly rare occurrence and very few such cases have been reported.In this article, the published work about clinical features and management on intussusceptions in premature neonates has been reviewed. The authors intend to highlight the difficulty in distinguishing the NEC and intussusception. Subtle clinical and radiological features which can help in differentiating the two conditions have been emphasized. This can avoid the delay in diagnosis and management which can prove critical. High index of suspicion with timely intervention is the key for optimizing outcome. A diagnosis of intussusception should always be considered in any preterm infant with suspected NEC.  相似文献   
2.
3.
4.
After the interaction of estrogen with the ligand binding domain (LBD) of mouse estrogen receptor‐α (mERα) and hormone‐responsive elements of target genes, many nuclear proteins are recruited to regulate the expression of specific genes. Because it is not known which brain proteins interact with LBD or whether these proteins vary with age and sex, we used pull‐down assay and far Western blotting to detect five nuclear proteins of 160, 140, 87, 60, and 46 kD in the mouse brain. These interacting proteins were identified as PELP1, RIP140, PGC1α, BAF60, and ADA3, respectively. The level of PELP1, RIP140, PGC1α, and BAF60 decreased drastically in old compared with adult male mice, whereas the ADA3 level showed no significant change. PELP1, PGC1α, and BAF60 levels were lower in old male compared with female mice. Thus we report the identification and interaction of five nuclear proteins with mERα‐LBD, indicating their role in estrogen signaling and brain functions during aging. © 2009 Wiley‐Liss, Inc.  相似文献   
5.
6.
Ziprasidone (Geodone), a novel atypical antipsychotic agent, is recently approved for the treatment of schizophrenia. It undergoes extensive metabolism in preclinical species and humans after oral administration, and only a very small amount of administered dose is excreted as unchanged drug. In vitro studies using human liver microsomes have shown that the oxidative metabolism of ziprasidone is mediated primarily by CYP3A4. However, coadministration of ziprasidone with ketoconazole, a CYP3A4 inhibitor, showed only a modest increase in its exposure. Therefore, in vitro metabolism of ziprasidone was investigated in hepatic cytosolic fractions to further understand its clearance mechanisms in preclinical species and humans. The major metabolite from incubation of ziprasidone in cytosolic fractions of rat, dog, and human was characterized by liquid chromatography-tandem mass spectrometry and found to be the product of reductive cleavage. Derivatization and hydrogen/deuterium exchange were used to deduce that the addition of two hydrogen atoms had occurred at the benzisothiazole moiety. Further studies to determine the enzyme involved in the formation of this metabolite are currently in progress. The identification of this novel metabolite in cytosol has clarified the clearance mechanism of ziprasidone in humans and preclinical species.  相似文献   
7.
A 27-month longitudinal study of 140 Bangladeshi mothers living in three tea gardens examined the effect of maternal factors (mother's age, number of live births, birth interval, and mother's work status) and sex of the infant on the duration and bout frequency of breastfeeding over 8-hr daytime periods. Prolonged breastfeeding of the infant was observed, but there was a sharp decline in duration of breastfeeding over the first 6 months, followed by a more gradual diminution thereafter. The feeding bouts showed a different pattern, with a more gradual decline over time. Housewives consistently showed a greater duration and bout frequency than women in paid employment as tea-pluckers. Over the first 6 months, primigravid mothers breastfed more frequently, but not thereafter. Older mothers (>35 years of age) breastfed with higher frequency during the first 2 months, but thereafter, the bout frequency decreased with increasing age of the infant. Over the 27-month study, maternal work status was the main factor associated with the duration and frequency of breastfeeding, with significantly higher frequency and duration among housewives. However, in the first 6 months after birth, there was very little difference in frequency or duration of breastfeeding between tea-workers and housewives, indicating that working mothers probably adjusted their time to breastfeed their infants before going, or after coming back, from work.  相似文献   
8.
9.
10.
Sixteen patients receiving percutaneous endoscopic gastrostomy (PEG) feeding following a period of nasogastric (NG) feeding were investigated to assess acceptance and identify problems by means of a questionnaire. PEG was considered to be superior to NG feeding in terms of tolerance and cosmetic acceptance by 81% and 88% of participants respectively ( P < 0.001). Pain was an infrequent problem. Interruptions to feeding were consideed to be more common with NG feeding by 50% of participants; 38% considered interruptions equally common with both PEG and NG, and 12% considered interruptions more common with PEG feeding ( P = NS). The time for care was equivalent for both methods. Seventy-five percent considered PEG to have made a valuable contribution to enteral feeding. Leakage was however considered to be more frequent in PEG feeding by 81% of participants (compared to 12% who considered leakage to be more common with NG feeding; P < 0.001) and leakage was more frequent at die junctions in the catheter rather than from the stoma. Thirty-one percent of patients with PEG had needed systemic antibiotics for stomal infections. All patients with both PEG and NG feeding needed professional help. Sixty-two percent needed professional help more frequently with PEG than with NG feeding (compared to 19% who considered that the NG tube needed professional help more frequently; P <0.05). We conclude that leakage and infections are major problems in PEG enteral feeding.  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