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   34488篇
  免费   3464篇
  国内免费   46篇
耳鼻咽喉   417篇
儿科学   1111篇
妇产科学   960篇
基础医学   4765篇
口腔科学   782篇
临床医学   3641篇
内科学   7173篇
皮肤病学   459篇
神经病学   2739篇
特种医学   1213篇
外国民族医学   9篇
外科学   4395篇
综合类   787篇
一般理论   28篇
预防医学   3940篇
眼科学   853篇
药学   2390篇
中国医学   37篇
肿瘤学   2299篇
  2021年   458篇
  2020年   259篇
  2019年   462篇
  2018年   535篇
  2017年   456篇
  2016年   442篇
  2015年   473篇
  2014年   741篇
  2013年   1138篇
  2012年   1575篇
  2011年   1624篇
  2010年   891篇
  2009年   797篇
  2008年   1433篇
  2007年   1585篇
  2006年   1522篇
  2005年   1417篇
  2004年   1284篇
  2003年   1262篇
  2002年   1276篇
  2001年   1135篇
  2000年   1180篇
  1999年   991篇
  1998年   389篇
  1997年   363篇
  1996年   390篇
  1995年   342篇
  1994年   329篇
  1993年   318篇
  1992年   919篇
  1991年   915篇
  1990年   827篇
  1989年   781篇
  1988年   688篇
  1987年   701篇
  1986年   704篇
  1985年   686篇
  1984年   555篇
  1983年   439篇
  1982年   335篇
  1981年   294篇
  1980年   260篇
  1979年   534篇
  1978年   325篇
  1977年   265篇
  1976年   286篇
  1975年   317篇
  1974年   353篇
  1973年   293篇
  1972年   273篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.

Background Population screening for osteoporosis using bone mineral density scan is not feasible in Malaysia as this test is costly. Hence, there is a need to develop a more efficient method to screen for osteoporosis.Objectives To determine the feasibility of an interprofessional collaborative osteoporosis screening programme (IPC-OSP). Methods Postmenopausal women aged?≥?50 years, who had not been diagnosed with osteoporosis were recruited from a primary care clinic from June to August 2014. Patients were assessed for their osteoporosis risk and were counselled on prevention methods. Patients at risk were referred to the doctor with a recommendation for a bone mineral density (BMD) scan. Results Fifty out of 55 patients were recruited (response rate?=?90.9%). A total 26/50 (52.0%) went for a bone mineral density scan, none were osteoporotic, 17/50 (34%) were osteopenic, 2/50 (4.0%), were started on osteoporosis medications and 14/50 (28%) modified their lifestyle to improve bone health or started on calcium supplements. Osteoporosis knowledge significantly increased from baseline to month two (46.3?±?21.4 vs. 79.1?±?14.3, p?<?0.001). Patients had a satisfaction score of 89.8?±?12.4. Follow-up rates were 83.9% and 100% at months 1 (BMD appointment) and 2 (phone follow up), respectively. The intervention was successfully coordinated. Data entry was determined to be viable based on the researchers’ experience. Conclusion The interprofessional collaborative osteoporosis screening programme was found to be feasible in Malaysia.

  相似文献   
993.
We utilized synthetic photochemistry to generate novel sp3-rich scaffolds and report the design, synthesis, and biological testing of a diverse series of amides based on the 1-(amino-methyl)-2-benzyl-2-aza-bicyclo[2.1.1]hexane scaffold. Preliminary antimalarial screening of the library provided promising compounds with activity in the 1–5 μM range with an enhanced hit rate. Further evaluation (solubility, drug metabolism and pharmacokinetics (DMPK), and toxicity) of a selected compound (9) suggested that this series represents an excellent opportunity for further optimization with the framework offering multiple opportunities for the addition of uniquely vectorally positioned extra functionality.  相似文献   
994.
ContextPain can be a debilitating side effect of radiation therapy (RT). Data from the general population have shown that sleep disturbance can influence pain incidence and severity; however, less is known about this relationship in patients with breast cancer receiving RT.ObjectivesThis secondary analysis examined the association of pretreatment moderate/severe levels of sleep disturbance with subsequent RT-induced pain after adjusting for pre-RT pain.MethodsWe report on 573 female patients with breast cancer undergoing RT from a previously completed Phase II clinical trial for radiation dermatitis. Sleep disturbance, total pain, and pain subdomains—sensory pain, affective pain, and perceived pain intensity were assessed at pre-RT and post-RT. At pre-RT, patients were dichotomized into two groups: those with moderate/severe sleep disturbance (N = 85) vs. those with no/mild sleep disturbance (control; N = 488).ResultsAt pre-RT, women with moderate/severe sleep disturbance were younger, less likely to be married, more likely to have had mastectomy and chemotherapy, and more likely to have depression/anxiety disorder and fatigue than the control group (all Ps < 0.05). Generalized estimating equations model, after controlling for pre-RT pain and other covariates (e.g., trial treatment condition and covariates that were significantly correlated with post-RT pain), showed that women with moderate/severe sleep disturbance at pre-RT vs. control group had significantly higher mean post-RT total pain as well as sensory, affective, and perceived pain (effect size = 0.62, 0.60, 0.69, and 0.52, respectively; all Ps < 0.05).ConclusionThese findings suggest that moderate/severe disturbed sleep before RT is associated with increased pain from pre-to-post-RT in patients with breast cancer.  相似文献   
995.

