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   1013篇
  免费   57篇
  国内免费   3篇
耳鼻咽喉   2篇
儿科学   60篇
妇产科学   8篇
基础医学   108篇
口腔科学   18篇
临床医学   63篇
内科学   224篇
皮肤病学   10篇
神经病学   97篇
特种医学   73篇
外科学   132篇
综合类   9篇
预防医学   30篇
眼科学   23篇
药学   69篇
肿瘤学   147篇
  2022年   7篇
  2021年   21篇
  2020年   8篇
  2019年   11篇
  2018年   13篇
  2017年   16篇
  2016年   12篇
  2015年   20篇
  2014年   31篇
  2013年   39篇
  2012年   52篇
  2011年   47篇
  2010年   29篇
  2009年   49篇
  2008年   41篇
  2007年   41篇
  2006年   43篇
  2005年   24篇
  2004年   18篇
  2003年   27篇
  2002年   27篇
  2001年   26篇
  2000年   35篇
  1999年   26篇
  1998年   18篇
  1997年   30篇
  1996年   25篇
  1995年   20篇
  1994年   16篇
  1993年   18篇
  1992年   35篇
  1991年   28篇
  1990年   29篇
  1989年   21篇
  1988年   13篇
  1987年   22篇
  1986年   20篇
  1985年   17篇
  1983年   14篇
  1981年   6篇
  1980年   5篇
  1979年   8篇
  1978年   6篇
  1977年   4篇
  1976年   6篇
  1975年   8篇
  1973年   5篇
  1971年   6篇
  1967年   6篇
  1965年   4篇
排序方式: 共有1073条查询结果,搜索用时 15 毫秒
91.
92.
A number of problems concerning both clinical and genetic or cytogenetic aspects of the fragile-X syndrome remain unsolved. In the present work, a large 5-generation fragile-X family has been clinically and cytogenetically investigated. The results of our study indicated that an unusually high proportion of affected males was present in the family examined; all fragile-X-positive males were profoundly retarded and showed the phenotype typically described for this syndrome; moreover, we observed a variability of penetrance within the pedigree and all fragile-X-positive females in the 4th and 5th generation had some degree of mental impairment. A multistep mutation model has been proposed in order to explain some of these findings.  相似文献   
93.
94.
Children with acute lymphoblastic leukemia (ALL) and high hyperdiploidy (>50 chromosomes) are considered to have a relatively good prognosis. The specific extra chromosomes are not random; extra copies of some chromosomes occur more frequently than those of others. We examined the extra chromosomes present in high hyperdiploid ALL to determine if there were a relation of the specific extra chromosomes and modal number (MN) and if the extra chromosomes present could differentiate high hyperdiploid from near-triploid and near-tetraploid cases. Karyotypes of 2,339 children with ALL and high hyperdiploidy at diagnosis showed a distinct nonrandom sequential pattern of gain for each chromosome as MN increased, with four groups of gain: chromosomes 21, X, 14, 6, 18, 4, 17, and 10 at MN 51-54; chromosomes 8, 5, 11, and 12 at MN 57-60; chromosomes 2, 3, 9,16, and 22 at MN 63-67; chromosomes 1, 7 13, 15, 19, and 20 at MN 68-79, and Y only at MN >or=80. Chromosomes gained at lower MN were retained as the MN increased. High hyperdiploid pediatric ALL results from a single abnormal mitotic division. Our results suggest that the abnormal mitosis involves specific chromosomes dependent on the number of chromosomes aberrantly distributed, raising provocative questions regarding the mitotic mechanism. The patterns of frequencies of tetrasomy of specific chromosomes differs from that of trisomies with the exception of chromosome 21, which is tetrasomic in a high frequency of cases at all MN. These results are consistent with different origins of high hyperdiploidy, near-trisomy, and near-tetrasomy.  相似文献   
95.
96.
Ughetto  Stefano  Migliore  Cristina  Pietrantonio  Filippo  Apicella  Maria  Petrelli  Annalisa  D&#;Errico  Laura  Durando  Stefania  Moya-Rull  Daniel  Bellomo  Sara E.  Rizzolio  Sabrina  Capel&#;a  Tania  Ribisi  Salvatore  Degiuli  Maurizio  Reddavid  Rossella  Rapa  Ida  Fumagalli  Uberto  De Pascale  Stefano  Ribero  Dario  Baronchelli  Carla  Sgroi  Giovanni  Rausa  Emanuele  Baiocchi  Gian Luca  Molfino  Sarah  Manenti  Stefania  Bencivenga  Maria  Sacco  Michele  Castelli  Claudia  Siena  Salvatore  Sartore-Bianchi  Andrea  Tosi  Federica  Morano  Federica  Raimondi  Alessandra  Prisciandaro  Michele  Gloghini  Annunziata  Marsoni  Silvia  Sottile  Antonino  Sarotto  Ivana  Sapino  Anna  Marchi&#;  Caterina  Cassoni  Paola  Guarrera  Simonetta  Corso  Simona  Giordano  Silvia 《Gastric cancer》2021,24(4):897-912
Gastric Cancer - Trastuzumab is the only approved targeted therapy in patients with HER2-amplified metastatic gastric cancer (GC). Regrettably, in clinical practice, only a fraction of them...  相似文献   
97.
BackgroundDoublets plus anti‐epidermal growth factor receptors (EGFRs) are the preferred upfront option for patients with left‐sided RAS/BRAF wild‐type metastatic colorectal cancer (mCRC). Initial therapy with FOLFOXIRI‐bevacizumab is superior to doublets plus bevacizumab independently from primary tumor sidedness and RAS/BRAF status. No randomized comparison between FOLFOXIRI‐bevacizumab versus doublets plus anti‐EGFRs is available in left‐sided RAS/BRAF wild‐type mCRC.Materials and MethodsWe selected patients with left‐sided RAS and BRAF wild‐type mCRC treated with first‐line FOLFOX‐panitumumab or FOLFOXIRI‐bevacizumab in five randomized trials: Valentino, TRIBE, TRIBE2, STEAM, and CHARTA. A propensity score‐based analysis was performed to compare FOLFOXIRI‐bevacizumab with FOLFOX‐panitumumab.ResultsA total of 185 patients received FOLFOX‐panitumumab and 132 received FOLFOXIRI‐bevacizumab. Median progression‐free survival (PFS) and median overall survival (OS) were 13.3 and 33.1 months in the FOLFOXIRI‐bevacizumab group compared with 11.4 and 30.3 months in the FOLFOX‐panitumumab group (propensity score‐adjusted hazard ratio (HR) for PFS, 0.82; 95% confidence interval (CI), 0.64–1.04; p = .11; propensity score‐adjusted HR for OS, 0.80; 95% CI, 0.59–1.08; p = .14). No significant differences in overall response rate and disease control rate were observed. A statistically nonsignificant difference in favor of FOLFOXIRI‐bevacizumab was observed for OS after secondary resection of metastases. Chemotherapy‐related adverse events were more frequent in the FOLFOXIRI‐bevacizumab group, with specific regard to grade 3 and 4 neutropenia (48% vs. 26%, adjusted p = .001).ConclusionAlthough randomized comparison is lacking, both FOLFOXIRI‐bevacizumab and FOLFOX‐panitumumab are valuable treatment options in left‐sided RAS/BRAF wild‐type mCRC.Implications for PracticeA propensity score‐based analysis of five trials was performed to compare FOLFOX‐panitumumab versus FOLFOXIRI‐bevacizumab in left‐sided RAS/BRAF wild‐type metastatic colorectal cancer (mCRC). No significant differences were observed, but FOLFOXIRI‐bevacizumab achieved numerically superior survival outcomes versus FOLFOX‐panitumumab. Chemotherapy‐related adverse events were more frequent in the FOLFOXIRI‐bevacizumab group. These observations suggest that although doublet chemotherapy plus anti‐EGFRs remains the preferred treatment in patients with left‐sided RAS/BRAF wild‐type mCRC, FOLFOXIRI‐bevacizumab is a valuable option able to provide similar, if not better, outcomes at the price of a moderate increase in toxicity and may be adopted based on patients’ preference and potential impact on quality of life.  相似文献   
98.
99.
Non-Hodgkin's lymphoma (NHL) is the most common human immunodeficiency virus (HIV)-associated malignancy in hemophiliacs. We studied the incidence and clinicopathologic features of NHL in 3,041 hemophiliacs followed at 18 US Hemophilia Centers between 1978 and 1989. Of the 1,295 (56.6%) who were HIV(+), 253 (19.5%) developed acquired immunodeficiency syndrome (AIDS), of whom 14 (5.5%) developed NHL. Three NHL occurred in HIV(-) hemophiliacs, for a 36.5-fold greater risk in HIV(+) than HIV(-) hemophiliacs (P < .001). The NHL incidence rate was 29-fold greater than in the US population by Surveillance, Epidemiology, and End Results (SEER) estimates (P < .001). Between 0 and 4 lymphomas have been observed per year between 1978 and 1989. At presentation 13 (92.9%) of the HIV(+) NHL were extranodal. Ten were stage IV, 1 stage II, and 3 stage IE. Ten (71.4%) were high-grade, 3 (21.4%) intermediate-grade, and 1 (7.1%) was a low-grade B-cell lymphoma. Epstein-Barr virus (EBV) DNA was detected in 36% by in situ hybridization, including one central nervous system (CNS) lymphoma. The mean CD4 cell count at NHL diagnosis was 64/mm3, the mean latency from initial HIV infection was estimated to be 59 months, and the median survival was 7 months. The incidence of basal cell carcinoma in HIV(+) hemophiliacs was 18.3-fold greater than in HIV(-) hemophiliacs (P < .001) and 11.4-fold greater than in the US population (P < .001). In conclusion, incidence rates of NHL and basal cell carcinoma in HIV(+) hemophiliacs are significantly increased over rates in HIV(-) hemophiliacs and over rates in the US population. Clinicopathologic presentation of NHL in HIV(+) hemophiliacs is similar to that in HIV(+) homosexual men.  相似文献   
100.

