全文获取类型
收费全文 | 24373篇 |
免费 | 1194篇 |
国内免费 | 211篇 |
专业分类
耳鼻咽喉 | 235篇 |
儿科学 | 536篇 |
妇产科学 | 214篇 |
基础医学 | 2949篇 |
口腔科学 | 511篇 |
临床医学 | 1492篇 |
内科学 | 7188篇 |
皮肤病学 | 582篇 |
神经病学 | 1750篇 |
特种医学 | 815篇 |
外科学 | 4284篇 |
综合类 | 102篇 |
一般理论 | 3篇 |
预防医学 | 537篇 |
眼科学 | 560篇 |
药学 | 1398篇 |
中国医学 | 50篇 |
肿瘤学 | 2572篇 |
出版年
2023年 | 193篇 |
2022年 | 346篇 |
2021年 | 656篇 |
2020年 | 372篇 |
2019年 | 526篇 |
2018年 | 572篇 |
2017年 | 446篇 |
2016年 | 547篇 |
2015年 | 566篇 |
2014年 | 753篇 |
2013年 | 910篇 |
2012年 | 1545篇 |
2011年 | 1678篇 |
2010年 | 953篇 |
2009年 | 761篇 |
2008年 | 1283篇 |
2007年 | 1482篇 |
2006年 | 1380篇 |
2005年 | 1410篇 |
2004年 | 1291篇 |
2003年 | 1215篇 |
2002年 | 1262篇 |
2001年 | 484篇 |
2000年 | 489篇 |
1999年 | 470篇 |
1998年 | 294篇 |
1997年 | 268篇 |
1996年 | 233篇 |
1995年 | 196篇 |
1994年 | 160篇 |
1993年 | 142篇 |
1992年 | 291篇 |
1991年 | 269篇 |
1990年 | 249篇 |
1989年 | 234篇 |
1988年 | 179篇 |
1987年 | 206篇 |
1986年 | 168篇 |
1985年 | 161篇 |
1984年 | 121篇 |
1983年 | 98篇 |
1982年 | 51篇 |
1981年 | 56篇 |
1980年 | 48篇 |
1979年 | 92篇 |
1978年 | 64篇 |
1977年 | 64篇 |
1971年 | 61篇 |
1969年 | 47篇 |
1968年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
We report herein the case of a 56-year-old woman who developed secondary Kwashiorkor 9 years after undergoing a total gastrectomy for early gastric cancer. Until she began developing the symptoms of Kwashiorkor, including general fatigue, edema of the face and extremities, anemia, alopecia, and weight loss, she had been leading a normal life post-gastrectomy. Her symptoms were alleviated by total parenteral nutrition (TPN) therapy, but reappeared soon after TPN therapy was discontinued. Therefore, she required several subsequent courses of TPN. In an attempt to permanently resolve the ongoing Kwashiorkor symptoms, reconstructive surgery involving transposition of the jejunum from the previous Graham method to the interposition method was performed 10 years after the initial gastrectomy. After the second operation, her malnutrition was completely alleviated, and she has been in good health for the 8 years since. To our knowledge, there has been no other report of the symptoms of secondary Kwashiorkor after total gastrectomy being alleviated by altering the procedure of reconstruction of the intestinal tract. Thus, we recommend surgical treatment to alter the digestive continuity to a more physiological pathway for selected patients with secondary Kwashiorkor syndrome. 相似文献
92.
Thirteen patients with sickle cell disease (SCD) undergoing transfusion therapy and 8 control patients were examined by magnetic resonance imaging to discriminate bone marrow change due to iron deposition from hematologic marrow hyperplasia. Using T1-weighted spin echo images, only two subjects showed extremely low signal intensity marrow compatible with iron deposition. However, using T2-weighted fast spin echo images with fat suppression, cranial bone marrow in SCD patients with transfusion therapy showed considerably lower signal than that of controls. The main cause of marrow signal decrease in SCD patients with transfusion therapy was considered to be iron deposition due to repeated transfusion therapy rather than red marrow hyperplasia. 相似文献
93.
