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   15399篇
  免费   1033篇
  国内免费   188篇
耳鼻咽喉   380篇
儿科学   199篇
妇产科学   288篇
基础医学   2683篇
口腔科学   293篇
临床医学   1198篇
内科学   3026篇
皮肤病学   441篇
神经病学   1167篇
特种医学   1036篇
外科学   2074篇
综合类   69篇
现状与发展   3篇
一般理论   10篇
预防医学   594篇
眼科学   426篇
药学   1257篇
中国医学   168篇
肿瘤学   1308篇
  2024年   10篇
  2023年   91篇
  2022年   262篇
  2021年   661篇
  2020年   268篇
  2019年   439篇
  2018年   524篇
  2017年   409篇
  2016年   610篇
  2015年   871篇
  2014年   951篇
  2013年   1043篇
  2012年   1594篇
  2011年   1435篇
  2010年   839篇
  2009年   709篇
  2008年   900篇
  2007年   912篇
  2006年   771篇
  2005年   629篇
  2004年   519篇
  2003年   466篇
  2002年   379篇
  2001年   293篇
  2000年   237篇
  1999年   174篇
  1998年   71篇
  1997年   55篇
  1996年   35篇
  1995年   36篇
  1994年   25篇
  1993年   32篇
  1992年   38篇
  1991年   39篇
  1990年   34篇
  1989年   36篇
  1988年   28篇
  1987年   32篇
  1986年   17篇
  1985年   15篇
  1984年   10篇
  1983年   10篇
  1981年   14篇
  1980年   7篇
  1979年   14篇
  1978年   10篇
  1977年   10篇
  1976年   10篇
  1975年   9篇
  1973年   6篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
Recent clinical trials showed that bortezomib, a novel proteasome inhibitor, had therapeutic activity in multiple myeloma. However, there was no data about the feasibility of bortezomib in Korean patients. We performed a pilot study of bortezomib in patients with relapsed or refractory myeloma (1.3 mg/m2 twice weekly for 2 week in a 3-week cycle). Seven patients were enrolled. The median age of patients was 59 yr. All patients previously received VAD (vincristine, doxorubicin and dexamethasone) and thalidomide chemotherapy. Three patients previously received alkylator-containing chemotherapy and 4 patients, autologous stem cell transplantation. Bortezomib monotherapy resulted in 3 partial remissions (43%), 3 no changes (43%) and 1 progressive disease (14%). One patient who had no response to bortezomib monotherapy experienced partial remission after addition of dexamethasone to bortezomib. The most common serious toxicity was thrombocytopenia (grade 3/4, 10 of 20 cycles (50%)) and grade 3 peripheral neuropathy was developed in 2 of 20 cycles (10%). Drug-related adverse event led to discontinuation of bortezomib in 1 patient. There was no treatment related mortality. Overall, bortezomib seems to be effective and feasible. Conduction of larger clinical studies on Korean patients is necessary to characterize clinical efficacy and safety of bortezomib more precisely.  相似文献   
72.
Hepatic stem cells participate in the recovery process of liver with severe injury or impaired hepatocyte regeneration. Oval cells (an oval-shaped liver cell population newly emerging from the portal or periportal zones following severe hepatic cellular damage) are believed to be the progeny of liver stem cells and precursor cells of both hepatocytes and bile duct cells. An attempt was made to define the differentiation processes of hepatic oval cells into mature hepatocytes in hamsters fed a choline-deficient diet and treated with diethylnitrosamine and 2-acetyl aminofluorene, on the basis of histopathological, electron microscopical, histochemical and immunohistochemical characterization of hepatic cell components. Two putative differentiation pathways of oval cells toward mature hepatocytes are proposed, namely (1) the differentiation of ductular-like oval cells via ductular/acinar-type hepatocytes, and (2) the differentiation of individual oval cells via small hepatocytes. Those proposals were strongly supported by consistent immunoreactivity of the cells for OV-6, an oval cell marker, and differential expression patterns for CK19 and PAS-positive cytoplasmic glycogen granules.  相似文献   
73.
