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   3841篇
  免费   186篇
  国内免费   46篇
耳鼻咽喉   150篇
儿科学   233篇
妇产科学   99篇
基础医学   244篇
口腔科学   126篇
临床医学   310篇
内科学   939篇
皮肤病学   61篇
神经病学   155篇
特种医学   157篇
外科学   954篇
综合类   38篇
一般理论   2篇
预防医学   80篇
眼科学   168篇
药学   173篇
中国医学   10篇
肿瘤学   174篇
  2024年   12篇
  2023年   62篇
  2022年   85篇
  2021年   124篇
  2020年   85篇
  2019年   90篇
  2018年   100篇
  2017年   92篇
  2016年   165篇
  2015年   210篇
  2014年   225篇
  2013年   276篇
  2012年   385篇
  2011年   340篇
  2010年   185篇
  2009年   146篇
  2008年   240篇
  2007年   288篇
  2006年   210篇
  2005年   194篇
  2004年   173篇
  2003年   140篇
  2002年   144篇
  2001年   24篇
  2000年   12篇
  1999年   20篇
  1998年   15篇
  1997年   6篇
  1996年   5篇
  1995年   5篇
  1994年   3篇
  1993年   2篇
  1992年   4篇
  1990年   1篇
  1983年   1篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
排序方式: 共有4073条查询结果,搜索用时 15 毫秒
1.
2.
3.
OBJECTIVE: To introduce 1,1,1,2 tetrafluoroethane (TFE), as a new material for cryosurgery of gingival melanin pigmentation (GMP). STUDY DESIGN: Twenty-one patients with GMP were treated using a TFE-cooled cotton swab. Standard digital images of pigmented areas were measured preoperatively and postoperatively with image-analyzing software. The Mann-Whitney U test was used for statistical analysis. RESULTS: Keratinization was completed 3 to 4 weeks after application, without any trace of pigmentation. Statistical analysis revealed a significant difference between preoperative and postoperative measurements of pigmented areas (P < .05). During the follow-up period, no side effects were observed and improved esthetics were maintained up to month 30. CONCLUSIONS: The clinical outcomes of cryosurgery with TFE for treatment of GMP are very satisfactory. The use of TFE for cryosurgical treatment of GMP is practical and inexpensive. Moreover, unlike other cryosurgery methods no special equipment is required, and it is safe to store in the dental clinic.  相似文献   
4.
OBJECTIVE: The purpose of this presentation is to show the imaging findings of the common and uncommon variants of adenomyosis as seen on sonography and magnetic resonance imaging (MRI). METHODS: A 3-year database search was performed to identify women who had pelvic sonography and pelvic MRI within a 6-month interval. Images of these cases were retrospectively reviewed. RESULTS: Eighty women were identified. Adenomyosis was diagnosed on MRI, which was used as the reference standard, in 45 of these women. The correct diagnosis was made on sonography in 73% of the cases. CONCLUSIONS: Awareness of the spectrum of imaging features of adenomyosis is important to use sonography effectively for diagnosing this entity and to help avoid misdiagnosis.  相似文献   
5.
Spatial analysis of (90)Sr artificial radionuclide in consequence of global fallout and Chernobyl nuclear accident has been carried out by using the point cumulative semivariogram (PCSV) technique based on 40 surface water station measurements in Keban Dam Lake during March, April, and May 2006. This technique is a convenient tool in obtaining the regional variability features around each sampling point, which yields the structural effects also in the vicinity of the same point. It presents the regional effect of all the other sites within the study area on the site concerned. In order to see to change of (90)Sr, the five models are constituted. Additionally, it provides a measure of cumulative similarity of the regional variable, (90)Sr, around any measurement site and hence it is possible to draw regional similarity maps at any desired distance around each station. In this paper, such similarity maps are also drawn for a set of distances. (90)Sr activities in lake that distance approximately 4.5 km from stations show the maximum similarity.  相似文献   
6.