Shohachi Suzuki Satoshi Nakamura Hideki Ishida Takanori Sakaguchi Atsushi Serizawa Hiroyuki Konno Shozo Baba Hiroyuki Muro Isao Kosugi Eisaku Gu 《Surgery today》1996,26(8):635-639
Hepatic angiomyolipoma is a rare tumor composed of spindle-shaped and epithelioid smooth muscle cells, adipose tissue, and proliferating blood vessels. We report the first documented case of this tumor developing in a patient with ulcerative colitis. A solitary tumor (7.5×7.5×7cm) was detected in the left lateral segment of the liver and a left hepatic lobectomy was performed. The diagnosis of angiomyolipoma was confirmed by a pathological examination. We also review the literature on previously reported cases of hepatic angiomyolipoma. 相似文献
94.
Toyofuku T Yoshida J Sugimoto T Zhang H Kumanogoh A Hori M Kikutani H 《Nature neuroscience》2005,8(12):1712-1719
Sema3A, a prototypical semaphorin, acts as a chemorepellent or a chemoattractant for axons by activating a receptor complex comprising neuropilin-1 as the ligand-binding subunit and plexin-A1 as the signal-transducing subunit. How the signals downstream of plexin-A1 are triggered upon Sema3A stimulation, however, is unknown. Here we show that, in the presence of neuropilin-1, the FERM domain-containing guanine nucleotide exchange factor (GEF) FARP2 associates directly with plexin-A1. Sema3A binding to neuropilin-1 induces the dissociation of FARP2 from plexin-A1, resulting in activation of FARP2's Rac GEF activity, Rnd1 recruitment to plexin-A1, and downregulation of R-Ras. Simultaneously, the FERM domain of FARP2 sequesters phosphatidylinositol phosphate kinase type I isoform PIPKIgamma661 from talin, thereby inhibiting its kinase activity. These activities are required for Sema3A-mediated repulsion of outgrowing axons and suppression of neuronal adhesion. We therefore conclude that FARP2 is a key molecule involved in the response of neuronal growth cones to class-3 semaphorins. 相似文献
95.
Kitajima T Kanbayashi T Saito Y Takahashi Y Ogawa Y Sugiyama T Kaneko Y Aizawa R Shimizu T 《Neuroscience letters》2004,355(1-2):77-80
It is known that benzodiazepines have a hypotensive effect, but the mechanism has not been well elucidated yet. To clarify whether this effect is due to central or peripheral mechanism, we administered 5 mg of diazepam or saline intravenously to healthy volunteers and assessed the change in blood pressure, heart rate, muscle sympathetic nerve activity and heart rate variability. After diazepam administration, systolic and mean blood pressure decreased significantly. Muscle sympathetic nerve activity was also significantly reduced but heart rate did not change, whereas the variables of spectral analysis of heart rate variability did not show significant change. We concluded that the hypotensive effect of diazepam in human is mainly due to the central mechanism. 相似文献
96.
Breast, prostate, lung, and other cancers can metastasize to bone and lead to pathological fracture. To lay the groundwork for new clinical techniques for assessing the risk of pathological fracture, we identified relationships between density measured using quantitative computed tomography (rhoQCT), longitudinal mechanical properties, and ash density (rhoAsh) of cortical bone from femoral diaphyses with and without metastatic lesions from breast, prostate, and lung cancer (bone with metastases from six donors; bone without metastases from one donor with cancer and two donors without cancer). Moderately strong linear relationships between rhoQCT and elastic modulus, strength, and rhoAsh were found for bone with metastases (0.73相似文献
97.
98.
