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   24802篇
  免费   1183篇
  国内免费   160篇
耳鼻咽喉   211篇
儿科学   608篇
妇产科学   271篇
基础医学   3330篇
口腔科学   426篇
临床医学   1476篇
内科学   6527篇
皮肤病学   690篇
神经病学   1803篇
特种医学   992篇
外科学   4111篇
综合类   124篇
预防医学   598篇
眼科学   622篇
药学   1620篇
中国医学   41篇
肿瘤学   2695篇
  2023年   142篇
  2022年   296篇
  2021年   499篇
  2020年   277篇
  2019年   358篇
  2018年   510篇
  2017年   393篇
  2016年   478篇
  2015年   508篇
  2014年   743篇
  2013年   842篇
  2012年   1418篇
  2011年   1603篇
  2010年   900篇
  2009年   808篇
  2008年   1424篇
  2007年   1586篇
  2006年   1545篇
  2005年   1684篇
  2004年   1681篇
  2003年   1758篇
  2002年   1626篇
  2001年   332篇
  2000年   290篇
  1999年   358篇
  1998年   411篇
  1997年   333篇
  1996年   328篇
  1995年   272篇
  1994年   268篇
  1993年   224篇
  1992年   191篇
  1991年   181篇
  1990年   156篇
  1989年   174篇
  1988年   170篇
  1987年   141篇
  1986年   125篇
  1985年   109篇
  1984年   127篇
  1983年   86篇
  1982年   80篇
  1981年   86篇
  1980年   106篇
  1979年   85篇
  1978年   55篇
  1977年   56篇
  1976年   41篇
  1975年   34篇
  1974年   34篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
OBJECTIVES: Laparoscopic surgery for kidney treatment is a common procedure. However, the efficacy of this procedure in patients with several comorbidities has not been well investigated. We conducted a retrospective comparison of results of laparoscopic surgery between patients with several comorbidities and patients with no comorbidity to access the efficacy and safety of this procedure. METHODS: The subjects were 20 patients with three or more comorbidities (group A) and 46 patients with less than three comorbidities (group B). These 66 patients were 48 men and 18 women with a mean age of 62.3 years (age range, 24-83 years). The data from these two groups were compared for American Society of Anesthesiology (ASA) physical status score, previous surgical history, duration of surgery, estimated blood loss, tumor size, complications during and after surgery, conversion rates, time to oral intake, and length of hospital stay. RESULTS: The initial ASA score and age were significantly higher for the patients with comorbidities (P < 0.0001, P = 0.0008, respectively). All other variables before, during, and after surgery were similar for both laparoscopic groups. However, the incidence of atelectasis of laparoscopy was higher than that of open surgery. CONCLUSIONS: Laparoscopic nephrectomy for patients with comorbidities is safe and minimally invasive. Further investigation to prevent atelectasis is necessary.  相似文献   
12.
Although the prevalence of a learned voiding dysfunction and non-neurogenic neurogenic bladder (NNB), which is one type of dysfunctional elimination syndrome, is considered to be relatively rare, the association of NNB with Down syndrome (DS) has been elucidated in male patients. We herein describe the occurrence of NNB in an adult female with DS. The diagnosis was confirmed after completely ruling out any neurological or anatomical anomalies that could be related to a lower urinary tract dysfunction. She had renal dysfunction and multiple obstructive uropathies for which clean intermittent catheterization was successfully introduced.  相似文献   
13.
The case of a 75-year-old man with three synchronous carcinomas of the lung (large cell carcinoma, adenocarcinoma, and small cell carcinoma) is reported. This is the eighth well-documented case report in the literature; however, our case is the first to be reported with the newly described histological combination.  相似文献   
14.
15.