In the 50 years since it was first introduced, cognitive therapy has been shown to be as efficacious as antidepressant medications (on average) in the acute treatment of nonpsychotic depression, although some patients will do better on one than on the other. Moreover, patients treated to remission with cognitive therapy are less than half as likely to relapse following treatment termination as patients treated to remission with medications. However, a recent study suggests that adding medications interferes with any such enduring effect and medications themselves may have an iatrogenic effect that suppresses symptoms at the expense of prolonging the underlying episode. Neural imaging suggests that cognitive therapy works from the “top down” to facilitate cortical regulation of affect processes whereas medications work from the “bottom up” to dampen the stress response. Adaptationist theory suggests that depression is an evolved adaptation that served to keep our ancestors ruminating about complex social problems until they arrived at a solution; if true then any intervention that facilitates problem solving is likely preferable to one that merely anesthetizes distress.

  相似文献   
996.
997.
MS2 phage (MS2 Ø) is a coli phage, non-pathogenic to eukaryotic cells, which has been used as a simulant for viral biothreats, such as those causing smallpox and hemorrhagic fever. MS2 Ø consists of an icosahedral capsid, 28 nm in diameter, and a single stranded RNA genome; the viral capsid is composed of 180 copies of coat protein (CP). In this study, we isolated anti-MS2 Ø single domain antibodies (sdAbs) for the sensitive detection of the MS2 Ø. To achieve this, a first immune sdAb library was prepared from llamas immunized with purified coat protein and a second from animals immunized with MS2 Ø. By panning the two libraries against CP, MS2 Ø, or alternating between the two targets, anti-MS2 Ø and anti-CP sdAbs were selected, sequenced, and characterized for their binding affinity. Both direct binding assays and capture sandwich assays were performed on the MAGPIX platform. One of the best anti-MS2 Ø sdAb, Lib2CP12H, could detect MS2 Ø concentrations as low as 1.45 ng/mL (~5.0E+6 pfu/mL), providing equivalent detection to conventional antibodies. This sdAb is thermally stable with a melting temperature around 60 °C and recovered 80% of its secondary structure after heat denaturation.  相似文献   
998.
Functional magnetic resonance imaging was used to compare brain activation associated with basic-level (e.g. bird) and subordinate-level (e.g. eagle) processing for both visual and semantic judgements. We localised the putative face area for 11 subjects, who also performed visual matching judgements for pictures and aurally presented words. The middle fusiform and occipital gyri were recruited for subordinate minus basic visual judgements, reflecting additional perceptual processing. When the face area was localised individually for each subject, analyses in the middle fusiform gyri revealed that subordinate-level processing activated the individuals face area. We propose that what is unique about the way faces engage this region is the focal spatial distribution of the activation rather than the recruitment of the face per se. Eight subjects also performed semantic judgements on aurally presented basic- and subordinate-level words. The parahippocampal gyri were more activated for subordinate-level than basic-level semantic judgements. Finally, the left posterior inferior temporal gyrus was activated for subordinate-level judgements, both visual and semantic, as well as during passive viewing of faces.  相似文献   
999.
Abstract

The authors investigated the relationship between brief warm social and physical contact among cohabitating couples and blood pressure (BP) reactivity to stress in a sample of healthy adults (66 African American, 117 Caucasian; 74 women, 109 men). Prior to stress, the warm contact group underwent a 10-minute period of handholding while viewing a romantic video, followed by a 20-second hug with their partner, while the no contact group rested quietly for 10 minutes and 20 seconds. In response to a public speaking task, individuals receiving prestress partner contact demonstrated lower systolic BP, diastolic BP, and heart rate increases compared with the no contact group. The effects of warm contact were comparable for men and women and were greater for African Americans compared with Caucasians. These findings suggest that affectionate relationships with a supportive partner may contribute to lower reactivity to stressful life events and may partially mediate the benefit of marital support on better cardiovascular health.  相似文献   
1000.
PurposeBrachytherapy (BT) after surgical resection of keloids reduces the risk of local recurrence, but standardization of dose/technique is lacking. Typical keloid BT treatment utilizes a single-channel source prescribed to 5-mm depth. We investigated the dosimetry of a volume-based target definition for interstitial high-dose-rate BT treatment of keloids.Methods and MaterialsWe retrospectively identified consecutive 14 patients who had a total of 20 keloids treated with interstitial high-dose-rate BT for keloids at our institution between 2004 and 2014. Keloids were treated with a single 8 Gy fraction prescribed to 5 mm beneath the scar within 36 h of surgery. Retrospectively, a 3-mm skin high-risk clinical target volume (HR-CTV) was contoured under the scar for volume-based dose calculations.ResultsMean (SD) HR-CTV was 3.91 cm3 (3.1) and mean (SD) HR-CTV dose was 11.3 Gy (3.6). Mean D90 (SD) was 62.9% (25.8) and mean V100 (SD) was 56.5% (26.4). The mean V150 (SD), V200 (SD), and V300 (SD) were as follows: 37.6% (19.9), 25.1% (14.4), and 11.3% (6.5), respectively. No local failures were reported at 9 months median followup. There were no Grade 2 or higher late toxicities.ConclusionsUsing a volume-based target definition, a wide range of target coverage was observed. This is likely a consequence of the curvature of the skin and the challenges of keeping the catheter equidistant from the skin across the target. Additional data are needed to define the potential clinical impact on outcomes/toxicities of dosimetric correlates with single-catheter BT keloid treatment.  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