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   657篇
  免费   27篇
  国内免费   26篇
儿科学   47篇
妇产科学   64篇
基础医学   42篇
口腔科学   24篇
临床医学   58篇
内科学   134篇
皮肤病学   4篇
神经病学   13篇
特种医学   118篇
外科学   29篇
综合类   4篇
预防医学   15篇
眼科学   5篇
药学   75篇
肿瘤学   78篇
  2022年   3篇
  2021年   6篇
  2020年   3篇
  2019年   3篇
  2018年   8篇
  2017年   3篇
  2016年   4篇
  2015年   8篇
  2014年   8篇
  2013年   19篇
  2012年   15篇
  2011年   9篇
  2010年   16篇
  2009年   18篇
  2008年   18篇
  2007年   35篇
  2006年   9篇
  2005年   19篇
  2004年   14篇
  2003年   15篇
  2002年   15篇
  2001年   29篇
  2000年   13篇
  1999年   20篇
  1998年   43篇
  1997年   46篇
  1996年   51篇
  1995年   40篇
  1994年   30篇
  1993年   31篇
  1992年   9篇
  1991年   11篇
  1990年   8篇
  1989年   19篇
  1988年   18篇
  1987年   12篇
  1986年   10篇
  1985年   11篇
  1984年   9篇
  1983年   5篇
  1982年   8篇
  1981年   5篇
  1980年   5篇
  1979年   4篇
  1978年   2篇
  1977年   8篇
  1976年   6篇
  1975年   8篇
  1954年   1篇
排序方式: 共有710条查询结果,搜索用时 15 毫秒
11.
A 74-year old man underwent a radical cholecystectomy for presumed gallbladder cancer. The histology of the resected specimen in fact revealed the lesion to be metastatic renal cell carcinoma from his resected right nephrectomy performed 14 years previously.  相似文献   
12.
13.
Charache  S; Dover  GJ; Moyer  MA; Moore  JW 《Blood》1987,69(1):109-116
Five patients with sickle cell anemia were treated with hydroxyurea (HU), in hopes of augmenting their production of fetal hemoglobin. Laboratory responses in two patients treated for more than 2 years were encouraging and there were suggestions of clinical improvement. Long- term HU therapy should be considered for severely affected adults with sickle cell anemia who are willing to accept what is probably a small risk of carcinogenesis. Preliminary chromosomal analysis and knowledge of the clastogenic properties of HU suggest that conception and pregnancy should be avoided. Pharmacokinetic studies will probably be necessary to adjust individual dosage schedules so that cytotoxicity is avoided. F cell responses can be seen in 2 to 3 weeks if the HU dose is optimal, but establishment of a large number of F cells in the circulation may take a month or longer.  相似文献   
14.
Ovarian cancer, in particular epithelial ovarian cancer (EOC), is commonly diagnosed when the tumor has metastasized into the abdominal cavity with an accumulation of ascites fluid. Combining histopathology and genetic variations, EOC can be sub-grouped into Type-I and Type-II tumors, of which the latter are more aggressive and metastatic. Metastasis and chemoresistance are the key events associated with the tumor microenvironment that lead to a poor patient outcome. Kallikrein-related peptidases (KLKs) are aberrantly expressed in EOC, in particular, in the more metastatic Type-II tumors. KLKs are a family of 15 serine proteases that are expressed in diverse human tissues and involved in various patho-physiological processes. As extracellular enzymes, KLKs function in the hydrolysis of growth factors, proteases, cell membrane bound receptors, adhesion proteins, and cytokines initiating intracellular signaling pathways and their downstream events. High KLK levels are differentially associated with the prognosis of ovarian cancer patients, suggesting that they not only have application as biomarkers but also function in disease progression, and therefore are potential therapeutic targets. Recent studies have demonstrated the function of these proteases in promoting and/or suppressing the invasive behavior of ovarian cancer cells in metastasis in vitro and in vivo. Both conventional cell culture methods and three-dimensional platforms have been applied to mimic the ovarian cancer microenvironment of patients, such as the solid stromal matrix and ascites fluid. Here we summarize published studies to provide an overview of our understanding of the role of KLKs in EOC, and to lay the foundation for future research directions.  相似文献   
15.
SUMMARY Assessment of clinical and laboratory markers of HIV infection may be used to individualise antiretroviral therapy. Data suggest that measures of viral load may be of considerable value as both a baseline and dynamic therapy marker, making these tools particularly useful in driving therapeutic decisions. Similarly, in-vitro data regarding intracellular pharmacokinetics and activity, resistance patterns and potential synergy of antiretroviral agents may be used to guide selection of optimal treatment regimens in clinical practice.  相似文献   
16.
Principles and practice of HIV-protease inhibitor pharmacoenhancement   总被引:1,自引:2,他引:1  
GJ Moyle  D Back 《HIV medicine》2001,2(2):105-113
Continually maintaining maximally suppressive drug concentrations represents a key defence against the emergence of resistance. If drug levels fall and replication occurs, the opportunity for mutant virus to be selected occurs. It has been increasingly recognized that variability in the pharmacokinetics of antiretrovirals, particularly protease inhibitors (PIs), means that drug exposure is not always optimal, giving the virus a chance to replicate. A significant number of patients receiving PIs two or three times daily will have trough (Ctrough or Cmin) plasma concentrations, which are close to, or below, the plasma protein binding‐corrected inhibitory concentration (IC50 or IC95) during the dosing interval. It is primarily in this context that therapeutic drug monitoring of PIs has been proposed as an aid to patient management, to ensure that patients maintain adequate drug concentrations throughout the dosing interval. Ideally, an antiretroviral drug will have a pharmacokinetic (PK) profile that maintains drug levels well above the viral inhibitory concentration throughout the entire dosing interval. Beneficial drug–drug interactions have been shown to improve PI pharmacokinetics. Ritonavir (RTV) inhibits the key enzymes that limit the bioavailability or speed the metabolism of other PIs. It is therefore increasingly used for boosting and maintaining PI plasma concentrations. At low (100 mg twice a day) doses it acts as a pharmacoenhancer of indinavir (IDV), amprenavir, saquinavir, lopinavir and to a more limited degree nelfinavir. Using a pharmacoenhancer with a PI results in increased exposure to the PI, higher Cmin levels, and in most cases prolonged elimination half‐lives. The long‐term clinical benefits of PK enhancing are unknown as are the long‐term toxicities, although the incidence of nephrolithiasis with IDV appears increased when IDV is combined with low‐dose RTV in HIV‐infected patients. Head‐to‐head clinical comparisons of boosted PI regimens will help answer some of the questions that remain with regard to PK enhancement.  相似文献   
17.