Yoshida A Tanaka R Kodama A Yamamoto N Ansari AA Tanaka Y 《Clinical & developmental immunology》2005,12(4):235-242
We have previously reported that immunization of the severe combined immunodeficiency (SCID) mice reconstituted with human peripheral blood mononuclear cells (PBMC) (hu-PBL-SCID mice) with inactivated human immunodeficiency virus type-1 (HIV-1)-pulsed-autologous dendritic cells (HIV-DC) elicits HIV-1-reactive CD4(+) T cells that produce an as yet to be defined novel soluble factor in vitro with anti-viral properties against CCR5 tropic (R5) HIV-1 infection. These findings led us to perform studies designed to identify the lineage of the cell that synthesizes such a factor in vivo and define the epitopes of HIV-1 protein that have specificity for the induction of such anti-viral factor. Results of our studies show that this property is a function of CD4(+) but not CD8(+) T cells. Human CD4(+) T cells were thus recovered from the HIV-DC-immunized hu-PBL-SCID mice and were re-stimulated in vitro by co-culture for 2 days with autologous adherent PBMC as antigen presenting cells, APC previously pulsed with inactivated HIV in IL-2-containing medium to expand HIV-1-reactive CD4(+) T cells. Aliquots of these re-stimulated CD4(+) T cells were then co-cultured with similar APC's that were previously pulsed with 10 microg/ml of a panel of HIV peptides for an additional 2 days, and their culture supernatants were examined for the production of both the R5 HIV-1 suppression factor and IFN-gamma. The data presented herein show that the HIV-1 primed CD4(+) T cells produced the R5 suppression factor in response to a wide variety of HIV-1 gag, env, pol, nef or vif peptides, depending on the donor of the CD4(+) T cells. Simultaneous production of human interferon (IFN)-gamma was observed in some cases. These results indicate that human CD4(+) T cells in PBMC of HIV-1 naive donors have a wide variety of HIV-1 epitope-specific CD4(+) T cell precursors that are capable of producing the R5 HIV-1 suppression factor upon DC-based vaccination with whole inactivated HIV-1. 相似文献
99.
Traf6 is essential for murine tooth cusp morphogenesis. 总被引:5,自引:0,他引:5
Atsushi Ohazama Jo-Maree Courtney Abigail S Tucker Asuka Naito Sakae Tanaka Jun-Ichiro Inoue Paul T Sharpe 《Developmental dynamics》2004,229(1):131-135
Ectodermal appendages such as skin, hair, teeth, and sweat glands are affected in patients with hypohidrotic (anhydrotic) ectodermal dysplasia (HED). It has been established that mutations in the tumor necrosis factor (TNF) superfamily of molecules, i.e., ectodysplasin (EDA), EDA receptor (EDAR), and EDAR-associated death domain (EDARADD; the intracellular adaptor for EDAR), are responsible for several forms of HED in humans and mice. We show here by in situ hybridisation that another TNF family (orphan) receptor, TROY (also known TAJ, TAJ-alpha, TRADE, and TNFRSF19), is strongly coexpressed with Edar in the epithelial enamel knot signalling centres that are believe to regulate cuspal morphogenesis during murine tooth development. Traf6 is known to function as an intracellular adaptor protein for Troy and examination of Traf6 mutant mice revealed abnormalities in molar teeth that are similar but more severe than those produced by mutations in Eda signalling molecules. This finding suggests that, in additional to ectodysplasin, another TNF pathway involving Troy/Traf6 is involved in molar tooth cusp formation and identifies an essential role for a Traf in tooth development. Developmental Dynamics 229:131-135, 2004. 相似文献
100.
Nakama S Kikuchi M Yashiro T Sakamoto A Kikkawa I Ookami H Saita K Hoshino Y 《Medical molecular morphology》2005,38(3):173-180
Ossification or calcification of the ligamentum flavum (LF) is relatively common in the middle and lower cervical, thoracic, and lumbar spine but extremely rare in the upper cervical region. This clinical fact suggests that there exist local factors promoting or preventing ossification or calcification of LF. However, little is known about the differences in the ultrastructure and cellular alterations of the LF between the different spinal levels, even in the cervical spine. With electron microscopy, we examined samples of LF collected surgically from the upper and lower cervical spine regions; we then studied the apoptotic appearance of ligament cells using a preferential labeling method. We found direct evidence of apoptosis of ligament cells in the LF. Apoptosis was more apparent in the upper region samples than in the lower region samples. The spaces around the normal fibroblasts were filled with thick collagen fibrils, but the collagen fibrils disappeared around the apoptotic bodies and thin fibrils were formed. The difference of the level of apoptosis may correlate to the ultrastructual difference of LF, and our data will benefit further investigations seeking to clarify the mechanism of various pathological conditions in the human LF. 相似文献