Background:

The melanocortin-1-receptor (MC1R) gene regulates human pigmentation and is highly polymorphic in populations of European origins. The aims of this study were to evaluate the association between MC1R variants and the risk of non-melanoma skin cancer (NMSC), and to investigate whether risk estimates differed by phenotypic characteristics.

Methods:

Data on 3527 NMSC cases and 9391 controls were gathered through the M-SKIP Project, an international pooled-analysis on MC1R, skin cancer and phenotypic characteristics. We calculated summary odds ratios (SOR) with random-effect models, and performed stratified analyses.

Results:

Subjects carrying at least one MC1R variant had an increased risk of NMSC overall, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC): SOR (95%CI) were 1.48 (1.24–1.76), 1.39 (1.15–1.69) and 1.61 (1.35–1.91), respectively. All of the investigated variants showed positive associations with NMSC, with consistent significant results obtained for V60L, D84E, V92M, R151C, R160W, R163Q and D294H: SOR (95%CI) ranged from 1.42 (1.19–1.70) for V60L to 2.66 (1.06–6.65) for D84E variant. In stratified analysis, there was no consistent pattern of association between MC1R and NMSC by skin type, but we consistently observed higher SORs for subjects without red hair.

Conclusions:

Our pooled-analysis highlighted a role of MC1R variants in NMSC development and suggested an effect modification by red hair colour phenotype.  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