FVB and BALB/c mice show different morbidity, development of Clonorchis sinensis, and pathological changes following C. sinensis infection. FVB mice are susceptible and BALB/c mice are relatively more resistant to C. sinensis infection. To investigate the relationship between cytokine reaction and susceptibility to C. sinensis infection in FVB and BALB/c mice, we described both the patterns and kinetics of Th1 cytokines and Th2 cytokines in spleen cell culture. Interleukin (IL)-4 and IL-10 cytokine production in the culture supernatants of the concanavalin-A-stimulated spleen cells increased at 2–3 weeks post-infection in both strains. IL-5 production increased between 2 and 5 weeks post-infection in both strains, and reached a peak level at 2 weeks post-infection in BALB/c mice and 4 weeks post-infection in FVB mice. In contrast, gamma interferon (IFN-) production decreased between 2 and 4 weeks in both strains. IL-2 production increased slightly in BALB/c mice following infection, but was unchanged in FVB mice. IL-4 production over preinfection levels was significantly higher in FVB mice, whereas IFN-, IL-2, and IL-10 production were significantly higher in BALB/c mice. The levels of serum immunoglobulin E (IgE) and blood eosinophils in both mouse strains significantly increased between 3 and 6 weeks postinfection. Serum IgE levels were significantly higher in FVB mice than in BALB/c mice. The results of this study suggest that susceptibility to C. sinensis infection is associated with Th2 cytokine production, especially IL-4 which is predominant in relatively susceptible FVB mice.  相似文献   
74.
75.
In order to determine the effect of ultraviolet radiation (UVR) on the cell adhesion molecules expressed in human dermal microvascular endothelial cells (HDMEC), the cells were exposed to varying UVR doses and the cell surface was examined for expression of intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM- 1), and E-selectin. The effect of UVB irradiation on the binding of T lymphocytes to HDMEC was also examined. UVA irradiation did not affect the surface expression of ICAM-1, VCAM-1, or E-selectin on the HDMEC. However, following UVB exposure, ELISA demonstrated a significant increase in the baseline ICAM-1 cell surface expression on the HDMEC. However, no induction of either E-selectin or VCAM-1 was noted. UVB also significantly augmented ICAM-1 induction by IL-1alpha and TNF-alpha. VCAM-1 was induced by stimulating HDMEC with IL-1alpha following a UVB irradiation dose of 100 mJ/cm2. Flow cytometric analysis of the HDMEC stimulated with IL-1alpha for 24h demonstrated that 12% of the cells expressed VCAM-1 but either IL-1alpha or UVB irradiation alone failed to induce VCAM-1 expression. Enhancement of T cell-HDMEC binding by IL-1alpha or TNF-alpha treatment was not significantly affected after UVB irradiation. This study demonstrated that UVB irradiation can alter ICAM-1 and VCAM-1 expression on the HDMEC surface and that augmentation of ICAM-1 expression and the IL-1alpha-dependent induction of VCAM-1 following UVB exposure might be important steps in the pathogenesis of sunburn.  相似文献   
76.
Ring-opening polymerization of a new anhydro ribose-type monomer, 1,4-anhydro-3-azido-3-deoxy-2-O-tert-butyldimethylsilyl-α-D -ribopyranose (A3ASR), was investigated. The monomer was synthesized from 1,4-anhyro-α-D -xylopyranose by three steps comprising Walden inversion at the C3 position into ribose configuration. Ring-opening polymerization of A3ASR by Lewis acid catalysts such as boron trifluoride etherate and stannic chloride gave a stereoregular 3-azido-3-deoxy-2-O-tert-butyldimethylsilyl-(1→5)-α-D -ribofuranan having specific rotations of +246 ~ +271 deg · dm?1 · g?1 · cm3 and number-average molecular weights of 18,7 × 103 ~ 25,1 × 103. When the polymerization was carried out by antimony pentachloride at 0°C, the resulting polymer exhibited a negative specific rotation of ?6 deg · dm?1 · g?1 · cm3 and the C1 absorption in the 13C NMR spectrum shifted downfield to 107,5 ppm, suggesting that the polymer might consist of 1,5-β furanosidic unit. The reduction of the azido group of the 1,5-α and 1,5-β furanosidic polymers into amino group and subsequent desilylation gave 3-amino-3-deoxy-(1→5)-α- and -β-D -ribofuranans, respectively. In addition, copolymerization of A3ASR with 1,4-anhydro-2,3-di-O-tert-butyldimethylsilyl-α-D -ribopyranose (ADSR) in various feeds was performed by boron trifluoride etherate as catalyst to give copolymers with different monomeric components. The structural analysis of the homopolymers and copolymers was examined by means of 1H and 13C NMR spectroscopies, IR spectroscopy, and optical rotation.  相似文献   
77.