Abstract: We analyzed the expression of CEA, CA19-9, CA125, CA15-3 (DF3), PCNA and p53 immunohistochemically in 14 tissue specimens of mucosal cancers in adenoma, seven tubulovillous adenoma specimens, and 16 tubular adenoma specimens. The rates of positive staining for mucosal cancer in adenoma, tubulovillous adenoma and tubular adenoma specimens, respectively, were: for CEA: 100%, 85.7% and 75%; for CA19-9: 71.4%, 71.4% and 56.2%; for CA125:0%, 0% and 0%;for CA15-3 (DF3): 64.3 %, 0% and 0 %; for PCNA: 100%, 88.9% and 56.2%; and for p53: 35.7%, 0% and 0% . The results suggest that the expressions of CEA, CA19-9, CA15-3 (DF3), PCNA and p53 are related to colorectal tumorigenesis. None of the specimens studied showed staining for CA125, suggesting that CA125 is not involved in the early stages of colorectal carcinogenesis. There was no significant difference in the rates of positive staining for CEA and CA19-9 among mucosal cancer in adenoma, tubular adenoma and tubulovillous adenoma specimens. However, the rates of positive staining for PCNA and p53 were significantly higher in mucosal cancer in adenoma specimens than for tubular adenoma specimens (p<0.05), and the rate of CA15-3 (DF3) positive staining was significantly higher for mucosal cancer in adenoma than for tubulovillous adenoma (p<0.01) and tubular adenoma (p< 0.001) specimens. Therefore, the CA15-3 (DF3) antigen is an immunohistochemical marker for colorectal carcinomas. The present results suggest that CA15-3 (DF3), PCNA and p53 play important roles in the genesis of colorectal adenomas.  相似文献   
16.
The matrix metalloproteinase matrilysin (MMP-7) is a member of the matrix metallo-proteinase gene family, which is believed to play an important role in tumor invasion and metastasis. We have previously found that matrilysin mRNA is specifically expressed in colorectal cancers and adenomas and that its message is localized in the tumor cells themselves. We examined the effects of activated Ki-ras oncogene on the expression of matrilysin in colon cancer cells. We showed that both mRNA and the enzymatic activity of matrilysin were induced by the introduction of activated Ki-ras into SW1417 colon cancer cells. To understand the mechanisms regulating this induction, we analyzed alterations of AP-1 activity induced by activated Ki-ras, using the chloramphenicol acetyltransferase assay. AP-1 activity in SW1417 cells expressing activated Ki-ras was higher than that in control cells. The gel-shift assay also showed higher levels of AP-1 binding protein in SW1417 cells expressing activated Ki-ras than those in control cells. Our results suggest that activated Ki-ras may play a role in inducing expression of matrilysin through an AP-1-dependent pathway in colon cancer cells.  相似文献   
17.
A 52‐year‐old Japanese woman who presented with gastrointestinal (GI) bleeding underwent a proximal gastrectomy for a gastrointestinal stromal tumor (GIST) with a foveolar hyperplasia at the apex of the tumor, 4.5 cm in size, located in the upper body of the stomach. Although GIST are often asymptomatic and are found only incidentally, clinical symptoms such as bleeding, abdominal pain, or obstruction, occasionally lead to a premorbid diagnosis. When submucosal tumors present GI bleeding, the source of the bleeding usually is an ulceration of the mucosa over the tumor. However, in the present study, it was thought that the bleeding originated from the region of foveolar hyperplasia.  相似文献   
18.
19.
A 65-year old female, who had been suffered from rheumatoid arthritis, was admitted to our hospital because of fever, oral ulcers, perianal skin ulcers, petechiae in the both legs, hepatosplenomegaly and cervical lymphadenopathy. Her laboratory data showed severe anemia, leukocytopenia, and thrombocytopenia as well as low PT activity, prolonged APTT, decreased fibrinegen and elevated FDP. In addition to raised values of liver enzymes and triglyceride, marked elevation of several cytokines were found. IgM and IgG class antibodies to cytomegalovirus were demonstrated positive and their titers were 2.60 and 938.0, respectively. The study for the aspiration of bone marrow revealed hemophagocytosis of erythrocytes, leukocytes and thrombocytes. Based upon these findings, she was diagnosed as having hemophagocytic syndrome associated with cytomegalovirus infection. Steroid treatment inducing mini-pulse therapy was introduced to her and bought full recovery from the illness. The association of hemophagocytic syndrome to rheumatoid arthritis was reviewed in the literature and five cases were documented to have good prognosis with steroid treatment.  相似文献   
20.
We have investigated the effects of short-contact topical application of tretinoin using 16 male db/db mice by creating two full-thickness wounds on the skin of the back. A 0.1% tretinoin aqueous gel was applied to one wound for five minutes daily for five successive days while only aqueous gel was applied to the other (control). The mean (SD) percentage surface area unhealed before and after treatment were 0.88 (0.3) and 0.64 (0.15). In tretinoin-treated mice and non-treated mice (controls), the mean (SD) thicknesses of granulation were 1.383 (697) micro m and 683 (413) micro m, the density of capillary vessels in granulation was 12.2 (5.5)% and 5.7 (3.9)%, respectively. Differences between the two groups were significant for each variable. Wound healing was accelerated with short-contact topical application of tretinoin in db/db mice.  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