Objective

To explore factors influencing how well-informed women felt about hysterectomy, influences on their decision making, and on them receiving a less-invasive alternative to open surgery.

Methods

Online questionnaire, conducted in 2015–2016, of women who had received a hysterectomy in Australia, in the preceding two years.

Results

Questionnaires were completed by 2319/6000 women (39% response). Most women (n = 2225; 96%) felt well-informed about hysterectomy. Women were more aware of the open abdominal approach (n = 1798; 77%), than of less-invasive vaginal (n = 1552; 67%), laparoscopic (n = 1540; 66%), laparoscopic-assisted (n = 1303; 56%), and robotic approaches (n = 289; 12%). Most women (n = 1435; 62%) reported their gynaecologist was the most influential information source. Women who received information about hysterectomy from a GP (OR = 1.47; 95% CI 1.15-1.90), or from a gynaecologist (OR = 1.3; 95% CI 1.06-1.58), were more likely to feel better informed (p < 0.01).

Conclusion

This study is important because it helps clinicians, researchers and health policy makers to understand why many women still receive an open abdominal approach despite many learned societies recommending to avoid it if possible.

Practice implications

Additional information, or education about avoiding open abdominal approach where possible may lead to a greater number of women receiving less-invasive types of hysterectomy in the future.  相似文献   
18.

Objective

Uterine Papillary Serous Carcinoma (UPSC) is uncommon and accounts for less than 5% of all uterine cancers. Therefore the majority of evidence about the benefits of adjuvant treatment comes from retrospective case series. We conducted a prospective multi-centre non-randomized phase 2 clinical trial using four cycles of adjuvant paclitaxel plus carboplatin chemotherapy followed by pelvic radiotherapy, in order to evaluate the tolerability and safety of this approach.

Methods

This trial enrolled patients with newly diagnosed, previously untreated patients with stage 1b-4 (FIGO-1988) UPSC with a papillary serous component of at least 30%. Paclitaxel (175 mg/m2) and carboplatin (AUC 6) were administered on day 1 of each 3-week cycle for 4 cycles. Chemotherapy was followed by external beam radiotherapy to the whole pelvis (50.4 Gy over 5.5 weeks). Completion and toxicity of treatment (Common Toxicity Criteria, CTC) and quality of life measures were the primary outcome indicators.

Results

Twenty-nine of 31 patients completed treatment as planned. Dose reduction was needed in 9 patients (29%), treatment delay in 7 (23%), and treatment cessation in 2 patients (6.5%). Hematologic toxicity, grade 3 or 4 occurred in 19% (6/31) of patients. Patients' self-reported quality of life remained stable throughout treatment. Thirteen of the 29 patients with stages 1-3 disease (44.8%) recurred (average follow-up 28.1 months, range 8-60 months).

Conclusion

This multimodal treatment is feasible, safe and tolerated reasonably well and would be suitable for use in multi-institutional prospective randomized clinical trials incorporating novel therapies in patients with UPSC.  相似文献   
19.
Supravalvular aortic stenosis (SVAS) is an inherited obstructive vascular disease that affects the aorta, carotid, coronary and pulmonary arteries. Previous molecular genetic data have led to the hypothesis that SVAS results from mutations in the elastin gene, ELN. In these studies, the disease phenotype was linked to gross DNA rearrangements (35 and 85 kb deletions and a translocation) in three SVAS families. However, gross rearrangements of ELN have not been identified in most cases of autosomal dominant SVAS. To define the spectrum of ELN mutations responsible for this disorder, we refined the genomic structure of human ELN and used this information in mutational analyses. ELN point mutations co-segregate with the disease in four familial cases and are associated with SVAS in three sporadic cases. Two of the mutations are nonsense, one is a single base pair deletion and four are splice site mutations. In one sporadic case, the mutation arose de novo. These data demonstrate that point mutations of ELN cause autosomal dominant SVAS.   相似文献   
20.
We have recently shown using dansyl-L-lysine exclusion studies that the release of human chorionic gonadotrophin (HCG) in conjunction with L- lactate dehydrogenase (LDH) from first trimester villi during organ culture is symptomatic of syncytiotrophoblast degeneration. The purpose of this study was to examine chorionic villi at the ultrastructural level in order to determine events occurring during organ culture. The tissue was sampled after 0, 24, 48 and 120 h in culture and processed for electron microscopy. In addition to confirming the previously recorded syncytial degeneration, the electron micrographs showed clearly the generation of a new syncytiotrophoblast layer. The new layer, derived from differentiating cytotrophoblast cells, was largely formed by 48 h and was maintained for at least 120 h in culture. This study demonstrates a model which provides an opportunity to study the differentiation of cytotrophoblast cells whilst they retain their anatomical relationships within the villous structure.   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