The calcium-binding proteins, parvalbumin and calbindin D-28k, are markers of different classes of GABAergic interneurons and display different functions. The present study was attempted to determine immunoreactivities and colocalization of the parvalbumin and calbindin D-28k in the developing canine hippocampus by immunohistochemistry. The calcium-binding protein-containing neurons showed different developmental patterns. The first appearance of parvalbumin immunoreactive nonpyramidal cells was observed at P7. Parvalbumin immunoreactivity was elicited by the sequence from CA3 to CA1 to reach an adult-like distribution pattern, which was reached at P60, while calbindin D-28k immunoreactivity appeared from P0, including pyramidal and nonpyramidal cells. The characteristic distribution of calbindin D-28k immunoreactive pyramidal cells was clarified by P28, and an adult-like distribution pattern was reached by the end of the second postnatal month. Double-labeled nonpyramidal cells were frequently seen in the subareas, CA3 of P14/CA1-CA2 of P28, where parvalbumin immunoreactive nonpyramidal cells were emerging. These data suggest that the colocalization of the two calcium-binding proteins during development is related closely to the area-specific maturation of parvalbumin expression, although either prenatal expression of calbindin D-28k or parvalbumin was not determined.  相似文献   
78.
Non-alcoholic duct-destructive chronic pancreatitis is a new entity that differs morphologically and pathogenetically from alcoholic chronic pancreatitis. Some clinical and imaging features of this entity resemble those of pancreatic cancer, and hence most of the reported cases underwent pancreatic resections including an invasive pancreaticoduodenectomy. Recognition of this new entity before a definitive treatment is therefore important to avoid an unnecessary pancreatic resection. Recently, we experienced a case of non-alcoholic duct-destructive chronic pancreatitis in an 80-year-old man presenting with obstructive jaundice and whose radiologic features were characteristic as originally described. Recognition of this new entity before definitive treatment enabled us to manage this patient optimally. In addition, the relation between non-alcoholic duct-destructive chronic pancreatitis and chronic pancreatitis with diffuse irregular narrowing of the main pancreatic duct is discussed.  相似文献   
79.
Malignant transformation of mature cystic teratoma of the ovary can develop with an incidence of 1-2%. Squamous cell carcinoma is the most common malignant tumor arising in benign cystic teratoma. The authors have recently experienced a case of combined microcystic adnexal carcinoma and squamous cell carcinoma arising in a benign cystic teratoma of the ovary in a 72-year-old Korean woman. The right ovarian cystic mass had been ruptured and firmly adhered with salpinx and omental fat tissue on operation. Thickened cystic wall with yellowish white solid infiltrative lesion was noted grossly, and two different malignant tumors of microcystic adnexal carcinoma exhibiting both eccrine and hair follicular differentiation and squamous cell carcinoma were observed microscopically. PAS and CEA positivities suggested eccrine differentiation in areas of microcystic adnexal carcinoma.  相似文献   
80.
The diabetogenic capacity of the M-variant of encephalomyocarditis (EMC) virus was markedly diminished after passage in mouse kidney cell cultures. One passage in mice fully restored this capacity. Virus harvested after five passages in either susceptible (SWR/J) or resistant (C57BL/6J) strains of mice was capable of producing diabetes in susceptible SWR/J mice but not in resistant C57BL/6J mice. Resistance was not overcome by inoculating mice with high concentrations of virus. Immunofluorescence studies showed that islets from strains of mice (i.e. CBA, AKR, C57BL/6J, A/J) that did not develop diabetes after infection with EMC virus, nonetheless, contained virus antigens. The percentage of cells in the islets containing virus antigens varied from 3-6% in CBA to 13-5% in A/J. In contrast 38% of the islet cells in susceptible SWR/J mice contained virus antigens. It is concluded that both the genetic background of the host and the passage history of the virus influence the development of diabetes.  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