Antioxidant capacity and nitric oxide in patients with hepatic cirrhosis   总被引:2,自引:0,他引:2  
This study investigated the relationship between the antioxidant capacity of blood and the serum level of nitric oxide (NO) in patients with hepatic cirrhosis. The study included 20 patients with compensated cirrhosis (group I), 30 with decompensated cirrhosis (group II), and 30 healthy controls (group III). The serum levels of NO, albumin, bilirubin, and uric acid, and the erythrocyte activity of superoxide dismutase (SOD) were measured in all groups. The mean erythrocyte SOD activity (5.94 +/- 3.21 U/mg protein) and serum NO level (25.19 +/- 8.15 micromol/L) in group I were similar to those of controls (6.86 +/- 2.47 U/mg protein and 21.67 +/- 6.51 micromol/L, respectively). However, erythrocyte SOD activity in group II was significantly lower than in groups I and III and mean serum NO level was significantly higher in group II than in groups I and III. In regard to non-enzymatic antioxidants, the mean serum albumin level was lower and the mean serum total bilirubin level was higher in group II than in groups I and III. As expected, group I had higher mean serum total bilirubin level than the control group. Correlation analysis showed that erythrocyte SOD activity in cirrhotic patients was negatively correlated with their serum levels of NO. These results suggest that disturbances of antioxidative mechanisms may diminish hepatic resistance to oxidative stress, thereby contributing to the development of fibrogenesis.  相似文献   
7.
8.
We have conjugated the murine monoclonal anti-CD 19 antibody B43 to the tyrosine kinase inhibitor genistein to construct an effective immunoconjugate against CD 19 antigen positive hematologic malignancies. The scaled-up production and purification of B43 antibody, genistein, and B43-Genistein immunoconjugate permitted the manufacturing of a highly purified clinical-grade B43-Genistein preparation. In clonogenic assays, B43-Genistein elicited selective and potent cytotoxicity against CD 19 antigen positive human leukemia cells. To our knowledge, this work represents the first effort of producing a clinical-grade genistein immunoconjugate for treatment of B-lineage leukemia and lymphoma.  相似文献   
9.
OBJECTIVE: An endometrioid adenocarcinoma (EAC) with true trophoblastic differentiation is a rare event with a highly aggressive clinical course. CASE: We report an endometrioid adenocarcinoma of the endometrium in which there was a morphologically conventional-appearing EAC component admixed with multinucleated giant cells and large pleomorphic tumor cells that resembled a choriocarcinoma without an elevated serum level of human chorionic gonadotropin (hCG) in a 42-year-old unmarried woman with a history of abnormal uterine bleeding. A total abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymph node dissection were performed. Histopathologic study of the specimen showed endometrioid adenocarcinoma extended to the deep myometrium with a focus of hemorrhagic and necrotic tumor composed of multinucleated giant cells, large pleomorphic tumor cells, suggesting choriocarcinomatous differentiation (CD). Immunohistochemical studies demonstrated intense reactivity of tumor cells for human chorionic gonadotropin (hCG) confirming the diagnosis. A complete clinical workup ruled out metastatic spread to the brain, lungs, skeleton, or abdomen. The patient was alive with no evidence of disease 6 months later. CONCLUSION: Although endometrioid adenocarcinoma with choriocarcinomatous differentiation is known to behave in a more aggressive course, this disease may have a good prognosis with a clinically indolent course when it is small, and without elevated serum hCG levels.  相似文献   
10.
BACKGROUND: Peutz-Jeghers Syndrome (PJS) is a rare autosomal dominant disorder characterized by gastrointestinal hamartomatous polyps and mucocutaneous pigmentation. Patients with PJS have increased risk for gastrointestinal, breast, and female genital tract cancers. CASE: Multiple genital tract cancers in a 34-year-old woman with PJS are described. The patient, who was admitted to our department with severe vaginal bleeding, was performed right salpingo-oophorectomy because of pure gonadoblastoma in 1996. In 2003, concomitant to cervical carcinoma, breast cancer was diagnosed. Patient underwent left modified radical mastectomy due to the invasive papillary carcinoma. The patient received six cycles combination chemotherapy and radiation therapy because of stage IIIB cervical cancer. CONCLUSION(S): This is the first case report presenting PJS associated with multiple genital tract tumors including ovarian gonadoblastoma in literature. The clinical significance of these tumors in PJS patients has been reviewed.  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